Patterns of androgen deprivation therapies among men diagnosed with localised prostate cancer: a population-based...

Many men diagnosed with localised prostate cancer will eventually be treated with androgen deprivation therapy (ADT). ADT is associated with adverse effects and its timing is controversial. Data on patterns of use are scarce. We describe patterns of ADT use, defined as castration (medical and surgical) or antiandrogen monotherapy initiated after primary treatment, in a population-based cohort.

Data were extracted from the population-based Prostate Cancer data Base Sweden (PCBaSe). Totally 45,147 men diagnosed between 1997 and 2009 with clinical stage T1-2, N0-NX, M0-MX and prostate specific antigen (PSA)<50ng/ml without primary ADT were included. Outcomes in the period 2006 through 2010 were analysed using a period analysis approach.

The cumulative incidence of castration at 10years after diagnosis was 11.6% (95% confidence interval (CI), 11.0-12.2%). The corresponding proportion of antiandrogen monotherapy was 10.8% (95% CI, 10.2-11.4%). Castration was the dominant therapy among men on deferred treatment. The probability of receiving castration rather than antiandrogen monotherapy increased with age. Estimated median durations of castration ranged from 4years in the deferred treatment high-risk group to 17years in the prostatectomy low-risk group. The main limitation was the lack of information on progression to metastatic disease and PSA at the time for initiation of ADT.

When initiated early after curative treatment, the duration of castration can be decades. The findings indicate that more accurate tools are necessary to guide which men should be selected for ADT as secondary treatment.