Weight changes in women with metastatic breast cancer treated with megestrol acetate: a comparison of standard versus high-dose therapy.

One hundred seventy-two patients with advanced breast cancer were randomized to receive 160 or 800 mg megestrol acetate per day. Patients were monitored monthly for weight, blood pressure, performance status, edema, measurement of clinically evident lesions, and toxicities. Pretreatment characteristics were similar in both arms. Weight gain was the most commonly seen side effect, with 52% of patients gaining in excess of 10 lb and 28% gaining more than 20 lb. Median weight gain for standard-dose treatment was 5 lb compared with 18 lb for high-dose treatment. There was no dose modification for excessive weight gain in any of the patients receiving the standard dose but doses were modified in 15% of those receiving high-dose megestrol acetate. Weight gains for both groups were analyzed at 30, 90, and 180 days after study entry. Treatment arm, age, prior therapy, response to prior endocrine therapy, race, performance status, dominant disease site, and number of disease sites were included in the analysis. At 30 days, patients taking high-dose megestrol acetate had a mean weight gain of 2.5 lb whereas patients taking the standard dose had stable weights. Factors predictive of weight gain were younger age (P = .0012) and fewer disease sites (P = .017). At 90 and 180 days, patients taking high-dose megestrol acetate had consistently gained more weight than those taking the standard dose (9.0 and 16.0 lb v 2.5 and 9.0 lb, respectively). Significant covariables were treatment arm (P = .0006) and younger age (P = .0211). Probability of gaining 20 lb was dependent only on treatment dose (P = .0002), and median time to a 20-lb weight gain was 217 days. Increases in systolic and diastolic blood pressures were seen in both groups, but the differences were not significant. Megestrol acetate is associated with weight gain in women with advanced breast cancer, and the amount of weight gained correlates directly with dose of megestrol acetate, length of treatment, and age of patient.