Outcomes of active surveillance for Japanese patients with prostate cancer (PRIAS‐JAPAN)

Objective To report the outcomes of repeat biopsies, metastasis and survival in the Prostate Cancer Research International: Active Surveillance (PRIAS)‐JAPAN study, a prospective observational study for Japanese patients, initiated in 2010. Patients and Methods At the beginning, inclusion criteria were initially low‐risk patients, prostate‐specific antigen (PSA) density (PSAD) <0.2, and ≤2 positive biopsy cores. As from 2014, GS3+4 has also been allowed for patients aged 70 years and over. Since January 2021, the age limit for Gleason score (GS) 3 + 4 cases was removed, and eligibility criteria were expanded to PSA ≤20 ng/mL, PSAD <0.25 nd/mL/cc, unlimited number of positive GS 3 + 3 cores, and positive results for fewer than half of the total number of cores for GS 3 + 4 cases if magnetic resonance imaging fusion biopsy was performed at study enrolment or subsequent follow‐up. For patients eligible for active surveillance, PSA tests were performed every 3 months, rectal examination every 6 months, and biopsies at 1, 4, 7 and 10 years, followed by every 5 years thereafter. Patients with confirmed pathological reclassification were recommended for secondary treatments. Results As of February 2024, 1302 patients were enrolled in AS; 1274 (98%) met the eligibility criteria. The median (interquartile range) age, PSA level, PSAD, and number of positive cores were 69 (64–73) years, 5.3 (4.5–6.6) ng/mL, 0.15 (0.12–0.17) ng/mL, and 1 (1–2), respectively. The clinical stage was T1c in 1089 patients (86%) and T2 in 185 (15%). The rates of acceptance by patients for the first, second, third and fourth re‐biopsies were 83%, 64%, 41% and 22%, respectively. The pathological reclassification rates for the first, second, third and fourth re‐biopsies were 29%, 30%, 35% and 25%, respectively. The 1‐, 5‐ and 10‐year persistence rates were 77%, 45% and 23%, respectively. Six patients developed metastasis, and one patient died from prostate cancer. Conclusion Pathological reclassification was observed in approximately 30% of the patients during biopsy; however, biopsy acceptance rates decreased over time. Although metastasis occurred in six patients, only one death from prostate cancer was recorded.