35th ESMO Congress, 8–12 October 2010, Milan
Interview with Professor Sten Nilsson (Karolinska Institutet, Stockholm, Sweden)
Active monitoring of prostate cancer
Thank you for coming to tell us about the session you’re moderating. It’s a very controversial area – active monitoring of prostate cancer, yes or no? What are the issues that this debate is going to be covering?
Actually prostate cancer is a very special disease, one could almost say it is a variety of different diseases where you have tumours that are more aggressive and you also have tumours that are less aggressive. Since prostate cancer is such a common disease, it’s very important to find out whether or not it’s necessary always to treat the patient that has got the diagnosis of prostate cancer.
So that’s the issue behind the controversy about whether to find and detect prostate cancer in the first place?
Yes, it sort of goes together. You detect much more prostate cancer nowadays than you did before, very much due to better diagnosis methods like you have the PSA and you take the biopsy. The question then is what to do with the prostate cancer once you detect it and there has been a very sustained controversy on what to do. Several years ago we did not treat prostate cancer as much as we do today and then some years later on we started to treat almost everybody with a diagnosis of prostate cancer, either surgery or radiotherapy or a combination of them both. But the thing is, if we start treating everybody, we know for sure that we are over-treating a lot of persons and so we’re back again to the question is it possible to actively monitor a patient? The reason that we can do so is that we have some tools in our hands like the PSA that we can follow over time to see if the patient really needs treatment or not. So this is the controversy.
But PSA is not without its problems?
No it’s not.
If it were a clear-cut marker there wouldn’t be quite such an issue.
No, that’s right. It’s not specific for prostate cancer at all, but still it’s the best golden standard that we have when it comes to tumour markers in prostate cancer. So in this concept of active surveillance or active monitoring we use PSA, the prostate specific antigen, to follow a patient. Certainly we also have to find out in that patient, to start with, if the tumour is aggressive or not, so we really have to do biopsies in such a patient and look at the histopathology. Really it shouldn’t contain any signs of more aggressive tumours.
So how confident are you with the present predictive biomarkers like RAID and so on?
What we have is grade, which is the most important thing. So if we have a Gleason score that contains grade 4 cancer then we know it’s a more aggressive tumour and then we should be very hesitant in suggesting active surveillance. But if it’s a less aggressive one we could certainly use that concept.
So Gleason is the best?
It’s the best, yes, and then what we rely on after that is the PSA, the development of PSA.
And where’s the cut-off for that?
I think one really has to follow a patient. It could be a PSA that is below 10, it should be, and then if it’s 4.9 or 5.1 or 3.8, whatever, it really doesn’t matter because if you follow the PSA it shouldn’t start rising because then you have to reconsider your decision. And also one has to re-biopsy the patient after a couple of years to see that it’s not just…
Re-biopsy and biopsy in the first instance, they’re not without problems themselves, there are deaths occasionally, very occasionally, from septicaemia and so on, but it does happen. Are there no better tools for imaging what’s going on inside the prostate, for instance? All these NMR, PETs, CT-PET, nothing is any good?
Well we believe very much in a lot of things will happen and I believe very much in modern techniques with respect to MRI, for example. It could also be that PET in the future, if we get better tracers, will have a place but especially MRI will give us more information.
And there are on-going trials of active watching and waiting versus…?
Yes, there are. So in Great Britain there is the ProtecT study that has completed its recruitment of patients and that is a study comparing active monitoring with surgery and radiotherapy. So patients with low risk cancer are being asked to participate in that trial.
When will we get an answer to that? Ten years?
Well, to get overall survival in such a slowly progressing disease it takes a long time. So that will be in many years from now. But still the concept is being tested and there are also other studies on this topic with active surveillance. So that’s an important treatment option.
Professor Nilsson, thank you very much indeed.