Same-day post-therapy imaging with a new generation whole-body digital SPECT/CT in assessing treatment response to [177Lu]Lu-PSMA-617 in metastatic castration-resistant prostate cancer

• Published in: European journal of nuclear medicine and molecular imaging 2024-07, Vol.51 (9), p.2784-2793
• Main Authors: Song, Hong, Leonio, Maria Isabel, Ferri, Valentina, Duan, Heying, Aparici, Carina Mari, Davidzon, Guido, Franc, Benjamin L., Moradi, Farshad, Shah, Jagruti, Bergstrom, Colin P., Fan, Alice C., Shah, Sumit, Khaki, Ali Raza, Srinivas, Sandy, Iagaru, Andrei
• Format: Article
• Language: English
• Subjects: Cadmium; Cardiology; Castration; Computed tomography; Digital imaging; Image analysis; Image processing; Imaging; Lesions; Lutetium; Lutetium isotopes; Medical imaging; Medicine; Medicine & Public Health; Metastases; Metastasis; Nuclear Medicine; Oncology; Original Article; Orthopedics; Parenchyma; Patients; Prostate cancer; Quantitative analysis; Radiology; Side effects; Single photon emission computed tomography; Survival; Therapy; Tumors
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-024-06718-6

Purpose Lutetium-177 [ 177 Lu]Lu-PSMA-617 radioligand therapy (RLT) represents a significant advancement for metastatic castration-resistant prostate cancer (mCRPC), demonstrating improvements in radiographic progression free survival (rPFS) and overall survival (OS) with a low rate of associated side effects. Currently, most post-therapy SPECT/CT is conducted at 24 h after infusion. This study examines the clinical utility of a next-generation multi-detector Cadmium-Zinc-Telluride (CZT) SPECT/CT system (StarGuide) in same-day post-infusion assessment and early treatment response to [ 177 Lu]Lu-PSMA-617. Methods In this retrospective study, 68 men with progressive mCRPC treated with [ 177 Lu]Lu-PSMA-617 at our center from June 2022 to June 2023 were evaluated. Digital whole-body SPECT/CT imaging was performed after [ 177 Lu]Lu-PSMA-617infusion (mean ± SD: 1.8 ± 0.6 h, range 1.1–4.9 h). Quantitative analysis of [ 177 Lu]Lu-PSMA-617 positive lesions was performed in patients who underwent at least 2 post-therapy SPECT/CT, using liver parenchyma uptake as reference. Metrics including [ 177 Lu]Lu-PSMA-617 positive total tumor volume (Lu-TTV), SUV max and SUV mean were calculated. These quantitative metrics on post-infusion SPECT/CT images after cycles 1, 2 and 3 were correlated with overall survival (OS), prostate specific antigen-progression free survival (PSA-PFS) as defined by prostate cancer working group 3 (PCWG3), and PSA decrease over 50% (PSA50) response rates. Results 56 patients (means age 76.2 ± 8.1 years, range: 60–93) who underwent at least 2 post-therapy SPECT/CT were included in the image analysis. The whole-body SPECT/CT scans (~ 12 min per scan) were well tolerated, with 221 same-day scans performed (89%). At a median of 10-months follow-up, 33 (58.9%) patients achieved PSA50 after [ 177 Lu]Lu-PSMA-617 treatment and median PSA-PFS was 5.0 months (range: 1.0–15 months) while median OS was not reached. Quantitative analysis of SPECT/CT images showed that 37 patients (66%) had > 30% reduction in Lu-TTV, associated with significantly improved overall survival (median not reached vs. 6 months, P  = 0.008) and PSA-PFS (median 6 months vs. 1 months, P