Researchers at the University of Cambridge have just published a paper in the British Journal of Cancer that highlights the difficulty doctors have when trying to determine how serious a man’s prostate cancer is. This story was also reported by the BBC, The Guardian and The Telegraph, as well as other news outlets.
The story has had a lot of coverage, but should men be overly worried about these results?
The study looked at 848 patients who had a radical prostatectomy, 415 of whom had what’s known as Gleason 3+3 disease at biopsy. This is the lowest stage that’s still defined as prostate cancer, and means that all the cancerous cells look likely to be slow growing, and at low risk of spreading. Gleason score is one of the characteristics that doctors take into account when deciding whether or not prostate cancer is likely to be harmless or not, and so whether a man should be recommended for active surveillance, where he would continue to be monitored, but wouldn’t be treated yet (although this may be recommended in the future).
At the moment, there are three main models for defining prostate cancer as clinically insignificant, which vary slightly in their criteria. One model defines prostate cancer as clinically insignificant if the Gleason score is 3+3 and the cancer is confined to the prostate. The other models also take the size of the tumour into account. This study looked at how accurate these models are.
The 415 men whose prostate cancer was given a Gleason score of 3+3 when they were biopsied may have had this defined as clinically insignificant cancer if it had fit the other criteria in the three models. However, after surgery when pathologists could look at the whole prostate, rather than just the bits picked out by the biopsy, the Gleason score was upgraded to 4 or 5 in 209 cases – revealing that these were clinically significant prostate cancers after all.
This study really emphasises the need for better tests to tell the difference between aggressive and non-aggressive prostate cancer – which is a major focus of our research strategy.
The other side of this story is that better ways to tell the difference between aggressive and non-aggressive prostate cancer would also help men and their doctors decide with certainty that active surveillance is a suitable choice for them – which is hugely important, because we know that many men with clinically insignificant prostate cancer are still needlessly undergoing invasive and life-changing treatments.
Professor Malcolm Mason, Head of the Oncology and Palliative Medicine at Cardiff University said:
"Despite the limitations that this study shows, all evidence so far points to active surveillance being safe provided men are carefully selected. But we need better methods of assigning a grade and stage so that no man has to unnecessarily undergo treatment, while at the same time making sure we detect and treat the cancers that really need it."
Dr Iain Frame, Director of Research at Prostate Cancer UK says;
“Accurate prostate cancer diagnosis continues to be one of the biggest challenges facing the disease today. The results of this study highlight yet again that existing tests cannot provide a precise picture of the aggressiveness of a man’s cancer, often leaving men and their doctors to make difficult decisions about treatment without all the facts.
“Prostate Cancer UK is committed to finding a better diagnostic option for the 40,000 men diagnosed with the disease every year through research. In the meantime, until the accuracy of tests improve, it is important that men have the opportunity to discuss the pros and cons of every treatment option available with their clinician, so that they can decide what is best for them and their situation.”
You can read more about what might happen when you get the results of any tests for prostate cancer you undergo on our website. If you have any concerns about this story, or anything else concerned with your prostate cancer diagnosis, you can call our specialist nurses on 0800 074 8383.