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Endoscopic resection of large sessile colorectal polyps
0016-5107/92/3803-0303$03.00 GASTROINTESTINAL ENDOSCOPY Copyright © 1992 by the American Society for Gastrointestinal Endoscopy
Endoscopic resection of large sessile colorectal polyps R. Matthew Walsh, MD Frederick W. Ackroyd, MD Paul C. Shellito, MD Boston, Massachusetts
Colonoscopic removal of large, sessile polyps is difficult, but can be successfully carried out by experienced endoscopists. "Piecemeal" resection with an electrocautery snare was performed at our institution in 108 patients with 132 such lesions. The mean size of the unresected polyps was 3.0 cm. Complications occurred in 3.0% of polypectomies (3.8% of patients), with bleeding necessitating transfusion in 2.3% of polypectomies (2.8% of patients), and microperforation (probable) in the remainder. No patient required emergency surgery due to a complication. In 65 patients (60%), colonoscopic resection and follow-up alone was carried out. Of these, adenomas recurred/persisted in 28%, most of which were successfully re-resected. Nearly half of all recurrent polyps occurred after at least one negative intervening examination. Carcinoma later appeared in 17% of the recurrences despite apparent initial complete resection of a previously benign polyp. Cure was ultimately achieved in 88% of endoscopically managed patients. Surgical resection was required in 27% of patients, mostly following the initial polypectomy when invasive carcinoma was found in the specimen. No residual tumor was later found in 41 % of the colon specimens from these patients. Ninetyone percent of cancers were favorable stage, whether discovered early or late. Follow-up colonoscopy was achieved in 77% of patients over an average of 3.7 years. Metachronous polyps were excised in 52 patients (63%) and metachronous carcinoma was diagnosed in 3 patients (3.6%). An aggressive regimen of surveillance colonoscopy is warranted in these patients to detect and manage local recurrences and to remove subsequent adenomas. Endoscopic resection of large sessile adenomas can be safe and effective. (Gastrointest Endosc
1992;38:303-309)
All colon polyps should be removed whenever feasible, preferably through a colonoscope. Most polyps are adenomas, which may contain or transform to malignancy/ so diligent detection and extirpation is prudent. Because adenoma size correlates with the likelihood of cancer, large lesions in particular should be removed. Large sessile polyps can be technically the most difficult and perhaps dangerous to endoscopically resect, but open surgical removal is an unattractive alternative, especially in frail patients. A retrospective, ll-year review of all "piecemeal" snare reReceived August 19, 1991. For revision October 7, 1991. Accepted December 16, 1991. From the Surgical Services, Massachusetts General Hospital and the Department of Surgery, Harvard Medical School, Boston, Massachusetts. Reprint requests: Paul C. Shellito, MD, Massachusetts General Hospital, Ambulatory Care Center, #336, 15 Parkman Street, Boston, Massachusetts 02114.
VOLUME 38, NO.3, 1992
sections of sessile colorectal polyps performed in the Surgical Endoscopy Unit at the Massachusetts General Hospital was undertaken to assess the success and complication rates of endoscopic removal. MATERIALS AND METHODS
The records of all patients who underwent colonoscopic piecemeal resection of sessile colorectal polyps between January 1980 and December 1990 were reviewed. Patients were included in the study group if piecemeal resection was explicitly noted in the endoscopy report (i.e., multiple cuts with the snare cautery). Piecemeal resection was required because a polyp was large (usually >2.0 em in diameter), or occasionally because of a relatively inaccessible location. Patients were excluded if the lesion was not considered to be completely resectable in either one or multiple colonoscopy sessions, if the specimens taken were only snare biopsies, or if the neoplasm was firm, ulcerated, or otherwise 303
frankly malignant. 2 Thus, the lesions in this study were almost always large on initial inspection, but were thought to be endoscopically resectable and most likely benign. To minimize the degree of variability in size estimations and operative technique, all of the resections in this study were performed by either one of two senior, experienced endoscopists (S. E. H.* or P. C. S.). One hundred eight patients were identified. During the same time interval the combined experience of the two surgeons included 3276 colonoscopies, in which 1467 patients had a total of 3589 polyps excised. All procedures were performed initially on an outpatient basis. Colon preparation was usually achieved with 4 liters of oral polyethylene glycol electrolyte lavage solution or, occasionally, laxatives and enemas. Intravenous antibiotics were administered pre-operatively for endocarditis prophylaxis when valvular heart disease was present, or when there were implanted prosthetic devices. Intravenous fluid was given during the procedure as well as sedation with diazepam and meperidine. Patients were monitored with periodic automatic blood pressure determinations, electrocardiography, and pulse oximetry. Occasional post-operative admission for observation was at the discretion of the surgeon and was influenced by the polyp size, technical difficulties with the resection, and associated medical conditions. A variety of colonoscopic equipment was used during the course of the study. Initially the ACMI 'F-9A was used, followed by the Welch Allyn Video colonoscope 8451, and Olympus 1TL, 10L, and most recently VIOL. Piecemeal resections were performed using a Microvasive (Milford, Mass.) polypectomy snare (catalogue no. 6095; 240-cm length, standard loop size, and hex-shaped). Electrocautery was used after appropriate patient grounding with either the Valley-Lab SSEZ unit or Neomed (Birthcher Co., EI Monte, Calif.) 3000A. In some cases bleeding was produced which was controlled by irrigation with 60 ml of 1:20,000 epinephrine solution, allowing precise cauterization of bleeding points with the slightly opened snare. RESULTS
A total of 132 endoscopic piecemeal resections were performed on 108 patients, representing 3.7% of all polypectomies and 3.3% of all colonoscopies by two surgeons during the same time interval. Ages ranged from 43 to 88 years, with a mean age of 69 years. Eighteen percent were over 80 years of age. Many patients were considered to be a poor risk for laparotomy and colon resection, prompting an aggressive colonoscopic approach. There were 62 (57%) men and 46 (43%) women. The most common indication for colonoscopy was to evaluate rectal bleeding in 30 patients (28%). Many of these patients had first undergone a barium enema for bleeding which demonstrated the polyp. Fifteen patients (14%) had undergone a barium enema for various reasons which revealed a filling defect. Other indications for colonoscopy included routine follow-up after surgical resection of a colon carcinoma in 17 patients (16%), history of previous endoscopic polypectomy in 20 (19%), oc-
* Stephen E. Hedberg died in October 1984. 304
cult gastrointestinal blood loss in 14 (13%), and discovery of a rectosigmoid tumor on routine digital examination or sigmoidoscopy in 5 (5%) (Table 1). Surprisingly, 28 patients (26%) had undergone a previous colonoscopy before the extensive sessile polyp was later found. The average time between these examinations was 2.5 years, with a range of 6 months to 5 years. The location of the polyp undergoing piecemeal resection is summarized in Table 2. The assigned segment was estimated by the endoscopist during the procedure. There were 116 lesions, 16 of which underwent piecemeal resection twice. Twenty lesions (17%) were found in the cecum and the same number in the ascending colon, including the hepatic flexure. Fifteen lesions (13%) were excised from the transverse colon, 6 (5 %) from the descending colon including the splenic flexure, 30 (26%) from the sigmoid, and 25 (22%) from the rectum. Collectively, right-sided lesions represented 34% and rectosigmoid lesions 48%. Multiple piecemeal resections, either of the same polyp or of multiple polyps at various sites, were carried out in 21 patients (19%). Twelve percent were known to have an incomplete excision at the completion of the initial procedure. A total of 265 synchronous polyps were found in 75 patients (69%). The number of coincidental polyps per patient ranged from 1 to 20 and averaged 3.5. There were no synchronous carcinomas. The maximum diameter of the polyp was estimated before resection and ranged from 1.0 to 8.0 cm with a mean of 3.0 cm. Eight patients had lesions that encompassed at least one third of the colon circumference and were judged to be greater than 5 cm in diameter. The size of the polyps is summarized in Table 3. Table 1. Indications for initial colonoscopy Indication Rectal bleeding Previous polypectomy Previous colectomy for carcinoma Lesion on barium enema Occult gastrointestinal bleeding Routine physical examination Other Total
