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Surgery for colorectal cancer
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Surgery for colorectal cancer
factors, key mutations appear to involve APC, KRAS and p53 genes. The most common histopathology for colorectal cancer is adenocarcinoma. The development of colorectal adenocarcinoma is postulated to follow the adenomaecarcinoma sequence. In this model, there may be a natural progression from benign polyps into invasive cancerous lesions. The national bowel cancer screening programme was set up in 2006 based on this model, which is widely accepted. About 20% of cases present as emergencies and these are associated with a poorer outcome.3 Early presentation is key to improving outcomes for colorectal cancer and the management of pre-invasive lesions. Approximately 30% of cases occur in the rectum and 20% in the sigmoid colon. About 20% develop in the right colon and 10% are found in the transverse or left colon. Approximately 80% of newly diagnosed cases will require surgery. Surgery remains the primary treatment for the majority of cases of colorectal cancer both as treatment with curative intent and as a palliative therapy.
Jason George Timothy Rockall
Abstract Colorectal cancer surgery represents a major component of the colorectal service workload. A solid understanding of key anatomical and oncological principles is essential for safe practice. In this article we discuss these fundamental aspects of colorectal cancer surgery. The first part of the article will deal with preoperative staging, surgical planning and principles of oncological surgery. The second part will focus on some of the most common operations. We will describe key intraoperative principles involved in performing a right hemicolectomy, left hemicolectomy, anterior resection and abdomino-perineal resection. Laparoscopic colorectal cancer surgery is increasingly widespread and therefore our perspective will assume this approach by default. In the final section, we discuss the role of radiotherapy in rectal cancers, transanal surgery, resection of colorectal liver metastases and the rationale behind follow-up.
Staging and imaging of colorectal cancer The single most important factor that determines the outcome is the stage of cancer at presentation. The international standard used for staging is referred to as the TNM classification. Prognosis is intimately linked to the invasiveness of the tumour (T ), extent of regional lymph node (N ) involvement and the presence of distant extra-intestinal metastases (M ). Clinical staging is with colonoscopy, computed tomography (CT) scan of the chest abdomen and pelvis and magnetic resonance imaging (MRI) scan of the pelvis for rectal tumours. Indeterminate lesions in the liver may require further assessment with MRI or ultrasound. Positron emission tomography (PET) scan may also be helpful in determining sites of disseminated disease. Diagnosis is usually by colonoscopic examination. Even if diagnosis has been by alternative methods such as CT, colonoscopy is mandatory in order to acquire biopsies and exclude synchronous lesions. The reported incidence of synchronous colorectal lesions ranges between 2% and 9%.4 The incidence is variable as it depends on the degree of diligence with which the rest of the large bowel is assessed after detecting one lesion. CT may be used as a tool not only for diagnosis but also for assessment of local complications such as fistula and abscess formation. CT will also identify common sites of metastatic spread such as liver or lungs. MRI may be particularly useful in assessment of rectal tumours in order to gain an appreciation of relationship with the mesorectal fascia and mesorectal nodal status (Figure 1). Involvement of this fascial boundary known as the circumferential resection margin (CRM) may be an indication for neoadjuvant therapy in order to downgrade tumour size and reduce the likelihood of a positive CRM. MRI is also more sensitive at detecting colorectal metastases to the liver. PETeCT is a combined modality not usually used for staging, however it does play an important role in identification of possible recurrent disease. A pitfall is that areas of infection or inflammation may ‘light up’ on PET scans due to uptake of the radiolabelled isotope, fluorodeoxyglucose (FDG).
Keywords Colorectal cancer; laparoscopic; surgical resection
Introduction Colorectal cancer is the fourth most common cancer in the UK. In 2013, there were approximately 41,000 new cases in the UK; 23,000 (56%) cases in men and 18,000 (44%) in women, giving a male:female ratio of 13:10.1 Geographically, the incidence of colorectal cancer is highest in Western Europe and North America. Multiple risk factors are associated with its development; these include smoking, alcohol, diet (excessive red meat and processed food consumption), obesity and decreased physical activity. Inflammatory bowel disease is also associated with increased risk in proportion to the extent of bowel involvement and duration of disease. The majority of colorectal cancers are sporadic whereas 5 e10% are inherited syndromes, for example, hereditary nonpolyposis colon cancer (HNPCC) and familial adenomatous polyposis (FAP). There may be some overlap of genetic abnormalities involving sporadic and inherited forms. The risk of colorectal cancer for an individual with a first-degree relative with the disease is three times greater than one who has no family history. Vogelstein proposed a multi-step model identifying key mutations.2 Although colorectal carcinogenesis involves a complex interplay between environmental and genetic
Jason George MA (Cantab) MRCS is a Research Fellow at the Minimal Access Therapy Training Unit (MATTU), Guildford, UK. Conflicts of interest: none declared. Timothy Rockall MD FRCS is Professor of Surgery at the University of Surrey and Consultant Surgeon and Director of the MATTU, Guildford, UK. Conflicts of interest: none declared.
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Figure 2 Photograph of a patient doing a cardiopulmonary exercise test. (With permission from Young et al., A systematic review of the role of cardiopulmonary exercise testing in vascular surgery, European Journal of Vascular & Endovascular Surgery, Volume 44, Issue 1, pp. 64-71, Elsevier, 2012).
Figure 1 Axial T2 weighted image of the pelvis e arrows mark the mesorectal fascia. (With permission from Griffin and Grant, Grainger & Allison’s Diagnostic Radiology Essentials, pp. 294-313, Elsevier, 2013).
that it is possible to discharge selected patients as early as 23 hours after laparoscopic colorectal surgery by incorporating such techniques within an ERAS pathway.8
Preoperative considerations
Oncological principles in colorectal cancer surgery
As with all cancer surgery today, a careful multidisciplinary team (MDT) approach should be employed to ensure the best possible decision and outcome for each patient. The first step is to establish whether disease is localized or disseminated. The operative strategy should be based on fundamental principles of oncological surgery, discussed in the next section. Laparoscopic colorectal surgery is gradually becoming the standard of care around the UK rather than something carried out only in ‘specialist’ centres. The introduction of the LAPCO training programme5 has resulted in an increase in consultant surgeons performing laparoscopic colorectal surgery. A key aspect in generating successful outcomes from colorectal cancer surgery is to work closely in concert with anaesthetists, cardiologists and respiratory physicians, amongst others, to stratify risk and address modifiable factors e.g. ischaemic heart disease, asthma, diabetes. Cardiopulmonary exercise testing (CPET) (Figure 2) may be used to stratify high-risk patients. A frequently debated topic is whether to give routine bowel preparation or not. Bowel preparation may cause significant dehydration and electrolyte derangement6 and is unpleasant for the patient. It can also precipitate obstruction or create dilated fluid-filled bowel proximal to near obstructing lesions. At the Minimal Access Therapy Training Unit (MATTU) in Guildford, we have a policy of no bowel preparation for right-sided lesions, a preoperative enema for left-sided lesions and restrict full bowel preparation to patients having low rectal resections with anastomosis and defunctioning ileostomy. This represents just one aspect of ERAS (enhanced recovery after surgery).7 Other key components that require attention are preoperative carbohydrate loading, opioid-sparing analgesia, perioperative fluid regimes, early mobilization and nutrition. The standard of care in our unit for patients undergoing laparoscopic colorectal surgery is to receive a spinal or patient-controlled analgesia for postoperative analgesia and oesophageal Doppler monitoring (ODM) for goaldirected fluid therapy. The Guildford experience has shown
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The goal of surgery is to resect the primary tumour en bloc with clear resection margins and include all draining locoregional lymphatics that may contain micrometastases. In order to understand the extent of bowel resection and lymphadenectomy one must have a clear understanding of the anatomical principles behind lymphatic spread. Longitudinal intramural lymphatic spread in the colon rarely exceeds 2 cm, hence the rationale for 5 cm resection margins proximally and distally. For rectal cancers, sphincter-saving techniques allow most patients to avoid abdomino-perineal resection and a permanent colostomy; a 1 cm distal clearance is considered the minimum for an adequate rectal resection. Circumferential lymphatic spread proceeds centrally, usually in a step-wise fashion from epicolic and paracolic nodes eventually to the ‘apical node’, associated with a major vascular pedicle. In rectal cancers, Heald et al. advocated total mesorectal excision (TME).9 TME is now the standard of treatment and has led to decreased recurrence rates. Since the lymphatics run alongside arteries, the extent of segmental resection is determined by the vascular territories involved. The evidence increasingly confirms that laparoscopic resections are safe, oncologically equivalent to open surgery and have better short-term outcomes.10 The choice of approach is perhaps more dependent on the individual department, surgeon expertise and training than anything else. The robotic approach is discussed elsewhere in this issue. Discussion of complications is beyond the scope of this article.
