MedWire News: Overweight or obese women with breast cancer tend to have a poorer response to chemotherapy than their healthy-weight counterparts, study results show.
The findings suggest that overweight patients may improve their chances of responding to chemotherapy by losing weight.
Dr Abenaa Brewster, from the University of Texas MD Anderson Cancer Center in Houston, USA, and team studied data on 1169 patients who were diagnosed with invasive breast cancer and treated with chemotherapy before surgery.
In total, 30% of patients were obese, defined as a body mass index of 30 kg/m2 or higher, 32% were overweight, with a body mass index of 25-29.9 kg/m2, and the remaining patients were normal or underweight, with a body mass index of less than 25 kg/m2.
Analysis revealed that overweight and obese patients were around 40% less likely to have a complete response to chemotherapy than patients who were normal or underweight.
The researchers also found that obese breast cancer patients had poorer survival rates over the first 4 years than those with a healthy weight.
The findings "may be attributed to the influence of body mass index on the clinical effectiveness of chemotherapy or the underdosing of overweight and obese patients by clinicians because of fears of [drug] toxicity," they say.
Writing in the Journal of Clinical Oncology, Dr Brewster and team conclude: "Higher body mass index was associated with worse... response to neoadjuvant chemotherapy.
"In addition, its association with worse overall survival suggests that greater attention should be focused on this risk factor to optimize the care of breast cancer patients."