N
%
30 21 17 15 14 6 5
28 19 16 14 13 5 5
108
100
Table 2. Distribution of piecemeal resections Colon segment
N
%
Cecum Ascending colon Transverse colon Descending colon Sigmoid colon Rectum
20 20 15 6 30 25
17 17 13 5 26 22
116
100
Total
GASTROINTESTINAL ENDOSCOPY
Almost all of the polyps requiring piecemeal resection were large (at least 2.0 em in diameter). Tubulovillous adenoma was the most common histologic type and comprised 33 (28%) ofthe specimens. This was closely followed by tubular adenoma in 26 specimens (22%) and villous adenoma in 19 specimens (16%). Unsuspected invasive carcinoma, defined as penetration of the muscularis mucosa by malignant cells,2 was found in 18 samples (16%). Least frequent were hyperplastic polyps in nine specimens (8%), carcinoma in situ in eight (7%) (malignant cells not penetrating the muscularis mucosa), and histologic information was not available for three specimens (3%) (Table 4). There was no mortality or frank perforation. The
early complications after piecemeal resection were bleeding and possible microperforation or transmural burn (Table 5). Two patients were admitted because of a concern about perforation, one for 24 hours and the other for 7 days. The latter patient developed fever, and right lower quadrant pain and tenderness following endoscopic resection of a 3-cm tubular adenoma of the ascending colon. No pneumoperitoneum developed, and the patient recovered uneventfully with intravenous antibiotics and bowel rest. This may have been a transmural burn or small sealed perforation. Notable initial bleeding occurred in 10 resections (7.6% of polypectomies, 9.3% of patients). Seven of these episodes were limited to hemorrhage during endoscopy only, which ceased spontaneously with the help of epinephrine solution irrigation. None of these patients required transfusion. Three patients (2.3% of polypectomies, 2.8% of patients) had persistent marked bleeding requiring hospitalization and transfusion. The first of these patients was chronically anticoagulated for a heart valve prosthesis and underwent resection of an adenoma of the transverse colon which was more than 5 em in diameter and covered one third of the bowel circumference. She required 7 units of blood and was admitted for 13 days. Another patient was receiving long-term prednisone when he underwent resection of a 2-cm carcinoma of the sigmoid. He was transfused 2 units and hospitalized for 3 days. Last, a patient was given 2 units and admitted for 9 days after resection of a 3-cm adenoma of the cecum. The average polyp size in those who sustained either an immediate or delayed hemorrhage was 3 em. No patient required emergency celiotomy. This was a retrospective review, and there were no formal initial selection criteria for surgical or endoscopic resection. Nevertheless, the general intent was to perform an endoscopic resection whenever complete colonoscopic removal looked attainable and when the lesion appeared likely to be benign. At colonoscopy,
Table 3. Polyp size Diameter (cm)
N
%
15 48
36
1.0-1.9 2.0-2.9 3.0-3.9 4.0-4.9 >5.0
33
Total
132
11.5 25 11.5
15 21
16 100
Table 4. Initial polyp pathology Histology
N
%
Tubulovillous adenoma Tubular adenoma Villous adenoma Carcinoma Hyperplastic polyp Carcinoma in situ Not available
33 26
22
Total
28
18
16 16
9 8 3
8 7 3
116
100
19
Table 5. Polypectomy complications Bleeding Patient
Hospitalized
1
8 9 10
No No No No No No 24 hr 13 days 3 days 9 days
1
7 days
2
3 4 5 6
7
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Units transfused
Polyp diameter (cm)
o
5
o o
o o
o o 7
2 2
4
2 2 >5 3 2.5 >5 2 3
Polyp location
Polyp pathology
Transverse Sigmoid Sigmoid Sigmoid Sigmoid Transverse Ascending Transverse Sigmoid Cecum
Villous adenoma Carcinoma Tubulovillous adenoma Tubulovillous adenoma Villous adenoma Villous adenoma Tubulovillous adenoma Tubulovillous adenoma Carcinoma Tubulovillous adenoma
Possible microperforation or transmural burn 0 3 Ascending
Tubular adenoma
305
all patients underwent aggressive snare excision of the polyp to the extent that was deemed possible, along with the removal of all synchronous lesions. Continued colonoscopic management was preferred, especially in patients of poor surgical risk. Surgery was chosen when the adenoma could not be eradicated endoscopically (initially or later), whenever invasive carcinoma was discovered, or occasionally because of patient preference. The actual management of these patients following the initial attempt at endoscopic resection is summarized in Table 6. Twenty-two patients (20%) received no further colonoscopy or surgery because of very poor medical condition, death from other causes, or, most often, non-compliance with the physician's recommendations. Sixty-five patients (60%) underwent primary colonoscopic management and surveillance. In this endoscopically managed group, all received at least 1, and a maximum of 10, follow-up colonoscopy, with a mean of 4 endoscopies per patient. The average interval between procedures was 1.25 years. The length of total colonoscopic follow-up ranged from 3 months to 10 years, with an average of 2.8 years. One hundred ninety-five metachronous polyps were subsequently removed in 46 of 65 patients (71 %), with a range of 1 to 17 and a mean of 4.2 polyps per patient. Locally recurrent/persistent neoplasia was discovered in 18 of 65 patients (28%). In eight of these patients with recurrent polyps (44%), at least one negative examination was documented prior to the recurrence and the average time interval between a negative examination and a recurrent lesion was 2.2 years. When complete excision of the recurrence was possible, it required an average of three colonoscopies (range, 2 to 6) over an average time period of 12 months (range Table 6. Patient management following initial polypectomy Management strategy
N
%
Colonoscopy Recurrent adenomas Endoscopic failures Surgical resection No further therapy
65 18
60
8 22
12 20 20
108
100
Total
21
28
of 3 to 24 months). Endoscopic management ultimately failed in 8 of 65 patients (12%). These people subsequently underwent surgical resection either because of an inability to adequately endoscopically resect a recurrent or persistent polyp, or the development of carcinoma in a recurrence of a previously benign polyp. The latter event occurred in three patients, representing 5% of the endoscopically managed group and 17% of all recurrent lesions. A total of 29 of '108 patients (27%) underwent surgical resection. Twenty-one patients (19%) underwent surgery soon after endoscopic resection of the initial neoplasm. Table 7 summarizes the data for all patients who underwent surgical resection. One patient underwent transanal excision of a recurrent rectal villous adenoma, but in the remainder either segmental colectomy (26) or total abdominal colectomy (2) was done. One patient required two surgical resections, a subtotal colectomy for a locally recurrent tubulovillous adenoma with a focus of invasive carcinoma and subsequently an abdominoperineal resection for a rectal carcinoma found on follow-up endoscopy. The pre-operative pathologic diagnosis was invasive carcinoma in 20 of 29 patients (69%), villous adenoma in 5 patients (17%), and tubular adenoma and tubulovillous adenoma in 2 patients (7%) each. The pathology report for the surgical specimens differed from the pre-operative endoscopic diagnosis in two cases (7%). In both, invasive carcinoma was discovered in a previously diagnosed tubulovillous adenoma. Thus, actually 22 (76%) of these patients harbored cancer. Histologic evaluation of the colon specimens revealed unsuspected residual adenoma or carcinoma tissue in three cases (10%), and each of these cases contained invasive carcinoma in the original polypectomy specimens. Tumor classification by Astler-Coller modified Dukes staging3 revealed that 2 ofthe 22 specimens (9%) were stage A, 9 (41%) B-1, 1 (4.5%) B-2, and 1 (4.5%) stage C. Surprisingly, nine cases (41%) with a pre-operative finding of invasive carcinoma had no residual tumor. Overall, 20 specimens (91 %) had a favorable surgical stage. In the three patients who developed carcinoma at the site of a previously endoscopically resected benign lesion, staging after resection was no malignancy in one and