Surgery for colon cancer Laparoscopic right hemicolectomy Surgical anatomy: the use of a laparoscopic approach does not imply deviation from fundamental oncologic principles stated above. To reiterate, this includes proximal and distal resection
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flexure to the pelvic brim by lateral peritoneal attachments. Dissection along this line converts the left colon to a midline structure. The left colon is attached to the retroperitoneum through a midline mesentery. The key vessel of the hindgut is the inferior mesenteric artery (IMA), arising just superior to the aortic bifurcation. The IMA branches into left colic, sigmoid and superior rectal arteries, supplying the entire hindgut. An important anastomosis occurs between the superior mesenteric artery (SMA) and IMA through the marginal artery of Drummond, at the splenic flexure. The blood supply in this region is variable and recognized as a vulnerable ‘watershed area’. Although the splenic flexure is not always mobilized, it may be necessary to ensure a tension-free anastomosis. The inferior mesenteric vein (IMV) is also important in colorectal disease as it tethers the left colon e high ligation facilitates full colonic mobilization. As with the right side, there are important retroperitoneal relations; the left ureter and gonadal vessels lie posteriorly.
margins, proximal ligation of the main vascular pedicle(s) along with attached mesentery and en bloc resection of locally advanced colorectal tumours. Proximal or ‘high’ ligation at the origin of the feeder vessels is important to ensure the maximum number of lymph nodes within a complete mesenteric specimen (‘total mesocolic excision’). For an oncologic resection, a minimum of twelve nodes within the mesentery is considered adequate. In the case of right-sided colonic tumours, the key vessels are the ileocolic, right colic and right branch of the middle colic. The lymphatics follow the arterial supply. Care must be taken to avoid injury to the duodenum, right ureter and gonadal vessels. Operative steps: Accesse the surgeon stands on the patient’s left side and ports are placed in a fashion that permits triangulation onto the lesion in the right colon. After entering the abdomen and establishing a pneumoperitoneum, the patient is placed in a gentle head-down position with left lateral tilt. This allows the greater omentum to be easily positioned above the transverse colon and the small bowel to be positioned in the left side of the abdomen exposing the right colonic and terminal ileum mesentery, the ileocolic vessels and the duodenum. Dissectione there are a number of different approaches described. Dissection begins by incising the peritoneum inferior to the ileocolic vessels. Elevating the vessels from the retroperitoneum allows dissection in an avascular plane progressing cranially over the duodenum and laterally anterior to the ureter and gonadal vessels. An energy source such as the Harmonic scalpel is commonly used for this dissection and can also be used to divide the vessels. The ileocolic artery and vein are constant features. The right colic and branches of the middle colics have significant variability. Depending on the site of the tumour and the vascular anatomy these vessels may need to be individually ligated. After dividing the vessels mobilization of the right colon is accomplished by dividing the inferior and lateral peritoneal reflections and the hepatic flexure is mobilized by repositioning the patient in a head-up position and incising the gastrocolic ligament, revealing the duodenum posteriorly. The extent to which the omentum needs to mobilized depends on the position of the tumour. Resection and anastomosise once the right colon has been fully mobilized, the umbilical port site is enlarged to a size that will allow exteriorization of the mobilized segment. Wound protectors/retractors reduce the incidence of surgical site infections. The mesentery and marginal vessels are divided at the planned point of division of both the terminal ileum and transverse colon. The anastomosis is then constructed using a handsewn end-to-end or stapled side-to-side technique. An extended right hemicolectomy may be carried out for tumours in the transverse colon and splenic flexure. For such cases the dissection is carried round to divide the middle colic and ascending branch of the left colic artery. The anastomosis is then created between the ileum and descending colon.
Operative technique: Accesse the patient is placed in lithotomy position. The surgeon stands to the patient’s right side, with ports triangulating onto the left lower quadrant. By placing the patient in steep Trendelenburg and right lateral tilt, this allows gravity to aid the placement of the small bowel in the right upper quadrant away from the base of the left colon mesentery where dissection is usually initiated. Dissectione the first step in a medial to lateral dissection is to identify the anatomical landmarks. The initial incision in the peritoneum is anterior to the right iliac artery and extended cranially towards the origin of the IMA. The IMA is elevated, allowing development of an avascular plane anterior to the hypogastric nerves, left ureter and gonadal vessels. The medial to lateral dissection is continued cephalad and laterally. The IMA is divided with a sealing device, clip or stapler close to its origin, proximal or distal to the left colic branch e depending on the proposed operation. Next the IMV is dissected and transected with an energy source or using clips. The lateral colonic attachments are then incised joining the previous medial to lateral dissection and releasing the left colon. Finally, in reverse Trendelenburg position, the splenic flexure and omental attachments are released to aid complete mobilization of the colon, taking care to avoid injury to the left kidney, spleen and tail of pancreas. Resection and anastomosise attention can be redirected to the pelvis in the Trendelenburg position. Lateral attachments of the rectosigmoid are released and the mesorectum divided using a vessel-sealing device. The rectosigmoid junction is divided using a laparoscopic articulated stapler. Next, a Pfannenstiel incision is made to permit exteriorization. The left colon is delivered and the pericolic mesentery containing the marginal vessel is divided. The specimen is divided and removed from the field. A purse-string suture is applied to the well-vascularized colonic conduit and the anvil of the circular stapler positioned and secured. The colon is returned into the abdomen and the incision closed before re-establishing pneumoperitoneum. A circular stapler is inserted into the rectum and the anastomosis carefully created under laparoscopic control, with clear instructions from the lead surgeon. Following this, an air-leak test may be performed, followed by a final check for haemostasis.
