Surgical outcomes of left hemicolon sparing resection versus extensive resection in treating synchronous colorectal cancer involving the right-sided colon and sigmoid colon or rectum

Background There are different surgical strategies that can treat synchronous colorectal cancer (SCRC) involving separate segments, namely extensive resection (EXT) and left hemicolon-sparing resection (LHS). We aim to comparatively analyze short-term surgical results, bowel function, and long-term oncological outcomes between SCRC patients treated with the two different surgical strategies. Methods One hundred thirty-eight patients with SCRC lesions located in the right hemicolon and rectum or sigmoid colon were collected at the Cancer Hospital, Chinese Academy of Medical Sciences, and the Peking University First Hospital from January 2010 to August 2021 and divided into EXT group ( n = 35) and LHS group ( n = 103), depending on their surgical strategies. These two groups of patients were compared for postoperative complications, bowel function, the incidence of metachronous cancers, and prognosis. Results The operative time for the LHS group was markedly shorter compared with the EXT group (268.6 vs. 316.9 min, P = 0.015). The post-surgery incidences of total Clavien-Dindo grade ≥ II complications and anastomotic leakage (AL) were 8.7 vs. 11.4% ( P = 0.892) and 4.9 vs. 5.7% ( P = 1.000) for the LHS and EXT groups, respectively. The mean number of daily bowel movements was significantly lower for the LHS group than for the EXT group (1.3 vs. 3.8, P < 0.001). The proportions of no low anterior resection syndrome (LARS), minor LARS, and major LARS for the LHS and EXT groups were 86.5 vs. 80.0%, 9.6 vs. 0%, and 3.8 vs. 20.0%, respectively ( P = 0.037). No metachronous cancer was found in the residual left colon during the 51-month (median duration) follow-up period. The overall and disease-free survival rates at 5 years were 78.8% and 77.5% for the LHS group and 81.7% and 78.6% for the EXT group ( P = 0.565, P = 0.712), respectively. Multivariate analysis further confirmed N stage, but not surgical strategy, as the risk factor that independently affected the patients’ survival. Conclusions LHS appears to be a more appropriate surgical strategy for SCRC involving separate segments because it exhibited shorter operative time, no increase in the risk of AL and metachronous cancer, and no adverse long-term survival outcomes. More importantly, it could better retain bowel function and tended to reduce the severity of LARS and therefore improve the post-surgery life quality of SCRC patients.