MP23-20 LOW PSA DENSITY AT BASELINE IS ASSOCIATED WITH PROLONGED MRI-BASED ACTIVE SURVEILLANCE FOR GLEASON 6 PROSTATE CANCER

Abstract

INTRODUCTION AND OBJECTIVE: PSA density (PSAD) could potentially predict outcome in MRI-based active surveillance (AS). We investigate the association of PSAD with time to AS discontinuation in a large cohort of men with Gleason 6 prostate cancer. METHODS: Outcomes were collected for 488 men with Gleason 3+3 cancer who enrolled in the UCLH AS programme between 2004 and 2017 (inclusion: Gleason 3+3 or low-volume 3+4, PSA<20 ng/mL and baseline mpMRI). The baseline was the date of first MRI and all patients included had at least 12 months of follow up. Men were stratified to those with “visible” disease at baseline (Likert 4-5) and those without (Likert 1-3). Patients were further stratified to those with PSAD above and below the median (0.12 ng/ mL/mL). An “event” was defined as any prostate cancer treatment, transition to watchful waiting (WW) and/or pathological progression to ≥ Gleason 4+3 on follow up biopsy. The Kaplan-Meier method and log rank test were used to compare event-free survival (EFS) in the four different strata. RESULTS: In the non-visible group, 65/295 (22%) men a underwent treatment (prostatectomy, radiotherapy or focal therapy), whereas in the visible group 70/193 (36.3%) men were treated. In each respective group, 9 and 7 men upgraded to Gleason ≥4+3 on follow up biopsy. Five men in the non-visible and eight in the visible group transitioned to WW (age, personal preference, co-morbidities). Men with visible disease had higher odds of treatment compared to those without (2.03; 95%CI: 1.36-3.04, p=0.00028). Similarly, these odds were increased in men with a PSAD higher than 0.12 compared to those with PSAD lower than 0.12 (OR 1.53; 95%CI: 1.0433 to 2.2361, p=0.0294). Almost 75% of men with Gleason 3+3, nonvisible disease at baseline and low PSAD (<0.12) remained on AS after 8 years, whereas this proportion was <50% for those with visible lesions and high PSAD. There was a significant difference in EFS between patients stratified according to MRI visibility and PSAD (log rank test; p=0.00052). CONCLUSIONS: PSA density can have prognostic significance in the context of imaging-based AS. Men with Gleason 6, non-visible cancer at baseline and low PSAD are at lowest risk of progression to treatment and could be considered for less intense AS. (Figure Presented).