Laparoscopic left hemicolectomy Surgical anatomy: the same oncological principles apply as described earlier. The left colon is suspended from the splenic
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stay. These trials provide reassuring evidence that laparoscopic rectal surgery does not compromise oncological aspects of the operation.
Surgery for rectal cancer Laparoscopic anterior resection: Surgical anatomye relative to colectomies, laparoscopic surgery for rectal cancer introduces a further degree of complexity. Within the bony confines of the pelvis, resections may be technically demanding. It is crucial to understand the concept of TME in the management of mid and low rectal cancer. Detailed anatomical description of the rectum and its relations is beyond the scope of this article however, TME involves complete removal of the rectum and mesorectum, (which contains perirectal fat and lymphatics) in order to excise the tumour with clear distal and circumferential margins and all the lymph nodes contained within the mesorectal envelope. The distinct circumferential fascial layer containing the mesorectum is known as the mesorectal fascia. Sharp dissection just outside this fascial layer, while maintaining an intact mesorectal envelope, is key to preserving important autonomic nerves. Injury to these nerve plexuses can lead to bladder dysfunction or erectile and/or ejaculatory problems in men. There is an optimal dissection plane that envelopes the rectal cancer and mesorectum as one distinct lymphovascular entity e this is referred to as the ‘holy plane’ of rectal surgery.11 Heald’s technique has become widely accepted producing excellent recurrence and survival rates with better functional preservation. Important anterior anatomical relations are the urogenital structures, for example the prostate and seminal vesicles in men, separated by Denonvillier’s fascia. In women, the equivalent ‘fascia’ is known as the rectovaginal septum. For oncological resections, a high anterior resection refers to cancer at the rectosigmoid junction. Low anterior resection implies that the tumour is in the lower two-thirds of the rectum (below the peritoneal reflection). Operative techniquee as with a left hemicolectomy, the left colon is mobilized via a medial to lateral approach. The ureter is identified and protected, as always. The inferior mesenteric pedicle is divided and the splenic flexure is often mobilized in order to minimize anastomotic tension and ensure good vascularization. The posterior dissection of the rectum proceeds with sharp dissection, always visualizing and protecting the sympathetic plexus. Anterior and lateral dissection continues with traction, counter-traction and sharp dissection. The rectum is transected using a linear articulated stapler. The bowel is exteriorized and the remaining proximal sigmoid mesentery and bowel is divided. A purse-string suture is placed proximally to secure the anvil of the circular stapler. The bowel can then be returned into the abdominal cavity, the incision closed and pneumoperitoneum restored. Finally, the anastomosis can again be performed laparoscopically with the anvil docking onto a stapler inserted via the anus. Following TME, better initial bowel function may be gained by performing a side-to-end anastomosis or creating a colo-pouch. Early results from the CLASICC trial did raise concerns over the rate of positive radial circumferential margins from laparoscopic rectal resections when compared to open; findings did not reach statistical significance however and longer term outcomes have revealed no difference in recurrence rates or survival. Subsequent data from COLOR2 and COREAN trials have shown equivalent oncological outcomes in laparoscopic versus open. Patients undergoing laparoscopic surgery also had less blood loss, decreased analgesic requirements and shorter length of
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Abdomino-perineal excision of the rectum (APER) Abdomino-perineal resection encompasses a number of slightly varied operations depending on the pathology including an intersphincteric approach e preserving the pelvic floor and a extralevator approach that removes the external sphincter and levator ani en bloc. APER is usually carried out for tumours in the lower third of the rectum that involve the sphincters or where sphincter-saving surgery is impossible due to inadequate distal margin. It may also be carried out in cases of resectable recurrent rectal cancer. We will not discuss the surgical management of anal cancers here. The laparoscopic approach has been shown to produce equivalent oncological results while having a shorter length of stay and decreased time to ambulation. The operation starts laparoscopically and is as for anterior resection but unlike in low anterior resections, splenic flexure mobilization is usually not needed. The pelvic dissection is carried out in a manner similar to anterior resection, ensuring dissection in the mesorectal plane but dissection stops when the levator muscles are reached. The colon is then divided where the proposed colostomy will be created. The aims of the perineal phase of the operation are to complete excision of rectum and mesorectum, resect surrounding fat from the ischiorectal space and obtain the widest possible circumferential resection of the levator muscles.
Further topics Radiotherapy and rectal cancer Historically, cancers of the rectum had a higher risk of local recurrence than colon cancers. Reasons for this include the challenging anatomical location and the difficulty of establishing precise dissection planes for total mesorectal excision. For this reason, adjuvant therapies have been investigated intensely over the last few decades. The Swedish Rectal Cancer Trial randomized 1100 cT1-3 patients into two groups between 1987 and 1990.12 One group received short course preoperative radiotherapy (SCPRT) followed by surgery and the other group received surgery alone. The SCPRT group was found to have decreased recurrence rates and higher 5-year survival. A limitation with the Swedish trial is that it occurred in the pre-TME era. In the late 1990s, a Dutch trial subsequently randomized 1800 cT1-3 patients to SCPRT þ TME versus TME alone.13 The Dutch study did not show any differences in survival between the two groups but it did reveal lower recurrence rates in the radiotherapy group. Risk of local recurrence at 5 years was 5% in the SCPRT þ TME group, versus 11% in TME alone. Subsequent evidence to support SCPRT has been more controversial. The benefits appear to be modest and MDTs need to carefully balance this against the risks of radiotherapy-induced toxicity. Transanal endoscopic microsurgery (TEM) Access to rectal cancers can sometimes be difficult due to the bony confines of the pelvis. There are also significant potential complications to performing rectal excision and there is a recognition that this may represent over-treatment in patients
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Figure 5 Positron emission tomographyecomputed tomography image of the hypodense colorectal liver metastasis from Figure 4, demonstrating high uptake of fluorodeoxyglucose. (With permission from Dunne et al., Colorectal Liver Metastases, Hepatobiliary and Pancreatic Surgery, pp. 109-131, Elsevier, 2014).
Figure 3 Rectoscope with face piece and sleeves for instruments and optics. (With permission from Mortensen and Hompes, Transanal endoscopic microsurgery, in Shackelford’s Surgery of the Alimentary Tract, pp. 2086-2093, Elsevier, 2013).
The gold standard for rectal cancer treatment in terms of longterm oncological outcomes remains TME. However, the oncological excellence associated with TME is associated with significant risk in terms of morbidity. There is a trade-off to be made here between oncological excellence and potential morbidity. For early rectal cancers less than 3 cm in diameter, with low risk of lymph node metastases (cT1N0), TEM may be the procedure of choice. The Association of Coloproctology of Great Britain and Ireland (ACPGBI) currently advocates further treatment (‘completion surgery’) if high-risk features are present on histopathological examination. Complication rates are generally low, around 10%. The role of TEM in T2 rectal cancers is more controversial as these often have lymphovascular invasion. Such cases may require additional treatment with a course of neoadjuvant therapy. Further work is needed to establish the precise role of TEM combined with neoadjuvant therapy in this subgroup.
