A prospective evaluation of distal margins in carcinoma of the rectum.

The controversy regarding the ideal distal margin after a "curative" anterior resection is currently unresolved. To clarify this issue, a prospective study was undertaken. Two hundred and forty-three patients who underwent "curative" anterior resection were included in this study. Patients were divided into 1 centimeter groups based upon the length of the distal margin (from 0.0 to 8.0 centimeters), and recurrence, local and distant, and survival were analyzed. There was no significant difference in local or distant recurrence or survival when each centimeter interval was studied to 1 centimeter. Patients with a distal margin of less than 0.8 centimeter (group 1) had more frequent anastomotic recurrences (30 percent) when compared with patients (group 2) with a distal margin greater than 0.8 centimeter (10.5 percent; p = 0.01). Both groups were well matched for age, gender, tumor size, length of proximal margin, number of positive lymph nodes, histologic factors, grade of differentiation, Dukes' classification, type of operation, preoperative and postoperative radiotherapy, follow-up evaluation and surgeon. Both groups had a similar pelvic area recurrence (5.0 versus 8.7 percent, p = NS) and distance recurrence rates (10.0 versus 14.2 percent, p = NS). The five year survival rate was adversely affected by a distal margin of less than 0.8 centimeter (49.3 percent in group 1 and 67.5 percent in group 2; p = 0.01). The data suggest that a distal margin of 1 centimeter in the pathologic specimen is adequate distal clearance for most carcinomas of the rectum.