ANAHEIM, CA (UroToday.com) - Dr. Samir Taneja, New York University moderated a session on "With the Evidence Available, What is the Role for Intermittent Androgen Blockade?" at the annual SUO meeting at the AUA. The talks were presented by Drs. Martin Gleave, University of British Columbia and Laurence Klotz, University of Toronto.

Dr. Taneja started with a description of the side effects of ADT to include cardiovascular toxicities. Dr. Gleave presented a talk "Intermittent Androgen Ablation is the Standard of Care". He described a shift in the CaP population with earlier detection, longer life expectancies and earlier treatment strategies. However, the contribution of early ADT adds cost and toxicity. Intermittent androgen suppression (IAS) is feasible is it has less adverse effects and equivalent to continuous therapy. Early ADT is supported in animal trials and in the EORTC "Bolla" and ECOG "Messing" trials. Careful patient selection is important, as the EPC trial showed a worse outcome for Casodex treated low risk patients compared to placebo. He showed biologic rationale that IAS in mice had prolonged time to progress and delay in onset of AI disease. The phase II data showed that application in humans could continue out to 5-7 cycles with about a 20% dropout rate at each cycle. The benefit was 50% time off therapy with the QoL benefits associated with this. A meta-analysis recently published supported this. Two large randomized trials have completed accruing patients and data will be forthcoming. Two small European phase III trials showed no inferiority in time to progress or survival using IAS compared to continuour therapy. This points to IAS as the standard of care, and should be confirmed with the randomized trial outcomes.

Dr. Klotz presented "Continuous and Maximal Androgen Blockade; Are We Overtreating?" He started with an answer "sometimes yes, sometimes no". He said that PSA failure was the most common impetus to initiate ADT and this is a heterogeneous group. With intermediate to high-risk CaP, the data supports early therapy, but the EORTC 30891 trial by Dr. Studor did not demonstrate a big difference with early therapy. It seems that only high risk patients benefit, and lower risk men with a rising PSA may not. Thus, IAS would be appropriate or treating patients at a later point in time when it is more appropriate to use continuous treatment. If IAS is begun when the PSA is >20ng/ml, then the off treatment interval is shorter.

Regarding maximal androgen blockade, (MAB), he pointed out that AR is still active in AICaP and ligands other than androgen can facilitate its binding to the ARE. He showed a trial just published from Japan suggesting that patients with stage C and D CaP have better progression free survival than those on ADT alone.

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Written by Christopher P. Evans, MD, a Contributing Editor with UroToday.

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