Clinicopathological characteristics and prognosis of patients with mucinous adenocarcinoma originating from the left colon, right colon, or rectum: a nationwide retrospective study in China

Background: The clinicopathological and prognostic features of colorectal cancer (CRC) originating from different locations differ greatly. However, the impact of tumour location on the clinicopathological features and prognosis of patients with colorectal mucinous adenocarcinoma (MAC) remains underexplored. This longitudinal international cohort study aimed to investigate the influence of tumour location on clinicopathological features, recurrence, and survival in patients with MAC. Methods: The clinicopathological data of CRC patients who underwent curative surgery and were pathologically diagnosed with MAC across 23 hospitals in China from 2016 to 2021 were collected. Data from 2016 to 2021 MAC patients in the Surveillance, Epidemiology, and End Results (SEER) database were also collected. The study was approved by the Institutional Review Board of The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital [approval No. YXLL-KY-2024(116)]. Chi-squared analysis, Fisher’s exact test, or Kruskal-Wallis analysis of variance (ANOVA) was used to assess differences in categorical variables where appropriate. Kaplan-Meier curves were generated to assess survival, which was compared via log-rank tests. Univariable and multivariable survival analyses with Cox regression models were conducted to identify prognostic factors. Results: A total of 2,646 patients from the SEER cohort and 2,439 patients from the Chinese cohort met the eligibility criteria for inclusion in this study. In the SEER cohort, compared with the right-sided colon (RS) group and the left-sided colon (LS) group, the rectum (RC) group was significantly associated with aggressive histologic features, including a worse N (node) stage (P