[The prostate biopsy during the follow-up of a cohort of 400,000 asymptomatic men undergoing PSA testing in the Agency for Health Protection of the Metropolitan Area of Milan].

Abstract

Objectives: to describe the frequency of prostate biopsy and its determinants, as well as the incidence of prostate cancer, in a cohort of asymptomatic residents of the Agency for Health Protection of the Metropolitan Area of Milan (ATS Milano) who underwent total prostate-specific antigen (PSA) testing.

Design: cohort study of resident men aged 30-84 years who underwent at least one PSA test (index test) in 2018-2019 and 2021-2023, with follow-up until December 2024.

Setting and participants: from the administrative and healthcare databases of ATS Milano, 414,731 residents who underwent at least one PSA test during the study period, presumably for screening purposes, were identified.

Main outcome measures: frequency of specific follow-up procedures (repeat PSA testing, urological consultation, ultrasound, magnetic resonance imaging), with particular focus on prostate biopsy, and cumulative incidence at 3, 6, and 12 months after the index test. Logistic regression analysis of the probability of undergoing prostate biopsy within 6 months of the index test.

Results: overall, 1.6% of subjects underwent a prostate biopsy within one year (N. 6,598). This proportion increased markedly with higher initial PSA values (13.8% among those with PSA >=6 ng/mL). On average, 11.7% of biopsies were the first procedure after the index test, 22.4% followed one of the procedures considered, 33.7% followed two procedures, 24.9% followed after three procedures, and 7.3% followed four procedures. Prostate cancers diagnosed were 1,157 at 3 months and 3,219 at 1 year, compared by means of the observed-to-expected ratio, to the incidence of the general population. The biopsy-to-cancer ratio was approximately 2. At 6 months, prostate biopsy was positively associated with age (up to 70-79 years), strongly associated with PSA level (>=6 ng/mL, OR: 28.7) and with Italian citizenship, while a lower risk was observed in the presence of comorbidities. The observed-to-expected ratio was greater than 1 for initial PSA values >=3 ng/mL and increased progressively with higher PSA levels.

Conclusions: among residents of the ATS Milano area, a PSA level equal to or greater than 3 ng/mL identifies an early increased risk of prostate carcinoma. To ensure the timely identification of all clinically significant cases, biopsy should be integrated into a multimodal diagnostic pathway including advanced imaging, which was not always available in the analysed cohort.