Post-Ablative Monitoring of Prostate Cancer: Differentiating Recurrence from Insignificant Disease Using PSA Kinetics and PSA Density

Tuesday, April 1, 2025

4:03 PM – 4:12 PM CT

Location: Music City Center, 204

Presenting Author(s)

Eric M. Walser, MD, FACR (he/him/his)

Professor and Chairman of Radiology
UTMB, United States

Author/Co-author(s)

JG

Jack Gunn, BA

Medical student
UTMB, United States
ZH

Zain S. Hussain, MD

Medical Student
University of Medicine and Health Sciences, United States

Purpose: Focal ablative therapies offer organ-sparing alternatives to traditional surgery for the treatment of prostate cancer (PCa). However, post-ablation monitoring remains challenging due to PSA fluctuations and imaging difficulties. This study investigates the utility of PSA kinetics and PSA density in distinguishing clinically insignificant disease from PCa recurrence in patients post-ablation.

Materials and Methods: A single-center retrospective analysis included 94 patients treated with focal ablation between 2013 and 2022, encompassing 105 post-ablation biopsies following focal laser ablation and 2 following transurethral ultrasound ablation. Patients were categorized into two cohorts: 1) clinically insignificant (Gleason 3+3/benign) and 2) proven malignancy (Gleason 3+4 and higher). PSA kinetics, including % change from PSA nadir, PSA velocity, and PSA density, were analyzed. Statistical analysis included logistic regression with 95% confidence intervals for odds ratio (OR). Statistical significance was achieved at p < 0.05.

Results: The mean prostate volume measured 35.32 cm³ ranging from 7.2 to 97.8 cm³. The median % change in PSA from nadir was 77.25% ranging from -10.36-1190.91%. Of 107 biopsies, 33 (30.8%) were clinically insignificant, while 74 (69.2%) were classified as malignant, with an average mean time to suspicion of 859 days ranging 123-3232 days. PSA density demonstrated a significant association with malignancy (OR = 25.501, 95% CI: 1.471–441.949, p = 0.026). Additionally, % change in PSA from nadir trended towards significant association with malignancy (OR = 1.001, 95% CI: 0.999–1.003, p = 0.362). However, PSA velocity did not provide reliable results due to high variability.

Conclusion: PSA kinetics, particularly PSA density and % change in PSA from nadir, are promising markers for distinguishing recurrence from clinically insignificant disease post-ablation. These markers may aid in post-ablation management and clinical decision-making. Further validation is required to integrate these findings into clinical practice.