Medical Research: What is the background for this study? What are the main findings?
Dr. Zafar: Multiple studies have suggested that obesity and colorectal cancer are related. For instance, obesity has been linked with an increased incidence of colon cancer. Obesity has also been associated with a greater risk of colon cancer recurrence. To date, no study has looked at the role of obesity in outcomes for patients with metastatic colorectal cancer. In our study of over 6000 patients receiving treatment for metastatic olcolorectal cancer, we found that patients with the lowest body mass index (BMI) were at greatest risk for worse survival. This does not mean that obesity is good. More likely, it means that those who are very underweight are least able to tolerate the best treatment, or being very underweight is a biologic marker of poor prognosis.
Medical Research: What should clinicians and patients take away from your report?
Dr. Zafar: It might be useful to pay special attention to very underweight patients, as those patients might be at higher risk for worse outcomes. This means understanding which treatment is optimal for their individual situation, taking their low weight into account.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Zafar: Future work should focus on prospectively assessing why underweight patients do poorly, paying particular attention to
1) the biology of being underweight and
2) receipt of treatment for those who are most underweight.
Zafar, J. Hubbard, E. Van Cutsem, F. Hermann, A.J. Storm, E. Gomez, C. Revil, and A. Grothey
Survival outcomes according to body mass index (BMI): results from a pooled analysis of 5 observational or phase IV studies of bevacizumab in metastatic colorectal cancer (mCRC) Ann Oncol (2015) 26 (suppl 4): iv117 doi:10.1093/annonc/mdv262.01
S. Yousuf Zafar, MD, MHS (2015). Underweight Colon Cancer Patients May Have Worse Prognosis