Prognostic Significance of Tumor Deposits in Combination with Lymph Node Metastasis in Stage III Colon Cancer: A Propensity Score Matching Study

Tumor deposits in colon cancer are related to poor prognosis, whereas the prognostic power of tumor deposits in combination with lymph node metastasis (LNM) is controversial. This study aimed to compare the overall survival between LNM alone and LNM in combination with tumor deposits, and to verify whether the number of tumor deposits can be considered LNM in patients with both LNM and tumor deposits in stage III colon cancer by propensity score matching (PSM). Patients carrying resected stage III adenocarcinoma of colon cancer were identified from the Surveillance, Epidemiology, and End Results database (2010-2015). The Kaplan-Meier method, Cox proportional hazard models and PSM were used. On the whole, 23,168 patients (20,451 (88.3%) with only LNM and 2,717 (11.7%) with both LNM and tumor deposits) were selected. After undergoing PSM, patients with both LNM and tumor deposits showed worse overall survival (hazard ratio = 1.33, 95% confidence interval: 1.20-1.47, P < 0.001). After the number of tumor deposits was added with that of positive regional lymph nodes, patients with both LNM and tumor deposits seemed to have prognostic implications similar to those with LNM alone (hazard ratio = 1.02, 95% confidence interval: 0.93-1.12, P = 0.66). The simultaneous presence of LNM and tumor deposits, as compared with the presence of only LNM, had an association with a worse outcome. Tumor deposits should be considered as LNM in patients with both tumor deposits and LNM in stage III colon cancer.