Intersphincteric resection with excision of internal anal sphincter for conservative treatment of very low rectal cancer

PURPOSE: Standard surgical treatment for low rectal cancer situated below 5 cm from the anal verge or at less than 1 cm from the anal ring is abdomino perineal resection. This is because of the necessity both to achieve a suff icient distal margin and to preserve the whole of the anal sphincter. The a im of this study was to evaluate morbidity, oncologic, and functional resul ts of intersphincteric resection with excision of the internal anal sphinct er and low coloanal anastomosis for carcinomas of the anorectal junction. M ETHODS: From January 1990 to December 1996, 16 patients were studied prospe ctively. All patients had an infiltrating adenocarcinoma (5 T2 and 11 T3), located between 2.5 and 4.5 (mean, 3.6) cm from the anal verge. Rectal rese ction with a minimum distal margin of 2 (mean, 2.4) cm was performed in all cases; six patients underwent partial resection of the internal sphincter, and ten patients had a subtotal resection. A colonic J-pouch was associate d with coloanal anastomoses in eight cases. Twelve patients had preoperativ e radiotherapy, 3 with concomitant chemotherapy; 5 patients had postoperati ve chemotherapy. RESULTS: There was no postoperative mortality. Morbidity o ccurred in four patients, of whom two underwent permanent colostomy after p elvic hemorrhage or anovaginal fistula. After a median follow-up of 44 (ran ge, 11-92) months, no local recurrence was observed, and two patients died of distal metastases. The five-year actuarial survival rate was 75 percent. Continence was normal in one-half of patients and was altered in the other patients who suffered from occasional minor leaks. The median resting pres sure was lower after subtotal than after partial resection of the internal sphincter (40 vs. 70 cm H2O; P = 0.02), but functional results were similar in the two groups. CONCLUSION: These preliminary results suggest that inte rsphincteric resection can be an alternative to abdominoperineal resection for selected rectal tumors situated at the anorectal junction, without comp romising chance of cure. Functional results and continence were not altered by subtotal resection of the internal anal sphincter.