Increased Body Mass Index Shows a Link to Breast Cancer

In an interview with CancerNetwork®, Neil M. Iyengar, associate professor of medicine at Memorial Sloan Kettering Cancer Center, spoke about the importance of exercise in mitigating adverse effects (AEs) related to cancer treatment. Iyengar highlighted his study, “Obesity promotes breast epithelium DNA damage in women carrying a germline mutation in BRCA1 or BRCA2” to discuss the effects of body mass index as an established risk factor for breast cancer. Iyengar also discussed the relationship between exercise and genetic dispositions of cancer.

The study found that there was mechanistic evidence between body mass index and patients who developed breast cancer with a BRCA mutation.

Transcript:

Exercise is an important component of taking care of one's own well-being. We’re also learning that exercise may be helpful for mitigating AEs related to cancer therapy and symptoms related to cancer.¹ There is a growing body of evidence that [shows that] exercise may also have some direct anti-cancer activity. There are several professional bodies, like the American Society of Clinical Oncology [ASCO], the American Cancer Society, and the American College of Sports Medicine, that recommend exercise as part of a cancer treatment plan. We have conducted several research studies, as well as many other groups, which have demonstrated that exercise is feasible during cancer treatment, including during chemotherapy. It can be helpful for general well-being but may also help to improve response to cancer therapies, and that's an ongoing area or area of research right now.

Whenever we publish our findings regarding lifestyle interventions in cancer, a very common question is: what about [patients] with a genetic predisposition, like a breast cancer gene [BRCA] mutation? Does it matter if they’re exercising, eating well, or doing other lifestyle or environmental-related [activities] when they have a genetic predisposition to developing certain types of cancer? This was the question that came from a lot of patients. That stimulated us to conduct this study, in collaboration with Kristy A. Brown’s lab [from Weill Cornell Medicine], to try and understand: do we see the same types of obesity-related inflammation and changes within the breast microenvironment that we do in [patients] who don’t have a genetic predisposition?² We found that levels of DNA damage in the breast epithelium are increased in association with obesity, in association with insulin resistance independent of obesity in women who carry germline BRCA1/2 mutations. This suggests that these lifestyle components can further increase the risk or penetrance of BRCA-related cancers.

References

1. Iyengar NM. Inclusion of exercise in cancer treatment planning. JACC CardioOncol. 2022;4(4):504-506. doi:10.1016/j.jaccao.2022.10.002
2. Bhardwaj P, Iyengar NM, Zahid H, et al. Obesity promotes breast epithelium DNA damage in women carrying a germline mutation in BRCA1 or BRCA2. Sci Transl Med. 2023;15(684):eade1857. doi:10.1126/scitranslmed.ade1857