ESTRO 2024 - Abstract Book

S2506

Clinical - Urology

ESTRO 2024

Keywords: Prostate Cancer, SBRT, SDRT

2209

Poster Discussion

Local ablative RT in crPC: first results of the randomized OLI-CR-P study (NCT04141709)

Tobias Hölscher 1,2,3 , Fabian Lohaus 1,2,3 , Steffen Löck 1,3 , Angelika Borkowetz 4 , Christian Thomas 4 , Jörg Kotzerke 5,2 , Mechthild Krause 1,6,3 , Esther Troost 1,7,8 1 Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Department of Radiotherapy and Radiation Oncology, Dresden, Germany. 2 National Center for Tumor Diseases (NCT), Partner Site Dresden, Dresden, Germany. 3 Helmholtz-Zentrum Dresden - Rossendorf, OncoRay - National Center for Radiation Research in Oncology, Dresden, Germany. 4 Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Department of Urology, Dresden, Germany. 5 Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Department of Nuclear Medicine, Dresden, Germany. 6 German Cancer Consortium (DKTK), and German Cancer Research Center (DKFZ), Partner Site Dresden, Heidelberg, Germany. 7 Helmholtz-Zentrum Dresden – Rossendorf, OncoRay – National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany. 8 Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology – OncoRay, Dresden, Germany

Purpose/Objective:

PSMA-PET-CT identifies oligoprogressive metastatic lesions in castration resistant prostate cancer patients (omCRPC). The value of metastases directed therapy in this situation on outcome is unclear. In the ongoing randomized OLI-CR-P study local ablative radiotherapy (aRT) without modification of systemic treatment (androgen deprivation therapy (ADT) +/- new androgen receptor pathway inhibitor (ARPI)) is assessed (NCT04141709).

Material/Methods:

Patients with rising PSA during castration after curative primary treatment and < 6 PSMA-positive bone- or lymph node metastases without history of chemotherapy were eligible and randomized 2:1 in aRT and continuation of systemic therapy (Arm 1) or unchanged treatment (Arm 2). aRT was either a stereotactic body radiotherapy (RT) with 3 x 10 Gy or local ablative RT with 25 x 2 Gy fractions, at physicians’ discretion. The primary endpoint is proportion of patients without PSA progression (defined as nadir +2 ng/ml) after 1 year. The planned accrual is 66 patients. The local ethics committee reviewed the protocol. After inclusion of the first 30 patients, a planned interim analysis of the primary endpoint was performed. We report PSA response to aRT and time to PSA-progression. The criteria for stopping the study with a negative result was a difference in the primary endpoint between the two arms < 10%, and with a positive result, if the difference between the two arms was statistically highly significant (p<0.001).