HRS Improves Active Surveillance for Prostate Cancer by Timely Identification of Progression

Active surveillance (AS) is the preferred management strategy for low-risk prostate cancer. This study aimed to evaluate the impact of Habitat Risk Score (HRS), an automated approach for mpMRI analysis, for early detection of progressors in a prospective AS clinical trial (MAST NCT02242773). The MAST protocol includes Confirmatory mpMRI ultrasound fusion (MRI-US) biopsy and yearly surveillance MRI-US biopsies for up to 3 years. Clinical and mpMRI data from patients that progressed based on protocol criteria at years 1–3 were reviewed. Patients were classified as “MRI/HRS Progressors” if the PI-RADS lesion(s) had been targeted throughout the surveillance and resulted in positive biopsies, or as "Missed Progressors" if the lesion(s) were not identified by PI-RADS (“PI-RADS Miss”) or were missed by the biopsy (“Needle Miss”). HRS maps were generated for each patient and evaluated for association with histopathological progression. Of the 34 patients, 15 were classified as “MRI/HRS Progressors” and 19 as "Missed Progressors" (12 "PI-RADS Miss", seven "Needle Miss"). In all cases, HRS confirmed the PI-RADS assessment. In the "PI-RADS Miss" group, HRS identified the lesions in all patients that were not targeted by biopsy and resulted in patient reclassification. HRS volumes showed clear association with tumor evolution both in terms of volume and aggressiveness over time. HRS volumes can serve as a quantitative biomarker for early detection of progression and lead to timely conversion to treatment, thereby improving patient outcomes and reducing the burden of unnecessary surveillance.