Blog | Tuesday, August 28, 2012

QD: News Every Day--Heavier women do worse with breast cancer recurrence, survival

Heavier women treated for breast cancer have higher rates of recurrence and mortality, a study found.

Obesity was associated with inferior outcomes in patients with hormone receptor-positive operable breast cancer treated with standard chemohormonal therapy, reported researchers who looked at the relationship between body-mass index (BMI) and outcomes in three adjuvant trials that included chemotherapy regimens with doxorubicin and cyclophosphamide.

Results appeared online at Cancer.

When evaluated as a continuous variable, increasing BMI in obese women (greater than 30 kg/m2) and overweight women (BMI between 25 and 29.9 kg/m2) was associated with inferior outcomes in hormone receptor-positive, human epidermal growth receptor 2 (HER-2)/neu-negative disease for disease-free survival (P=.0006) and overall survival (P=.0007), but not in HER-2/neu-overexpressing or triple-negative disease.

When evaluated as a categorical variable, obesity was associated with inferior disease-free survival (hazard ratio [HR], 1.24; 95% confidence interval [CI], 1.06-1.46; P=.0008) and overall survival (HR, 1.37; 95% CI, 1.13-1.67; P=.002) in hormone receptor-positive disease, but not other subtypes. In a model including obesity, disease subtype, and their interaction, the interaction term was significant for overall survival (P=.02) and showed a strong trend for disease-free survival (P=.07). Similar results were found in two other trials.

The study's lead author told Reuters that heavier women may produce more estrogen, and that higher insulin levels can stimulate breast cancer cells.

"The highest priority is just getting through the chemotherapy if chemotherapy is necessary and taking their endocrine therapy," Dr. Sparano said. "But for those who are obese or overweight, there may be additional benefits that one can achieve through diet and through weight reduction that may produce a reduction in the risk of recurrence that's just as significant as the reduction that they get from the standard therapies."