Assessing prostate cancer risk of death – Experts Respond

Men diagnosed with prostate cancer can be given a more accurate estimate of their risk of death from the disease, according to new research.

Diagnosis prostate cancer written in the diagnostic form and pills.A UK-based study, published in PLOS Medicine, used routine measurements – including prostate-specific antigen (PSA) testing – to group men diagnosed with prostate cancer into five levels of risk.

The researchers first developed the five-level model based on data from over 10,000 UK men with prostate cancer. Then they compared the model with the current three-tier system endorsed by most international guidelines, including New Zealand.

They found their system was better at assessing the risk of death and since it used data routinely available to clinicians – like PSA levels, tumor grade, and histological grade – it would be simple to adopt internationally. It will, however, need further testing to confirm their results are replicated in other groups and over longer time frames.

Registered journalists can access the research on Scimex.orgThe SMC collected the following expert commentary.

Professor Helen Nicholson, Clinical Anatomy Research Group, Deputy Vice-Chancellor, University of Otago, comments:

“Prostate cancer is common and increasing in its incidence. Prostate cancer is a heterogeneous disease, which means not all cancer cells in a patient will behave the same. This can make it difficult for the clinician to provide accurate information to a patient about their likely clinical outcome and the best treatment options.

“Currently, doctors use a combination of tumour stage, histological grade (the microscopic appearance of the tumour) and PSA concentration to categorise the disease into low, intermediate and high risk.

“However, there is still a wide range of variability in outcomes, particularly in the intermediate group. The authors of this paper have used cancer registry data to develop 5 sub-groups of risk and then tested their model on a separate sample. The results suggest that the model is able to subdivide the intermediate and high-risk groups and more accurately predict the risk of a patient dying from prostate cancer.

“The study sample used data from men in the UK where routine screening for prostate cancer does not occur, a situation that is similar to New Zealand. In developing the model the authors have used data that are routinely available to urologists and thus does not involve more tests or cost.

“However, the testing of the model used a comparatively small sample size and further validation of a larger cohort and longer follow-up period is required. It also used registry records rather than a prospective study.

“While the model suggests it can better predict the risk of prostate specific cancer death it does not yet provide information of best treatment options for each group of patients and further evaluation is needed to determine this.”

Dr Jim Vause, Blenheim-based GP, comments:

“Men with newly diagnosed prostate cancer often face the dilemma of having to choose between the various treatment options on offer, namely surgery, radiotherapy, hormone treatment or just ‘watchful waiting’. This is the result of the variable effectiveness of the treatment options dependent upon the probability of a given cancer proving lethal within the man’s likely lifetime. Simply put, there is little point in aggressively treating a cancer if it is unlikely to kill a man and there is no point in watching one that is certain to kill.

“Currently, the tools doctors’ use for this prediction with prostate cancer lack good accuracy. Therefore researchers in the UK categorised men with newly diagnosed prostate cancer into five groups of differing risk of death. They used cancer characteristics, both as used currently and also newer indices from 10,139 men with proven prostate cancer to develop this five group ‘risk of death’ prediction (as opposed to the current three). This was then compared against a currently in use calculation and found to be a significant improvement.

“Better targeting of the differing treatment options for prostate cancer is central to the Ministry of Health’s Prostate Cancer Quality Improvement Program and central to this targeting is improved accuracy in risk of death prediction prior to commencing cancer treatment.”

Dr Vause is on the Ministry of Health’s prostate primary care advisory board, but his comments above are issued in his personal capacity.

Dr Helen Conaglen, senior research fellow, Waikato Clinical School, University of Auckland, comments:

“The improvement of clinical information for men with prostate problems is a possibility from this new method of stratifying prostate disease. However, the quality of life issues that men with prostate cancer experience are unlikely to be altered by this methodology.

“Men with a prostate cancer diagnosis often find it difficult to choose among options offered with a view to the longer-term outcomes beyond the presence or absence of cancer.

“A system that better predicts their trajectory with the disease will only assist the men if their clinician can provide information that provides long-term reassurance and enables them to see the benefits of options that involve waiting to undergo invasive treatment and revisiting the issue on a regular basis.

“Using this predictive tool to delay those outcomes will only provide them with a better quality of life for longer if they are not anxious, depressed and feel supported in their pre-treatment therapy. The system promises to be able to predict which men might benefit from waiting but has yet to be proven over the timeframes necessary to hail it as a breakthrough.

“In a recent NZ study, 87% of men who had undergone prostate cancer treatments reported changes in their sexual experience and 56% said that they had unmet therapeutic needs with respect to their sexuality; only 11% had received any counseling.

“These aspects of men’s prostate experience are the things that need to be improved for a greater quality of life for them and their partners. This should happen alongside the potential changes in therapy timelines that this new stratification system offers.”