ESTRO 2021 Abstract Book

S1085

ESTRO 2021

PO-1322 Clinical outcome of MRI based high-dose-rate brachytherapy for prostate cancer S. Buus 1 , H.A.S. Hansen 2 , S. Rylander 2 , S.B. Hokland 2 , K. Tanderup 2 , L.N. Bentzen 2 1 Aarhus University Hospital, Dept of Oncology, Aarhus, Denmark; 2 Aarhus University Hospital , Dept of Oncology , Aarhus , Denmark Purpose or Objective MR imaging following catheter implantation in high-dose-rate brachytherapy (HDR BT) provides superior anatomical details for improved definition of the prostate gland, organs at risk, and catheters. The purpose of this study was to evaluate the clinical outcomes of MRI based HDR BT in a single institution prostate cancer patient cohort. Materials and Methods The study included 113 consecutive prostate cancer patients treated with combined EBRT and HDR BT; 11 D´Amico intermediate-risk (IR), 99 D´Amico high-risk (HR), and three lymph node positive (N1) patients. Patients were planned to receive a course of image guided EBRT of 46 Gy in 23 fractions to the pelvis followed by two separate 8.5 Gy boosts of HDR BT to the prostate gland added a 3-mm margin. Neoadjuvant/adjuvant androgen deprivation therapy (ADT) was prescribed for three years for all HR and N1 patients and for 6 months for 2 of 11 IR patients. Patients were evaluated at baseline, after EBRT, and at 6 weeks, 3, 6, 12, 24, 36, 60 and 96 months after HDR BT. Evaluation included clinical examination, blood samples, CTCAE v.4.0 toxicity assessment, EORTC QLQ C30, and patient-reported- outcomes consisting of items from the RT-ARD score, DAN- PSS, and EPIC-26 questionnaires. Results The included patients had a median age of 69 years (range 49-79), a prostate gland volume at EBRT of median 35 ml (range 14-72), and a PSA of median 16 ng/ml (range 4 -108). The ISUP grade distribution in the cohort was; 3% ISUP grade 1, 35% grade 2, 20% grade 3, 27% grade 4, and 15% grade 5. The follow-up period was median 5 years. 5-year recurrence free survival was estimated by Kaplan Meier method to 95% ( Figure 1 ). Six patients experienced a recurrence of prostate cancer; of which one was a local recurrence, one was a nodal recurrence, and four were distant recurrences. There were six recorded deaths during the follow-up period, none of which were related to prostate cancer. Grade 2 or greater CTCAE GI toxicity was 4%, 10% and 11% at baseline, 12 months and 60 months, respectively. Similarly, CTCAE urinary toxicity grade 2 or higher was reported at 1%, 18% and 13% at baseline, 12 months and 60 months, respectively ( Figure 2 ). Finally, the mean global health score (GHS) was 82, 78 and 77 at baseline, 12 months and 60 months after HDR BT, respectively. No significant decrease in GHS was observed from baseline to 12 months (p=0.50) or from baseline to 60 months (p=0.47).

Conclusion Combined EBRT and MRI based HDR BT provides excellent clinical outcomes with a high local control, low physician assessed toxicity, and no significant negative effects on patient reported global health.

PO-1323 Low toxicity in LDR brachytherapy boost with real time intraoperative planning in prostate cancer M. Barrado 1 , E. Villafranca Iturre 1 , A. Sola Galarza 1 , I. Visus Fernández de Manzano 1 , P. Navarrete Solano 1 , N. Fuentemilla Urio 2 , S. Pellejero Pellejero 2 , A. Galbete Jiménez 3 , M.A. Rodríguez Mendizabal 1 , L.O. Rosas Gutierrez 1 , A. Barco Gómez 1 , E.G. Martínez López 4 1 Complejo Hospitalario de Navarra, Radiation Oncology, Pamplona, Spain; 2 Complejo Hospitalario de Navarra, Medical Physics, Pamplona, Spain; 3 Fundación Miguel Servet-NavarraBioMed , Department of Statistics, Pamplona, Spain; 4 Complejo Hospitalario de Navarra, Radiation Oncology, Papmlona, Spain