Table 7. Surgery following colonoscopic resection Resection performed
No. of procedures
Transanal excision Segmental colectomy Total abdominal colectomy
26
Abdominoperineal resection Total
306
1
:] 30
No. of patients
1 26
Preoperative pathology
N
%
Carcinoma Villous adenoma Tubulovillous adenoma Tubular adenoma
20 5 2 2
69
29
100
17 7 7
2
GASTROINTESTINAL ENDOSCOPY
B-1 tumors in two. The stage of the two carcinomas, which were serendipitously discovered in the surgical specimens initially thought to harbor only a benign polyp, was B-1 in both. Twenty-two of the 29 patients (76%) underwent continued endoscopic surveillance after surgical resection and 6 patients (27%) developed metachronous polyps. A total of 15 metachronous polyps were colonoscopically removed after surgery, averaging 2.5 polyps per patient, with a range of 1 to 16. The mean duration of colonoscopic follow-up for this group was 4.5 years. When the entire study population is considered, 83 patients (77%) had ongoing surveillance colonoscopy performed either as primary treatment following initial polypectomy or following surgical resection. A total of 298 procedures were performed, averaging 3.6 endoscopies per patient (range, 1 to 10) during a mean follow-up of 3.7 years. Two hundred ten metachronous polyps were excised in 52 patients (63%), with a mean of 4.0 polyps per patient (range, 1 to 29). Metachronous carcinoma was found in three patients (3.6%). These data, as well as statistics for synchronous lesions, are summarized in Table 8. TECHNIQUE
Proper technique is essential when performing polypectomy (Figs. 1 to 6).10 Every effort should be made to keep the instrument shaft straight during insertion, in order to preserve maneuverability of the endoscope tip. Repeated clockwise rotation and withdrawal motions aid in reducing the sigmoid loop. Residual fluid in the colon should be completely suctioned out during insertion so that all of the specimens may be easily retrieved later. The colon should not be overinflated, since that will thin the bowel wall and increase the risk of perforation. It is important to obtain a clear and complete view of a polyp before starting the endoscopic resection. Sometimes changing a patient's position facilitates access to a difficult polyp. The endoscope should be rotated so that the polyp is viewed at the six o'clock position which corresponds to the location of the operating channel. Endoscopic resection should probably not be attempted if a good colonoscopic position cannot be attained, or if for any Table 8. Incidence of coincidental polyps and carcinomas
N~. of % patIents Synchronous polyps Metachronous polyps Primary colonoscopic management Following surgical resection Total Metachronous carcinoma
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Mean no. of polyps! patient
75
69
3.5
46 6
71 27
4.2 2.5
52
63
4.0
3
3.6
Figure 1. A large sessile adenoma in the rectosigmoid. Figures 2. to 4. Segments· of adenoma are sequentially removed with cautery snare. Figure 5. Completed piecemeal resection. Figure 6. A smooth scar visible at follow-up colonoscopy.
other reason the polyp is not satisfactorily visible and accessible. Also, endoscopic removal is unwise if the lesion is ulcerated or quite indurated, since malignancy is likely in that case. The snare should initially be placed around a portion of the lesion that is most accessible, and no more than a 1.0- to 1.5-cm portion should be removed at a time. In the difficult circumstance of a polyp situated just above a fold or flexure, the snare may be opened proximal to the lesion and the colonoscope withdrawn until the polyp comes into view. Some adjusting of the opened snare may be required to position it properly at the base of the lesion before tightening. The adenoma should be kept under direct view as the snare is closed, until resistance is felt. Care must be taken that normal mucosa proximal to the polyp is not gathered up with the adenoma. Pulling the trapped polyp toward the center of the lumen during transection creates a "pseudopedicle" and spares the deeper bowel wall from electrocoagulation. Short bursts of coagulating current are given while slowly tightening the snare until it cuts through. In general, it is best to remove the entire 307
polyp during the initial attempt (which is usually possible), but overaggressive resection can be dangerous. Electrocautery can induce mucosal edema around the excision site that may acutely resemble residual polyp tissue. Cauterization also produces necrosis that reaches deeper than the immediately visible tissue damage. If there is doubt, it is better to stop the procedure and re-evaluate the area at a subsequent colonoscopy. It is wise to attempt removal of all of the major specimen fragments even if multiple endoscopic insertions are required. Afterward, the polypectomy site should be rechecked for bleeding and completeness of excision. Oozing may be stanched by careful recauterization. When alarming bleeding appears, irrigation with epinephrine solution may stop it or at least retard the hemorrhage so that discrete bleeding points can be identified. In those cases in which a perforation is suspected, hospitalization for bowel rest, intravenous antibiotics, and observation to exclude worsening peritonitis is appropriate. If a microperforation has occurred, most patients will recover without surgery. Nevertheless, if laparotomy is required, a watersoluble contrast enema x-ray may be an invaluable guide for the surgical resection, especially If multiple polypectomies were done, or if there is doubt about the exact location of a polyp within the colon. For any polyp, a careful judgment should be made about where it was located within the colon. Thus, if a polyp is later found to contain invasive cancer, the appropriate bowel resection can be performed. When firm or particularly large lesions are resected, it is wise to obtain a frozen section pathologic diagnosis. Invasive cancer found in combination with appreciable bleeding or suspected microperforation warrants an immediate colectomy. This approach will eliminate wasting time with observation and conservative treatments. DISCUSSION
Colonoscopic electrocautery snare excision of large or difficultly situated sessile polyps can be performed safely and effectively. This report evaluates a large number of procedures with minimal variation in management approach and technique. Complication rates were quite acceptable. There was major morbidity in 3.0% of our procedures, three bleeds requiring hospitalization and transfusion, and one possible microperforation. Previous studies have found a similar incidence of serious bleeding after endoscopic piecemeal resection of large sessile polyps. In other study populations of 22 and 42 patients with large polyps, appreciable bleeding occurred in 4.5%4 and 4.7%.5 In reports of complications after polypectomy for all polyp types, frank perforation has occurred in 0.3 to 0.5% and bleeding in 1 to 2%.6-8 The risk of bleeding after endoscopic polypectomy is 10 to 20 times that of diagnostic colonoscopy,6 and the potential for bleeding from extensive snare resections 308
