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Background: Local radiation therapy of metastases in prostate cancer patients has become increasingly important in recent years. In order to improve the evaluation of the outcome, we have studied oligometastatic prostate cancer patients who were treated with stereotactic radiation therapy., Patients and Methods: 24 patients with a total of 30 bone metastases were included in the study. We examined the response to SBRT (biochemical and imaging), as well as progression-free survival and time to start of antihormonal therapy (aHT)., Results: The mean follow-up interval after completion of SBRT was 32.7 months (1.4 - 84 months). The SBRT was well tolerated, without acute or late adverse effects. In 16 patients, the PSA value decreased from a mean of 4.58 ng/mL (0.05 - 50.25 ng/mL) before SBRT to 1.19 ng/mL (0.01 - 8.85 ng/mL) after completion of SBRT. The mean biochemical progression-free survival of these patients was 17.6 months (0.7 - 85.0 months). Six patients received aHT, either before or during SBRT. In ten patients, the aHT was initiated after a mean interval of 20.6 months (1.8 - 85.0 months) after completion of the SBRT. Another six patients were not given any aHT during the whole period of observation. In 18 of 30 metastases, there was a decrease in PSMA expression within the area of SBRT in the PSMA-PET - in accordance with a partial functional response. In five patients, PSMA hyperexpression was unchanged; in 7 patients there was no PSMA imaging for follow up. In 17 patients, distant metastasis progression was diagnosed by imaging after a mean of 16.2 months (1.6 - 40.6 months). Three patients had a local recurrence in the prostatic fossa., Conclusion: SBRT of bone metastases in oligometastatic prostate carcinoma patients is an effective and well tolerated therapy and can help to achieve high local control in the area of the metastases as well as delay the start or the escalation of systemic therapy. Nevertheless, the high rate of progression of distant metastases shows how important correct patient selection is and that combination with aHT may be necessary., Competing Interests: Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht., (© Georg Thieme Verlag KG Stuttgart · New York.)

The aim of this retrospective study was to evaluate the detection rate of Glu-NH-CO-NH-Lys-(Ahx)-[ 68 Ga(HBED-CC)] ( 68 Ga-PSMA ligand; PSMA is prostate-specific membrane antigen) PET/CT in patients with biochemical recurrent prostate cancer defined by Phoenix criteria after external-beam radiotherapy or brachytherapy as primary treatment. Methods: One hundred eighteen patients with a median prostate-specific antigen (PSA) of 6.4 ng/mL (range, 2.2-158.4 ng/mL; interquartile range, 4.2-10.2 ng/mL) were finally eligible for this retrospective analysis. Seventy-seven and 41 patients had been treated by external-beam radiotherapy or brachytherapy, respectively. Of the 118 patients, 45 were receiving androgen-deprivation therapy (ADT) within at least 6 mo before the PET/CT. The detection rates were stratified by PSA. The influence of primary Gleason score and ADT was assessed. Relationships between SUV and clinical as well as pathologic features in patients with positive findings were analyzed using univariate and multivariable linear regression models. Results: One hundred seven of 118 patients (90.7%) showed pathologic findings indicative for tumor recurrence in 68 Ga-PSMA ligand PET/CT. The detection rates were 81.8% (36/44), 95.3% (41/43), and 96.8% (30/31) for PSA of 2 to <5, 5 to <10, and ≥10 ng/mL, respectively ( P = 0.0377). 68 Ga-PSMA ligand PET/CT indicated local recurrence in 68 of 107 patients (63.5%), distant lesions in 64 of 107 patients (59.8%), and local recurrence as well as distant lesions in 25 of 107 patients (23.4%). The detection rate was significantly higher in patients with ADT (97.7%) versus without ADT (86.3%, P = 0.0381), but independent from primary Gleason score ≥ 8 (92.0%) versus ≤ 7 (90.2%, P = 0.6346). SUV max and SUV mean were significantly associated with PSA and ADT ( P = 0.018 and 0.004 for SUV max , respectively; P = 0.025 and 0.007 for SUV mean , respectively). Conclusion: 68 Ga-PSMA ligand PET/CT demonstrates high detection rates in patients with biochemical recurrence of prostate cancer after primary radiation therapy. The detection rate was positively associated to increasing PSA as well as concomitant ADT. 68 Ga-PSMA ligand PET/CT enables discrimination of local versus metastatic disease and thus might have a crucial impact on further clinical management. A major limitation of this study is the lack of histopathologic proof in most patients., (© 2017 by the Society of Nuclear Medicine and Molecular Imaging.)