The role of radiotherapy in the treatment of prostate cancer

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Published: 11 Jan 2011
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Prof Malcolm Mason - Cardiff University, UK
Prof Malcolm Mason discusses the results of an intergroup study - carried out by the UK Medical Research Council (MRC), the National Cancer Institute of Canada (NCIC) and the Southwest Oncology Group (SWOG) from the United States - looking at patients with locally advanced prostate cancer or high risk localised prostate cancer who would normally be treated with androgen deprivation therapy (ADT). This trial compared ADT alone with ADT plus radiotherapy and conclusively demonstrated the benefit of adding radiotherapy to ADT. Prof Mason speaks about the level of side effects experienced by the patients and looks forward to the results of the ongoing NCRI CHHIP study into hypofractionated radiotherapy.

NCRI Cancer Conference 2010, 7 November 2010, Liverpool

Professor Malcolm Mason – Cardiff University, UK

The role of radiotherapy in the treatment of prostate cancer

I was presenting the results of the intergroup study which was a study jointly conducted by the MRC, the UK Research Council, the National Cancer Institute of Canada and SWOG in the United States. This was a study in patients with locally advanced prostate cancer or with high risk localised prostate cancer, for whom the standard treatment was androgen deprivation therapy alone. It was a randomised trial comparing androgen deprivation therapy, or ADT, alone versus ADT plus radiotherapy to the prostate. The trial showed a significant benefit in terms of overall survival and disease specific survival for patients who received radiotherapy, and in fact the reduction in the chances of death from prostate cancer at seven years was 43%. So that’s a very substantial reduction in the risk of dying of prostate cancer.

How have these results been received in the UK?

It’s interesting because there are a lot of developments going on in this group of patients. They are a group who many people are wanting to study and to optimise therapy, quite rightly, and I don’t think androgen deprivation therapy and radiotherapy is a treatment that is completely devoid of side effects; we are knowing more and more about the long term effects of hormone therapy particularly. So I’ll make several points. One is that the reception that this has had has reinforced the view we had at the beginning that one of the barriers to giving radiotherapy was the perception that somehow it’s a nasty treatment, it’s very toxic. And I’ve even had the comment from urological colleagues that it’s all very well for you as a radiation oncologist but we’re the ones that have to deal with the side effects. Actually in this study the toxicity was very carefully studied, and you know this really isn’t that toxic a treatment. If you look at the grade 3 or more toxicity, so this is the serious toxicity, the only increase was seen in diarrhoea and that was an absolute increase of 0.6%, so that is a very small increase in serious toxicity. This is not a toxic treatment and the argument that somehow radiotherapy is felt to be a nasty treatment, it just doesn’t hold up when you look at the data and it is really important to emphasise that point.

What other exciting advances have been seen in prostate cancer?

There’s clearly a lot of interest in prostate cancer in looking at altered fractionation and there a number of different programmes looking at this in the States, and these are going to be really very interesting. I do think also that the NCRI’s own study looking at hypofractionated radiotherapy, the CHHIP study, which is recruiting incredibly well, is going to be a major, major study and I just felt if we had the results of CHHIP alongside some of the data that was coming out of the States, I think that the UK study is going to prove itself to be a very, very major world study. So the results of that, which are still some way off at the moment, but they are going to be very keenly anticipated I think.

What is the time scale for the CHHIP study?

I don’t know, is the honest answer. It may be it will be finishing recruitment perhaps even this year but it’s probably still going to be a few years off its first report coming through. And it is very important in prostate cancer to have mature reporting because you know one of the things about our study is the study was first launched in Canada in 1995, closed recruitment in 2005. Well here we are 2010, nearly 2011, and we are getting an interim analysis, final analysis expected next year. It takes a long time to do these studies, to get good outcome data, good efficacy outcome data. Toxicity data takes less time but it’s important to get late toxicity data and mature late toxicity data and not just early toxicity which is something which although it’s important, it’s not the major determinant of how this is going to be accepted.