ECC 2015

Results of 5 year phase III randomised trial treating localised prostate cancer

Prof David Dearnaley - Institute of Cancer Research, London, UK

You are looking at prostate cancer here, localised prostate cancer. You’re treating with curative intent, you’ve got a phase III study, what were you trying to do?

What we were trying to establish was whether we could exploit the radiobiology of prostate cancer which may be particularly sensitive to fraction size and to change the standard curative radiotherapy treatment from a 7½ week treatment into a shorter four week treatment.

So you’ve been doing hypofractionated radiotherapy, what exactly did you do?

We compared the standard treatment using 2Gy doses per day with a larger dose of 3Gy per day and we performed the largest randomised trial ever undertaken in localised prostate cancer, treating altogether over 3,100 men.

And you’ve got five year results now, what were they?

The results showed that the shorter hyperfractionated treatments give similar efficacy when treated to a dose of 60Gy in 20 fractions and this was non-inferior to the standard treatment. The other experimental arm, which was 57Gy in 19 fractions, so a slightly lower dose, we could not demonstrate was non-inferior. However, very importantly, the therapeutic ratio, that is the balance between efficacy and side effects, was good. In the trial as a whole the side effect profile was very low because we used sophisticated up-to-date radiotherapy techniques with scrupulous quality assurance. So the side effect profile was actually half that in the preceding trial that was undertaken in the UK. So we’re very, very pleased with those results for the whole trial but specifically we’ve shown that you can safely reduce the number of treatments from 37 to 20.

So although you’re increasing the dose per fraction which could risk more collateral damage you’re not seeing much?

We’re not seeing that. We reduced the total dose to compensate for the bigger dose per fraction. It’s like, a little analogy, a boxer using a lot of big punches rather than a large number of small punches.

So what, potentially, are the advantages for the patient?

It reduces the number of hospital visits from 37 to 20, a big advantage, there’s a big advantage to the patient. There are also issues of resource because we can treat more patients with the same equipment. But I do want to stress again that we’ve only shown that this is effective and safe using high quality radiotherapy techniques. So that is part of the trial and we used the trial as a vehicle for introducing these high quality techniques across the UK and in the centres in Ireland, Switzerland and New Zealand that took part as well.

And high quality is a big issue, then, that means centres of excellence presumably. What are the big pointers for doctors, then, to summarise?

We can do this, we can generalise this. We had 70 centres taking part so this isn’t just the specialised centres. Smaller centres can get up to the mark if they’re given the assistance which this trial did give them. So the key point is that you can reduce the number of visits a patient has to make to hospital and you can do that safely, that improves treatment for the patient and it saves resources at the same time. But high quality treatment is essential.

Thank you very much.