My colleagues and I have performed a very large randomised controlled trial in the UK comparing a new type of prostate biopsy technique termed local anaesthetic transperineal biopsy, where we biopsy up through the skin, and compared that against the more traditional transrectal biopsy approach. The reason we conducted this trial is that despite there being three trials that have reported in the last year or so, there remains uncertainty about the best way to do a prostate biopsy. Our main focus of evaluation as a primary outcome was detection of what we call clinically significant prostate cancer, defined as grade group 2 or above, but we also looked at some very important secondary outcomes.
This was a UK-wide study, ten centres in the UK, and we recruited and randomised 1,126 participants and randomised them 1:1 either to the more historical transrectal biopsy versus the transperineal technique. All of these patients were biopsy naïve and they had all received pre-biopsy MRI.
What were the results of this study?
For our primary outcome, we found an uplift of 5.7% in the detection of grade group 2 and above prostate cancer for the local anaesthetic transperineal procedure compared to TRUS and this reached statistical significance. We saw that both in the intention to treat analysis and in the per population analysis which is a very important finding.
When we looked at the secondary outcomes there were many very interesting observations. So in terms of infection, which has been the main driver to do transperineal biopsy over transrectal, we do see fewer infections in the transperineal group which is important, although it did not reach statistical significance. Although the study was not powered for infection, it was powered for detection of cancer. Importantly, the men who received the transperineal biopsy through the skin, almost 90% of them could have that biopsy safely without antibiotics and that’s very important for antibiotic stewardship.
When we looked at the tolerability of what men report from the biopsy, in the immediate post-biopsy evaluations men more often reported the transperineal biopsy as being embarrassing and painful. When we then evaluated the men at one week after the biopsy, those who had had a transrectal biopsy were more likely to report ongoing symptoms. So that’s interesting when we inform men now of the trade-offs between one technique versus another. When we looked at other complications of biopsy, broadly there was no difference. Urinary and sexual function side effects broadly no difference, but cost effectiveness was interesting. This work we’ve not yet published but I presented a slide today showing that, bearing in mind this was done in the UK in the UK health setting and with four months of follow-up, the probability of the transperineal biopsy being cost effective is actually very low. And that’s largely driven by the longer time it takes to do that type of biopsy. So this is all important data to now help patients, urologists, healthcare providers, guidelines committees, to inform them which type of biopsy to consider performing into the future.
What is the clinical significance of these results and what is next for this study?
Importantly, we’ve now added level 1 evidence to the field in addition to the three trials that I mentioned that have already been done. It will now be up to healthcare providers and policy makers such as NICE in the UK and other similar bodies elsewhere to help make some recommendations. The other important thing is going into the future we don’t quite know what the clinical significance is of finding that extra 5.7% of grade group 2 and above prostate cancer. The definition of significant disease for localised prostate cancer is still evolving. What we would very much like to do is follow up these patients into the future because we had quite short follow-up in this study. What we’d like to see is, for example, did this 5.7% uplift influence what treatments they have? That will also affect ongoing health economics. And can, indeed, there be additional improvements that can be made to the biopsy process that will help future patients?
