Post-diagnosis BMI and related factors have been understudied when it comes to their interactions with cancer mortality and morbidity. This meta-analysis provides clarity on the topic.
Previous studies that evaluated body fatness and mortality of patients after breast cancer have been too limited to provide robust conclusions. This study, published in the International Journal of Cancer, provided a systematic review of previous research articles on this topic in order to evaluate evidence pertaining to body mass index (BMI), waist circumference, waist-to-hip ratio, and weight change in relation to breast cancer prognosis. Data were gathered from PubMed and Embase, and the study used data from studies published up to October 31 of 2021.
Higher BMI Contributes to Mortality in Cancer Patients
The authors used various methods to evaluate the gathered data, including random-effects meta-analyses to estimate summary relative risks. The evidence was evaluated by an expert panel using defined grading criteria, and the study used data from one randomized controlled trial and 225 observational studies, from a total of 220 publications. They found strong evidence that higher post-diagnosis BMI associates with increased all-cause mortality, breast cancer-specific mortality, and second primary breast cancer. Positive associations were also observed for waist–hip ratio, waist circumference, and all-cause and breast-cancer-specific mortality. Additionally, the randomized controlled trial showed some potential benefit to intentional weight loss on disease-free survival, but additional interventional trials are needed in more diverse population groups in order to reach more firm conclusions.
A Healthy, Active Lifestyle Can Help Improve Post-Cancer Outcomes
Some evidence for post-diagnosis BMI being associated with a higher risk of recurrence, non-breast cancer deaths, and cardiovascular death was found, but it was not conclusive. The authors note that adherence to lifestyle recommendations in line with the recently released American Cancer Society Guideline on Diet and Activity for Cancer Survivors has been shown to lower all-cause mortality, but that although a healthy diet and physical exercise are helpful, additional data would be beneficial.
Chan, D. S. M., Vieira, R., Abar, L., Aune, D., Balducci, K., Cariolou, M., Greenwood, D. C., Markozannes, G., Nanu, N., Becerra-Tomás, N., Giovannucci, E. L., Gunter, M. J., Jackson, A. A., Kampman, E., Lund, V., Allen, K., Brockton, N. T., Croker, H., Katsikioti, D., . . . Tsilidis, K. K. (2023). Postdiagnosis body fatness, weight change and breast cancer prognosis: Global Cancer Update Program (CUP global) systematic literature review and meta-analysis. Int J Cancer, 152(4), 572-599. https://doi.org/10.1002/ijc.34322