Figure 4 CT image demonstrating a hypodense colorectal liver metastasis. (With permission from Dunne et al., Colorectal Liver Metastases, Hepatobiliary and Pancreatic Surgery, pp. 109-131, Elsevier, 2014).
Colorectal liver metastases Recall of the anatomy reminds us that most of the blood draining from the GI tract will eventually reach the portal venous system and therefore the liver (Figures 4 and 5). This explains the high preponderance of colorectal cancer liver metastases (CLM). Traditionally, cancer to a distant site has been regarded as a sign of systemic disease and therefore not amenable to locoregional control (i.e. surgery). Some colorectal liver metastases appear to be an exception to this rule. This paradigm was overturned following Scheele’s work14 which demonstrated impressive results. Resection of CLM can result in increased median survival and potential cure. In most cases of metastatic spread, disease is either too widespread or liver disease is unresectable. 5e10% of patients are potential candidates for CLM resection. Therapies for CLM are evolving rapidly. Advances in hepatic surgery and chemotherapy have greatly improved prospects for well-selected patients. Combination of chemotherapy and complete CLM resection is associated with 50e60% long-term survival.15 Recurrence and chronic multimodal therapy are common. Morbidity is relatively high so careful selection and honest patient education is important to establish realistic expectations.
with benign lesions or with early stage cancers. Transanal surgery to locally excise lesions may avoid abdominal surgery, reduce functional consequences of rectal resection and potentially avoid a permanent stoma. In cases where local excision is deemed oncologically adequate TEM is a useful technique. A number of different devices are now available that enable this technique. Originally TEM referred to a minimally invasive technique employing a specialized 4 cm proctoscope with ports for CO2 insufflation, water irrigation, pressure monitoring and suction (Figure 3). Long instruments are inserted through ports to perform a full-thickness excision under direct vision. It is possible to perform a mucosal resection for benign disease or a full-thickness resection and local resection of adjacent mesorectum. The technique allows for closing the defect by suturing when appropriate. The same technique can now be applied using adapted single port access devices placed in the anal canal.
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metastases and more effective adjuvant therapies to improve outlook and survival. Surgery represents the gold standard of treatment for colorectal cancer. A
Follow-up after colorectal cancer surgery The aims of follow-up from a strictly oncological perspective are mainly twofold; firstly, detection of recurrence and secondly, detection of metachronous disease. There is widespread variation in terms of the intensity and modalities employed for followup around the world. Very little robust evidence actually exists for current schedules. However, there are certain basic principles that appear sensible to follow. The vast majority of recurrences occur within the first 3 years of surgical resection. Therefore, it is common to practice to follow up patients more intensively over this period. Subsequently the frequency of visits and tests can be relaxed. Most protocols advise 3- to 6-monthly visits for 3 years, comprising physical examination and carcinoembryonic antigen (CEA) measurement. A rising CEA can prompt further investigation with CT, MRI, or PETeCT if equivocal. While CEA is a relatively simple and inexpensive test, opponents argue that there is a lack of survival benefit from regular measurement. Many protocols recommend annual CT of chest, abdomen and pelvis for 3 years and colonoscopy at 3 years. If patients did not have complete colonoscopic visualization before surgery, then early colonoscopy (within 12 months) should be undertaken. If normal, 5-yearly colonoscopic surveillance is recommended thereafter, though some centres choose to shorten the time interval. Luminal recurrences at the site of surgery are generally rare, assuming the original resection has been adequate. Therefore, the rationale behind colonoscopic surveillance is directed at identifying metachronous disease rather than recurrence, per se. Detection of liver and lung metastases at an early stage may allow resection of these lesions, with subsequent increase in survival and possibly even cure. Routine clinical follow-up is usually complete by 5 years and any further follow-up arrangements depend on individual circumstances. Further trials are on-going to determine the ideal intensity and modalities used for follow-up. Although there is no solid evidence to suggest that intensive follow-up increases detection of recurrence, there is no doubt that patients obtain valuable psychological support from follow-up. As surgical research advances it may become possible to develop a more individually tailored approach. Based on biological factors, such as tumour aggressiveness and immune response, we may be able to better predict the patients that will benefit from more intensive follow-up.
REFERENCES 1 Bowel cancer incidence statistics. Available at: http://www. cancerresearchuk.org/health-professional/cancer-statistics/ statistics-by-cancer-type/bowel-cancer/incidence. 2 Vogelstein B, Fearon ER, Hamilton SR, et al. Genetic alterations during colorectal-tumor development. N Engl J Med 1988; 319: 525e32. 3 Wallace D, Walker K, Kuryba A, Finan P, Scott N, van der Meulen J. Identifying patients at risk of emergency admission for colorectal cancer. Br J Cancer 2014; 111: 577e80. 4 Nikoloudis N, Saliangas K, Economou A, et al. Synchronous colorectal cancer. Tech Coloproctol 2004; 8: s177e9. 5 Coleman MG, Hanna GB, Kennedy R. The National Training Programme for Laparoscopic Colorectal Surgery in England: a new training paradigm. Colorectal Dis 2011; 13: 614e6. 6 Holte K, Nielsen KG, Madsen JL, Kehlet H. Physiologic effects of bowel preparation. Dis Colon Rectum 2004; 47: 1397e402. 7 Kehlet H. Multimodal approach to control postoperative pathophysiology and rehabilitation. Br J Anaesth 1997; 78: 606e17. 8 Levy BF, Scott MJP, Fawcett WJ, Rockall TA. 23-Hourstay laparoscopic colectomy. Dis Colon Rectum 2009; 52: 1239e43. 9 Heald RJ, Ryall RD. Recurrence and survival after total mesorectal excision for rectal cancer. Lancet 1986; 1: 1479e82. 10 Jayne DG, Thorpe HC, Copeland J, Quirke P, Brown JM, Guillou PJ. Five-year follow-up of the Medical Research Council CLASICC trial of laparoscopically assisted versus open surgery for colorectal cancer. Br J Surg 2010; 97: 1638e45. 11 Heald RJ. The ‘Holy Plane’ of rectal surgery. J R Soc Med 1988; 81: 503e8. 12 Improved survival with preoperative radiotherapy in resectable rectal cancer. Swedish Rectal Cancer Trial. N Engl J Med 1997; 336: 980e7. 13 van Gijn W, Marijnen CA, Nagtegaal ID, et al. Preoperative radiotherapy combined with total mesorectal excision for resectable rectal cancer: 12-year follow-up of the multicentre, randomised controlled TME trial. Lancet Oncol 2011; 12: 575e82. 14 Scheele J, Stangl R, Altendorf-Hofmann A. Hepatic metastases from colorectal carcinoma: impact of surgical resection on the natural history. Br J Surg 1990; 77: 1241e6. 15 Carpizo DR, Are C, Jarnagin W, et al. Liver resection for metastatic colorectal cancer in patients with concurrent extrahepatic disease: results in 127 patients treated at a single center. Ann Surg Oncol 2009; 16: 2138e46.
