Utilization of adjuvant chemotherapy in “ideal candidates” with stage III colon cancer.

Abstract

4103 Background: Prior studies have observed under-utilization of adjuvant chemotherapy (ACT) in stage III colon cancer. Our aims were to observe the rate of utilization of ACT in very healthy or “ideal candidates”, identify reasons for omission and socioeconomic factors associated with ACT use, and observe patient outcomes. Methods: We queried patients from the National Cancer Database (NCDB) with stage III colon cancer, age<65, and Charlson-Deyo score of 0 who underwent resection in the United States between 2004-2015. Patients who received ACT were compared to patients who had surgery only (SO). We used chi-square test for categorical variables, Kaplan-Meier and Cox regression method for survival analyses. Results: Out of 243,388 stage III colon cancer patients during the study time, a total of 49,046 patients met the specific criteria of “ideal candidate”. Out of these, 88.5% received ACT and 11.5% underwent SO. The primary reason for chemotherapy omission was: no reason given (54.2%), patient/guardian refusal (26.7%), physician recommended against (9.3%), patient died (3%), unknown (6.7%). Patients who received ACT were more likely to be female, non-Hispanic white, have a higher level of education, travel shorter distance for cancer treatment, have private insurance or higher income as compared to counterpart ( all p<.001). Patients who received ACT had significantly better overall survival (5-year survival rate 74% vs. 54%, p<.001). This persisted after multivariable Cox regression analysis [HR:0.48 (CI:0.45-0.50), p<.001]. Conclusions: We observed a high rate of utilization (88.5%) of ACT in patients with stage III colon cancer who were under age 65 and without comorbidities. However, the omission of chemotherapy in this population remains a problem, partially due to patient refusal. Socioeconomic factors associated with lower utilization were primarily related to insurance status (private vs non-private). Patients who received ACT had significantly improved survival as compared to SO group. [Table: see text]