Optimizing Prostate Cancer Diagnostic Work-Up Through Micro-Ultrasound: Minimizing Unnecessary Procedures and Reducing Overdiagnoses.

Abstract

Introduction: We aim to critically assess Microultrasound (mUS) clinical performance in an outpatient setting, focusing on its ability to reduce unnecessary diagnostic procedures, potentially reshape prostate cancer (PCa) diagnostic protocols, and increase the ability to rule out clinically significant (Gleason Score ≥ 3 + 4) PCa (csPCa).

Materials and methods: Between November 2018 and April 2022, we conducted a prospective study involving men who underwent mUS examination due to clinical symptoms, PSA elevation, or opportunistic early detection of PCa. Experienced urologists performed mUS assessments in an outpatient setting using the prostate risk identification using micro-ultrasound (PRI-MUS) protocol to identify lesions suspicious of csPCa (PRI-MUS score ≥ 3). Men with negative mUS results were followed through consistent phone follow-up calls and visits until October 2023 to assess their diagnostic and therapeutic pathways. Using Cox regression models adjusted for PSA levels, DRE results, age, and previous biopsy history, we calculated the hazard ratio (HR) for biopsy-free (BFS), defined as the time from mUS to biopsy or last follow-up, cancer-free survival (CFS), and clinically significant cancer-free survival (csCFS) within the cohort based on mUS results.

Results: Overall, 425 men were enrolled. The median (IQR) age was 66 (59-72) years, PSA levels were 5.7 (4.0-7.9) ng/mL, prostate volume was 44 (31.5-62.1) mL, and the median follow-up was 39 months (27-53). mUS identified lesions suggesting csPCa in 201/425 (47.3%) men. Overall, mUS resulted negative in 224/425 (52.7%) men, of whom 207/224 (92.4%) did not undergo subsequent mpMRI, while 22/224 (9.8%) proceeded with mpMRI according to the referring physician's decision. The latter detected suspicious lesions in 12/22 cases (54.5%), but only 2/12 (16.7%) were confirmed by biopsy as csPCa. Among those with negative mUS results, 192/224 (85.7%) men avoided additional biopsies during follow-up. Men with negative mUS results exhibited superior BFS (aHR: 0.17; p < 0.001), CFS (aHR:0.12; p < 0.001), and csCFS (aHR:0.09; p < 0.001) survival rates compared to their mUS-positive counterparts.

Conclusions: Our findings suggest that mUS can potentially refine patient stratification and transform PCa screening and diagnostic protocols. Pending validation by other studies, a wider implementation of mUS could optimize resource allocation, minimize wastage, and reserve additional costly tests.