A. Z. Becerra1, C. P. Probst1, C. T. Aquina1, B. Hensley1, M. G. Gonzalez1, K. Noyes1, J. R. Monson1, F. J. Flemming1 1University Of Rochester,Surgery,Rochester, NY, USA
Introduction:
There is strong evidence supporting the efficacy of adjuvant chemotherapy for pathological stage III colon cancer patients. Therefore, understanding factors associated with receipt of chemotherapy is important in order to identify subpopulations that might be at risk of not receiving optimal care. This study explores differences in adherence to evidence-based adjuvant chemotherapy guidelines for pathological stage III colon cancer cases across hospitals and patient subgroups. In addition, the relationship between receipt of chemotherapy and 5-year survival was examined.
Methods:
Stage III colon cancer patients were identified from the 2003 – 2011 National Cancer Data Base (NCDB). Bivariate analyses assessed factors associated with receipt of adjuvant chemotherapy. Factors achieving a p-value < 0.2 were included in multivariable analyses. Logistic regressions were used to estimate receipt of adjuvant chemotherapy across varying hospital characteristics including geographic location, cancer center type, and hospital volume. Patient factors included were age at diagnosis, year of diagnosis, sex, race/ethnicity, insurance type, household income, education, urban/rural classification, Charlson comorbidity scale, and tumor histology. Kaplan-Meier curves and multivariable Cox proportional hazards models were used to estimate the association between receipt of chemotherapy and 5-year survival for patients diagnosed from 2003-2006. In addition, the population attributable risk of death was calculated to estimate the number of deaths per year that could be avoided had everyone in the sample received adjuvant chemotherapy.
Results:
There were 124,008 patients who met the inclusion criteria. Adjuvant chemotherapy was not administered to 34% of the sample. Of these, 66% did not have a reason as to why chemotherapy was not offered as part of the planned first course of therapy. The rates of adjuvant chemotherapy have shown little improvement over time (63 % in 2003 vs. 66% in 2011). Factors associated with lower odds of receiving adjuvant chemotherapy include no insurance, lower income, worse comorbidity status, and black race. The Kaplan-Meier curves (Figure 1) indicate that patients receiving chemotherapy have better survival (p <0.001). This effect persisted in the multivariable analysis, which estimated a 52% reduction in the hazard of death (HR = 0.48, 95% CI: 0.47-049) in patients who received chemotherapy as compared to those who did not. The population attributable risk is 21% which indicates that over 1,400 deaths per year could be avoided if all stage III patients received adjuvant chemotherapy.
Conclusion:
There has been no meaningful improvement in receipt of chemotherapy in patients with stage III colon cancer. The fact that chemotherapy was not being considered or offered to over 20% of patients with node positive colon cancer suggests that there are significant process failures across many institutions and regions in the United States.
