Login to Access Video or Poster Abstract: MP57-11
Sources of Funding: Programme Hospitalier de Recherche Clinique (PHRC) 2013. Number of project: 13-0257

Introduction

Background. Observational studies suggested that androgen deprivation therapy (ADT) is associated with an increased cardiovascular (CV) risk. They all compared ADT-treated cancer patients to non-treated patients or non-cancer subjects and there has not been to date a single trial with CV harm as a primary end point._x000D_ Objective. To evaluate whether CV risk differs by type of ADT._x000D_

Methods

Design. Through nationwide population-based claims reimbursement database linked to hospital discharge database, we identified adult men with prostate cancer who initiated ADT (GnRH agonist or antagonist, antiandrogen [AA], combined androgen blockade [CAB]) or had orchiectomy (OT) between 1st July 2010 and the 31st December 2011, and followed them up to 31st December 2013. _x000D_ _x000D_ Outcome measurements and statistical analysis. The main analysis followed an 'on-treatment' approach that censored all patients at the time of first therapeutic modification; it used Cox regression analysis to estimate hazard ratios (HR) for hospitalizations for ischemic events (myocardial infarction or ischemic stroke, whichever came first), adjusted on age, baseline co-morbidities and taking into account death as a competing risk._x000D_

Results

Among the 35 118 new ADT users, 70.8% received GnRH agonist (reference group), 12.1 % CAB, 13.0 % AA, 3.6 % GnRH antagonist and 0.6 % had OT. During a median follow-up of 972 days, we observed 5 258 (15.0 %) overall death in a median time of 525 days. Through the 'on-treatment' approach, 472 ischemic events were eligible: 213 MI and 259 strokes. CAB was associated with an increased risk (adjusted HR [95%CI], 1.60 [1.27-2.03]) and AA with a decreased risk (adjusted HR [95%CI], 0.61 [0.43-0.88]) of ischemic events when compared to GnRH agonist. No significant association was found with GnRH antagonist (adjusted HR [95%], 1.20 (0.67-2.14)). Residual confounding might exist as CV risk factors have been under-estimated though non-differentially.

Conclusions

CV risk appeared different across ADT modalities and had to be taking into account as regard oncologic benefit of each modality. The probability of a clinically meaningful difference when comparing GnRH antagonists to agonists appears rather low.

Funding

Programme Hospitalier de Recherche Clinique (PHRC) 2013. Number of project: 13-0257