CHICAGO — Women who are obese when they are diagnosed with early stage breast cancer have poorer outcomes than do women of normal weight—yet another reason for physicians to encourage weight control in their patients, according to Penny R. Anderson, M.D., a radiation oncologist at Fox Chase Cancer Center in Philadelphia.
“Obesity at the time of diagnosis significantly predicts poorer outcomes,” she reported at the annual meeting of the Radiological Society of North America. “We found an increased risk of breast cancer death and distant metastases in obese women, compared with normal-weight patients, although they did not present with more advanced-stage disease.”
The study included more than 2,000 women with stage I/II breast cancer who underwent lumpectomy, axillary dissection, and radiation therapy with or without systemic therapy.
The median age of the women was 58 years, with 22% considered normal weight, 43% considered overweight, and 35% considered obese.
The study, which had a median follow-up of 61 months, compared women in the three weight categories to determine independent predictors of local failure, distant metastases, cause-specific survival, and overall survival.
It found that the actuarial 5-year rates of distant metastases, cause-specific survival, and overall survival were the worst in obese women. (See table.)
There were some statistically significant baseline differences between the weight groups, with the obese group comprising more women who were older and postmenopausal. However, there were no statistically significant differences between the groups in terms of tumor size or number of involved lymph nodes, she said. In addition, the local failure rate was no worse in the obese women.
“Interventions to enhance weight control can have a beneficial effect on breast cancer outcome,” she concluded.