[68Ga]Ga-PSMA-11 PET/CTas a diagnostic method for assessment of treatment response to androgen deprivation therapyin patients with prostate cancer
Medical Review (Med. pregled), 2024, 60(3), 44-54.
M.Dyankova1,2, P. Ilieva-Gabarska3, T. Stoeva1,2, Z. Dancheva1,2, B. Chaushev1,2
1 Department of Diagnostic Imaging, Interventional Radiology and Radiation Therapy,Medical University „Prof. Dr. Paraskev Stoyanov” – Varna
2 Clinic of Nuclear Medicine and Metabolic Therapy, „Sv. Marina“ University Hospital – Varna
3 Nuclear Medicine Laboratory in Medical Center „Sv. Marina“ – Pleven
Abstract. Introduction: Тhe application of 68Ga-prostate-specific membrane antigen (PSMA) for evaluation of response to androgen deprivation therapy in males with prostate cancer (PC) is insufficiently reported in the literature. The aim of our research was to evaluate response to ADT in hormone-naïve PC and to confirm the supposition of a distinctive response for various locations of PC involvement. Materials and Methods: The retrospective research concerned 55 male patients with PC who un¬derwent a staging PSMA PET/CT imaging and a follow-up restaging scan for evalu¬ation of treatment response conducted in 3-12 months after initiation of androgen deprivation therapy. Variations in radiopharmaceutical uptake were semiquantita¬tively assessed on twofold PSMA PET/CT scans. Results: Overall, 110 PET/CT scans of 55 males were assessed. Complete response (CR) was determined for males in accordance with the various localizations of PC involvement a median of 6 months after the initiation of androgen deprivation therapy: for the PC in prostate gland – 0.0%, for regional pelvic lymph nodes – 25.0%, for distant lymph nodes – 21.7%, for distant metastatic lesions (overall rate) – 14.3%. Disease progression (PD) was determined for males in accordance with the various locations of PC le¬sions. Treatment effect for regional lymph nodes was superior in M0 stage in com¬parison to M+ condition. Oligometastatic disease demonstrated better treatment effect in comparison to polymetastatic involvement. A positive correlation between the decrease in SUVmax of the primary PC in the prostate gland and the reduc¬tion in prostate-specific antigen (PSA) values was found. Conclusion: Malignant lymphadenopathy and distant metastatic involvement are more likely to respond to androgen deprivation therapy compared to primary tumor. Lesions with persistent prominent PSMA-expression can be a novel target for a discriminative local therapy of oligometastatic disease.
Key words: 68Ga-PSMA PET/CT, prostate cancer, treatment response
Address for correspondence: Marina Dyankova, MD, PhD, e-mail: Marina.Dyankova@mu-varna.bg