Background:
Lu-177 PSMA therapy significantly improves survival, reduces pain, and has a manageable safety profile, acting as a valuable option for advanced disease. As per VISION Trial Lu-177 PSMA reduced the risk of death by 38% and improved median overall survival by 4 months (15.3 vs. 11.3 months) compared to standard care alone [1]. This is important to identify prognosticators to predict any change (improvement/ decline) in outcome in the form of overall survival.
Hypothesis/Objective:
This retrospective clinical study is conducted to identify imaging biomarkers, metastasis, and PSMA expression as prognosticators for overall survival in PCa patients receiving Lu-177 PSMA therapy.
Methods:
This retrospective clinical study was conducted at a tertiary cancer care institute after IBR approval (225-N/L) in 2026. Tracing it backwards from 2026 to 2019 included observation and recording of prostate cancer patient’s (50 in number) age, serum PSA levels, Gleason score, visceral mets, pattern of mets and cycles of Lu-177 therapy. Imaging biomarkers were calculated from baseline Ga-PSMA PET-CT, enlisting PSMA tumor volume (PSMA-TV), Total PSMA Tumor volume (TPSMA-TV), CT volume (CTV), Total CTV, Total Lesion PSMA (TL-PSMA), Total body TL-PSMA, SUVmax, SUVmean, SUVpeak and PSMA expression (PSMA score). The data was analysed utilizing SPSS version 25 applying COX regression , calculation of hazard ratio and plotting survival curves to evaluate the role of above mentioned factors as survival prognosticators.
Results:
A total of 34 patients were included in the analysis. On univariate Cox regression, SUVmean (HR 0.93, p=0.01), PSA (HR 1.0005, p=0.01), visceral metastases (HR 2.30, p=0.02), and therapy cycles (HR 0.75, p=0.002) were significantly associated with overall survival. On multivariable Cox regression analysis, visceral metastases (HR 2.1, p=0.03) and PSA levels (HR 1.0004, p=0.02) were independent predictors of poorer overall survival. SUVmean was associated with improved survival (HR 0.94, p=0.04). Therapy cycles showed a protective association (HR 0.78, p=0.01), though this may reflect treatment duration bias. Kaplan–Meier analysis demonstrated significantly poorer survival in patients with visceral metastases and higher PSA levels, while higher SUVmean and greater number of therapy cycles were associated with improved survival.
Conclusion:
Our results underscore the prognostic importance of visceral disease burden and treatment exposure, while also suggesting that functional imaging parameters such as SUVmean may provide additional, clinically relevant insights into patient outcomes. PSMA-TV demonstrated only borderline statistical significance, suggesting a possible prognostic role that may be limited by sample size and requires validation in larger cohorts.
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Author
Tahira Yasmin, Dr
Institute of Nuclear Medicine and oncology Lahore Pakistan