Opportunity lost: Adjuvant chemotherapy in patients with stage III colon cancer remains underused

Abstract

Introduction: There is strong evidence supporting the efficacy of adjuvant chemotherapy for patients with pathologic, stage III colon cancer. This study examines differences in adherence to evidence-based adjuvant chemotherapy guidelines for pathologic, stage III colon cancer cases across hospital and patient subgroups.

Methods: Patients with stage III colon cancer were identified from the 2003 to 2011 National Cancer Data Base (NCDB). A logistic regression model was used to estimate the odds of receipt of adjuvant chemotherapy across varying hospital and patient characteristics. A multivariable Cox proportional hazards model was used to estimate the association between receipt of adjuvant chemotherapy and 5-year survival. Risk adjusted observed/expected (O/E) outcome ratios were calculated for each hospital to compare hospital-specific quality of care during the study period.

Results: A total of 124,008 patients met the inclusion criteria. Adjuvant chemotherapy was not administered to 34%. The rates of adjuvant chemotherapy have shown little improvement over time (63% in 2003 vs 66% in 2011). The Cox model indicates that patients receiving adjuvant chemotherapy had better survival (hazard ratio = 0.48, 95% confidence interval 0.47-0.49). Analysis of risk adjusted O/E ratios indicated no consistent pattern as to which hospitals were performing optimally or subopitmally over time.

Conclusion: There has been no meaningful improvement in receipt of chemotherapy in patients with stage III colon cancer. The fact that chemotherapy is not being considered or offered to more than 20% of patients with node-positive colon cancer suggests that there are substantial process failures across many institutions and regions in the United States.