further refined through a modified Delphi process. We developed n[20 quality indicators (QIs) targeting measure quality of AS at population level. AS-specific QIs were tested among low-risk PC who were managed with AS between 2002-2014 using population-level cancer registry databases. We assessed adherence to clinical guidelines using QIs, and compared with health care system-related characteristics.RESULTS: In this cohort study of 35,531 low risk PC men with a mean (SD) age at diagnosis of 64.9 (8.6) years. At diagnosis mean PSA level was 6.2 (IQR 4.7-8.6) ng/mL, mean positive core (SD) was 2.5 (1.9). Overall use of Initial AS was 40.5% in 35531 eligible men with low-risk disease. 82.3% of patients underwent at least 8 or more core diagnostic biopsy. 67.1% of low volume patients went on AS and 77.7% had regular follow up with urologist as per guidelines. Only 44.5% patients on AS underwent confirmatory biopsy within 6-12months from diagnosis, and 80.6% patients had biopsy prior to receiving definitive therapy. 91.0% of patients who eventually received definitive therapy did so after upgrade in Gleason score. Specific to outcomes indicators, 52.8% of patients discontinued AS within 5 years from diagnosis, the 5-and 10-year metastases free survival rates were 98.5% and 95.5% respectively. 5-and 10-year PC specific survival rates were 99.6% and 98.4% respectively. Overall survival at 10 years was 90.0% with median follow up 9 years.CONCLUSIONS: This study establishes a foundation on which to build quality of care assessment to monitor the quality of AS patients at population level. In this Canadian population based cohort study based on OCR database, although the use of AS increased, considerable quality of AS care variation appeared with QIs related to process of care and outcome of AS care.

The presence of a high PI-RADS lesion at MRI is not related with worse outcomes at final pathology in men with a targeted and or systematic biopsy showing Gleason 3þ3. Therefore, these men should be reassured that pathological outcomes are favorable and that therefore initial conservative management is feasible and safe.