Chemotherapy exacerbates the survival paradox of colon cancer: a propensity score matching analysis

BACKGROUND: Colon cancer is one of the most common tumor diseases in the world. Currently, clinicians usually evaluate the survival and prognosis of patients according to their tumor-node-metastasis (TNM) stage. However, current studies have found that there is a certain survival paradox in TNM staging. METHODS: In the Surveillance, Epidemiology, and End Results (SEER) database, patients diagnosed with colon cancer by surgical pathology from 2004 to 2011 were selected for analysis of 5-year overall survival (OS). Propensity score matching (PSM) was performed to analyze the difference in survival between different stages and the effect of chemotherapy on prognosis. RESULTS: The OS of stage IIIA colon cancer sufferers was significantly superior to stage IIB/IIC and separate stage IIB or IIC colon cancer patients before and after PSM analysis (P<0.05 for all). Moreover, the difference in survival was more significant when stage IIB/IIC patients were compared with stage IIIA patients with chemotherapy. CONCLUSIONS: The survival paradox existed both in all stage IIB/IIC patients, or individual stage IIB or IIC patients compared with stage IIIA sufferers, and the survival paradox between stage IIIA and stage IIC was more obvious. Moreover, chemotherapy had a positive effect on the prognosis of patients with stage IIIA, IIC and IIB in this study. Chemotherapy exacerbates the survival paradox of colon cancer, even if it is not the cause of the survival paradox.