Concomitant abdominal aortic aneurysm and colorectal carcinoma: Priority of resection

Concomitant abdominal aortic aneurysm and colorectal carcinoma: Priority of resection John D. Nora, M_D, Peter C. Pairolero, M D , Santhat Nivatvongs, M D , Kenneth J. Cherry, MD, John W. Hallett, MD, and Peter Gloviczki, MD,

Rochester, Minn. Seventeen patients (15 men and two women) tmderwent operation for concomitant abdominal aortic aneurysm (AAA) and colorectal carcinoma (Ca) during a recent 12year period. Ages ranged from 59 to 89 years (median 75.2 years). Diameter of the AAA ranged from 3,5 to 9.5 cm (median 5.5 cm). The Ca was staged by the Astler-Coller modification of Dukes' classification as B1 in three patients, B2 in eight, C2 in three, D in two, and unclassified in one. Personal preference, presence of symptoms, and extent of malignant involvement determined preference of resection. The Ca was eventually resected in 16 patients and the AAA in nine. Thirteen patients underwent resection of the Ca first, two the AAA first, and two concomitantly. Eight patients (47%) underwent resection of both the AAA and Ca, eight underwent resection of the Ca only, and one underwent resection of the AAA only. There were three deaths in 24 operations. Followup ranged from 5 weeks to 8 years (median 11/2 years). Only five patients (29.4%) were long-term survivors without evidence of recurrent Ca and all occurred in the eight patients (62.5%) who had undergone resection of both the Ca and AAA. Three late deaths occurred as a result of complications from the unresected AAA in the eight patients who had undergone resection of the Ca only (37.5%). We conclude that if the Ca is not symptomatic and localized the AAA should be resected first. However, both lesions need to be resected eventually for long-term survival. (J Vasc SuRG 1989;9:630-6.)

Patients with simulataneous abdominal aortic aneurysms and colorectal carcinomas are uncommon. When this association does occur, however, a therapeutic dilemma of which lesion to treat first invariably arises. There is a paucity of experience in the literature to assist in making an appropriate decision. Published reports generally suggest treating the symptomatic lesion first. 1'2 However, most patients are generally frec of symptoms, and one lesion is often discovered incidently at dectivc resection of the other. In an attempt to develop guidelines for the management of patients seen with these two lesions simultaneously, a retrospective review of patients who had concomitant abdominal aortic aneurysm and colorectal carcinoma was undertaken. MATERIAL AND METHODS

The records of all patients who were found to have concurrent abdominal aortic aneurysm and colorectal carcinoma at the Mayo Clinic in the years From the Sections of Vascular Surgery and Colon and Rectal Surgery, Department of Surgery, Mayo Clinic and Mayo Foundation. Presented at the Twelfth AnnualMeeting of the Midwestern Vascular Surgical Society, Rochester, Minn., Sept. 23-24, 1988. Reprint requests: Peter C. Pairolero, MD, Mayo Clinic, 200 First St. S.W., Rochester, MN 55905. 630

1975 to 1986 were reviewed. There were 17 such patients. The records of these patients were anNyzed for preoperative signs and symptoms, timing of diagnosis, operative findings, interval between operations, complications, and long-term survival. After resection of the colorectal cancer all tumors were staged by the Astler-Coller modification of Dukes' classification system? ,4 Follow-up was accomplished by patient interview or review of death certificate and was complete in all patients. Clinical experience. The study included 15 men and two women with a median age of 75.2 years (range 59 to 89 years). All 17 abdominal aortic aneurysms were located infrarenally. The diameter of the aneurysms ranged from 3.5 to 9.5 cm with a median of 5.5 cm. Two patients had associated renal artery stenosis. Nine of the patients had a pulsatile abdominal mass (Table I). Only one patient had pain when first seen that was believed to be secondary to the aneurysm. The colorectal cancer was located in the cecum in three patients, the ascending colon in one, transverse colon in one, descending colon in two, sigmoid colon in seven, and rectum in three. The carcinoma was staged as B1 in three patients, B2 in eight, C2 in three, D in two, and unclassified in one. The most common initial signs relating to the carcinoma were