of this type can be assumed to be higher still. Fortunately, post-polypectomy hemorrhage can usually be managed medically. Transmural colonic burn or microperforation occurs less frequently after polypectomy than does bleeding. 9 Typically, early localized abdominal pain and peritoneal irritation herald this complication. When a patient develops these signs and symptoms, it may be impossible to differentiate clinically between a small transmural burn and a microperforation. The treatment of both lesions is the same: namely, nothing by mouth and intravenous antibiotics. This approach is usually successful. Obvious perforation may be evident by free intraperitoneal air seen on plain abdominal x-ray, endoscopic observation of intra-abdominal viscera, or extravasation noted on water-soluble contrast enema. Treatment in this circumstance should be individualized. If the endoscopist believes that the iatrogenic hole in the colon is tiny, medical treatment may be attempted, even in the presence of pneumoperitoneum. Nevertheless, the patient should be examined frequently, with plans to proceed to laparotomy if the abdominal tenderness worsens. For larger perforations, such as when the whole shaft of the endoscope pierces the bowel wall or when an anti-mesenteric longitudinal tear results from too much pressure on an enlarging bow of the colonoscope within a colon loop, urgent laparotomy is best. An important consideration in the safe performance of endoscopic resections is an accurate assessment of polyp size and position. Proper evaluation of a lesion is facilitated both by correct colonoscopic technique and the experience of the endoscopist. An exact determination of polyp size is difficult, especially when a lesion is extracted in fragments, but the estimate of an accomplished colonoscopist is probably quite accurate. Location within the colon can also be a difficult endoscopic judgment. For a given length of inserted colonoscope, the location of the tip can vary widely. The best approximation of polyp location is made when the colonoscope shaft is straight; then the splenic flexure lies at 40 to 50 cm, the hepatic flexure at 60 to 70 cm, and the cecum at 80 to 100 em from the anal verge. Colonoscopic landmarks also aid navigation, such as the ileo-cecal valve in the right colon, a triangular lumen in the transverse colon (sometimes), and the spleen seen through the bowel wall at the splenic flexure. Definitive colonoscopic management of these patients is appropriate and efficacious. Sixty percent of our patients with large sessile adenomas were managed with an aggressive endoscopic approach and, of these, the neoplasm was cured in 88%. Failure resulted when a recurrent adenoma technically could not be resected endoscopically, or when cancer later appeared in a recurrent lesion. The documentation and treatment of a locally recurrent adenoma is the crux of GASTROINTESTINAL ENDOSCOPY
successful endoscopic management. Local recurrence was found in 28% despite the fact that an aggressive removal was carried out during the initial colonoscopic piecemeal resection. In those patients with recurrent adenomas, 44% had at least one negative interval colonoscopy and over half of these patients were ultimately cured by further colonoscopic resection. Interestingly, in 17% of the local recurrences, malignant degeneration of a previously benign polyp occurred, emphasizing the need for complete retrieval and histologic examination of all endoscopically resected tissue, as well as follow-up surveillance. The importance of proper tissue orientation and ink marking of margins during histologic evaluation has been made by others. 4 Recurrence rates of 11 to 25% following resection of sessile polyps have been reported previously.4, 5, 9 Our local recurrence rate was a bit higher, perhaps because of less complete initial removal (although there is no reason to believe that others would be more endoscopically aggressive than we were), but more likely as a consequence of our comparatively long follow-up. It is possible that some of our recurrences were due to macroscopically incomplete initial polypectomies rather than recurrent neoplasm after an apparently complete initial endoscopic resection. This was probably a small contribution, since our policy was always to persist in performing as thorough an initial polypectomy as possible. Indeed, only 12% of our patients were felt to have macroscopically residual tissue at the completion of the initial procedure. Also, nearly half the patients with recurrences had at least one negative endoscopy before the recurrence appeared. Nevertheless, if the interval for follow-up endoscopy had been shorter, persistent adenoma might have been discovered and eradicated earlier, possibly even preventing some of the three later cancers. This was a retrospective study and as such there was no specific follow-up plan. The optimum surveillance regimen is unknown, but analysis of our results now would suggest that for endoscopic treatment of large sessile neoplasms, colonoscopy should be done more frequently than every 1.25 years, at least initially. Repeat colonoscopy should initially be performed every 1 to 3 months until all recurrent or persistent neoplasm is removed, which in our experience required an average of 12 months. The fact that nearly half of the patients with recurrences had a negative repeat endoscopy before the recurrence appeared aptly illustrates that continued follow-up after polyp eradication is essential. Celiotomy with segmental colectomy is occasionally required to definitively manage large sessile lesions, and was ultimately required in nearly a third of our patients. A lesion harboring invasive carcinoma was the most common indication for colectomy (69%). The rather high incidence of carcinoma in large sessile adenomas is well known. 5 In 7% of the colectomy VOLUME 38, NO.3, 1992
specimens, the diagnosis of invasive cancer was missed on the endoscopic biopsies. Thus, it is always important to excise a lesion completely, either endoscopically or surgically. There was a high incidence (76%) of invasive carcinoma among patients who subsequently underwent colectomy in our study. This is consistent with the aggressive approach taken for endoscopic resection in these sometimes poor risk patients. It might also indicate an excessively liberal selection process, but if so, little was lost since the complication rate was low. Also, most of the cancers were diagnosed pre-operatively, were surgically resected soon after the initial endoscopy, and were not advanced. Early stage tumors were found in 91 % of the patients who underwent surgery, including those in whom later malignant degeneration of a polyp had occurred. Thus, even "failed" patients have an excellent chance for cure. Careful surveillance for local recurrences can potentially aid in the detection of early cancers even if they should arise at the site of a previous excision. These patients demonstrated a high predilection for the development of synchronous and metachronous polyps. Sixty-nine percent of the patients in this study had synchronous polyps removed as a component of the initial examination. Over the course of a mean follow-up of 3.7 years, 63% developed metachronous polyps which were excised. Metachronous cancers were discovered in 3.6%. These data lend additional support for an aggressive surveillance regimen. For large sessile polyps, follow-up colonoscopy every 1 to 3 months is recommended until all recurrent or persistent neoplasm is removed. Colonoscopy a year later is reasonable once a negative examination is documented. Repeated endoscopy should be continued at successively longer intervals to diagnose and manage metachronous adenomas or carcinomas.
REFERENCES 1. Tierney RP, Ballantyne GR, Modlin 1M. The adenoma to carcinoma sequence. Surg Gynecol Obstet 1990;171:81-94. 2. Christie JP. Polypectomy or colectomy? Management of 106 consecutively encountered colorectal polyps. Am Surgeon 1988;54:93-9. 3. Spratt JS. Neoplasms of the colon, rectum and anus. Philadelphia: WB Saunders, 1984:207. 4. Nivatvongs S, Snover DC, Fang DT. Piecemeal snare excision oflarge sessile colon and rectal polyps: is it adequate? Gastrointest Endosc 1984;30:18-20. 5. Christie JP. Colonoscopic excision of large sessile polyps. Am J GastroenteroI1977;67:430-8. 6. Johnson SM. Colonoscopy and polypectomy. Am J Surg 1978;136:313-6. 7. Webb WA, McDaniel L, Jones L. Experience with 1000 colonoscopic polypectomies. Ann Surg 1985;5:626-32. 8. Nivatvongs S. Complications in colonoscopic polypectomy: lessons to learn from an experience with 1576 polyps. Am Surg 1988;54:61-3. 9. Bedogni G, et al. Colonoscopic excision of large and giant colorectal polyps. Dis Colon Rectum 1986;29:831-5. 10. Waye JD. Techniques of polypectomy: hot biopsy forceps and snare polypectomy. Am J Gastroenterol 1987;82:615-8.
