Oncologic outcomes of intersphincteric resection without preoperative chemoradiotherapy for very low rectal cancer

When a rectal cancer is located at less than 4cm from the anal verge, abdominoperineal resection (APR) is generally performed. If an ideal surgery that could replace APR were to be developed, it could contribute to anal preservation in patients with very low rectal cancer. The aim of this study was to investigate oncologically whether intersphincteric resection (ISR) could replace APR for a very low rectal cancer.

Between 2001 and 2011, ISR was curatively performed in 124 patients with a very low rectal cancer who might otherwise have been treated with APR. No patient received preoperative chemoradiotherapy. The median duration of follow-up was 65 months (range 14-122 months). Local recurrence was defined as only intra-pelvic recurrences including lateral lymph node metastasis. The survival rate was calculated using the Kaplan-Meier method.

Postoperative morbidity including anastomotic leakage (5.6%) was 12%. There was no in-hospital mortality. In those patients with Stages I, II, and III disease, the local recurrence rate was 4.7%, 4.9%, and 5.0%, respectively. The recurrence-free 5-year survival rates were 92.2% (95% CI: 84-100%), 81.9% (95% CI: 70-94%) and 69.6% (95% CI: 53-87%) at each stage, respectively. The cancer-specific 5-year survival rates were 90.5% (95% CI: 81-100%), 91.0% (95% CI: 82-100%), and 83.6% (95% CI: 70-97%) at each stage, respectively. The overall recurrence-free survival and local recurrence rates after ISR were similar to those after APR.

The ISR procedure appears to be oncologically acceptable, replacing APR in selected patients. Accumulated experience supports this practice worldwide in future.