Factors Associated with Receipt of Adjuvant Chemotherapy in Stage II Colon Cancer

The benefits of chemotherapy in stage II colon cancer remain unclear, but it is recommended for high-risk stage II disease. Which patients receive chemotherapy and its impact on survival remains undetermined.

The National Cancer Database was surveyed between 2004 and 2016 for stage II colon cancer patients. Patients were categorized as high- or average-risk as defined by the National Comprehensive Cancer Network. The demographic characteristics of high- and average-risk patients who did and did not receive chemotherapy were compared using univariate and multivariable analyses. The survival of high- and average-risk patients was compared based on receipt of chemotherapy with Cox hazard ratios and Kaplan-Meier curves.

Overall, 84,424 patients met the inclusion criteria. A total of 34,868 patients were high-risk and 49,556 were average-risk. In high-risk patients, the risk factors for not receiving chemotherapy included increasing age, distance from the treatment facility, Charlson-Deyo score, and lack of insurance. In average-risk patients, factors associated with receipt of chemotherapy were decreasing age, distance from the treatment facility, Charlson-Deyo score, and non-academic association of the treatment facility. In both, chemotherapy was significantly associated with increased survival on the Kaplan-Meier curve. In the Cox hazard ratio, only high-risk patients benefited from chemotherapy (hazard ratio 1.183, confidence interval 1.116-1.254).

Factors associated with not receiving chemotherapy in high-risk stage II colon cancers included increasing age, medical comorbidities, increasing distance from the treatment facility, and lack of insurance. Chemotherapy is associated with improved overall survival in high-risk patients.