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Endoscopic resection of large sessile colorectal polyps R. Matthew Walsh, MD Frederick W. Ackroyd, MD Paul C. Shellito, MD Boston, Massachusetts
Colonoscopic removal of large, sessile polyps is difficult, but can be successfully carried out by experienced endoscopists. "Piecemeal" resection with an electrocautery snare was performed at our institution in 108 patients with 132 such lesions. The mean size of the unresected polyps was 3.0 cm. Complications occurred in 3.0% of polypectomies (3.8% of patients), with bleeding necessitating transfusion in 2.3% of polypectomies (2.8% of patients), and microperforation (probable) in the remainder. No patient required emergency surgery due to a complication. In 65 patients (60%), colonoscopic resection and follow-up alone was carried out. Of these, adenomas recurred/persisted in 28%, most of which were successfully re-resected. Nearly half of all recurrent polyps occurred after at least one negative intervening examination. Carcinoma later appeared in 17% of the recurrences despite apparent initial complete resection of a previously benign polyp. Cure was ultimately achieved in 88% of endoscopically managed patients. Surgical resection was required in 27% of patients, mostly following the initial polypectomy when invasive carcinoma was found in the specimen. No residual tumor was later found in 41 % of the colon specimens from these patients. Ninetyone percent of cancers were favorable stage, whether discovered early or late. Follow-up colonoscopy was achieved in 77% of patients over an average of 3.7 years. Metachronous polyps were excised in 52 patients (63%) and metachronous carcinoma was diagnosed in 3 patients (3.6%). An aggressive regimen of surveillance colonoscopy is warranted in these patients to detect and manage local recurrences and to remove subsequent adenomas. Endoscopic resection of large sessile adenomas can be safe and effective. (Gastrointest Endosc
1992;38:303-309)
All colon polyps should be removed whenever feasible, preferably through a colonoscope. Most polyps are adenomas, which may contain or transform to malignancy/ so diligent detection and extirpation is prudent. Because adenoma size correlates with the likelihood of cancer, large lesions in particular should be removed. Large sessile polyps can be technically the most difficult and perhaps dangerous to endoscopically resect, but open surgical removal is an unattractive alternative, especially in frail patients. A retrospective, ll-year review of all "piecemeal" snare reReceived August 19, 1991. For revision October 7, 1991. Accepted December 16, 1991. From the Surgical Services, Massachusetts General Hospital and the Department of Surgery, Harvard Medical School, Boston, Massachusetts. Reprint requests: Paul C. Shellito, MD, Massachusetts General Hospital, Ambulatory Care Center, #336, 15 Parkman Street, Boston, Massachusetts 02114.
VOLUME 38, NO.3, 1992
sections of sessile colorectal polyps performed in the Surgical Endoscopy Unit at the Massachusetts General Hospital was undertaken to assess the success and complication rates of endoscopic removal. MATERIALS AND METHODS
The records of all patients who underwent colonoscopic piecemeal resection of sessile colorectal polyps between January 1980 and December 1990 were reviewed. Patients were included in the study group if piecemeal resection was explicitly noted in the endoscopy report (i.e., multiple cuts with the snare cautery). Piecemeal resection was required because a polyp was large (usually >2.0 em in diameter), or occasionally because of a relatively inaccessible location. Patients were excluded if the lesion was not considered to be completely resectable in either one or multiple colonoscopy sessions, if the specimens taken were only snare biopsies, or if the neoplasm was firm, ulcerated, or otherwise 303
frankly malignant. 2 Thus, the lesions in this study were almost always large on initial inspection, but were thought to be endoscopically resectable and most likely benign. To minimize the degree of variability in size estimations and operative technique, all of the resections in this study were performed by either one of two senior, experienced endoscopists (S. E. H.* or P. C. S.). One hundred eight patients were identified. During the same time interval the combined experience of the two surgeons included 3276 colonoscopies, in which 1467 patients had a total of 3589 polyps excised. All procedures were performed initially on an outpatient basis. Colon preparation was usually achieved with 4 liters of oral polyethylene glycol electrolyte lavage solution or, occasionally, laxatives and enemas. Intravenous antibiotics were administered pre-operatively for endocarditis prophylaxis when valvular heart disease was present, or when there were implanted prosthetic devices. Intravenous fluid was given during the procedure as well as sedation with diazepam and meperidine. Patients were monitored with periodic automatic blood pressure determinations, electrocardiography, and pulse oximetry. Occasional post-operative admission for observation was at the discretion of the surgeon and was influenced by the polyp size, technical difficulties with the resection, and associated medical conditions. A variety of colonoscopic equipment was used during the course of the study. Initially the ACMI 'F-9A was used, followed by the Welch Allyn Video colonoscope 8451, and Olympus 1TL, 10L, and most recently VIOL. Piecemeal resections were performed using a Microvasive (Milford, Mass.) polypectomy snare (catalogue no. 6095; 240-cm length, standard loop size, and hex-shaped). Electrocautery was used after appropriate patient grounding with either the Valley-Lab SSEZ unit or Neomed (Birthcher Co., EI Monte, Calif.) 3000A. In some cases bleeding was produced which was controlled by irrigation with 60 ml of 1:20,000 epinephrine solution, allowing precise cauterization of bleeding points with the slightly opened snare. RESULTS
A total of 132 endoscopic piecemeal resections were performed on 108 patients, representing 3.7% of all polypectomies and 3.3% of all colonoscopies by two surgeons during the same time interval. Ages ranged from 43 to 88 years, with a mean age of 69 years. Eighteen percent were over 80 years of age. Many patients were considered to be a poor risk for laparotomy and colon resection, prompting an aggressive colonoscopic approach. There were 62 (57%) men and 46 (43%) women. The most common indication for colonoscopy was to evaluate rectal bleeding in 30 patients (28%). Many of these patients had first undergone a barium enema for bleeding which demonstrated the polyp. Fifteen patients (14%) had undergone a barium enema for various reasons which revealed a filling defect. Other indications for colonoscopy included routine follow-up after surgical resection of a colon carcinoma in 17 patients (16%), history of previous endoscopic polypectomy in 20 (19%), oc-
* Stephen E. Hedberg died in October 1984. 304
cult gastrointestinal blood loss in 14 (13%), and discovery of a rectosigmoid tumor on routine digital examination or sigmoidoscopy in 5 (5%) (Table 1). Surprisingly, 28 patients (26%) had undergone a previous colonoscopy before the extensive sessile polyp was later found. The average time between these examinations was 2.5 years, with a range of 6 months to 5 years. The location of the polyp undergoing piecemeal resection is summarized in Table 2. The assigned segment was estimated by the endoscopist during the procedure. There were 116 lesions, 16 of which underwent piecemeal resection twice. Twenty lesions (17%) were found in the cecum and the same number in the ascending colon, including the hepatic flexure. Fifteen lesions (13%) were excised from the transverse colon, 6 (5 %) from the descending colon including the splenic flexure, 30 (26%) from the sigmoid, and 25 (22%) from the rectum. Collectively, right-sided lesions represented 34% and rectosigmoid lesions 48%. Multiple piecemeal resections, either of the same polyp or of multiple polyps at various sites, were carried out in 21 patients (19%). Twelve percent were known to have an incomplete excision at the completion of the initial procedure. A total of 265 synchronous polyps were found in 75 patients (69%). The number of coincidental polyps per patient ranged from 1 to 20 and averaged 3.5. There were no synchronous carcinomas. The maximum diameter of the polyp was estimated before resection and ranged from 1.0 to 8.0 cm with a mean of 3.0 cm. Eight patients had lesions that encompassed at least one third of the colon circumference and were judged to be greater than 5 cm in diameter. The size of the polyps is summarized in Table 3. Table 1. Indications for initial colonoscopy Indication Rectal bleeding Previous polypectomy Previous colectomy for carcinoma Lesion on barium enema Occult gastrointestinal bleeding Routine physical examination Other Total
