Ultralow anterior resection with intersphincteric dissection--what is the limit of safe sphincter preservation?

In the treatment of low rectal cancer, the possibility of sphincter preserving surgery is increased by partial sphincteric resection which may allow an oncologically safe resection margin in some patients who would traditionally have been treated by abdominoperineal resection. The aim of this study is to evaluate the morbidity, mortality and the oncological and functional results of intersphincteric resection to determine whether the technique may be considered a safe means of sphincter preservation.

Between May 1992 and December 1999, 26 patients (mean age 55 years, range 28-82) with adenocarcinoma of the rectum had partial sphincteric resection by an abdominal approach with a colonic J-pouch anal anastomosis. The mean distance between the tumour and the anal verge 4.25 (range 3.1-5.25) cm. Four tumours were T1, 14 T2 (3 N+), 7 T3 (3 N+), and 1 T4 (N+). Neoadjuvant radiotherapy was used in 10 patients. The distal resection margin was positive in one patient who then proceeded to safe abdominoperineal resection (APR). In the remaining patient the mean distal resection margin on the fixed specimen was 1.6 (range 0.3-3.5) cm.

There were no deaths. Morbidity was 30% with an anastomotic leak rate of 11%. At mean follow-up of 39 (range 11-93) months the local recurrence rate was 3.4%. Functional results were evaluated in 25 patients at mean follow-up of 27 (8-66) months: 65% had 0-2 bowel motions per 24 h, 31% had 3-5 and 4% between 6 and 9. Nine patients (36%) had nocturnal defecation. Continence was normal in 50% with 23% reporting incontinence to gas and 27% reporting minor episodes of incontinence. None had major incontinence and 85% considered their outcome satisfactory.

This study supports the current literature indicating that partial sphincteric resection is an oncologically and functionally safe alternative to abdominoperineal resection for some selected low rectal tumours.