SWOP – The Prostate Cancer Research Foundation, Reeuwijk

General patient criteria for application of risk calculator 5

• Men age 55 to 74 years old
• All parameters are known or can be reliably estimated
• Lateralised sextant biopsies have been taken
• The cancer has been detected by screening and not on clinical grounds (Micturition complaints can be left out of consideration)

Specific patient selection criteria

• Men who have T1c
• T2a-c prostate cancer
• PSA < 20ng/ml
• Gleason grades <=3
• <= 50% of positive sextant biopsies
• < 20mm cancer
• >= 40mm benign tissue.

Validation process

• Risk calculator 5 is based on the prediction of an ‘indolent’ prostate cancer rather than one that is aggressive.
• An initial attempt to differentiate indolent and aggressive cancers was first made through a nomogram, produced by Kattan et al (J Urol 2003).
• This was validated by replacing clinically detected cancers by screen detected cancers, using information from men who underwent radical prostatectomy in Rotterdam as part of the European Randomized Study of Screening for Prostate Cancer.
• The results of this validation (Steyerberg et al, J Urol 2007) form the basis of the fifth medical calculator – providing a means of classifying the likelihood of a prostate cancer being indolent.

Validation results

• In a population of screen-detected prostate cancers 46% or 32% of the tumours can be classified as indolent by using probability cut-off values 60 or 70%.
• The table shows that the use of a cut-off value for the probability of having indolent cancer of 70% assigns 94% of clinically relevant cancers correctly to immediate treatment.
• There is a 6% chance that a non-indolent tumour would be classified as indolent and therefore not treated properly by more aggressive management.
• In the same situation, using a probability cut-off of 60%, 46% of the potentially indolent tumours would be classified correctly as indolent and advised active surveillance.
• 85% of the clinically relevant cancers would also be correctly identified as needing immediate treatment but 15% would be misclassified and incorrectly selected for observation.

Treatment Options

• With incomplete data or in presence of clinically diagnosed prostate cancer, modified applications are still possible. These are indicated in the original publication by Steyerberg et al, J Urol 2007.
• A structured follow-up protocol is necessary to allow for the possibility that prostate cancer classified as indolent will continue to remain indolent over time.
• This is offered within the prospective PRIAS study protocol (Prostate Cancer Research International Active Surveillance), (add link www.prias-project.org).
• If you wish to enter patients on line, you can organise access by getting in touch with the PRIAS office, T. +31-10-703 4548 of by email: m.roobol@erasmusmc.nl.

Start Risk Calculator 5