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Concomitant abdominal aortic aneurysm, colorectalcarcinoma 631

rectal bleeding, a recent change in bowel habit, and weight loss. Symptoms occurred in only two patients and both had abdominal pain secondary to intestinal obstruction (Table I). Diagnosis of these two lesions occurred in three patterns. Group A (10 patients) consisted of those patients in whom both the abdominal aortic aneurysm and colorectal cancer were discovered before surgery, group B (three patients) consisted of those patients in whom a colorectal carcinoma was discovered during elective resection of an abdominal aortic aneurysm, and group C (four patients) consisted of those patients found to have an abdominal aortic aneurysm during resection of a colorectal carcinoma. There was only one emergency operation. This occurred in a patient with colonic obstruction who at laparotomy was found to have a cecal perforation from a sigmoid carcinoma and a 6 cm abdominal aortic aneurysm. Group A (10 patients). The colorectal carcinoma was rcsccted first in eight patients, the abdominal aortic aneurysm first in one, and both simultaneously in one (Table II). After the first operation there were no perioperative deaths and only one complication. The single complication was an occlusion of the right femoral artery occurring in the patient in whom the aneurysm was resected first. A right femoral thrombectomy was necessary in the immediate postoperative period to successfully reestablish arterial flow. Six of the 10 patients subsequently underwent a second operation. The time interval between the first and second operations ranged from 2 to 71/2 months (median 3.8 months). At the second operation four patients underwent resection of the aneurysm, one resection of the carcinoma, and one exploration only. This latter patient, who underwent reoperation 71/2 months after resection of a rectosigmoid stage B1 cancer, was found to have liver metastases, and the aneurysm was not resected. After the second operation there was one complication and one perioperative death. Both occurred in the same patient, who suffered a massive stroke on the eighth postoperative day after resection of a 5.5 cm abdominal aortic aneurysm. Three of the five postoperative survivors are currently alive and well 3 to 4 years later without evidence of recurrent cancer. The other two patients died of metastatic cancer 1 and 21/2 years later. Two of the four patients who did not undergo a second operation refused the second operation. Both had previously undergone colon resection. Diameter of the unresected aortic aneurysm was 3.5 and 5.5 cm. Both died of metastatic cancer 6 months and 31/2 years after the colon operation. The third patient died

Table I. Preoperative signs and symptoms Signs and symptoms Secondary to colorectal cancer None Bleeding Change in bowel habit Weight loss Obstructive Secondary to abdominal aortic aneurysm None I'ulsatile mass Pain

Number 6 7 6 4 2 7 9 1

of complications of thrombosis of the aneurysm 6 weeks after resection of a splenic flexure cancer. There was no evidence of sepsis. The last patient who had undergone a combined resection of the aneurysm and cancer died 1 year later of metastatic cancer. Group B (three patients). Only one patient who underwent initial operation for repair of the abdominal aortic aneurysm underwent resection of the aneurysm after the colon carcinoma was discovered (Table III). This patient died on the first postoperative day secondary to an intraoperative myocardial infarction. The remaining two patients were found to have abdominal carcinomatosis at exploration, and the aneurysms (5.0 and 9.5 cm) were not resected. Instead a palliative colon resection and diverting colostomy were performed. The colostomy was closed in each patient 1 month later. Both patients subsequently died, one 3 months later of rupture of the abdominal aortic aneurysm and the other 11/2 years later of disseminated carcinoma. Group C (fourpatients). All four patients with only the colon cancer known before surgery underwent colon resection (Table IV). One patient died of sepsis on the second postoperative day. This was the patient who had a cecal perforation from an obstructing sigmoid lesion. The second patient had embolization from the aortic aneurysm to the lower extremity 48 hours after colon resection. After successful femoral embolectomy the patient was treated with anticoagulation only to die of rupture of the aneurysm 5 weeks after the colon resection. The third patient who returned 4 months after surgery for aneurysm resection died 8 years later of a myocardial infarction without evidence of recurrence of the cancer. The last patient underwent resection of the abdominal aortic aneurysm simultaneously with resection of the colon cancer and is doing well 11/2 years later. RESULTS

Overall the colorectal carcinoma was resected in 16 patients and the abdominal aortic aneurysm in

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Table II. Group A (10 patients): Both cancer and abdominal aortic aneurysm known before surgery Age (yr)

Sex

83

M

70

Signs and symptoms

Diameter AAA (cm) Stage

Location of cancer

First Second operation operation

Interval (mo)

