MP22-11\u2003CHANGES IN COMORBIDITY AFTER TREATMENT WITH GONADOTROPHIN RELEASING AGONISTS VERSUS ANTI-ANDROGEN MONOTHERAPY IN MEN WITH ADVANCED NON-METASTATIC PROSTATE CANCER

Abstract

INTRODUCTION AND OBJECTIVES: Studies on adverse effects of different androgen deprivation therapies (ADT) have previously focused on specific conditions (coronary heart disease, stroke, diabetes, fractures). None have reported effects on overall comorbidity. The objective of this study was to compare the increase in overall comorbidity among men receiving gonadotrophin releasing (GnRH) agonists with those on anti-androgen (AA) monotherapy (predominantly 150 mg bicalutamide daily) for advanced prostate cancer (PCa). METHODS: Men on either GnRH (n=4887) or AA (n=2078) for high risk or regionally advanced PCa were selected from the Swedish Prostate Cancer Database PCBaSE 3.0, along with age-matched PCa-free men for comparison. Incremental change in comorbidity was assessed in all study participants using the Charlson Comorbidity Index (CCI), calculated from 5yrs before through to 5yrs after the ADT start date. The difference in excess rate of CCI increase for men on GnRH agonists compared with men on AA monotherapy was determined using multivariable linear regression, with separate models for periods before and after starting ADT. The difference in risk of any new additional comorbidity after starting ADT was assessed using multivariable Cox proportional hazards regression. RESULTS: The difference in excess rate of change in CCI after starting ADT was greater for men on GnRH agonists than AA monotherapy (5.7% per year; 95%CI 2.9 to 8.5% per year). No difference was evident before starting ADT. Risk of any new comorbidity following the start of ADT was also increased in men on GnRH agonists compared with AA monotherapy (HR: 1.32; 95% CI:1.20-1.44). CONCLUSIONS: These findings suggest that the rate of increase in overall comorbidity is greater among men on GnRH agonists than men on AA monotherapy, irrespective of baseline comorbidity. Due to limitations inherent in observational studies, these results should be confirmed through randomized controlled trials to better inform treatment decisions for PCa when curative therapies are not an option. Source of Funding: Swedish Cancer Society; NHMRC