Background: The efficacy of intersphincteric resection (ISR) surgery for patients with lower rectal cancer remains unclear compared to abdominoperineal resection (APR). The aim of this study is to compare the oncologic outcomes for lower rectal cancer patients after ISR and APR through a systematic review and meta-analysis. Materials and Methods: A systematic electronic search of the Cochrane Library, PubMed, EMBASE, and MEDLINE was performed through January 12, 2022. The primary outcomes included 5-year disease-free survival (5y-DFS) and 5-year overall survival. Secondary outcomes included circumferential resection margin involvement, local recurrence, perioperative outcomes, and other long-term outcomes. The pooled odds ratios, mean difference, or hazard ratios (HRs) of each outcome measurement and their 95% CIs were calculated. Results: A total of 20 nonrandomized controlled studies were included in the qualitative analysis, with 1217 patients who underwent ISR and 1135 patients who underwent APR. There was no significant difference in 5y-DFS (HR: 0.84, 95% CI: 0.55–1.29; P=0.43) and 5-year overall survival (HR: 0.93, 95% CI: 0.60–1.46; P=0.76) between the two groups. Using the results of five studies that reported matched T stage and tumor distance, we performed another pooled analysis. Compared to APR, the ISR group had equal 5y-DFS (HR: 0.76, 95% CI: 0.45–1.30; P=0.31) and 5y-LRFS (local recurrence-free survival) (HR: 0.72, 95% CI: 0.29–1.78; P=0.48). Meanwhile, ISR had equivalent local control as well as perioperative outcomes while significantly reducing the operative time (mean difference: −24.89, 95% CI: −45.21 to −4.57; P=0.02) compared to APR. Conclusions: Our results show that the long-term survival and safety of patients is not affected by ISR surgery, although this result needs to be carefully considered and requires further study due to the risk of bias and limited data.

Background: Self-expandable metallic stent (SEMS), an alternative to diverting stoma (DS), has been used as a “bridge to surgery” (BTS) to decompress acute obstruction of colorectal cancer (CRC) for decades. However, whether SEMS is a safe technique for obstruction of CRC without compromising the long-term survival of patients remains unidentified compared to those of DS. The aim of the present study was to elucidate the safety and survival outcomes of SEMS and DS. Methods: Embase, PubMed, and Medline were searched for qualified studies published until October, 2020, in which SEMS or DS was performed as a BTS without resection at the same stage. The last search was on December 5th, 2020. The Newcastle–Ottawa scale (NOS) was used to assess the quality of included studies. The major complication rate, mortality, 3-year overall survival (OS), and permanent stoma rate were estimated as outcomes. Results: The present study was registered on INPLASY (No. 2020100079). Seven eligible studies were included, involving 646 and 712 patients who underwent SEMS and DS treatments, respectively. The Clavien-Dindo I/II grade complication rate was significantly lower in the SEMS group than in the DS group (8.68 vs. 16.85%; RR, 0.59; 95% confidence interval (CI) 0.41–0.84; P = 0.004). The Clavien-Dindo III/IV grade complication rate was comparable in two groups (7.69 vs. 8.79%; RR, 0.82; 95% CI 0.54–1.27; P = 0.37). There were no statistical differences in the short-term mortality (5.16 vs. 4.53%; RR, 1.25; 95% CI 0.75–2.08; P = 0.39), 3-year OS (71.91 vs. 76.60%; RR, 0.93; 95% CI 0.86–1.01; P = 0.10), and permanent stoma rate (22.08 vs. 27.54%; RR, 0.84; 95% CI 0.67–1.06; P = 0.14) between the two groups. Conclusions: To some extent, SEMS is a safe BTS technique for acute obstructive CRC, without significant adverse effect on the survival of patients. Given the advantage of minimal invasion, SEMS may be a better alternative to DS for obstructive CRC. However, the conclusions remain to be discussed because of lacking high-quality randomized controlled trails.