Abstract
BACKGROUND: Regional differences in active surveillance (AS) uptake for prostate cancer (PC) illustrate an inequality in treatment strategies. OBJECTIVE: To examine the association between regional differences in AS uptake and transition to radical treatment, start of androgen deprivation therapy (ADT), watchful waiting, or death. DESIGN SETTING AND PARTICIPANTS: A Swedish population-based cohort study was conducted including men in the National Prostate Cancer Register in Sweden with low-risk or favorable intermediate-risk PC, starting AS from January 1, 2007 and continuing till December 31, 2019. INTERVENTION: Regional tradition of low, intermediate, or high proportions of immediate radical treatment. OUTCOMES MEASUREMENTS AND STATISTICAL ANALYSIS: Probabilities of transition from AS to radical treatment, start of ADT, watchful waiting, or death from other causes were assessed. RESULTS AND LIMITATIONS: We included 13 679 men. The median age was 66 yr, median PSA 5.1 ng/ml, and median follow-up 5.7 yr. Men from regions with a high AS uptake had a lower probability of transition to radical treatment (36%) than men from regions with a low AS uptake (40%; absolute difference 4.1%; 95% confidence interval [CI] 1.0-7.2), but not a higher probability of AS failure defined as the start of ADT (absolute difference 0.4%; 95% CI -0.7 to 1.4). There were no statistically significant differences in the probability of transition to watchful waiting or death from other causes. Limitations include uncertainty in the estimation of remaining lifetime and transition to watchful waiting. CONCLUSIONS: A regional tradition of a high AS uptake is associated with a lower probability of transition to radical treatment, but not with AS failure. A low AS uptake suggests overtreatment. PATIENT SUMMARY: There are considerable regional differences in active surveillance (AS) uptake for prostate cancer. This study compared the outcomes of AS in different regions and found no association between AS uptake and failure of AS; it suggests that a low AS uptake indicates overtreatment.