New radiation therapy shows promise for slowing prostate cancer spread

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Histological proven adenocarcinoma of the prostate with sufficient archived tumor material. This material has to be archived till study closure. * Biochemical recurrence (PSA \> 1.0 µg/l). * PSA-doubling time \< 6 months. Serum PSA progression is defined as 2 consecutive rising PSA values measured at least 1 week apart. The minimal start value is 0.2 µg/l. * 18F-PSMA-PET-CT positive metastases in bones and/or lymph nodes (N1/M1ab): ≥1, maximally 5 metastases. * Local treatment for oligo-metastases with radiotherapy or surgery appears to be no option anymore (due to prior treatment or the location of the metastatic lesions or if the patient refuse these treatments). * No prior hormonal therapy (including any androgen directed treatment such as finasteride, dutasteride, bicalutamide, apalutamide, abiraterone or enzalutamide) or taxane based chemotherapy (docetaxel or cabazitaxel); testosterone \> 1.7 nmol/l. Exception: local prostate cancer treated with local radiotherapy plus adjuvant ADT; these patients need to be stopped with ADT at least 6 months. * A detectable lesion on the 18F-PSMA PET/CT with significant PSMA avidity, defined by a SUVmax \> 15 (partial volume corrected). * ECOG 0-1 * Patients must have a life expectancy \>6 months. * Laboratory values: * White blood cells \> 3.0 x 109/l * Platelet count \> 75 x 109/l * Hemoglobin \> 6.2 mmol/l * ASAT, ALAT \< 3 x ULN * MDRD-GFR ≥ 50 ml/min * Signed informed consent. Exclusion Criteria: * A known subtype other than prostate adenocarcinoma. * Previous PSMA based radioligand treatment. * Visceral or brain metastases. * Any medical condition present that in the opinion of the investigator will affect patients' clinical status when participating in this trial. * Prior hip replacement surgery potentially influencing performance of PSMA PET/CT. * Sjogren's syndrome * A second active malignancy other than prostate cancer. * Patients who are sexually active and not willing/able to use medically acceptable forms of barrier contraception.