Higher Body Mass Index May Increase Risk of Second Cancer in Breast Cancer Survivors
, by DCEG Staff
Breast cancer survivors with a higher body mass index (BMI) were more likely to develop a second cancer, according to a study published April 5, 2021 in the Journal of the National Cancer Institute.
Previous studies have shown that breast cancer survivors have an 18 percent increased risk of developing a second cancer, which is likely due to shared risk factors between the first and second cancers, genetics, and long-term effects of breast cancer therapy. Obesity is strongly associated with an increased risk of several types of cancer, however, little is known about the role of obesity and the risk of developing a second cancer. DCEG investigators in collaboration with researchers in Kaiser Permanente examined the association of BMI and second cancers among 6481 women diagnosed with invasive breast cancer at Kaiser Permanente Colorado and Washington, among whom 822 (12.7 percent) developed a second cancer. The majority of women were overweight (33.4 percent) or obese (33.8 percent) at the time of their initial diagnosis. The authors found that increasing BMI was associated with an increased risk of developing a second cancer. In particular, for every five unit increase in BMI the risk of developing a second cancer increased by seven percent, an obesity-related cancer by 13 percent, a second breast cancer by 11 percent, and an estrogen-receptor positive second breast cancer by 15 percent.
The results of this study increase the understanding of contributing factors to second cancer risk and may inform prevention strategies such as weight loss, nutrition, and physical activity for breast cancer survivors.
Feigelson HS et al, Body Mass Index and Risk of Second Cancer among Women with Breast Cancer. J Natl Cancer Inst. April 2021. DOI: 10.1093/jnci/djab053. [Epub ahead of print].