5.5

B1

Sigmoid

Ca

AAA

5.0

M

Change bowel habits, pulsatile mass, rectal bleeding Pulsatile mass

8.0

B2

Sigmoid

Ca

AAA

3.5

68

M

Asymptomatic

4.0

B2

Ca

AAA

4,0

74

F

5.0

B2

Ca

AAA

2.0

67

M

Pulsatile mass, weight loss Rectal bleeding

Descending colon Cecum

5.0

B1

Rectum

Ca

7.5

76

M

5.5

B2

Rectosigmoid

Ca

Exploration only Refused

80

M

3.5

C2

Ascending

Ca

Refused

--

80

M

7.5

C2

Splenic flexure

Ca

None

--

77

M

9.5

B1

Rectum

AAA

Ca

3.0

89

M

7.0

C2

Cecum

None

--

Change in bowel habits, weight loss, rectal bleeding, colon obstruction, pulsatile mass Abdominal pain, weight loss Change bowel habits, rectal bleeding, pulsatile mass Rectal bleeding, weight loss, pulsatile mass Rectal bleeding, change bowel habits, weight loss, pulsatile mass

Ca

--

Follow-up Died of stroke 8 days after second operation Died of metastases 21/2 yr later Alive and well 4 yr later Alive and well 4 yr later Died of metastases 1 yr later Died of metastases 31/2 yr later

Died of metastases 6 mo later Died of thrombosis of AAA 6 wk later Alive and well 3 yr later Died of metastases 1 yr later

AAA, Abdominal aortic aneurysm; Ca, cancer.

nine. Thirteen patients underwent resection of the colorectal carcinoma first, two the aneurysm first, and two both simultaneously. Eight patients (47%) ultimately underwent resection of both the aneurysm and cancer, eight underwent resection of only the cancer, and two underwent resection of only the aneurysm. One patient underwent an abdominoperineal resection; two others underwent diverting colostomies with the colon resection. Reconstruction of the abdominal aorta was performed with a straight Dacron prosthesis in six patients and a bifurcated Dacron graft in three. There were three perioperative deaths in 24 operations (procedure mortality rate 12.5%). Cause of death was sepsis, stroke, and myocardial infarction in one patient each. Follow-up in the 14 operative survivors ranged from 5 weeks to 8 years (median 11/2years). During the observation period 10 patients have died. Cause of death was disseminated cancer in six patients, complications of an unresected abdominal aortic aneurysm in three, and myocardial infarction in one. None of the patients had signs or symptoms suggestive of infection. Only four patients are presently alive and all have undergone resection of both the aneurysm and the

cancer. Length of survival in these four patients has ranged from 11/2 to 4 years, and none has had evidence of recurrent cancer. One of these patients had a stage B1 colorectal cancer; the remainder had B2 lesions. A fifth patient died at 8 years of a myocardial infarction without evidence of recurrence of a B2 cancer. Altogether five of the eight patients ( 62.5 %) who underwent resection of both the ancurysm and the cancer were long-term survivors without evidence of cancer. O f the nine patients who underwent resection of only one lesion (cancer, eight; aneurysm, one), two died of complications of the operation. Three patients died before returning for a second operation secondary to complications of the unresected aneurysm (rupture, two; thrombosis, one). The last four patients died of metastatic disease 3 months to 4 years after surgery. O f the eight patients in this series who did not undergo resection of the abdominal aortic aneurysm (range 3.5 to 9.5 cm; median 6.5 cm), three (37.5%) died of complications of the aneurysm. The remaining five patients have also died; four of disseminated cancer at 6, 12, 18, and 42 months and one of sepsis 36 hours after resection of a colon cancer. None of

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Concomitant abdominal aortic aneurysm, colorectal carcinoma

633

Table III. Group B (three patients): Cancer found during resection of abdominal aortic aneurysm Age (yr)

Sex

Signs and symptoms

Diameter AAA (cm)

Stage

Location cancer

First S e c o n d Interval operation operation (mo)

65

F

Pulsatile mass

4*

Unclassified

Sigmoid

AAA

None

--

85

M

Pulsatile mass

9.5

D

Descending

Ca?

None

--

59

M

Pulsatile mass

5.0

D

Sigmoid

Ca?

None

--

Follow-up Died of myocardial infarction 24 hr later Died of ruptured AAA 3 mo later Died of metastases 18 mo later

AAA, Abdominal aortic aneurysm; Ca, cancer. *Bilateral renal artery stenosis. ? Palliative colon resection and diverting colostomy.

