Study: Women Undergoing Chemotherapy for Breast Cancer Tend to Gain Weight

Women undergoing chemotherapy treatment for breast cancer are more likely to gain rather than lose weight because of both hormonal and behavior factors, according to researchers at the University of South Florida.

Researchers found that of 53 women with stage I to IIIb breast cancer, 32 percent gained weight after 3 months of chemotherapy and 58 percent gained weight after 6 months of chemotherapy.

Sixty percent of the women in the study were taking a 3-month regimen of cyclophosphamide and doxorubicin, and a third of the women received paclitaxel for an additional 3 months, according to the study presented at the American Institute for Cancer Research's 11th annual Research Conference on Diet, Nutrition and Cancer.

The amount of weight gain was two times greater with the 6-month regimen than with the 3-month regimen, according to Diane Riccardi, a research dietician at USF.

The women in the study kept a record of what they ate, indicating the percentage of fat intake increased from 26 percent to 30.2 percent for the women who gained weight by the end of their chemotherapy treatments. Riccardi reports that almost all the women were eating more fat and craving high-fat foods.

Study participants also reported feeling increased fatigue and decreased activity levels, with average hours worked dropping from 33.4 hours per week to 12.7 hours per week by the end of their chemotherapy regimen. Most of the women had decreased levels of estradiol and thyroid hormone after chemotherapy treatments were completed.

Researchers speculate that behavioral factors and a lower metabolic rate increase the likelihood of weight gain. They report that women usually expect to lose weight while on chemotherapy and are surprised and distressed when the opposite happens.

Other sources: University of South Florida, Reuters