Factors associated with use of chemoradiation for rectal cancer.

Abstract

607 Background: Adjuvant or neoadjuvant chemotherapy (chemo) and radiation therapy (RT) have been the standard of care for virtually all patients with stages II/III rectal cancer for 20 years. However, recent analyses of the SEER database have demonstrated variation in treatment. Leveraging the clinical characteristics and patient beliefs available in the Cancer Care Outcomes Research and Surveillance Consortium (CanCORS) cohort, we determined the proportion and associated characteristics of those who received chemo and RT. Methods: We identified CanCORS patients with stage II/III rectal cancer with primary site resection, and used data from patient surveys and abstracted medical records to construct variables (age, gender, marital status, race, education, income, insurance status, stage, comorbidity, patient treatment beliefs, staging procedures, tumor location/size, types of providers seen). Results: Of the 310 eligible patients, 14% received neither chemo nor RT, 13% received chemo or RT, and 73% received both. Receipt of chemo and RT was associated with younger age, stage III, rectosigmoid junction (vs. rectum NOS) tumor, receipt of staging PET, and patient beliefs that chemo/RT would help them live longer, cure their cancer and help with symptoms. In a logistic model, age (<55 vs >65; OR=2.2, 95% CI: 1.31, 3.46), stage (III vs. II; OR=1.52, 95% CI: 1.06, 2.17), PET (OR=2.41, 95% CI: 1.15, 5.03) and rectosigmoid junction tumor (OR=1.59, 95% CI: 1.10, 2.29) were associated with receipt of chemo; similarly, age and rectosigmoid junction tumor were associated with RT. Of those who did not receive chemo or RT, 35% reported they did not think chemo/RT would help, 65% reported their doctor said chemo/RT would not help and 18% were worried about side effects; 65% reported they never saw a medical or radiation oncologist and 26% reported that no doctor ever discussed the possibility of chemo or RT. Conclusions: A significant proportion of patients with stage II/III rectal cancer did not receive chemo and RT, and a number of those reported that no doctor ever discussed the possibility of chemo or RT with them. While deviation from guidelines may be warranted and/or patient driven, further analyses should determine reasons for lack of recommended treatments.