PSMA-PET/CT response after metastasis-directed radiotherapy of bone oligometastases in prostate cancer

Sheikh, Gabriel T.; Trapp, Christian; Schmidt-Hegemann, Nina-Sophie; Buchner, Alexander; Stief, Christian G.; Unterrainer, Marcus; Kunz, Wolfgang G.; Cyran, Clemens C.; Grawe, Freba; Delker, Astrid; Zacherl, Mathias J.; Holzgreve, Adrien; Unterrainer, Lena M.; Brendel, Matthias; Belka, Claus; Li, Minglun; Rogowski, Paul (2024): PSMA-PET/CT response after metastasis-directed radiotherapy of bone oligometastases in prostate cancer. EJNMMI Reports, 8: 25. ISSN 3005-074X

Abstract

Objective

Bone metastases are very common in advanced prostate cancer and can sensitively be detected utilizing PSMA-PET/CT. Therefore, our goal was to evaluate the suitability of PSMA-PET/CT-guided metastasis-directed external beam radiotherapy (MDT) as treatment option for patients with biochemical recurrence and oligometastatic bone lesions.

Materials & methods

We retrospectively examined 32 prostate cancer patients with biochemical recurrence and PSMA-positive oligometastatic disease limited to the bone (n = 1–3). A total of 49 bone lesions were treated with MDT. All patients received a post-radiotherapy PSMA-PET/CT-Scan. Changes in SUVmax, PSMA-positive tumor volume per lesion and PSA, as well as the correlation between the PET/CT-interval and SUVmax response were calculated.

Results

MDT lead to a SUVmax decrease in 46/49 (94%) of the lesions. The median relative decline of SUVmax was 60.4%, respectively. Based on PSMA-positive lesion volume with a SUV cut-off of 4, 46/49 (94%) of lesions showed complete response, two (4%) partial response and one lesion (2%) was stable on PSMA-PET/CT after MDT. Most of the treated patients (56.3%) showed an initial PSA decline at three months and a PSA nadir of median 0.14 ng/ml after a median time of 3.6 months after MDT. The median relative PSA change at three months after MDT was 3.9%.

Conclusion

MDT is a very effective treatment modality for prostate cancer bone oligometastases and lesion response to MDT can be assessed using the (semi-)quantitative parameters SUVmax and PSMA-positive lesion volume with established SUV cut-offs.

• Dokumententyp: Artikel (Klinikum der LMU)
• Organisationseinheit (Fakultäten): 07 Medizin > Klinikum der LMU München > Klinik und Poliklinik für Nuklearmedizin
• DFG-Fachsystematik der Wissenschaftsbereiche: Lebenswissenschaften
• DFG: Gefördert durch die Deutsche Forschungsgemeinschaft (DFG) - 491502892