RESUMO
<p><b>BACKGROUND</b>The technique of intersphincteric resection of tumors combined with coloanal anastomosis has been used to avoid permanent colostomy for patients with a rectal cancer located < 5 cm from the anal verge. This study aimed at assessing the preservation of continence function of the residual rectum and the clinical prognosis of patients with lower rectal cancer after intersphincteric resection using a prolapsing technique.</p><p><b>METHODS</b>This study included patients with the following inclusion criteria: (1) pathological evidence of rectal cancer and the tumors within distal margins located 5 cm or less from the anus by preoperative endoscopic examination; (2) no evidence by MRI of infiltration of either the external sphincter, puborectalis or the levator muscle; (3) the patients are eligible for intersphincteric resection and lower coloanal anastomosis with a preoperative biopsy showing the tumors with well-to-moderate differentiation. From January 2000 to June 2004, 23 patients with low rectal cancer were included in this study. We used the standard abdominoperineal approach to perform radical resection of tumors with excision of the mesorectum and total or part of the internal sphincters. The patients were followed for assessment of the function of the residual rectum and of cancer recurrence after the operations.</p><p><b>RESULTS</b>The median tumor distance from the anal margin was 4.5 (range 3.5 - 5.0) cm and the mean distal surgical margin 1.6 (range 1.0 - 2.0) cm. Cancer was classified into Stage I (30.4%), Stage II (47.8%), and Stage III (21.7%) according to the TNM classification. Two patients developed anastomotic fistula after the surgical resection and 2 patients (8.7%) developed later stages of anastomotic stricture at the site of coloanal anastomosis. The median follow-up period was 31.5 months (range 12 - 54) and 2 patients (8.7%) developed local recurrence. Three deaths were associated with distal organ metastasis. Twenty patients (87.0%) have maintained competence to control solid or liquid stool and the capacity of flatus continence after the surgery. Among these patients, 2 patients were able to control solid stool and occasionally lose continence of liquid stool. And only 1 patient (4.4%) has retained partial rectum function with good continence of solid stool but not liquid after the operations. Average times of defecation per day of 3, 6, 12, 24 and 36 months after the surgery were 13.1, 4.7, 3.1, 2.9, and 3.2 times/day. Anal manometer measurements showed a decrease of pressure during the resting time after intersphincteric resection and this change remained during the period of follow-up. The maximum squeeze pressure was improved after an initial decrease after the surgery.</p><p><b>CONCLUSIONS</b>More residual rectum function after the surgery may be preserved by intersphincteric resection of low rectum cancer. At the same time this technique is safe with few postoperative complication and low tumor recurrence after the surgery.</p>