Comparison of the clinical results of abdominoperanal intersphincteric resection and abdominoperineal resection for lower rectal cancer

The aim of this study was to compare the oncologic results of abdominoperanal intersphincteric resection (ISR) and abdominoperineal resection (APR). Between 2003 and 2014, 277 consecutive patients with stage I-III low rectal cancer located within 5 cm from the anal verge underwent curative ISR and APR. A retrospective comparison of these two procedures was performed. Overall, 128 patients underwent ISR and 149 underwent APR. The ISR group had earlier clinical stages and shorter distal margins (p < 0.01). The 5-year relapse-free survival rates in patients who underwent ISR/APR were 84.7/74.7% with T1-2 tumors and 51.3/67.6% with T3-4 tumors. In T3-4 tumors, the rate of local recurrence was higher in the ISR group (13.2%) than in the APR group (3.8%). The 5-year relapse-free survival rates in patients who underwent ISR/APR were 89.7/92.3% for stage I cases, 84.4/87.5% for stage II cases, and 39.8/51.8% for stage III cases. Patients with stage III tumors had high rates of distant recurrence in both groups (24.3 vs. 26.3%). ISR is a feasible surgical procedure for T1-2 tumors. Patients with stage III tumors should be considered for adjuvant therapy to control distant recurrence regardless of the surgical procedure.