N
%
30 21 17 15 14 6 5
28 19 16 14 13 5 5
108
100
Table 2. Distribution of piecemeal resections Colon segment
N
%
Cecum Ascending colon Transverse colon Descending colon Sigmoid colon Rectum
20 20 15 6 30 25
17 17 13 5 26 22
116
100
Total
GASTROINTESTINAL ENDOSCOPY
Almost all of the polyps requiring piecemeal resection were large (at least 2.0 em in diameter). Tubulovillous adenoma was the most common histologic type and comprised 33 (28%) ofthe specimens. This was closely followed by tubular adenoma in 26 specimens (22%) and villous adenoma in 19 specimens (16%). Unsuspected invasive carcinoma, defined as penetration of the muscularis mucosa by malignant cells,2 was found in 18 samples (16%). Least frequent were hyperplastic polyps in nine specimens (8%), carcinoma in situ in eight (7%) (malignant cells not penetrating the muscularis mucosa), and histologic information was not available for three specimens (3%) (Table 4). There was no mortality or frank perforation. The
early complications after piecemeal resection were bleeding and possible microperforation or transmural burn (Table 5). Two patients were admitted because of a concern about perforation, one for 24 hours and the other for 7 days. The latter patient developed fever, and right lower quadrant pain and tenderness following endoscopic resection of a 3-cm tubular adenoma of the ascending colon. No pneumoperitoneum developed, and the patient recovered uneventfully with intravenous antibiotics and bowel rest. This may have been a transmural burn or small sealed perforation. Notable initial bleeding occurred in 10 resections (7.6% of polypectomies, 9.3% of patients). Seven of these episodes were limited to hemorrhage during endoscopy only, which ceased spontaneously with the help of epinephrine solution irrigation. None of these patients required transfusion. Three patients (2.3% of polypectomies, 2.8% of patients) had persistent marked bleeding requiring hospitalization and transfusion. The first of these patients was chronically anticoagulated for a heart valve prosthesis and underwent resection of an adenoma of the transverse colon which was more than 5 em in diameter and covered one third of the bowel circumference. She required 7 units of blood and was admitted for 13 days. Another patient was receiving long-term prednisone when he underwent resection of a 2-cm carcinoma of the sigmoid. He was transfused 2 units and hospitalized for 3 days. Last, a patient was given 2 units and admitted for 9 days after resection of a 3-cm adenoma of the cecum. The average polyp size in those who sustained either an immediate or delayed hemorrhage was 3 em. No patient required emergency celiotomy. This was a retrospective review, and there were no formal initial selection criteria for surgical or endoscopic resection. Nevertheless, the general intent was to perform an endoscopic resection whenever complete colonoscopic removal looked attainable and when the lesion appeared likely to be benign. At colonoscopy,
Table 3. Polyp size Diameter (cm)
N
%
15 48
36
1.0-1.9 2.0-2.9 3.0-3.9 4.0-4.9 >5.0
33
Total
132
11.5 25 11.5
15 21
16 100
Table 4. Initial polyp pathology Histology
N
%
Tubulovillous adenoma Tubular adenoma Villous adenoma Carcinoma Hyperplastic polyp Carcinoma in situ Not available
33 26
22
Total
28
18
16 16
9 8 3
8 7 3
116
100
19
Table 5. Polypectomy complications Bleeding Patient
Hospitalized
1
8 9 10
No No No No No No 24 hr 13 days 3 days 9 days
1
7 days
2
3 4 5 6
7
VOLUME 38, NO.3, 1992
Units transfused
Polyp diameter (cm)
o
5
o o
o o
o o 7
2 2
4
2 2 >5 3 2.5 >5 2 3
Polyp location
Polyp pathology
Transverse Sigmoid Sigmoid Sigmoid Sigmoid Transverse Ascending Transverse Sigmoid Cecum
Villous adenoma Carcinoma Tubulovillous adenoma Tubulovillous adenoma Villous adenoma Villous adenoma Tubulovillous adenoma Tubulovillous adenoma Carcinoma Tubulovillous adenoma
Possible microperforation or transmural burn 0 3 Ascending
Tubular adenoma
305
all patients underwent aggressive snare excision of the polyp to the extent that was deemed possible, along with the removal of all synchronous lesions. Continued colonoscopic management was preferred, especially in patients of poor surgical risk. Surgery was chosen when the adenoma could not be eradicated endoscopically (initially or later), whenever invasive carcinoma was discovered, or occasionally because of patient preference. The actual management of these patients following the initial attempt at endoscopic resection is summarized in Table 6. Twenty-two patients (20%) received no further colonoscopy or surgery because of very poor medical condition, death from other causes, or, most often, non-compliance with the physician's recommendations. Sixty-five patients (60%) underwent primary colonoscopic management and surveillance. In this endoscopically managed group, all received at least 1, and a maximum of 10, follow-up colonoscopy, with a mean of 4 endoscopies per patient. The average interval between procedures was 1.25 years. The length of total colonoscopic follow-up ranged from 3 months to 10 years, with an average of 2.8 years. One hundred ninety-five metachronous polyps were subsequently removed in 46 of 65 patients (71 %), with a range of 1 to 17 and a mean of 4.2 polyps per patient. Locally recurrent/persistent neoplasia was discovered in 18 of 65 patients (28%). In eight of these patients with recurrent polyps (44%), at least one negative examination was documented prior to the recurrence and the average time interval between a negative examination and a recurrent lesion was 2.2 years. When complete excision of the recurrence was possible, it required an average of three colonoscopies (range, 2 to 6) over an average time period of 12 months (range Table 6. Patient management following initial polypectomy Management strategy
N
%
Colonoscopy Recurrent adenomas Endoscopic failures Surgical resection No further therapy
65 18
60
8 22
12 20 20
108
100
Total
21
28
of 3 to 24 months). Endoscopic management ultimately failed in 8 of 65 patients (12%). These people subsequently underwent surgical resection either because of an inability to adequately endoscopically resect a recurrent or persistent polyp, or the development of carcinoma in a recurrence of a previously benign polyp. The latter event occurred in three patients, representing 5% of the endoscopically managed group and 17% of all recurrent lesions. A total of 29 of '108 patients (27%) underwent surgical resection. Twenty-one patients (19%) underwent surgery soon after endoscopic resection of the initial neoplasm. Table 7 summarizes the data for all patients who underwent surgical resection. One patient underwent transanal excision of a recurrent rectal villous adenoma, but in the remainder either segmental colectomy (26) or total abdominal colectomy (2) was done. One patient required two surgical resections, a subtotal colectomy for a locally recurrent tubulovillous adenoma with a focus of invasive carcinoma and subsequently an abdominoperineal resection for a rectal carcinoma found on follow-up endoscopy. The pre-operative pathologic diagnosis was invasive carcinoma in 20 of 29 patients (69%), villous adenoma in 5 patients (17%), and tubular adenoma and tubulovillous adenoma in 2 patients (7%) each. The pathology report for the surgical specimens differed from the pre-operative endoscopic diagnosis in two cases (7%). In both, invasive carcinoma was discovered in a previously diagnosed tubulovillous adenoma. Thus, actually 22 (76%) of these patients harbored cancer. Histologic evaluation of the colon specimens revealed unsuspected residual adenoma or carcinoma tissue in three cases (10%), and each of these cases contained invasive carcinoma in the original polypectomy specimens. Tumor classification by Astler-Coller modified Dukes staging3 revealed that 2 ofthe 22 specimens (9%) were stage A, 9 (41%) B-1, 1 (4.5%) B-2, and 1 (4.5%) stage C. Surprisingly, nine cases (41%) with a pre-operative finding of invasive carcinoma had no residual tumor. Overall, 20 specimens (91 %) had a favorable surgical stage. In the three patients who developed carcinoma at the site of a previously endoscopically resected benign lesion, staging after resection was no malignancy in one and
