• Home
• CME test
• CME information and faculty disclosures
• Select publications
• Related audio program

DR OH: SWOG 9346, as many people know, has been a study that’s been going on for over 15 years, comparing intermittent versus continuous androgen deprivation therapy in men with metastatic prostate cancer. And the results were anticipated for a long time. This was a plenary session talk presented by Dr Hussein, and I was able to be the discussant for this, which really gave me a chance to kind of think about the issues around the study.

And the basic bottom line results were that, in fact, this was intended to be a noninferiority study to prove that intermittent was noninferior to continuous. And it did not show that. It was not proven to be noninferior. And, in fact, the hazard ratio for survival in the intermittent versus continuous arm was inferior by 9% — 1.09 was the hazard ratio.

So I think the real question around whether or not noninferior is the same as inferior was one of the big discussions that really came out around the data that were presented.

And, in fact, some people have pointed out that the 95% confidence intervals did cross one, which really would suggest that this did not prove that one arm was actually superior than the other. And I think that the debate around quality of life and around the cost of therapy and, really, the popularity of intermittent androgen deprivation came up as arguments that maybe intermittent was just as good as continuous.

DR LOVE: How did this trial’s results compare to others that have looked at this in the past?

DR OH: This was the only study that ever looked at metastatic prostate cancer comparing intermittent to continuous with survival as the primary endpoint.

Of course, in the New England Journal, the PR-7 study led by the NCIC was presented by Dr Crook and her colleagues. And this study looked at a different population, a rising PSA population without metastatic disease. And in that study, presented at ASCO in the prior year, there was no difference in survival outcomes between intermittent and continuous androgen deprivation therapy. So the belief really was that perhaps SWOG 9346 would also show a similar result, but it did not.

And so I think in the end, there have been many, many studies looking at this, but as I presented in the plenary session, most of them were small, underpowered really to look at this question in the metastatic population.

DR LOVE: So Dan, what does this all mean in terms of actually taking care of patients and this strategy from your point of view?

DR PETRYLAK: So the way I look at it is that it is acceptable to consider intermittent androgen blockade for those patients who are nonmetastatic, as we see in the Canadian study. It didn’t seem to make a difference in the overall survival.

So for a patient who is a PSA-only relapse, nonmetastatic disease, I think it’s appropriate to consider intermittent therapy.

The other situation, in a patient who’s metastatic, I think it’s an important discussion that needs to go on between a physician and a patient. There’s an 8-month difference in survival, but you have to balance that against the side effects that may go on with continuous therapy.