Dr Alawadhi on the Link Between Obesity/Overweight and Breast Cancer Outcomes

"These findings shed the light on the importance of finding the optimal strategy for tackling obesity and overweight [to achieve] better outcomes for [patients with] breast cancer."

Aydah Alawadhi, MBBS, a consultant medical oncologist and chair of the Haematology & Oncology Division at Sheikh Shakhbout Medical City, discussed data on the association between obesity and distant recurrence and breast cancer mortality across subgroups of patients with early-stage breast cancer.

Alawadhi began by stating that there has been a wealth of data on the effects of obesity, overweight, and body mass index (BMI) on breast cancer prevention, risk reduction and even survival. One such study, presented by Hongchao Pan, MSc, PhD, of The University of Oxford, at the 2024 San Antonio Breast Cancer Symposium, highlighted the significant effectof overweight status and obesity on breast cancer prognosis. The large-scale analysis, which included data from 206,904 women with early-stage breast cancer across 147 clinical trials, demonstrated a strong association between higher BMI and an increased risk of distant recurrence and breast cancer mortality, Alawadhi reported. Specifically, for every 5-kg/m² increase in BMI, the relative risk of distant recurrence was 1.06, with obese women experiencing an appoximately 17% higher risk compared with lean women, she said. This relationship remained consistent across subgroups, irrespective of patient characteristics—like menopausal status—or tumor biology, including estrogen receptor–positive vs –negative disease, Alawadhi noted.

The analysis also revealed a linear association between BMI and absolute risk of distant recurrence, Alawadhi continues. A 12-unit increase in BMI corresponded with an approximately 2% absolute increase in the 10-year risk of distant recurrence, whereas a 5-unit BMI increase was associated with a 1% absolute risk increase, she stated. These findings emphasize the challenge of achieving meaningful risk reduction through BMI management, as a 5-unit decrease in BMI is difficult to attain through lifestyle interventions alone, Alawadhi explained.

Despite the modest absolute risk difference between BMI subgroups, the consistency of the association between BMI and disease outcomes across all breast cancer subtypes underscores the importance of addressing obesity as a modifiable risk factor, Alawadhi emphasized. Given the well-established links between obesity, inflammation, metabolic dysregulation, and hormone-driven tumor progression, strategies to mitigate its effect on breast cancer outcomes are crucial, she said. Future research should focus on identifying optimal interventions to improve survival outcomes for patients with breast cancer, Alawadhi concluded.