Physicians' Beliefs About the Benefits and Risks of Adjuvant Therapies for Stage II and Stage III Colorectal Cancer

Background: Adjuvant therapy plays a major role in treating colorectal cancer, and physicians' views of its effectiveness influence treatment decisions. We assessed physicians' views of the relative benefits and risks of adjuvant chemotherapy and radiotherapy for stages II and III colon and rectal cancers. Methods: The Cancer Care Outcomes Research and Surveillance Consortium surveyed a geographically dispersed population of medical oncologists, radiation oncologists, and surgeons in the United States about the benefits and risks of adjuvant therapies for colorectal cancer. We used logistic regression to assess the association of physician and practice characteristics with beliefs about adjuvant therapies. Results: Among 1,296 respondents, > 90% believed the benefits of adjuvant therapies for stage III colorectal cancer outweigh the risks. Only 21.9%, 50%, and 50.4% believed in the net benefit of chemotherapy for stage II colon cancer, chemotherapy for stage II rectal cancer, and radiation for stage II rectal cancer, respectively. Younger physicians were less likely than others to perceive adjuvant therapy for stage II colorectal cancer as beneficial. Medical oncologists were more likely than surgeons and radiation oncologists to endorse the benefits of adjuvant chemotherapy and radiation for stage II rectal cancer, but less likely for stage II colon cancer. Conclusions: Physicians largely agreed that the benefits of adjuvant chemotherapy for stage III colon cancer, as well as chemotherapy, and radiation for stage III rectal cancer, outweigh the risks, consistent with strong evidence, but were divided over the net benefit of adjuvant therapies for stage II colorectal cancer, where evidence is inconsistent.