Table IV. Group C (four patients): Abdominal aortic aneurysm found during resection of cancer Age (yr)

Sex

Signs and symptoms

Diameter AAA (cm)

Stage

Location cancer

First Second Interval operation operation (too)

68

M

Colon obstruction, perforated cecum Change bowel habits

6.0

B2

Sigmoid

Ca

None

--

Died of sepsis 36 hr later

86

M

6.0

B2

Rectum*

Ca

None

--

Rectal bleeding, change bowel habits Asymptomatic

4.5

B2

Sigmoid

Ca

AAA

4.0

Died of ruptured AAA 5 wk later Died of myocardial infarction 8 yr later

69

M

82

M

7.0

B2

Cecum

AAA, Ca

None

--

Follow-up

Alive and well 18 mo later

AAA, Abdominal aortic aneurysm; Ca, cancer. * Abdominoperoneal resection.

the latter five patients had complications of the aneurysm. DISCUSSION Patients with concomitant abdominal aortic aneurysm and colorectal carcinoma are rare. During the period of this study approximately 3500 patients with abdominal aortic aneurysm underwent repair at our institution, and only 17 were found to have sinmltaneous colorectal cancer (0.49% incidence). However, because the age group of patients with the highest incidence of abdominal aortic aneurysm s is the same age group as that of patients with the highest incidence of colorectal cancer, 6 this combination will invariably occur. The therapeutic dilemma in treating this situation has been noted by others and revolves around what risk each lesion presents to the patient.l'2 Patients with symptoms caused by either lesion are at risk for a catastrophic event and require prompt intervention directed at that lesion. Patients with recent abdominal pain and a known abdominalaortic aneurysm may progress to rupture, with a subsequent operative mortality rate ranging from 25% to 75% depending on the age of the patient, hemodynamic stability, and the presence of myocardial ischemia. 7,8

Likewise patients with signs and symptoms of an obstructing colorectal carcinoma may progress to frank intestinal obstruction or colonic perforation, with a 17% and 33% operative mortality rate, respectively.9 In contrast, early and uncomplicated colorectal cancer manifested by occult rectal bleeding, anemia, and change in bowel habit is not associated with a high operative risk. However, many patients are symptom free for both lesions, and hence the controversy exists of which lesion to resect first. Proponents of initial colon resection stress that early treatment of the colorectal carcinoma potentially lowers the risk of further dissemination of the tumor. Whether this is true is uncertain, because tumor growth kinetics suggest that by the time of initial diagnosis most cancers are well advanced in their natural history? ° Likewise there is no evidence suggesting that deferment of a colon resection by a matter of a few weeks has a significantly deleterious effect on the spread of cancer.

Proponents of initial resection of the abdominal aortic aneurysm stress that patients with an aortic aneurysm are at an increased risk for rupture after laparotomy n as a result of increased activity of proteolytic enzymes, namely collagenase and elastase. 12,13

loumalof VASCULAR SURGERY

634 Nora et al.

It is our opinion, however, that this is entirely theoretical and should not influence the decision of which lesion to resect first. Another argument for initial aneurysm repair is that resection of either the right or left side of the colon removes the posterior peritoneum back to the midline and thereby also removes a protective tamponade barrier in the event of rupture. Finally, initial treatment of a colorectal cancer may potentially increase the risk of graft infection after subsequent aneurysm repair because of persistent subclinical intraperitoneal infection or anastomofic leakage. 1416 In our study untreated aneurysms after colon resection had a tendency to rupture. Two of our 13 patients (15%) had rupture of the aneurysm intraperitoneally within 3 months after colon resection, and both died. Concomitant resection of both lesions has several advantages. It eliminates a second operation and the associated risks in a patient population that tends to be older and have cardiovascular disease.. It also removes the risk of complications from the unresected lesion. Finally, a single operation would improve the psychologic attitude of the patient with the knowledge that both potentially life-threatening lesions had been treated definitively. The major disadvantage of simultaneous resection is subsequent graft infection. Whether this can be reduced with closed-bowel resection by a stapling technique remains to be seen. Although both of our patients who underwent concomitant 'resection did well, our experience is too limited to make any conclusions. The prominent feature of our data is the discouraging results that were obtained overall. Only 23.5% of our patients were alive at follow-up. The majority of patients (53%) either died before they could return for the second operation or were found to have metastatic cancer before or at a second operation. More ominous was the fact that there were no long-term survivors if the aneurysm was not resccted. However, half of our patients who underwent resection of both the abdominal aortic aneurysm and the bowel cancer were alive and well at follow-up. Because overall 5-year survival after resection of colorectal cancer and abdominal aortic aneurysm is approximately 50% and 60%, respectively, 1719our observed survival of 50% at follow-up is not too dissimilar from the 30% 5-year survival expected if both of these lesions were separate events. Two major factors affecting survival are disseminated cancer and unresccted abdominal aortic aneurysm. Because 16 of our patients (94%) underwent appropriate colon resections it is unlikely that