Summary The last three decades have seen rapid evolution in the surgical treatment of colorectal cancer. The most significant change has been the uptake of laparoscopic techniques. As surgical proficiency and expertise has developed, the number of patients and indications eligible for the laparoscopic approach has increased. Other advances in the field include surgery for locally resectable
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Surgery for colorectal cancer
factors, key mutations appear to involve APC, KRAS and p53 genes. The most common histopathology for colorectal cancer is adenocarcinoma. The development of colorectal adenocarcinoma is postulated to follow the adenomaecarcinoma sequence. In this model, there may be a natural progression from benign polyps into invasive cancerous lesions. The national bowel cancer screening programme was set up in 2006 based on this model, which is widely accepted. About 20% of cases present as emergencies and these are associated with a poorer outcome.3 Early presentation is key to improving outcomes for colorectal cancer and the management of pre-invasive lesions. Approximately 30% of cases occur in the rectum and 20% in the sigmoid colon. About 20% develop in the right colon and 10% are found in the transverse or left colon. Approximately 80% of newly diagnosed cases will require surgery. Surgery remains the primary treatment for the majority of cases of colorectal cancer both as treatment with curative intent and as a palliative therapy.
Jason George Timothy Rockall
Abstract Colorectal cancer surgery represents a major component of the colorectal service workload. A solid understanding of key anatomical and oncological principles is essential for safe practice. In this article we discuss these fundamental aspects of colorectal cancer surgery. The first part of the article will deal with preoperative staging, surgical planning and principles of oncological surgery. The second part will focus on some of the most common operations. We will describe key intraoperative principles involved in performing a right hemicolectomy, left hemicolectomy, anterior resection and abdomino-perineal resection. Laparoscopic colorectal cancer surgery is increasingly widespread and therefore our perspective will assume this approach by default. In the final section, we discuss the role of radiotherapy in rectal cancers, transanal surgery, resection of colorectal liver metastases and the rationale behind follow-up.
Staging and imaging of colorectal cancer The single most important factor that determines the outcome is the stage of cancer at presentation. The international standard used for staging is referred to as the TNM classification. Prognosis is intimately linked to the invasiveness of the tumour (T ), extent of regional lymph node (N ) involvement and the presence of distant extra-intestinal metastases (M ). Clinical staging is with colonoscopy, computed tomography (CT) scan of the chest abdomen and pelvis and magnetic resonance imaging (MRI) scan of the pelvis for rectal tumours. Indeterminate lesions in the liver may require further assessment with MRI or ultrasound. Positron emission tomography (PET) scan may also be helpful in determining sites of disseminated disease. Diagnosis is usually by colonoscopic examination. Even if diagnosis has been by alternative methods such as CT, colonoscopy is mandatory in order to acquire biopsies and exclude synchronous lesions. The reported incidence of synchronous colorectal lesions ranges between 2% and 9%.4 The incidence is variable as it depends on the degree of diligence with which the rest of the large bowel is assessed after detecting one lesion. CT may be used as a tool not only for diagnosis but also for assessment of local complications such as fistula and abscess formation. CT will also identify common sites of metastatic spread such as liver or lungs. MRI may be particularly useful in assessment of rectal tumours in order to gain an appreciation of relationship with the mesorectal fascia and mesorectal nodal status (Figure 1). Involvement of this fascial boundary known as the circumferential resection margin (CRM) may be an indication for neoadjuvant therapy in order to downgrade tumour size and reduce the likelihood of a positive CRM. MRI is also more sensitive at detecting colorectal metastases to the liver. PETeCT is a combined modality not usually used for staging, however it does play an important role in identification of possible recurrent disease. A pitfall is that areas of infection or inflammation may ‘light up’ on PET scans due to uptake of the radiolabelled isotope, fluorodeoxyglucose (FDG).
Keywords Colorectal cancer; laparoscopic; surgical resection
Introduction Colorectal cancer is the fourth most common cancer in the UK. In 2013, there were approximately 41,000 new cases in the UK; 23,000 (56%) cases in men and 18,000 (44%) in women, giving a male:female ratio of 13:10.1 Geographically, the incidence of colorectal cancer is highest in Western Europe and North America. Multiple risk factors are associated with its development; these include smoking, alcohol, diet (excessive red meat and processed food consumption), obesity and decreased physical activity. Inflammatory bowel disease is also associated with increased risk in proportion to the extent of bowel involvement and duration of disease. The majority of colorectal cancers are sporadic whereas 5 e10% are inherited syndromes, for example, hereditary nonpolyposis colon cancer (HNPCC) and familial adenomatous polyposis (FAP). There may be some overlap of genetic abnormalities involving sporadic and inherited forms. The risk of colorectal cancer for an individual with a first-degree relative with the disease is three times greater than one who has no family history. Vogelstein proposed a multi-step model identifying key mutations.2 Although colorectal carcinogenesis involves a complex interplay between environmental and genetic
Jason George MA (Cantab) MRCS is a Research Fellow at the Minimal Access Therapy Training Unit (MATTU), Guildford, UK. Conflicts of interest: none declared. Timothy Rockall MD FRCS is Professor of Surgery at the University of Surrey and Consultant Surgeon and Director of the MATTU, Guildford, UK. Conflicts of interest: none declared.
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Figure 2 Photograph of a patient doing a cardiopulmonary exercise test. (With permission from Young et al., A systematic review of the role of cardiopulmonary exercise testing in vascular surgery, European Journal of Vascular & Endovascular Surgery, Volume 44, Issue 1, pp. 64-71, Elsevier, 2012).
Figure 1 Axial T2 weighted image of the pelvis e arrows mark the mesorectal fascia. (With permission from Griffin and Grant, Grainger & Allison’s Diagnostic Radiology Essentials, pp. 294-313, Elsevier, 2013).
that it is possible to discharge selected patients as early as 23 hours after laparoscopic colorectal surgery by incorporating such techniques within an ERAS pathway.8
Preoperative considerations
Oncological principles in colorectal cancer surgery
As with all cancer surgery today, a careful multidisciplinary team (MDT) approach should be employed to ensure the best possible decision and outcome for each patient. The first step is to establish whether disease is localized or disseminated. The operative strategy should be based on fundamental principles of oncological surgery, discussed in the next section. Laparoscopic colorectal surgery is gradually becoming the standard of care around the UK rather than something carried out only in ‘specialist’ centres. The introduction of the LAPCO training programme5 has resulted in an increase in consultant surgeons performing laparoscopic colorectal surgery. A key aspect in generating successful outcomes from colorectal cancer surgery is to work closely in concert with anaesthetists, cardiologists and respiratory physicians, amongst others, to stratify risk and address modifiable factors e.g. ischaemic heart disease, asthma, diabetes. Cardiopulmonary exercise testing (CPET) (Figure 2) may be used to stratify high-risk patients. A frequently debated topic is whether to give routine bowel preparation or not. Bowel preparation may cause significant dehydration and electrolyte derangement6 and is unpleasant for the patient. It can also precipitate obstruction or create dilated fluid-filled bowel proximal to near obstructing lesions. At the Minimal Access Therapy Training Unit (MATTU) in Guildford, we have a policy of no bowel preparation for right-sided lesions, a preoperative enema for left-sided lesions and restrict full bowel preparation to patients having low rectal resections with anastomosis and defunctioning ileostomy. This represents just one aspect of ERAS (enhanced recovery after surgery).7 Other key components that require attention are preoperative carbohydrate loading, opioid-sparing analgesia, perioperative fluid regimes, early mobilization and nutrition. The standard of care in our unit for patients undergoing laparoscopic colorectal surgery is to receive a spinal or patient-controlled analgesia for postoperative analgesia and oesophageal Doppler monitoring (ODM) for goaldirected fluid therapy. The Guildford experience has shown
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The goal of surgery is to resect the primary tumour en bloc with clear resection margins and include all draining locoregional lymphatics that may contain micrometastases. In order to understand the extent of bowel resection and lymphadenectomy one must have a clear understanding of the anatomical principles behind lymphatic spread. Longitudinal intramural lymphatic spread in the colon rarely exceeds 2 cm, hence the rationale for 5 cm resection margins proximally and distally. For rectal cancers, sphincter-saving techniques allow most patients to avoid abdomino-perineal resection and a permanent colostomy; a 1 cm distal clearance is considered the minimum for an adequate rectal resection. Circumferential lymphatic spread proceeds centrally, usually in a step-wise fashion from epicolic and paracolic nodes eventually to the ‘apical node’, associated with a major vascular pedicle. In rectal cancers, Heald et al. advocated total mesorectal excision (TME).9 TME is now the standard of treatment and has led to decreased recurrence rates. Since the lymphatics run alongside arteries, the extent of segmental resection is determined by the vascular territories involved. The evidence increasingly confirms that laparoscopic resections are safe, oncologically equivalent to open surgery and have better short-term outcomes.10 The choice of approach is perhaps more dependent on the individual department, surgeon expertise and training than anything else. The robotic approach is discussed elsewhere in this issue. Discussion of complications is beyond the scope of this article.
