ASCO 2012, Chicago, USA

Intermittent hormonal therapy versus continuous therapy for advanced prostate cancer

Dr Maha Hussain – University of Michigan, Ann Arbor, USA


You’re looking at continuous hormone therapy versus intermittent hormone therapy and certain kinds of prostate cancer were different from other kinds. Can you tell me, first of all, what you did in the study?

We took patients who had metastatic prostate cancer, that’s cancer that has spread outside the pelvic region; they could have gone to lymph nodes, they could have gone to the bone in any area of the bone. We treated them with seven months of hormone treatment, which is standard, and then after seven months if their cancer was behaving in a good way, and a good way was if their PSA was going down, four or below, and was confirmed on two months’ values, then they were randomly assigned to the continuous treatment or intermittent treatment.

And this study took a very long time but you have got a very clear result, haven’t you? What did you find?

What we found is that in the overall population, the randomised population, intermittent therapy appears to be inferior to continuous therapy. The reason it took so long is that the survival of patients who were randomised is significantly improved by comparison to our forecast in the 1990s.

Now there was a difference depending on whether it was extensive disease or minimal disease, wasn’t there? What was that?

To go back, when we do clinical trials we stratify patients in general by prognostic criteria to ensure that these prognostic criteria are adequately represented in both arms so that at the end of the results if you have one treatment better than the other that is not because you have somehow put good acting cancers in one side and bad acting cancers in the other. So that’s the randomised and the stratification. What we did is, because we saw the differences in the outcome, we went back to try to explore the possibility, is it possible that certain groups of patients seem to do better or worse with the way the treatments worked. When we did that kind of analysis, and again this is what we call secondary exploratory type analysis, what we find out is that on all grounds of subgroups, whether people had pain, whether it was race, whether it was prior hormone exposure, everything seemed to trend in favour of the continuous treatment except when you’re looking at the two subgroups of extensive versus minimal disease. In those categories it looked like the extensive disease patients, which is patients who have disease that has gone outside their spine and pelvis region or lymph node, it has gone to the arms, to the legs, to the ribs, to the liver, to the lung, these are the patients that seem to do just as well whereas the patients who had minimal disease, they seemed to do a lot worse. One thing that I must caution about, these are considered secondary analyses and secondary analyses are not something that has been powered for prospectively but nonetheless it’s very striking and it goes against what I would call the conventional belief.

So the overall clinical message for cancer doctors would be what?

Would be that continuous treatment is the standard of care; that if a patient requests to be on intermittent therapy they must be very carefully counselled regarding the downside of the intermittent therapy. And this is only applicable, my comments are only applicable, to metastatic disease.