Management strategies and patient outcomes among LPC patients with persistently positive PSA after RP.

353 Background: Patients (pts) with localized high-risk/very high-risk prostate cancer (PCa) have an elevated risk of metastases and Prostate Cancer (PC)-specific death following local therapy. This risk is significantly higher for patients with a persistently elevated PSA (pPSA) after Radical Prostatectomy (RP) We aim to better understand the current management strategies for this population using real world data. Methods: We performed a retrospective population-based cohort study using province-wide linked administrative data from 2010-2022, in Ontario, Canada. Patterns of patient management in the intermediate (IR)/High-/very high risk (h/vHR) LPC patients who underwent RP with persistently elevated PSA≥0.1 ng/ml were analyzed. Results: In this retrospective cohort between 2010-2021, 31,571 patients diagnosed with LPC were identified. Cohorts were stratified by IR (58.2%, n=18,365) and H/vHR (41.8%, n=13,206). Overall, 13493 pts with IH/HvHR received RP as their treatment for LPC, from which 314 pts (Intermediate Risk=127; High-Very high risk=187) had a persistently positive PSA after RP. 46.8% (n=147) of pts with pPSA received RT, 40.4% (n=127) ADT and 21.7% (n=68) RT+ADT as their next line of treatment (p=<.0001; SD=0.880). PSA value after RP and immediately preceding start of next line of therapy was 0.6 ng/ml (Median IQR: 0.2-1.5 ng/ml) in the RT subgroup and 5.8 ng/ml (Median IQR 2.9-10.5 ng/ml) and 0.9 ng/ml in ADT and ADT+RT groups respectively (Median IQR 0.2-4.3 ng/ml; p=<.0001). Median (IQR) time to CRPC was 9 years (7-11.3) in pts without a pPSA and 7.4 years (5.2-10) in patients with a persistent PSA (P=<.0001). Conclusions: Patients who do not achieve a PSA<0.1 ng/ml after radical prostatectomy have a worse prognosis. LPC patients should be monitored closely after RP to identify the sub-population with persistent PSA that could benefit from additional therapies intensified systemic therapies including Androgen Receptor Pathway Inhibitors (ARPIs). Time to progression to CRPC, PC event, and mortality by persistent PSA status among patients with RP. Persistent PSA Label Total No Yes P Value Variable (Sample size) N=14,084 N=13,770 N=314 Time to CRPC n (%) 186 (1.3%) 148 (1.1%) 38 (12.1%) <.0001 Median (IQR), Years 9.1 (7-11.3) 9 (7-11.3) 7.4 (5.2-10) <.0001 Time to PC event n (%) 6,001 (42.6%) 5,744 (41.7%) 257 (81.8%) <.0001 Median (IQR), Years 6.7 (1.9-3.6) 6.8 (1.5-10) 0.8 (0.4-4) <.0001 PSA value before RP (PSA test closest to RP) Median (IQR), (1) ng/ml 6.7 (5.1-9.6) 6.7 (5.0-9.6) 9.0 (5.9-12.8) <.0001