The short-term and oncologic outcomes of younger VS older colorectal cancer patients undergoing primary surgery: a propensity score matching analysis

PURPOSE: The purpose of the current study is to analyze the difference of short-term and oncologic outcomes between younger and older colorectal cancer (CRC) patients who underwent primary CRC surgery using a propensity score matching (PSM) analysis. METHODS: We retrospectively collected CRC patients who underwent primary surgery in a single clinical database from Jan 2011 to Jan 2020. The short-term and oncologic outcomes were compared between younger aged group and older aged group. RESULTS: A total of 4599 patients were included in this study, and there were 4196 patients in older aged group and 403 patients in younger aged group. After 1:1 ratio PSM, there were 401 patients in each group. No significant difference was found in terms of baseline information after PSM (p>0.05). Younger aged group had larger retrieved lymph nodes before (p<0.001) and after PSM (p=0.001) than older aged group. In multivariate analysis, younger age was an independent predictor of better overall survival (OS) (p<0.001, HR=2.303, 95% CI=1.658-3.199) and disease-free survival (DFS) (p=0.008, HR=1.425, 95% CI=1.098-1.850). In terms of different tumor stage after PSM, younger aged group had better OS than older group in stage II (p<0.001) and stage IV (p=0.028) CRC, and younger aged group had better DFS than older group in stage II (p=0.016) CRC. CONCLUSION: Younger CRC patients had larger retrieved lymph nodes and better prognosis than older CRC patients after primary CRC surgery.