Is there a logical method for you to decide whether to receive treatment or not after receiving a prostate cancer diagnosis and your doctor's offer to keep you under observation rather than treat you?

What ought you to do? The GAP3 consortium has started to identify which people are in danger of the disease developing and which patients can continue to safely defer treatment using preliminary findings from analysis of the largest active surveillance prostate cancer database in the world.

The virtual European Association of Urology Congress is where this work is presented. According to the principal investigator, Dr. Mieke Van Hemelrijck of King's College London: "The procedures used today to determine whether or not to suggest treatment is valid. According to our findings, we should be able to develop a single global technique that would provide precise estimations of how aggressive certain malignancies are."

"These will immediately influence the treatment choice and provide men with the assurance they need to make that choice".

Prostate cancer is one of the leading causes of death in men, but many men who discover they have prostate cancer are not in any immediate danger: they have low-risk prostate cancer.

Over the past 10 years, an increasing number of these men have been given the option of going on active surveillance, rather than being immediately treated.

Active surveillance means that men continue to be monitored and tested (via PSA levels, biopsy, and other tests), with treatment only starting when cancer shows signs of developing.

The number of men on active surveillance varies from country to country, with up to 80% of men delaying treatment in some countries. However, there are no generally accepted ways of understanding who is at risk, and as many as 38% of men who start active surveillance drop out within 5 years.

Van Hemelrijck said: "Prostate cancer treatment can have significant side-effects such as erectile dysfunction and incontinence, so often avoiding intrusive surgery or radiotherapy can benefit the patient. Nevertheless, being told you have cancer puts great psychological pressure on men to agree to treatment, so understanding just how aggressive the cancer is before deciding on treatment is essential. At the moment we don't have that reassurance".

Although active surveillance is considered a real step forward in the management of low-risk prostate cancer, there is surprisingly little agreement on which men will benefit.

Doctors consider a range of factors, such as age, PSA score, biopsy details, technical details of cancer, and so on. But the decision on whether or not to start treatment is still often subjective.

Erasmus MC, department of Urology was tasked by Movember to coordinate the development of a global database on active surveillance (the GAP3 consortium). Dr Van Hemelrijck worked with a team of researchers from the GAP3 consortium to develop the world's most accurate active surveillance nomogram.

A nomogram is a treatment calculator, similar to an App: you feed in the details and it gives you advice on whether or not to treat. Local nomograms exist, but a global version is needed to be generally applicable.

Working with data from the 14,380 patients on the Movember database (the world's largest), they were able to input data such as age, size and condition of the tumour, PSA, biopsy details, time on active surveillance, genetic factors, etc.

"Not surprisingly, we have found that even accounting for these factors there was still differences in outcomes between participating centres. But this work has shown that it will be possible to produce a nomogram which can guide treatment. Just as importantly, the work shows which additional factors need to be included in the nomogram in future to enable us to eliminate this variation and produce accurate estimates of tumour aggressiveness".

Commenting, EAU Adjunct Secretary General Professor Hendrik Van Poppel (University of Leuven, Belgium) said; "This work shows that it should be possible to develop a global nomogram - in other words, a system which allows us to predict whether active surveillance will be suitable for individual low and intermediate-risk prostate cancer patients. This would be an important step forward in terms of the reassurance we can offer patients, and in choosing treatment pathways. The urology community would welcome this, and will be happy to cooperate in taking this project forward".