Active surveillance of men with localised prostate cancer is becoming increasingly popular. It is an observational approach, involving regularly testing, allowing men with low risk prostate cancer the opportunity to avoid or delay aggressive treatments.
Potentially, it’s of huge benefit to thousands of men: a recent study indicated that just 1% of men whose low risk prostate cancer is managed through active surveillance go on to die of the disease.
But, as delegates in Milan at last month’s third ESO Conference on Active Surveillance for Low Risk Prostate Cancer discussed, a big question looms: how do you identify the right men for active surveillance? Clearly, the implications of incorrectly defining “low risk” are major.
The problem is that you have to follow men for a long time to discover whether their prostate cancer will, in the end, prove life-threatening. The likelihood of cancer causing death depends on both the tumour (aggressiveness and extent) and the patient (age and co-morbidities). Without long-term studies characterising the type of disease and person suitable for active surveillance, selection is difficult.
How to define low risk?
In their absence, researchers are trying to find predictors of disease progression to support risk-based selection of patients. Existing prediction models help but, as Ewout Steyerberg from the Centre for Medical Decision Making at Erasmus University pointed out in Milan, much stronger predictors are needed to separate low risk from high risk patients.
The answers are likely to come from large studies analysing existing data from men with prostate cancer – and in particular a major study funded by the Movember Foundation, known as the Global Action Plan 3 project, or GAP3. Movember has five GAP projects, but GAP3 specifically addresses the question of how you select the right men for active surveillance.
It aims to create a global consensus on selecting and monitoring men with low risk prostate cancer through studying the cases of 10,491 men across 19 institutions worldwide. This is the largest prostate cancer active surveillance database, comprising the majority of the world’s active surveillance patient data.
The significance of GAP3 to preventing overtreatment in prostate cancer cannot be underestimated. Today, one and a half years into the project, all the data from participating centres has been uploaded into a central database. Each patient’s clinical history and biospecimen, imaging and biomarker data is being analysed.
This analysis, due to be complete in August this year, will feed into a simultaneous expert review of all current active surveillance guidelines available around the world, leading to a new consensus guideline setting out which patients are suitable for active surveillance, and what are the most effective ways of monitoring them.
And the end result – available in perhaps 18 months’ time – will be a web-based platform, based on the guidelines and using risk-based modelling derived from the new analysis, to help clinicians decide which patients are suitable for active surveillance.
Perhaps just as importantly, as Sophie Bruinsma from Erasmus Medical Centre pointed out in Milan, it will also provide some reassurance to men that that they have made the most sensible, risk-based decision about their disease.