Timo Soeterik

46 CHAPTER 3 Variation in follow-up strategy and compliancy with PRIAS The Dutch PCa guidelines recommend that AS follow-up should be in accordance with the study protocol of PRIAS. 12 This includes a PSA test every 3 months in the first 2yr and every 6 mo thereafter. Scheduled repeat biopsies should be performed at 1, 4, 7 and 10 yr following diagnosis. Definitions used for follow-up compliance with the PRIAS protocol were comparable to those published by the PRIAS study group. 13 PSA follow-up was regarded as concordant if a patient had undergone ≥75% of the recommended number of PSA tests for their follow-up duration. For example, a patient with an AS duration of 14 mo should have undergone three or more PSA tests to be regarded as compliant. To assess compliance with repeat biopsy testing, we evaluated the percentage of patients who underwent the first (1 yr), second (4 yr), and third biopsy (7 yr) among men with follow-up of >1.5, >4.5, and >7.5 yr, respectively. We also determined the percentage of patients who received all scheduled biopsies according to the protocol, taking AS duration into account. Follow-up was scored as discordant if a patient should have undergone one or more biopsies according to the follow-up scheme, but missed one or more. A separate analysis was performed to determine in how many cases MRI of the prostate were performed instead of a prostate biopsy. Protocol adherent follow-up was assessed in patients with an AS duration of >6 mo. We assessed whether discordant follow-up was associated with an higher rate of metastasis during AS follow-up using risk classification based on the PRIAS inclusion criteria: PSA ≤10 ng/ml, PSA density (PSAD) <0.2 ng/ml/ml, Gleason ≤6, fewer than three positive biopsy cores, and clinical stage ≤T2. 9 Patients were classified as “PRIAS-eligible” if they met all these inclusion criteria at baseline and as “PRIAS-ineligible” if they did not. Outcome measures Our primary outcome measure was the total percentage of patients who received PSA monitoring, repeat biopsy testing, and overall follow-up (PSA and biopsies combined) concordant with the PRIAS follow-up protocol. Differences between hospitals in the proportion of patients with concordant follow-up were determined. A secondary outcome measure was the rate of metastasis (bone and/or lymph node) during AS monitoring. A patient was considered to have developed metastatic PCa during AS follow-up (time between the date of diagnosis and discontinuation of AS) if metastases were detected via diagnostic imaging (MRI, choline or prostate-specific membrane antigen positron emission tomography/computed tomography for lymph node metastasis and/or visceral metastasis and a bone scan for bone metastasis) or lymph node metastasis detected by lymph node dissection.