Surgery for colon cancer Laparoscopic right hemicolectomy Surgical anatomy: the use of a laparoscopic approach does not imply deviation from fundamental oncologic principles stated above. To reiterate, this includes proximal and distal resection
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flexure to the pelvic brim by lateral peritoneal attachments. Dissection along this line converts the left colon to a midline structure. The left colon is attached to the retroperitoneum through a midline mesentery. The key vessel of the hindgut is the inferior mesenteric artery (IMA), arising just superior to the aortic bifurcation. The IMA branches into left colic, sigmoid and superior rectal arteries, supplying the entire hindgut. An important anastomosis occurs between the superior mesenteric artery (SMA) and IMA through the marginal artery of Drummond, at the splenic flexure. The blood supply in this region is variable and recognized as a vulnerable ‘watershed area’. Although the splenic flexure is not always mobilized, it may be necessary to ensure a tension-free anastomosis. The inferior mesenteric vein (IMV) is also important in colorectal disease as it tethers the left colon e high ligation facilitates full colonic mobilization. As with the right side, there are important retroperitoneal relations; the left ureter and gonadal vessels lie posteriorly.
margins, proximal ligation of the main vascular pedicle(s) along with attached mesentery and en bloc resection of locally advanced colorectal tumours. Proximal or ‘high’ ligation at the origin of the feeder vessels is important to ensure the maximum number of lymph nodes within a complete mesenteric specimen (‘total mesocolic excision’). For an oncologic resection, a minimum of twelve nodes within the mesentery is considered adequate. In the case of right-sided colonic tumours, the key vessels are the ileocolic, right colic and right branch of the middle colic. The lymphatics follow the arterial supply. Care must be taken to avoid injury to the duodenum, right ureter and gonadal vessels. Operative steps: Accesse the surgeon stands on the patient’s left side and ports are placed in a fashion that permits triangulation onto the lesion in the right colon. After entering the abdomen and establishing a pneumoperitoneum, the patient is placed in a gentle head-down position with left lateral tilt. This allows the greater omentum to be easily positioned above the transverse colon and the small bowel to be positioned in the left side of the abdomen exposing the right colonic and terminal ileum mesentery, the ileocolic vessels and the duodenum. Dissectione there are a number of different approaches described. Dissection begins by incising the peritoneum inferior to the ileocolic vessels. Elevating the vessels from the retroperitoneum allows dissection in an avascular plane progressing cranially over the duodenum and laterally anterior to the ureter and gonadal vessels. An energy source such as the Harmonic scalpel is commonly used for this dissection and can also be used to divide the vessels. The ileocolic artery and vein are constant features. The right colic and branches of the middle colics have significant variability. Depending on the site of the tumour and the vascular anatomy these vessels may need to be individually ligated. After dividing the vessels mobilization of the right colon is accomplished by dividing the inferior and lateral peritoneal reflections and the hepatic flexure is mobilized by repositioning the patient in a head-up position and incising the gastrocolic ligament, revealing the duodenum posteriorly. The extent to which the omentum needs to mobilized depends on the position of the tumour. Resection and anastomosise once the right colon has been fully mobilized, the umbilical port site is enlarged to a size that will allow exteriorization of the mobilized segment. Wound protectors/retractors reduce the incidence of surgical site infections. The mesentery and marginal vessels are divided at the planned point of division of both the terminal ileum and transverse colon. The anastomosis is then constructed using a handsewn end-to-end or stapled side-to-side technique. An extended right hemicolectomy may be carried out for tumours in the transverse colon and splenic flexure. For such cases the dissection is carried round to divide the middle colic and ascending branch of the left colic artery. The anastomosis is then created between the ileum and descending colon.
Operative technique: Accesse the patient is placed in lithotomy position. The surgeon stands to the patient’s right side, with ports triangulating onto the left lower quadrant. By placing the patient in steep Trendelenburg and right lateral tilt, this allows gravity to aid the placement of the small bowel in the right upper quadrant away from the base of the left colon mesentery where dissection is usually initiated. Dissectione the first step in a medial to lateral dissection is to identify the anatomical landmarks. The initial incision in the peritoneum is anterior to the right iliac artery and extended cranially towards the origin of the IMA. The IMA is elevated, allowing development of an avascular plane anterior to the hypogastric nerves, left ureter and gonadal vessels. The medial to lateral dissection is continued cephalad and laterally. The IMA is divided with a sealing device, clip or stapler close to its origin, proximal or distal to the left colic branch e depending on the proposed operation. Next the IMV is dissected and transected with an energy source or using clips. The lateral colonic attachments are then incised joining the previous medial to lateral dissection and releasing the left colon. Finally, in reverse Trendelenburg position, the splenic flexure and omental attachments are released to aid complete mobilization of the colon, taking care to avoid injury to the left kidney, spleen and tail of pancreas. Resection and anastomosise attention can be redirected to the pelvis in the Trendelenburg position. Lateral attachments of the rectosigmoid are released and the mesorectum divided using a vessel-sealing device. The rectosigmoid junction is divided using a laparoscopic articulated stapler. Next, a Pfannenstiel incision is made to permit exteriorization. The left colon is delivered and the pericolic mesentery containing the marginal vessel is divided. The specimen is divided and removed from the field. A purse-string suture is applied to the well-vascularized colonic conduit and the anvil of the circular stapler positioned and secured. The colon is returned into the abdomen and the incision closed before re-establishing pneumoperitoneum. A circular stapler is inserted into the rectum and the anastomosis carefully created under laparoscopic control, with clear instructions from the lead surgeon. Following this, an air-leak test may be performed, followed by a final check for haemostasis.
