Abstract
INTRODUCTION: Clinical guidelines recommend active surveillance (AS) as the preferred strategy for men with localized grade group (GG) 1 prostate cancer (PCa). We determined if the percentage of GG1 PCa patients in Ontario, Canada, managed by AS changed after the introduction of AS clinical guidelines and assessed adherence to the recommended followup protocol. METHODS: Using Ontario administrative databases, we conducted a time series analysis (autoregressive integrated moving average [ARIMA] models) in a population-based cohort of men diagnosed with GG1 PCa (2010-2018). Men were classified as managed by AS if they had repeat (confirmatory) biopsy within two years. Sensitivity analyses (treatment classification variation) and secondary analyses (low-risk GG1 and GG2 PCa) were conducted. RESULTS: We identified 12 236 eligible GG1 PCa patients, of which 7749 (63.3%) were initially managed by AS. Percentage AS increased from 44% in 2010 to 81% in 2018. Interrupted time series analysis estimated an immediate step change of 6.2 percentage points (95% confidence interval [CI] 3.0, 9.4) and a difference in slope of -2.3 percentage points (95% CI -6.9, 2.3) per year. Findings were robust to sensitivity analyses and similar for low-risk PCa. Adherence to monitoring and AS uptake in GG2 patients were not associated with guideline publication. Limitations include lack of treatment intent information in administrative data. CONCLUSIONS: The use of AS for low-grade PCa patients in Ontario increased from almost one in two patients in 2010 to four in five patients in 2017/2018. Adoption appeared to reflect the growing acceptance of AS prior to the guidelines, as well as an increase in response to the guideline introduction.