more aggressive colon resection would increase longterm survival. In contrast 13 of our patients (76%) still had an unresected abdominal aortic aneurysm after the first operation, and only five underwent repair of the aneurysm eventually. Most important, three of the eight patients (37.5%) who did not undergo resection of the aneurysm ultimately died of complications of that aneurysm. Clearly a more aggressive approach to the abdominal aortic aneurysm is warranted. We conclude that patients with concomitant abdominal aortic aneurysms and colorectal cancer treated with initial colon resection have a tendency to die of complications of the unresected aneurysm. Second, both lesions must be treated successfully to achieve long-term survival. With these conclusions in mind the following guidelines are suggested for management of patients with concomitant colorectal cancer and abdominal aortic aneurysm. Symptomatic aneurysms and cancers with intestinal obstruction should be resected first. If the colorectal cancer needs to be resected first because of obstructive symptoms the aneurysm should be resected 4 to 6 weeks thereafter by a retroperitoneal approach. A barium enema should be performed before the aneurysm resection to rule out the residual complication of a colonic anastomotic leak. If an abscess or fistula is demonstrated, computered tomography should be obtained to determine the extent of the infection. Corrective management of this complication would be necessary before proceeding with resection of the aneurysm. If both lesions are known before surgery and neither is symptomatic, the aneurysm, regardless of size, should be repaired first if there is no evidence of extension or metastasis of the cancer at the time of operation. Similarly if one lesion is discovered at the time of operation for the other lesion and if both are uncomplicated, the aneurysm, regardless of size, should be resected first if there is no evidence of cancer extension or metastasis. Finally, the role of simultaneous resection of both lesions is presently unknown. If done concomitantly, however, the aneurysm should be resected first and the retroperitoneum closed, interposing omentum between the graft and peritoneum, before resection of the cancer. REFERENCES

1. SzilagyiDE, Elliott JP, BerguerR. Coincidentalmalignancy and abdominalaortic aneurysm.Arch Surg 1967;95:402-12.

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2. Lobbato VJ, Rothenberg RE, LaRaja RD, Georgiou J. Coexistence of abdominal aortic aneurysm and carcinoma of the colon: a dilemma. J VASCSUV,G 1985;2:724-6. 3. Dukes CE. The classification of cancer of the rectum. J Pathol 1932;35:323-32. 4. Astler VB, Coller FA. The prognostic significance of direct extension of carcinoma of the colon and rectum. Ann Surg 1954; 139:846-51. 5. Bickerstaff LK, Hollier LH, Van Peenen HJ, Melton LJ HI, Pairolero PC, Cherry KJ. Abdominal aortic aneurysms: the changing natural history. ] VASCSURG 1984;1:6-12. 6. Silverberg E, Lubera JA. Cancer statistics, 1988. CA 1988; 35:5-22. 7. Gaylis H, Kessler E. Ruptured aneurysm. Surgery 1980; 87:300-4. 8. Donaldson MC, Rosenberg JM, Bucknam CA. Factors affecting survival after ruptured abdominal aortic aneurysm. J VASCSURG 1985;2:564-70. 9. Kelley WE Jr, Brown PW, Lawrence W Jr, Terz JJ. Penetrating, obstructing, and perforating carcinomas of the colon and rectum. Arch Surg 1981;116:381-4. 10. Fidler IJ, Balch CM. The biology of cancer metastasis and implications for therapy. Curr Probl Surg 1987;24:129-209. 11. Swanson RJ, Littooy FN, Hunt TK, Stoney RJ. Laparotomy as a precipitating factor in the rupture of intraabdominal aneurysms. Arch Surg 1980;115:299-304. 12. Busuttil RW, Abou-Zamzam AM, Machleder HI. Collage-

