Outcomes of ultra-low anterior resection combined with or without intersphincteric resection in lower rectal cancer patients

Purpose We evaluated the current practice of ultra-low anterior resection (uLAR) in patients with lower rectal cancer and compared uLARs using mostly transabdominal approach with or without intersphincteric resection (ISR). Methods A total of 624 consecutive lower rectal cancer patients undergoing curative uLAR were prospectively enrolled as ISR+ vs. ISR− groups (329 vs. 295 patients) between 2005 and 2012. The ISR+ group additionally received levator-sphincter reinforcement after distal resection. Results The circumferential resection margin (CRM) + rate (≤1 mm) was 2.1 % in the two groups. Postoperative ileus occurred more in the ISR– group than in the ISR+ group ( p = 0.02). Substantial erectile dysfunction occurred 1.8 times more frequently in the ISR– group than in the ISR+ group (32 vs. 18.1 %; p = 0.01) among male patients at 2 years postoperatively. The urge to defecate volume and maximal tolerance volume, closely correlated with maximal squeezing pressure and/or mean resting pressure, did not differ between patients with and without chemoradiotherapy until 24 months postoperatively. Nevertheless, the urge to defecate volume was lesser in the ISR− group than in the ISR+ group at 24 months postoperatively ( p = 0.022). For 301 patients in which >5 years had elapsed postoperatively, the mean 5-year local recurrence rate was 4.3 %, and the 5-year disease-free and overall survival rates were 78.9 and 92 %, respectively, without differences between the two groups. Conclusions Compared with uLAR without ISR, the transabdominal ISR with levator-sphincter reinforcement provides a safe resection plane with competent CRM, concurrently reduces substantial complications, and marginally promotes recovery of neorectal function.