There has been much conversation surrounding the use of intermittent androgen deprivation (IAD) as opposed to continuous androgen deprivation (CAD) in men with prostate cancer who need hormone therapy (ADT). The question that has been at issue is if either method is superior to the other.
There have been studies that have concluded that they either are equal in efficacy or that CAD is superior. However, all studies do conclude that IAD does provide a superior quality of life (QoL). We also know that IAD does save money, an increasing concern given the high cost of medical care.
The studies that have compared CAD with IAD have all been using luteinizing hormone-releasing hormone agonists like Eligard (leuprolide), Zoladex and Lupron. Until this recently reported study by Crawford, etal the hormone therapy agents have not included the newest addition, the gonadotrophin-releasing hormone (GnRH) antagonist degarelix.
The study included men who had a rising prostate-specific antigen (PSA) levels after prior definitive therapy and testosterone >150 ng/dl. These men were randomized to intermittent degarelix or to continuous degarelix or continuous leuprolide.
Initial treatment was 7 months of degarelix or leuprolide after which the men in the intermittent arm with a PSA that was less than 2 ng/ml discontinued therapy if their PSA was less than 2 ng/ml. Men in the continuous arm of the study remained on therapy.
They found that the intermittent use of degarelix is non-inferior to CAD in maintaining PSA suppression when administered in a regimen of 7 months of treatment and a 7 month off-treatment period for men with a PSA less than 2 ng/ml. Additionally, they found that 50% of men in the intermittent arm recovered from castration by 112 days after treatment discontinuation.
In reality, intermittent hormone therapy in the clinic should not be administered in such a lock step process. The timing of going on and off therapy should be a very individual process with factors such as Gleason scores, goal PSA numbers and re-starting numbers determined with a careful consultation with an experienced medical oncologist or specially trained and experienced urologist.
Presented by E. David Crawford, Neal Shore, Celestia Higano, Anders Neijber and Vladimir Yankov at the 24th International Prostate Cancer Update – February 19 – 22, 2014 – Cascade Conference Center – Vail, Colorado USA
Joel T. Nowak, M.A., M.S.W.