Editorial Comment on “Active Surveillance in Prostate Cancer With Intermediate-Risk Features: The PRIAS-JAPAN Study”

Abstract

The expansion of active surveillance (AS) beyond low-risk prostate cancer (PCa) continues to be a subject of ongoing debate. The PRIAS-JAPAN study by Blas et al. provides valuable prospective data on the medium-term outcomes of AS in Japanese men with intermediate-risk features—specifically ISUP grade group 2 and/or clinical stage T 2—compared to those in low-risk patients enrolled in the same protocol [1].

Among 1066 patients followed for a median of over 3 years, no statistically significant differences were found between low- and intermediate-risk groups in pathological reclassification rates, AS program persistence, or transition to active treatment. These findings align with recent studies suggesting that carefully selected men with intermediate-risk PCa may safely undergo AS in the short to medium term [2]. However, the short follow-up for the intermediate-risk cohort and its relatively small sample size warrant caution in overgeneralizing these conclusions.

A particularly noteworthy observation is the difference in treatment patterns post-AS: patients with ISUP grade group 1 were more likely to undergo radical prostatectomy, whereas those with grade group 2 more often received external beam radiotherapy. This likely reflects age-related treatment preferences, as the intermediate-risk cohort was older, partly due to PRIAS-JAPAN's historical age-based eligibility criteria for ISUP 2. These findings underscore the complexity of AS decision-making and the need for individualized patient counseling.

Despite reassuring similarities in reclassification and persistence rates, key limitations must be considered. The lack of central pathology review, limited clinical stage T2 subgroup stratification, and evolving eligibility criteria over time may have influenced the results. Moreover, while not statistically significant, ISUP grade 2 patients appeared more likely to be reclassified at the second biopsy, suggesting a need for closer monitoring. Longer-term follow-up is essential to assess whether AS remains oncologically safe for intermediate-risk PCa, particularly regarding metastasis-free and cancer-specific survival. Future studies should also explore the role of modern diagnostic tools—such as multiparametric MRI and genomic classifiers—to refine risk stratification and optimize surveillance strategies [3, 4].

In conclusion, the PRIAS-JAPAN study provides valuable real-world evidence supporting the cautious extension of AS to well-selected intermediate-risk PCa patients. It reinforces the importance of individualized decision-making, considering patient age, comorbidities, and personal preferences, as highlighted in the DETECTIVE Study [5].

Both authors equally contributed to the conception of the editorial comment, literature review, and writing of the manuscript. Both authors approved the final version.

The authors declare no conflicts of interest.