Laparoscopic left hemicolectomy Surgical anatomy: the same oncological principles apply as described earlier. The left colon is suspended from the splenic
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stay. These trials provide reassuring evidence that laparoscopic rectal surgery does not compromise oncological aspects of the operation.
Surgery for rectal cancer Laparoscopic anterior resection: Surgical anatomye relative to colectomies, laparoscopic surgery for rectal cancer introduces a further degree of complexity. Within the bony confines of the pelvis, resections may be technically demanding. It is crucial to understand the concept of TME in the management of mid and low rectal cancer. Detailed anatomical description of the rectum and its relations is beyond the scope of this article however, TME involves complete removal of the rectum and mesorectum, (which contains perirectal fat and lymphatics) in order to excise the tumour with clear distal and circumferential margins and all the lymph nodes contained within the mesorectal envelope. The distinct circumferential fascial layer containing the mesorectum is known as the mesorectal fascia. Sharp dissection just outside this fascial layer, while maintaining an intact mesorectal envelope, is key to preserving important autonomic nerves. Injury to these nerve plexuses can lead to bladder dysfunction or erectile and/or ejaculatory problems in men. There is an optimal dissection plane that envelopes the rectal cancer and mesorectum as one distinct lymphovascular entity e this is referred to as the ‘holy plane’ of rectal surgery.11 Heald’s technique has become widely accepted producing excellent recurrence and survival rates with better functional preservation. Important anterior anatomical relations are the urogenital structures, for example the prostate and seminal vesicles in men, separated by Denonvillier’s fascia. In women, the equivalent ‘fascia’ is known as the rectovaginal septum. For oncological resections, a high anterior resection refers to cancer at the rectosigmoid junction. Low anterior resection implies that the tumour is in the lower two-thirds of the rectum (below the peritoneal reflection). Operative techniquee as with a left hemicolectomy, the left colon is mobilized via a medial to lateral approach. The ureter is identified and protected, as always. The inferior mesenteric pedicle is divided and the splenic flexure is often mobilized in order to minimize anastomotic tension and ensure good vascularization. The posterior dissection of the rectum proceeds with sharp dissection, always visualizing and protecting the sympathetic plexus. Anterior and lateral dissection continues with traction, counter-traction and sharp dissection. The rectum is transected using a linear articulated stapler. The bowel is exteriorized and the remaining proximal sigmoid mesentery and bowel is divided. A purse-string suture is placed proximally to secure the anvil of the circular stapler. The bowel can then be returned into the abdominal cavity, the incision closed and pneumoperitoneum restored. Finally, the anastomosis can again be performed laparoscopically with the anvil docking onto a stapler inserted via the anus. Following TME, better initial bowel function may be gained by performing a side-to-end anastomosis or creating a colo-pouch. Early results from the CLASICC trial did raise concerns over the rate of positive radial circumferential margins from laparoscopic rectal resections when compared to open; findings did not reach statistical significance however and longer term outcomes have revealed no difference in recurrence rates or survival. Subsequent data from COLOR2 and COREAN trials have shown equivalent oncological outcomes in laparoscopic versus open. Patients undergoing laparoscopic surgery also had less blood loss, decreased analgesic requirements and shorter length of
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Abdomino-perineal excision of the rectum (APER) Abdomino-perineal resection encompasses a number of slightly varied operations depending on the pathology including an intersphincteric approach e preserving the pelvic floor and a extralevator approach that removes the external sphincter and levator ani en bloc. APER is usually carried out for tumours in the lower third of the rectum that involve the sphincters or where sphincter-saving surgery is impossible due to inadequate distal margin. It may also be carried out in cases of resectable recurrent rectal cancer. We will not discuss the surgical management of anal cancers here. The laparoscopic approach has been shown to produce equivalent oncological results while having a shorter length of stay and decreased time to ambulation. The operation starts laparoscopically and is as for anterior resection but unlike in low anterior resections, splenic flexure mobilization is usually not needed. The pelvic dissection is carried out in a manner similar to anterior resection, ensuring dissection in the mesorectal plane but dissection stops when the levator muscles are reached. The colon is then divided where the proposed colostomy will be created. The aims of the perineal phase of the operation are to complete excision of rectum and mesorectum, resect surrounding fat from the ischiorectal space and obtain the widest possible circumferential resection of the levator muscles.
Further topics Radiotherapy and rectal cancer Historically, cancers of the rectum had a higher risk of local recurrence than colon cancers. Reasons for this include the challenging anatomical location and the difficulty of establishing precise dissection planes for total mesorectal excision. For this reason, adjuvant therapies have been investigated intensely over the last few decades. The Swedish Rectal Cancer Trial randomized 1100 cT1-3 patients into two groups between 1987 and 1990.12 One group received short course preoperative radiotherapy (SCPRT) followed by surgery and the other group received surgery alone. The SCPRT group was found to have decreased recurrence rates and higher 5-year survival. A limitation with the Swedish trial is that it occurred in the pre-TME era. In the late 1990s, a Dutch trial subsequently randomized 1800 cT1-3 patients to SCPRT þ TME versus TME alone.13 The Dutch study did not show any differences in survival between the two groups but it did reveal lower recurrence rates in the radiotherapy group. Risk of local recurrence at 5 years was 5% in the SCPRT þ TME group, versus 11% in TME alone. Subsequent evidence to support SCPRT has been more controversial. The benefits appear to be modest and MDTs need to carefully balance this against the risks of radiotherapy-induced toxicity. Transanal endoscopic microsurgery (TEM) Access to rectal cancers can sometimes be difficult due to the bony confines of the pelvis. There are also significant potential complications to performing rectal excision and there is a recognition that this may represent over-treatment in patients
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Figure 5 Positron emission tomographyecomputed tomography image of the hypodense colorectal liver metastasis from Figure 4, demonstrating high uptake of fluorodeoxyglucose. (With permission from Dunne et al., Colorectal Liver Metastases, Hepatobiliary and Pancreatic Surgery, pp. 109-131, Elsevier, 2014).
Figure 3 Rectoscope with face piece and sleeves for instruments and optics. (With permission from Mortensen and Hompes, Transanal endoscopic microsurgery, in Shackelford’s Surgery of the Alimentary Tract, pp. 2086-2093, Elsevier, 2013).
The gold standard for rectal cancer treatment in terms of longterm oncological outcomes remains TME. However, the oncological excellence associated with TME is associated with significant risk in terms of morbidity. There is a trade-off to be made here between oncological excellence and potential morbidity. For early rectal cancers less than 3 cm in diameter, with low risk of lymph node metastases (cT1N0), TEM may be the procedure of choice. The Association of Coloproctology of Great Britain and Ireland (ACPGBI) currently advocates further treatment (‘completion surgery’) if high-risk features are present on histopathological examination. Complication rates are generally low, around 10%. The role of TEM in T2 rectal cancers is more controversial as these often have lymphovascular invasion. Such cases may require additional treatment with a course of neoadjuvant therapy. Further work is needed to establish the precise role of TEM combined with neoadjuvant therapy in this subgroup.
