Changes of bodyweight and lipids during intermittent maximum androgen blockade (IMAB) in the treatment of advanced prostate cancer

Abstract

4661 Background: The androgen-depleted state leads to physiological changes. The reversibility of these effects is unknown. Methods: Patients with either recurrent local or advanced disease were treated with a combination of Flutamide 250mg tid and a 3 monthly depot of Leuprolide 22.5mg (MAB) for 9 months. When serum PSA level at 9 months was <4.0 ng/ml, treatment was withheld until PSA reached >20 ng/ml or pretreatment level. This cycle of ON- and OFF-treatment was repeated until disease progression whilst on MAB therapy. Bodyweight, fasting serum lipids and testosterone were measured at set intervals during ON and OFF therapy. Results: 233 patients were enrolled in a prospective multicenter trial. Median follow up was 139 weeks. 229 completed cycle 1 ON-treatment (ON1), 204 cycle 1 OFF-treatment (OFF1), 89 ON2, 63 OFF2, 8 ON3 and 4 patients OFF3. Median duration in OFF1, OFF2 and OFF3 were 53, 28 and 11 weeks, respectively. From baseline until the end of follow-up 47.8% gained weight (26.3% 2–5 kg and 21.5% ≥5 kg). During ON1 51.3% gained ≥2kg. During OFF1 21% of these patients continued to gain ≥ 2kg, 53% stabilized and 26% lost ≥ 2kg. When these patients restarted MAB 46% regained ≥ 2kg, 43% remained stable and 11% lost ≥ 2kg. There were no significant changes in lipids and no correlation between changes in weight and lipids ON and OFF treatment. There was no significant correlation between baseline testosterone level and changes in weight or lipids. Conclusions: Almost 50% of patients gain weight during IMAB. Most weight gain is seen during the first 9 months of treatment. In a quarter of these patients, the weight gain was reversible when MAB was stopped and an additional half of these patients had stabilization of weight. Almost half of these patients regain weight once MAB recommenced. There was no significant change in lipids towards a pro- or anti-atherogenic direction. Baseline testosterone did not to predict for changes in weight or lipids. No significant financial relationships to disclose.