DISCUSSION Dr. L a r r y H . H o l l i e r (New Orleans, La.). What would the recommendation be if the problem were not a carcinoma but instead recurrent gastrointestinal bleeding in a patient who is stable at the moment? It is not a particularly uncommon situation to discover an incidental, moderate-sized aneurysm during the workup of either upper or lower gastrointestinal bleeding. H o w do you manage that? Dr. Nora. I believe I would defer my decision until the time o f surgical exploration. The primary goal is to attend to the life-threatening lesion first. I would think that the gastrointestinal bleeding that necessitated exploration would take priority. I f this were an elective exploration with prior knowledge of the aneurysm, you could consider simultaneous resection if the conditions were ideal. Dr. Dennis F. Bandyk (Milwaukee, Wis.). You have advocated guidelines similar to those proposed by Szilagyi et al. in 1967 (Axch Surg 1967;95:402-12). These included: (1) symptomatic lesions, whether they involved the colon or aorta, should be treated first, and (2) both the colon carcinoma and abdominal aortic aneurysm needs to be treated eventually. A conclusion o f your study was that in the absence o f symptoms treatment of the aortic aneurysm takes priority regardless o f its size. Review o f the study results demonstrates that all three major vascular complications occurred in aneurysms that were 6 cm or larger in diameter. No complications occurred in patients

13.

14.

15.

16.

17.

18.

19.

635

nase activity of the human aorta: a comparison of patients with and without abdominal aortic aneurysms. Arch Surg 1980;1i5:1373-8. Cohen IR, Mandell C, Nargolis I, Chang J, Wise L. Altered aortic protease and antiprotease activity in patients with ruptured abdominal aortic aneurysm. Surg Gynecol Obstet 1987;164:355-8. Bernhard VM. Management of graft infections following abdominal aortic aneurysm replacement. World J Surg 1980; 4:679-86. O'Hara PJ, Hertzer NR, Beveu EG, Krajewski LP. Surgical management of infected abdominal aortic grafts: review of a twenty-five-year experience. J VASC SURO 1986;3:725-31. Gingold BS, Jagelman DG. Value of pelvic suction irrigation in reducing morbidity of low anterior resection of the rectum-- a ten-year experience. Surgery 1982;91: 394-8. Szilagyi DE, Smith RF, DeRusso FJ, Elliott JP, Sherrin FW. Contribution of abdominal aortic aneurysmectomy to prolongation of life. Ann Surg 1966;164:678-99. Crawford ES, Saleh SA, Babb yvVIII, Glaesser DH, Vaccaro PS, Silvers A. Infrarenal abdominal aortic aneurysm: factors influencing survival after operation performed over a twentyfive-year period. Ann Surg 1981;193:699-709. Hollier LH, Plate G, O'Brien PC, et al. Late survival after abdominal aortic aneurysm repair: influence of coronary artery disease. J VASe SURG 1984;1:290-9.

with aneurysms 5 cm or less in diameter in whom the colon cancer was treated first. What is your rationale in advising aortic aneurysmorrhaphy as the first procedure in symptom-free patients? In your study, complications were encountered within 3 months o f the initial procedure. What is an appropriate interval to reoperate and correct the residual problem, be it either the aneurysm or colon cancer? Should the patient be sent home to recuperate or should both lesions be corrected during the same hospitalization? Did you use any special techniques or precautions to maintain blood supply to the colon via the inferior mesenteric artery or internal iliac arteries? Were inferior mesenteric arteries routinely reimplanted? Dr. James H . T h o m a s (Kansas City, Kan.). I believe we would resect the colon before an aneurysm measuring 3.5 cm or less in diameter. Fm-rhermore we are relatively aggressive about aneurysm resection even in patients who have some evidence o f metastatic disease, depending on the extent and location o f the colonic metastasis. Finally, perhaps you can give us some direction regarding the possible indications for concomitant resection o f both the aneurysm and the colon. Dr. N o r a (closing). Although the smallest aneurysm with which we had complications was 6 cm in diameter, there have been reports that rupture still can occur with lesions measuring 5 cm or less. We emphasized the management of smaller aneurysms because we did not want

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any of them to be ignored, particularly if they exceed 4 cm, because the risk for rupture of such aneurysms is rather unpredictable. With regard to maintaining the circulation to the left side of the colon, we do not hesitate to reimplant the inferior mesenteric artery. Alternatively, reestablishing flow into one of the hypogastric arteries is equally effective. We meant to be a bit noncommital concerning the timing of staged operations because that is something that usually is determined by the clinical course. We would plan

the second procedure as soon as the patient has made an optimal recovery, and in our experience this often is 6 to 8 weeks after the initial operation. The final question concerned the appropriate indications for the concomitant resection of both the aneurysm and the colon cancer. There are several prerequisites for that approach. First, one needs to be aware of both lesions beforehand. Second, a preoperative bowel preparation is necessary, and finally the procedure itself must be technically precise and tmcontaminated.

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