SCS AUA 2025: Impact of 177Lutetium-PSMA Therapy on SUVmax Values in Advanced Prostate Cancer

(UroToday.com) The 2025 South Central AUA annual meeting included a session on prostate cancer, featuring a presentation from Dr. Carlos Alexis Gonzalez-Martinez discussing the impact of ¹⁷⁷Lutetium-PSMA therapy on SUV_max values in advanced prostate cancer. ¹⁷⁷Lutetium has emerged as an important therapeutic radioisotope in oncology, particularly for metastatic castration-resistant prostate cancer based on the VISION and PSMAfore clinical trials.^1,2 This treatment employs theranostics technology where Lu-177 binds to PSMA ligands. The objective of this study, presented at the 2025 South Central AUA annual meeting, was to evaluate the impact of lutetium therapy on the SUV_max of PSMA PET.

This retrospective study analyzed 19 patients with advanced prostate cancer treated with ¹⁷⁷Lutetium-PSMA at a Mexican tertiary care center (2016-2024). Inclusion criteria included: (i) histologically confirmed prostate adenocarcinoma, (ii) progression after conventional therapies, and (iii) at least one dose of ¹⁷⁷Lutetium-PSMA. Patients received 1-6 treatment cycles (median: 4) at 6-8 week intervals, and SUV_max values were obtained from ⁶⁸Ga-PSMA PET/CT scans before and after therapy. Metabolic response categories included:

Significant (≥30% SUV_max reduction)
Moderate (10-30% reduction)
Stable (±10% change)
Progression (>10% increase)

Paired t-tests compared pre/post-treatment SUV_max values (p < 0.05 significance).

Of 19 patients with a mean age of 77.5 years (range: 62-93), 13 (68.4%) had complete SUV_max data. The mean pre-treatment SUV_max was 21.1 (2.5-59.5), decreasing to 11.0 (2.9-25.05) post-treatment. The mean initial PSA was 299.6 ng/mL (range: 0.16-5000 ng/mL), and the mean of the last recorded PSA was 0.89 ng/mL (0.00 - 1.00) without statistical significance (p < 0.10). However, a statistically significant reduction in post-treatment SUV_max was observed (mean change: -36.47%, 95% CI: -57.65% to -15.29%; p < 0.05). Among evaluable patients, 84.6% showed metabolic response: 8 patients (61.5%) with significant response, 3 (23.1%) with moderate response, and 2 (15.4%) with progression:

Response magnitude varied considerably (range: -87.50% to +57.75%). Favorable metabolic responses occurred across different treatment lines (2nd to 5th), suggesting efficacy even in advanced disease. However, these metabolic improvements did not consistently translate into sustained clinical benefit, indicating a complex relationship between metabolic response and clinical outcomes.

Dr. Gonzalez-Martinez concluded his presentation discussing the impact of ¹⁷⁷Lutetium-PSMA therapy on SUV_max values in advanced prostate cancer with the following take home messages:

¹⁷⁷Lutetium-PSMA therapy produces significant reductions in SUV_max values in advanced prostate cancer patients, demonstrating a meaningful metabolic response
The disconnect between favorable metabolic changes and continued clinical progression highlights the complexity of treatment response assessment in metastatic prostate cancer

Presented by: Carlos Alexis Gonzalez-Martinez, National Institute of Medical Sciences and Nutrition Salvador Zubirá, Mexico City, Mexico

Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Wellstar MCG Health, @zklaassen_md on Twitter during the 2025 South Central American Urological Association (AUA) Annual Meeting, Orlando, FL, Wed, Sept 10 – Sat, Sept 13, 2025.

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