RESUMEN
We retrospectively evaluated the utility of 68Ga-PSMA-11 PET for planning 223RaCl2 therapy of patients with metastatic prostate cancer and its impact on the therapeutic response as determined by prostate-specific antigen (PSA) and alkaline phosphatase (ALP), as well as the correlation of PSA changes with the results of prostate-specific membrane antigen (PSMA) PET follow-up scans. Methods: Sixty-three patients with a median age of 73 y who underwent 307 cycles of therapy with 223RaCl2 were analyzed. In 31 patients, bone scanning and radiologic imaging were performed for pretherapeutic imaging (group 1). In 32 patients, bone scanning and PSMA PET were performed before therapy (group 2). Patients with small lymph node metastases and local recurrence were not excluded from treatment, consistent with current guidelines. PSA and ALP were measured before each treatment cycle and 4 wk after the final cycle. Thirteen patients from group 2, who underwent a second PSMA PET scan as a follow-up, were evaluated to determine the significance of PSA changes as a follow-up marker. Results: In group 1, 4 patients (12.9%) showed a PSA decline, of whom 2 patients and 1 patient showed a PSA decline of more than 30% and more than 50%, respectively. In contrast, in group 2, 14 patients (43.8%) showed a PSA decline, of whom 10 and 8 patients showed a decline of more than 30% and more than 50%, respectively (P = 0.007). Thirty-seven patients had a high ALP level (19 from group 1 and 18 from group 2). Twelve (63.2%) and 16 (88.9%) patients in groups 1 and 2, respectively, showed an ALP decline. This difference was not significant; however, 7 (36%) and 13 (72.2%) patients in groups 1 and 2, respectively, showed an ALP decline of more than 30% (P = 0.04). Considering any ALP decline as a response, no patient with increasing ALP showed a PSA response (P = 0.036). There was a significant correlation between the PSA changes and the therapeutic response according to follow-up PSMA PET. Conclusion: When PSMA PET is used as the gatekeeper in addition to bone scanning, radionuclide therapy with 223Ra may be more effective and have more success regarding changes in the PSA. An increase in PSA during therapy cycles occurs because of disease progression.
Asunto(s)
Neoplasias Óseas/radioterapia , Neoplasias Óseas/secundario , Compuestos Organometálicos , Tomografía de Emisión de Positrones/métodos , Neoplasias de la Próstata/diagnóstico por imagen , Radio (Elemento)/uso terapéutico , Anciano , Neoplasias Óseas/diagnóstico por imagen , Ácido Edético/análogos & derivados , Isótopos de Galio , Radioisótopos de Galio , Humanos , Masculino , Oligopéptidos , Pronóstico , Neoplasias de la Próstata/radioterapia , Radioisótopos/uso terapéutico , Radiofármacos/uso terapéutico , Dosificación Radioterapéutica , Radioterapia Guiada por Imagen/métodos , Reproducibilidad de los Resultados , Estudios Retrospectivos , Sensibilidad y Especificidad , Resultado del TratamientoRESUMEN
A 75-year-old man with castrate-resistant prostate cancer and increasing prostate-specific antigen (PSA) level developed severe bone marrow depression during Ra radionuclide therapy. Because of this, he was treated with Lu-PSMA in compassionate use for this not-yet-approved therapy. At the beginning of Lu-PSMA therapy, repeated blood transfusions (BT) were necessary. Six months after the last BT, after 3 cycles of Lu-PSMA, his blood count stabilized. He required no further BTs and his PSA level remained lowered.