Enrollment criteria controversies for active surveillance and triggers for conversion to treatment in prostate cancer.

In the era of widespread prostate-specific antigen screening, low-risk and very-low-risk prostate cancers are commonly identified, many of which will be of clinical insignificance. This has led to overtreatment and undue exposure to treatment-related morbidity in men harboring indolent tumors. Over the past 10 years, active surveillance (AS) has been evolving as a management strategy for these cancers. With continual reevaluation, the intent is to definitively treat tumors that are clearly progressive before the window of opportunity for cure has closed. To date, many of the surveillance parameters are without validation of utility, variably used, and without a standardized schedule. However, new instruments for characterizing prostate cancer offer the potential to better distinguish which men are best managed definitively at the outset from those who would be better served with observation. The findings of currently available AS cohorts suggest that initial expectant management of early prostate cancer is reasonable, showing that only approximately 30% of observed tumors are reclassified to ones of intermediate risk with short-term follow-up. Prostate cancer survival for men undergoing AS is close to 100% in all available studies, but long-term data remain scarce for those requiring delayed curative therapy.