A United States Rectal Cancer Consortium study of inferior mesenteric artery versus superior rectal artery ligation: How high do we need to go?

Abstract

47 Background: The optimal level of pedicle ligation during proctectomy for rectal cancer, either at the origin of the inferior mesenteric artery (IMA) or the superior rectal artery (SRA), is still debated. Reasons for IMA ligation include facilitating a tension-free anastomosis and improved clearance of regional lymph nodes. Our aim was to determine if SRA ligation portends inferior outcomes. Methods: The US Rectal Cancer Consortium database (2007-2017) was reviewed for pts with primary, non-metastatic rectal adenocarcinoma who underwent treatment with low anterior resection or abdominoperineal resection. Primary outcomes were anastomotic leak rate and lymph node (LN) harvest. Secondary outcomes were locoregional recurrence-free survival (LRFS), recurrence-free survival (RFS), and overall survival (OS). Results: Of 877 pts, median age was 59 years (IQR52-67) and 62% were male (n = 541). 86% received an IMA ligation (n = 755) while 14% SRA (n = 122). 12% were pathologic stage 0 (n = 101), 33% stage I (n = 281), 24% stage II (n = 206), and 31% stage III (n = 269). Median follow-up was 34 mos. SRA ligation was more common in stage III disease (43vs30%, p = 0.005) while IMA ligation was more often performed with a minimally invasive approach (70vs42%, p < 0.001). SRA ligation was associated with a nearly identical anastomotic leak rate compared to IMA (9vs8%, p = 1.0). Similarly, the median number of LNs removed was the same between both ligation groups (15vs15, p = 0.38). On multivariable analysis accounting for an open approach, advanced pathologic stage, and positive resection margin status, SRA ligation was not associated with increased anastomotic leak rate or reduced LRFS, RFS, or OS (all p > 0.1). Conclusions: If a tension-free anastomosis is feasible, SRA ligation is not associated with either a worse technical outcome or inferior lymph node harvest. Furthermore, all cancer survival metrics are similar between SRA and IMA ligation. Given that either approach is safe and feasible from both a technical and oncologic standpoint, this study questions the routine practice of IMA ligation.