Incidence and patterns of recurrence after intersphincteric resection for very low rectal adenocarcinoma

Background: The aim of this study was to evaluate the incidence and patterns of recurrence, or oncologic safety, after intersphincteric resection (ISR) without radiotherapy for very low rectal adenocarcinoma. Study Design: One hundred eight consecutive patients with T1-T3 rectal cancers located 1 to 5 cm (median 3 cm) from the anal verge underwent ISR. A retrospective analysis of prospectively recorded data from the 106 patients not receiving radiotherapy was performed. Results: There were 23 T1, 40 T2, and 43 T3 tumors. Morbidity and mortality rates were 33% and 1%, respectively. The 3-year rates of overall local recurrence and survival were 5.7% and 95%, respectively. The 3-year cumulative local recurrence rate was 0% for the patients with T1-T2 tumors as compared with 15% for those with T3 tumors (p = 0.0012). In T3 tumors, the 2-year local recurrence rate was 5% for patients with negative surgical margins as compared with 33% for those with positive margins (p = 0.0001). The incidences of distant recurrence for stages 1, 11, 111, and IV disease were 4%, 5%, 18%, and 33%, respectively. Conclusions: ISR does not increase local or distant recurrences. For T1-T2 tumors, meticulous dissection and irrigation after closure of the distal stump allows local control without radiotherapy. With T3 tumors, preoperative therapy should be considered if resection margins are estimated to be insufficient.