Oncological outcome of ultra-low coloanal anastomosis with and without intersphincteric resection for low rectal adenocarcinoma

BACKGROUND: The value of ultra-low coloanal anastomosis (CAA) for rectal cancer is dependent on the oncological and functional results. The aim of this comparative study was to evaluate the long-term oncological outcome of CAA with or without intersphincteric resection (ISR) for low-lying rectal tumours. METHODS: The study population comprised consecutive patients with low rectal cancer who underwent CAA in a single institution between 1977 and 2004. Patients were divided into two groups according to whether or not a partial ISR had been performed. Cox multivariate models were used for survival analysis. RESULTS: Some 278 patients underwent CAA with curative intent; 173 had ISR and 105 had CAA without ISR. Mean follow-up was 66.8 months. The 5-year actuarial rate for local recurrence, regardless of tumour stage, was 10.6 per cent in the ISR group versus 6.7 per cent for CAA alone (P = 0.405), and the 5-year actuarial overall survival rate was 86.1 and 80.0 per cent respectively (P = 0.318). Cox multivariable analysis revealed that resection of the anal canal was not a prognostic factor for local or metastatic recurrence. CONCLUSION: Sphincter-preserving surgery appears to be oncologically adequate for very low-lying rectal tumours.