Oncologic and functional outcomes of external sphincter resection

Abstract

Objective:

The aim of this study was to evaluate the oncologic and functional outcomes of external sphincter resection (ESR) compared with those of intersphincteric resection (ISR).

Background:

Abdominoperineal resection (APR) has generally been performed in the past for very low rectal carcinomas located less than 4 cm from the anal verge. Recently, there has been increasing interest in the use of intersphincteric resection (ISR) to treat such carcinomas, since this procedure removes the internal sphincter but preserves the anus. However, the oncologic and functional outcomes of more aggressive anus-preserving technique, i.e. ESR for lower rectal cancers have not yet been adequately evaluated.

Patients and methods:

The surgical procedures were performed in 70 patients who were candidates for conventional APR during the period 2000–2008. Thirty patients received ESR, and the other 40 patients received ISR. The operative procedures were classified as partial-, subtotal- and total-ISR (P-ISR, ST-ISR, T-ISR); and partial- and extensive-ESR (P-ESR, E-ESR) depending on the volume of sphincter muscle resected. The Kaplan- Meier method was used to calculate survival rate. The Kirwan grade and manometry were used to evaluate anal function.

Results:

ESR procedures were performed in patients with a lower tumor, and had longer operative duration, more blood loss and lower anastomosis. We had neither mortality nor severe complications after surgery. There was local recurrence (LR) in 11.9% of patients, and a radial margin (RM) <1 mm was the most powerful independent determinant of LR (p=0.0047). Comparing ESR with ISR, there was no significant difference in the local recurrence rate (7.1% vs. 15.4%), and recurrence-free or cancer-specific 5-year survival rates (82% vs. 72% 91% vs. 85%respectively).Anal continencewas preserved in 54% of the E-ESR procedures and in approximately 80% of the P-ESR or ISR procedures.

Conclusion:

ESR procedures have acceptable oncological outcomes. More aggressive preoperative treatment including chemoradiotherapy is important to achieve a safe RM and to control LR. Some modification of the E-ESR procedure is needed to improve anal function.