ESTRO 2025 - Abstract Book

S2012

Clinical - Urology

ESTRO 2025

2803

Digital Poster Comparison of radiotherapy with Cyberknife or low dose rate brachytherapy of low-intermediate risk prostate cancer patients after six-year follow-up Péter Ágoston 1,2 , Péter Trauttwein 3 , Kliton Jorgo 1,2 , László Gesztesi 1 , Zsuzsa S. Kocsis 4,5 , Georgina Fröhlich 1,6 , Gábor Stelczer 1 , Tibor Major 1,2,5 , Csaba Polgár 1,2,5 1 Centre of Radiotherapy, National Institute of Oncology, Budapest, Hungary. 2 Department of Oncology, Semmelweis University, Budapest, Hungary. 3 Faculty of General Medicine, Semmelweis University, Budapest, Hungary. 4 Centre of Radiotherapy, Department of Radiobiology and Diagnostic Onco-Cytogenetics, National Institute of Oncology, Budapest, Hungary. 5 National Tumorbiology Laboratory, National Institute of Oncology, Budapest, Hungary. 6 Department of Biophysics, Eötvös Lorand University, Budapest, Hungary Purpose/Objective: The purpose of this study was to compare the outcome and toxicity of patients with low- and intermediate-risk prostate cancer treated with Cyberknife (CK) or low-dose rate brachyterapy (LDR-BT). Material/Methods: Survival outcome and toxicity data of 226 consecutive low- and intermediate-risk prostate cancer patients treated in 2018-19 either with 37.5-40 Gy CK teletherapy (n=119) or 145 Gy LDR-BT (n=107) was reported. The toxicity was registered according to the RTOG system. Propensity score weighting was performed to balance the differences in prognostic factors in the treatment groups, and the result of the matched population was presented. Results: The median follow-up was 63 months (range: 23-75 months). 6-year survival outcomes were reported. The local relapse-free survival was significantly better with CK vs. LDR-BT (99.2±0.8% vs. 94.4±2.3%, p=0.038). There was a trend in favor of the CK in the biochemical relapse-free survival (96.9±1.5% vs. 91.2±2.7%, p=0.061), and failure-free survival (96.1±1.7% vs. 89.4±3.2%, p=0.076). Disease-free survival for CK vs. LDR-BT was 96.9±1.5% vs. 91.7±3.0% (p=0.170) respectively. In patients treated with CK vs. LDR-BT, the regional relapse-free (97.7±1.3% vs. 95.5±2.4%), the distant metastasis-free (99.2±0.8% vs. 98.0±1.9%), salvage hormone therapy-free (96.9±1.5% vs. 92.9±2.7%) and overall survival (98.5±1.1% vs. 97.4±1.5%) were all in favor of CK, but the differences were not significant. In the CK vs. LDR-BT group, 6.0% vs. 1.7% (p=0.002) grade 2 acute gastrointestinal (GI) and 54.9% vs. 38.1% (p=0.017) grade ≥2 acute genitourinary (GU) toxicity was registered, however, there were less grade 3 acute UG toxicity in the CK (0.8%) than in the LDR-BT (2.5%) group (p=0.044). Late grade≥2 UG toxicity was more frequent in the CK vs. the LDR -BT group (29.3% vs. 22.9%, p=0.045). The late grade≥2 GI toxicity showed no significant difference in CK vs. LDR -BT with low rates in both groups (2.3% vs. 1.7%), but there was 1.5% grade 3 proctitis in the CK group, only. Conclusion: Cyberknife therapy is a safe treatment option with good long-term results in treating of low- and intermediate-risk prostate cancer patients. The 6-year outcome with CK is comparable to or even better than with LDR-BT. The different toxicity and survival profiles allow patients' preferences to be taken into account.

Keywords: Prostate, LDR-BT, Cyberknife

2807

Digital Poster Demographic disparities in patients recruited into prostate cancer radiotherapy clinical trials