Extended Procedure Has No Oncological Benefits over Segmental Resection in the Treatment of Non-metastatic Splenic Flexure Colon Cancer, a Population-Based Cohort Study

Abstract

Abstract AIM: To compare the oncological survival outcome between extended resections and segmental resection for non-metastatic splenic flexure tumors. METHODS: A total of 10063 splenic flexure colon cancers patients who underwent extended resection (n=5546) or segmental resection (n=4517) from 2010 to 2018 were included from the Surveillance, Epidemiology, and End Results (SEER)-registered database. Survival rates were compared between groups. To reduce the inherent bias of retrospective studies, propensity score matching (PSM) analysis was performed. RESULTS: Patients from the extended resection group had higher pT stage, pN stage, larger tumor size, and higher rates of elevated CEA level, perineural invasion, and tumor deposits than those from the segmental resection group (each P<0.05). The 5-year CSS rate was slightly lower in extended resection patients than that in segmental resection patients (79.2% vs. 81.6%, P =0.002), while the 5-year OS were comparable between groups (66.2% vs. 66.9%, P =0.513). After the PSM performed, both the 5-year CSS and 5-year OS rates in extended resection group and segmental resection group were comparable (5-year CSS: 84.9% vs. 83.0%, P =0.577; 5-year OS: 70.6% vs. 66.0%, P =0.415). These findings were similar in the subgroup analysis that included only patients with stage III disease or with tumor size ≥ 7 cm. In addition, although the number of harvested lymph nodes was larger in the extended resection group compared to the segmental resection group (12.7 vs. 14.4, P<0.001), the numbers of invaded lymph nodes remained similar between groups (0.5 vs. 0.5, P=0.90). CONCLUSION: Extended procedures have no significant oncological benefits over segmental resection in the treatment of non-metastatic splenic flexure colon cancer, even for locally advanced cases. The larger number of harvested lymph nodes in the extended resection group did not confer any advantage relative to segmental resection with regard to CSS, since it was not associated with an increase in the number of invaded lymph nodes harvested.