Figure 4 CT image demonstrating a hypodense colorectal liver metastasis. (With permission from Dunne et al., Colorectal Liver Metastases, Hepatobiliary and Pancreatic Surgery, pp. 109-131, Elsevier, 2014).
Colorectal liver metastases Recall of the anatomy reminds us that most of the blood draining from the GI tract will eventually reach the portal venous system and therefore the liver (Figures 4 and 5). This explains the high preponderance of colorectal cancer liver metastases (CLM). Traditionally, cancer to a distant site has been regarded as a sign of systemic disease and therefore not amenable to locoregional control (i.e. surgery). Some colorectal liver metastases appear to be an exception to this rule. This paradigm was overturned following Scheele’s work14 which demonstrated impressive results. Resection of CLM can result in increased median survival and potential cure. In most cases of metastatic spread, disease is either too widespread or liver disease is unresectable. 5e10% of patients are potential candidates for CLM resection. Therapies for CLM are evolving rapidly. Advances in hepatic surgery and chemotherapy have greatly improved prospects for well-selected patients. Combination of chemotherapy and complete CLM resection is associated with 50e60% long-term survival.15 Recurrence and chronic multimodal therapy are common. Morbidity is relatively high so careful selection and honest patient education is important to establish realistic expectations.
with benign lesions or with early stage cancers. Transanal surgery to locally excise lesions may avoid abdominal surgery, reduce functional consequences of rectal resection and potentially avoid a permanent stoma. In cases where local excision is deemed oncologically adequate TEM is a useful technique. A number of different devices are now available that enable this technique. Originally TEM referred to a minimally invasive technique employing a specialized 4 cm proctoscope with ports for CO2 insufflation, water irrigation, pressure monitoring and suction (Figure 3). Long instruments are inserted through ports to perform a full-thickness excision under direct vision. It is possible to perform a mucosal resection for benign disease or a full-thickness resection and local resection of adjacent mesorectum. The technique allows for closing the defect by suturing when appropriate. The same technique can now be applied using adapted single port access devices placed in the anal canal.
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metastases and more effective adjuvant therapies to improve outlook and survival. Surgery represents the gold standard of treatment for colorectal cancer. A
Follow-up after colorectal cancer surgery The aims of follow-up from a strictly oncological perspective are mainly twofold; firstly, detection of recurrence and secondly, detection of metachronous disease. There is widespread variation in terms of the intensity and modalities employed for followup around the world. Very little robust evidence actually exists for current schedules. However, there are certain basic principles that appear sensible to follow. The vast majority of recurrences occur within the first 3 years of surgical resection. Therefore, it is common to practice to follow up patients more intensively over this period. Subsequently the frequency of visits and tests can be relaxed. Most protocols advise 3- to 6-monthly visits for 3 years, comprising physical examination and carcinoembryonic antigen (CEA) measurement. A rising CEA can prompt further investigation with CT, MRI, or PETeCT if equivocal. While CEA is a relatively simple and inexpensive test, opponents argue that there is a lack of survival benefit from regular measurement. Many protocols recommend annual CT of chest, abdomen and pelvis for 3 years and colonoscopy at 3 years. If patients did not have complete colonoscopic visualization before surgery, then early colonoscopy (within 12 months) should be undertaken. If normal, 5-yearly colonoscopic surveillance is recommended thereafter, though some centres choose to shorten the time interval. Luminal recurrences at the site of surgery are generally rare, assuming the original resection has been adequate. Therefore, the rationale behind colonoscopic surveillance is directed at identifying metachronous disease rather than recurrence, per se. Detection of liver and lung metastases at an early stage may allow resection of these lesions, with subsequent increase in survival and possibly even cure. Routine clinical follow-up is usually complete by 5 years and any further follow-up arrangements depend on individual circumstances. Further trials are on-going to determine the ideal intensity and modalities used for follow-up. Although there is no solid evidence to suggest that intensive follow-up increases detection of recurrence, there is no doubt that patients obtain valuable psychological support from follow-up. As surgical research advances it may become possible to develop a more individually tailored approach. Based on biological factors, such as tumour aggressiveness and immune response, we may be able to better predict the patients that will benefit from more intensive follow-up.
REFERENCES 1 Bowel cancer incidence statistics. Available at: http://www. cancerresearchuk.org/health-professional/cancer-statistics/ statistics-by-cancer-type/bowel-cancer/incidence. 2 Vogelstein B, Fearon ER, Hamilton SR, et al. Genetic alterations during colorectal-tumor development. N Engl J Med 1988; 319: 525e32. 3 Wallace D, Walker K, Kuryba A, Finan P, Scott N, van der Meulen J. Identifying patients at risk of emergency admission for colorectal cancer. Br J Cancer 2014; 111: 577e80. 4 Nikoloudis N, Saliangas K, Economou A, et al. Synchronous colorectal cancer. Tech Coloproctol 2004; 8: s177e9. 5 Coleman MG, Hanna GB, Kennedy R. The National Training Programme for Laparoscopic Colorectal Surgery in England: a new training paradigm. Colorectal Dis 2011; 13: 614e6. 6 Holte K, Nielsen KG, Madsen JL, Kehlet H. Physiologic effects of bowel preparation. Dis Colon Rectum 2004; 47: 1397e402. 7 Kehlet H. Multimodal approach to control postoperative pathophysiology and rehabilitation. Br J Anaesth 1997; 78: 606e17. 8 Levy BF, Scott MJP, Fawcett WJ, Rockall TA. 23-Hourstay laparoscopic colectomy. Dis Colon Rectum 2009; 52: 1239e43. 9 Heald RJ, Ryall RD. Recurrence and survival after total mesorectal excision for rectal cancer. Lancet 1986; 1: 1479e82. 10 Jayne DG, Thorpe HC, Copeland J, Quirke P, Brown JM, Guillou PJ. Five-year follow-up of the Medical Research Council CLASICC trial of laparoscopically assisted versus open surgery for colorectal cancer. Br J Surg 2010; 97: 1638e45. 11 Heald RJ. The ‘Holy Plane’ of rectal surgery. J R Soc Med 1988; 81: 503e8. 12 Improved survival with preoperative radiotherapy in resectable rectal cancer. Swedish Rectal Cancer Trial. N Engl J Med 1997; 336: 980e7. 13 van Gijn W, Marijnen CA, Nagtegaal ID, et al. Preoperative radiotherapy combined with total mesorectal excision for resectable rectal cancer: 12-year follow-up of the multicentre, randomised controlled TME trial. Lancet Oncol 2011; 12: 575e82. 14 Scheele J, Stangl R, Altendorf-Hofmann A. Hepatic metastases from colorectal carcinoma: impact of surgical resection on the natural history. Br J Surg 1990; 77: 1241e6. 15 Carpizo DR, Are C, Jarnagin W, et al. Liver resection for metastatic colorectal cancer in patients with concurrent extrahepatic disease: results in 127 patients treated at a single center. Ann Surg Oncol 2009; 16: 2138e46.
Summary The last three decades have seen rapid evolution in the surgical treatment of colorectal cancer. The most significant change has been the uptake of laparoscopic techniques. As surgical proficiency and expertise has developed, the number of patients and indications eligible for the laparoscopic approach has increased. Other advances in the field include surgery for locally resectable
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