ESTRO 2022 - Abstract Book

S1161

Abstract book

ESTRO 2022

Purpose or Objective The aim of this study was to evaluate the outcomes and toxicities of local re-irradiation with stereotactic body radiation therapy (SBRT) in patients with local recurrence of prostate cancer after curative radiotherapy.

Materials and Methods Twenty patients were treated with SBRT between December 2010 and March 2020. All patients had clinical/radiological local relapse in the prostate and no distant metastasis. Fourteen patients (70%) received 30 Gy in 5 fractions/3w, 3 (15%) received 25 Gy in 5 fractions/3w, 2 (10%) received 23 Gy in single fraction and 1 (5%) 37.5 Gy in 5 fractions/3w. All patients underwent image-guided radiotherapy (IGRT) using cone-beam computed tomography (CBCT) system as daily pre-treatment imaging. Seven out of 20 patients (35%) received also hormonal deprivation therapy. Toxicity was evaluated using the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer Criteria. Biochemical control was assessed according to the Phoenix definition (NADIR + 2 ng ml (-1)).

Results Median follow-up was 36 months (range 2-85 months). Median age was 78 years (range 65-89 years), median pre-SBRT prostate specific antigen (PSA) was 3.3 ng ml (range 0.24-18.3 ng/ml). The median planning target volume (PTV) was 65 cm3 (range 8-148.7 cm3). The median overall survival (OS) was 57 months (95% i.c. 23.5-90.8) and the actuarial 2-year and 5-year OS was 89% and 40% respectively. Two-year and 5-year Biochemical free survival (BFS) was 55% and 47%, respectively. Local control (LC) at 2-year and 5-year was 73% and 62%, respectively. Disease free survival (DFS) at 2-year and 5-year was 67% and 57%, respectively. Median BFS, LC and DFS were not reached. Six patients (30%) experienced grade 1-2 acute urinary toxicities. Grade 1-2 late urinary toxicities were reported in 13 patients (65%). Conclusion SBRT re-irradiation for locally recurrent prostate cancer offers a satisfactory tumor control and shows a low toxicity profile.

PO-1370 Metastasis-Directed Therapy with Cyberknife for Oligometastatic Prostate Cancer

S. Exner 1 , F. Fehlauer 1 , S.E. Grau 1

1 Strahlenzentrum Hamburg, Radiotherapy, Hamburg, Germany

Purpose or Objective To investigate the effects of Cyberknife-stereotactic radiosurgery (CK-SRS) for oligometastatic prostate cancer patients. Materials and Methods We retrospectively identified all patients with oligometastatic prostate cancer ( ≤ 5 metastasis in ≤ 3 organs ) treated with CK-SRS at our institution since January 2012 to September 2021 and analyzed data of primary diseases, multimodality treatments and local therapy effect based on PSA testing and treatment safety. Patients were split in 3 groups depending on the time they received androgen deprivation therapy, Group A: never, Group B: after radiosurgery, Group C: before radiosurgery.