Table 7. Surgery following colonoscopic resection Resection performed
No. of procedures
Transanal excision Segmental colectomy Total abdominal colectomy
26
Abdominoperineal resection Total
306
1
:] 30
No. of patients
1 26
Preoperative pathology
N
%
Carcinoma Villous adenoma Tubulovillous adenoma Tubular adenoma
20 5 2 2
69
29
100
17 7 7
2
GASTROINTESTINAL ENDOSCOPY
B-1 tumors in two. The stage of the two carcinomas, which were serendipitously discovered in the surgical specimens initially thought to harbor only a benign polyp, was B-1 in both. Twenty-two of the 29 patients (76%) underwent continued endoscopic surveillance after surgical resection and 6 patients (27%) developed metachronous polyps. A total of 15 metachronous polyps were colonoscopically removed after surgery, averaging 2.5 polyps per patient, with a range of 1 to 16. The mean duration of colonoscopic follow-up for this group was 4.5 years. When the entire study population is considered, 83 patients (77%) had ongoing surveillance colonoscopy performed either as primary treatment following initial polypectomy or following surgical resection. A total of 298 procedures were performed, averaging 3.6 endoscopies per patient (range, 1 to 10) during a mean follow-up of 3.7 years. Two hundred ten metachronous polyps were excised in 52 patients (63%), with a mean of 4.0 polyps per patient (range, 1 to 29). Metachronous carcinoma was found in three patients (3.6%). These data, as well as statistics for synchronous lesions, are summarized in Table 8. TECHNIQUE
Proper technique is essential when performing polypectomy (Figs. 1 to 6).10 Every effort should be made to keep the instrument shaft straight during insertion, in order to preserve maneuverability of the endoscope tip. Repeated clockwise rotation and withdrawal motions aid in reducing the sigmoid loop. Residual fluid in the colon should be completely suctioned out during insertion so that all of the specimens may be easily retrieved later. The colon should not be overinflated, since that will thin the bowel wall and increase the risk of perforation. It is important to obtain a clear and complete view of a polyp before starting the endoscopic resection. Sometimes changing a patient's position facilitates access to a difficult polyp. The endoscope should be rotated so that the polyp is viewed at the six o'clock position which corresponds to the location of the operating channel. Endoscopic resection should probably not be attempted if a good colonoscopic position cannot be attained, or if for any Table 8. Incidence of coincidental polyps and carcinomas
N~. of % patIents Synchronous polyps Metachronous polyps Primary colonoscopic management Following surgical resection Total Metachronous carcinoma
VOLUME 38, NO.3, 1992
Mean no. of polyps! patient
75
69
3.5
46 6
71 27
4.2 2.5
52
63
4.0
3
3.6
Figure 1. A large sessile adenoma in the rectosigmoid. Figures 2. to 4. Segments· of adenoma are sequentially removed with cautery snare. Figure 5. Completed piecemeal resection. Figure 6. A smooth scar visible at follow-up colonoscopy.
other reason the polyp is not satisfactorily visible and accessible. Also, endoscopic removal is unwise if the lesion is ulcerated or quite indurated, since malignancy is likely in that case. The snare should initially be placed around a portion of the lesion that is most accessible, and no more than a 1.0- to 1.5-cm portion should be removed at a time. In the difficult circumstance of a polyp situated just above a fold or flexure, the snare may be opened proximal to the lesion and the colonoscope withdrawn until the polyp comes into view. Some adjusting of the opened snare may be required to position it properly at the base of the lesion before tightening. The adenoma should be kept under direct view as the snare is closed, until resistance is felt. Care must be taken that normal mucosa proximal to the polyp is not gathered up with the adenoma. Pulling the trapped polyp toward the center of the lumen during transection creates a "pseudopedicle" and spares the deeper bowel wall from electrocoagulation. Short bursts of coagulating current are given while slowly tightening the snare until it cuts through. In general, it is best to remove the entire 307
polyp during the initial attempt (which is usually possible), but overaggressive resection can be dangerous. Electrocautery can induce mucosal edema around the excision site that may acutely resemble residual polyp tissue. Cauterization also produces necrosis that reaches deeper than the immediately visible tissue damage. If there is doubt, it is better to stop the procedure and re-evaluate the area at a subsequent colonoscopy. It is wise to attempt removal of all of the major specimen fragments even if multiple endoscopic insertions are required. Afterward, the polypectomy site should be rechecked for bleeding and completeness of excision. Oozing may be stanched by careful recauterization. When alarming bleeding appears, irrigation with epinephrine solution may stop it or at least retard the hemorrhage so that discrete bleeding points can be identified. In those cases in which a perforation is suspected, hospitalization for bowel rest, intravenous antibiotics, and observation to exclude worsening peritonitis is appropriate. If a microperforation has occurred, most patients will recover without surgery. Nevertheless, if laparotomy is required, a watersoluble contrast enema x-ray may be an invaluable guide for the surgical resection, especially If multiple polypectomies were done, or if there is doubt about the exact location of a polyp within the colon. For any polyp, a careful judgment should be made about where it was located within the colon. Thus, if a polyp is later found to contain invasive cancer, the appropriate bowel resection can be performed. When firm or particularly large lesions are resected, it is wise to obtain a frozen section pathologic diagnosis. Invasive cancer found in combination with appreciable bleeding or suspected microperforation warrants an immediate colectomy. This approach will eliminate wasting time with observation and conservative treatments. DISCUSSION
Colonoscopic electrocautery snare excision of large or difficultly situated sessile polyps can be performed safely and effectively. This report evaluates a large number of procedures with minimal variation in management approach and technique. Complication rates were quite acceptable. There was major morbidity in 3.0% of our procedures, three bleeds requiring hospitalization and transfusion, and one possible microperforation. Previous studies have found a similar incidence of serious bleeding after endoscopic piecemeal resection of large sessile polyps. In other study populations of 22 and 42 patients with large polyps, appreciable bleeding occurred in 4.5%4 and 4.7%.5 In reports of complications after polypectomy for all polyp types, frank perforation has occurred in 0.3 to 0.5% and bleeding in 1 to 2%.6-8 The risk of bleeding after endoscopic polypectomy is 10 to 20 times that of diagnostic colonoscopy,6 and the potential for bleeding from extensive snare resections 308
