Prostate cancer Research International: Active Surveillance (PRIAS) MRI study

Prostate cancer often has an indolent growth pattern. Radical treatment of
these cancers therefore results in unnecessary side-effects and deterioration
of quality of life. Active surveillance aims at postponing or even avoiding
this radical treatment, without affecting oncological outcome.

The at the Erasmus MC initiated study *Active surveillance: Een afwachtend
beleid met de mogelijkheid tot uitgestelde curatieve behandeling bij mannen met
prostaatkanker; richtlijn en studie in de regio Rotterdam (PRIAS)* is
currently the largest active surveillance study worldwide. Although short term
results are promising, the selection of men with truly *indolent* prostate
cancer could be improved. Furthermore the criteria to switch to radical
treatment are not optimal, with some men being treated unnecessary and for some
men treatment is deferred to long.

MpMRI of the prostate with subsequent targeted biopsies could improve Gleason
grading of the prostate cancer and therefore improve upfront selection and
follow-up of men on active surveillance, further reducing the number of men
with intermediate risk instead of low risk cancers selected initially for
active surveillance . If mpMRI with targeted biopsies improves Gleason grading,
surrogate measures of Gleason progression currently used in the PRIAS study
(more than 2 cores positive, PSA-DT <3 year) could be improved and replaced.

This side study of the PRIAS study aims at investigating the value of mpMRI at
inclusion and during follow-up of men on active surveillance.

To study the value of mpMRI with subsequent targeted biopsies after inclusion
to more accurately grade prostate cancers of men on active surveillance.
Furthermore, the value of mpMRI in reducing the number and amount of biopsies
will be studied.

This side study of the PRIAS study is a prospective cohort study. Comparisons
will be made with historically matched PRIAS participants.

The additional burden consist of a maximum of 7 mpMRIs during 7 years of
follow-up and a maximum of 6 additional biopsies per repeat biopsy visit. Risk
of MRI include allergy to contrast media. This risk is reduced as much as
possible by excluding participants with a known contrast allergy. Studies have
shown that taking additional biopsies during a biopsy procedure does not
increase the risk of complications, except the pain that can be associated with
the extra biopsies taken. On the other hand mpMRI could reduce the amount of
repeat biopsy visits for some men with low PSA-DT. Furthermore it could improve
the Gleason grading of the prostate cancer at inclusion, therefore better
selecting men with true *indolent* prostate cancer, and at follow-up reducing
the amount of unnecessary radical treatments.