of this type can be assumed to be higher still. Fortunately, post-polypectomy hemorrhage can usually be managed medically. Transmural colonic burn or microperforation occurs less frequently after polypectomy than does bleeding. 9 Typically, early localized abdominal pain and peritoneal irritation herald this complication. When a patient develops these signs and symptoms, it may be impossible to differentiate clinically between a small transmural burn and a microperforation. The treatment of both lesions is the same: namely, nothing by mouth and intravenous antibiotics. This approach is usually successful. Obvious perforation may be evident by free intraperitoneal air seen on plain abdominal x-ray, endoscopic observation of intra-abdominal viscera, or extravasation noted on water-soluble contrast enema. Treatment in this circumstance should be individualized. If the endoscopist believes that the iatrogenic hole in the colon is tiny, medical treatment may be attempted, even in the presence of pneumoperitoneum. Nevertheless, the patient should be examined frequently, with plans to proceed to laparotomy if the abdominal tenderness worsens. For larger perforations, such as when the whole shaft of the endoscope pierces the bowel wall or when an anti-mesenteric longitudinal tear results from too much pressure on an enlarging bow of the colonoscope within a colon loop, urgent laparotomy is best. An important consideration in the safe performance of endoscopic resections is an accurate assessment of polyp size and position. Proper evaluation of a lesion is facilitated both by correct colonoscopic technique and the experience of the endoscopist. An exact determination of polyp size is difficult, especially when a lesion is extracted in fragments, but the estimate of an accomplished colonoscopist is probably quite accurate. Location within the colon can also be a difficult endoscopic judgment. For a given length of inserted colonoscope, the location of the tip can vary widely. The best approximation of polyp location is made when the colonoscope shaft is straight; then the splenic flexure lies at 40 to 50 cm, the hepatic flexure at 60 to 70 cm, and the cecum at 80 to 100 em from the anal verge. Colonoscopic landmarks also aid navigation, such as the ileo-cecal valve in the right colon, a triangular lumen in the transverse colon (sometimes), and the spleen seen through the bowel wall at the splenic flexure. Definitive colonoscopic management of these patients is appropriate and efficacious. Sixty percent of our patients with large sessile adenomas were managed with an aggressive endoscopic approach and, of these, the neoplasm was cured in 88%. Failure resulted when a recurrent adenoma technically could not be resected endoscopically, or when cancer later appeared in a recurrent lesion. The documentation and treatment of a locally recurrent adenoma is the crux of GASTROINTESTINAL ENDOSCOPY
successful endoscopic management. Local recurrence was found in 28% despite the fact that an aggressive removal was carried out during the initial colonoscopic piecemeal resection. In those patients with recurrent adenomas, 44% had at least one negative interval colonoscopy and over half of these patients were ultimately cured by further colonoscopic resection. Interestingly, in 17% of the local recurrences, malignant degeneration of a previously benign polyp occurred, emphasizing the need for complete retrieval and histologic examination of all endoscopically resected tissue, as well as follow-up surveillance. The importance of proper tissue orientation and ink marking of margins during histologic evaluation has been made by others. 4 Recurrence rates of 11 to 25% following resection of sessile polyps have been reported previously.4, 5, 9 Our local recurrence rate was a bit higher, perhaps because of less complete initial removal (although there is no reason to believe that others would be more endoscopically aggressive than we were), but more likely as a consequence of our comparatively long follow-up. It is possible that some of our recurrences were due to macroscopically incomplete initial polypectomies rather than recurrent neoplasm after an apparently complete initial endoscopic resection. This was probably a small contribution, since our policy was always to persist in performing as thorough an initial polypectomy as possible. Indeed, only 12% of our patients were felt to have macroscopically residual tissue at the completion of the initial procedure. Also, nearly half the patients with recurrences had at least one negative endoscopy before the recurrence appeared. Nevertheless, if the interval for follow-up endoscopy had been shorter, persistent adenoma might have been discovered and eradicated earlier, possibly even preventing some of the three later cancers. This was a retrospective study and as such there was no specific follow-up plan. The optimum surveillance regimen is unknown, but analysis of our results now would suggest that for endoscopic treatment of large sessile neoplasms, colonoscopy should be done more frequently than every 1.25 years, at least initially. Repeat colonoscopy should initially be performed every 1 to 3 months until all recurrent or persistent neoplasm is removed, which in our experience required an average of 12 months. The fact that nearly half of the patients with recurrences had a negative repeat endoscopy before the recurrence appeared aptly illustrates that continued follow-up after polyp eradication is essential. Celiotomy with segmental colectomy is occasionally required to definitively manage large sessile lesions, and was ultimately required in nearly a third of our patients. A lesion harboring invasive carcinoma was the most common indication for colectomy (69%). The rather high incidence of carcinoma in large sessile adenomas is well known. 5 In 7% of the colectomy VOLUME 38, NO.3, 1992
specimens, the diagnosis of invasive cancer was missed on the endoscopic biopsies. Thus, it is always important to excise a lesion completely, either endoscopically or surgically. There was a high incidence (76%) of invasive carcinoma among patients who subsequently underwent colectomy in our study. This is consistent with the aggressive approach taken for endoscopic resection in these sometimes poor risk patients. It might also indicate an excessively liberal selection process, but if so, little was lost since the complication rate was low. Also, most of the cancers were diagnosed pre-operatively, were surgically resected soon after the initial endoscopy, and were not advanced. Early stage tumors were found in 91 % of the patients who underwent surgery, including those in whom later malignant degeneration of a polyp had occurred. Thus, even "failed" patients have an excellent chance for cure. Careful surveillance for local recurrences can potentially aid in the detection of early cancers even if they should arise at the site of a previous excision. These patients demonstrated a high predilection for the development of synchronous and metachronous polyps. Sixty-nine percent of the patients in this study had synchronous polyps removed as a component of the initial examination. Over the course of a mean follow-up of 3.7 years, 63% developed metachronous polyps which were excised. Metachronous cancers were discovered in 3.6%. These data lend additional support for an aggressive surveillance regimen. For large sessile polyps, follow-up colonoscopy every 1 to 3 months is recommended until all recurrent or persistent neoplasm is removed. Colonoscopy a year later is reasonable once a negative examination is documented. Repeated endoscopy should be continued at successively longer intervals to diagnose and manage metachronous adenomas or carcinomas.
REFERENCES 1. Tierney RP, Ballantyne GR, Modlin 1M. The adenoma to carcinoma sequence. Surg Gynecol Obstet 1990;171:81-94. 2. Christie JP. Polypectomy or colectomy? Management of 106 consecutively encountered colorectal polyps. Am Surgeon 1988;54:93-9. 3. Spratt JS. Neoplasms of the colon, rectum and anus. Philadelphia: WB Saunders, 1984:207. 4. Nivatvongs S, Snover DC, Fang DT. Piecemeal snare excision oflarge sessile colon and rectal polyps: is it adequate? Gastrointest Endosc 1984;30:18-20. 5. Christie JP. Colonoscopic excision of large sessile polyps. Am J GastroenteroI1977;67:430-8. 6. Johnson SM. Colonoscopy and polypectomy. Am J Surg 1978;136:313-6. 7. Webb WA, McDaniel L, Jones L. Experience with 1000 colonoscopic polypectomies. Ann Surg 1985;5:626-32. 8. Nivatvongs S. Complications in colonoscopic polypectomy: lessons to learn from an experience with 1576 polyps. Am Surg 1988;54:61-3. 9. Bedogni G, et al. Colonoscopic excision of large and giant colorectal polyps. Dis Colon Rectum 1986;29:831-5. 10. Waye JD. Techniques of polypectomy: hot biopsy forceps and snare polypectomy. Am J Gastroenterol 1987;82:615-8.
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