ESTRO 2022 - Abstract Book

S478

Abstract book

ESTRO 2022

1 University of Milan; IEO European Institute of Oncology IRCCS, Department of Oncology and Hemato-Oncology; Division of Radiation Oncology, Milan, Italy; 2 IEO European Institute of Oncology IRCCS, Division of Radiation Oncology, Milan, Italy; 3 IEO European Institute of Oncology IRCCS, Department of Experimental Oncology, Milan, Italy; 4 IEO European Institute of Oncology IRCCS, Division of Radiology, Milan, Italy; 5 University of Milan; IEO European Institute of Oncology IRCCS, Department of Oncology and Hemato-Oncology; Division of Radiology, Milan, Italy; 6 IEO European Institute of Oncology IRCCS, Division of Urology, Milan, Italy; 7 IEO European Institute of Oncology IRCCS, Unit of Medical Physics, Milan, Italy; 8 University of Milan; IEO European Institute of Oncology IRCCS, Department of Oncology and Hemato-Oncology; Division of Urology, Milan, Italy; 9 IEO European Institute of Oncology IRCCS, Scientific Direction, Milan, Italy; 10 University of Milan; IEO European Institute of Oncology IRCCS, Department of Oncology and Hemato-Oncology; Division of Radiation Oncology , Milan, Italy Purpose or Objective The purpose of the study is to report updated toxicity and oncological results at 5 years of the Phase II prospective trial "Give Me Five" short-term high precision radiotherapy for early prostate cancer with simultaneous boost to the dominant intraprostatic lesion (DIL) for patients with early stage prostate cancer (PCa) (AIRC-IG-13218). Materials and Methods “Give me Five” enrolled 65 patients since June 2015. Patients with low and intermediate risk PCa meeting the inclusion criteria underwent extreme hypofractionated radiotherapy to the prostate (36.25 Gy in 5 fractions) and a simultaneous integrated boost to the DIL of 37.5 Gy. The DIL was identified by a multiparamentric MRI (mpMRI) co-registered with the planning computed tomography (CT). Toxicity was assessed according to Common Terminology Criteria for Adverse Events (CTCAE) v4.0 and Radiation Therapy Oncology Group (RTOG) and the European Organization for Research and Treatment of Cancer (EORTC) criteria. All patients have been evaluated by a medical visit and/or phone call. Quality of life (QoL) of contacted and alive patients was assessed by International Prostate Symptoms score (IPSS), European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire—Core 30 (EORTC QLQ-C30), EORTC QLQ prostate specific (QLQ-PR25), and sexual activity by International Index of Erectile Function (IIEF-5). For all patients with no evidence of disease (NED), prostate-specific antigen (PSA) values were collected and analysed. Results Five-year follow-up was available for 37 out of the 65 enrolled patients. After a median follow-up of 49 months (interquartile range, IQR 37-60 months), out of the 37 reachable patients, 27 (73%) resulted alive with NED, 3 (8%) alive with disease and 7 (19%) died for other causes. Biochemical progression-free survival at 5 years calculated on all patients and on patients still alive was 73% and 90%, respectively. Overall survival at 5 years was 81%. Out of the 27 NED patients, median PSA was 0.36 ng/ml (IQR 0.20-0.59 ng/ml). No grade (G) ≥ 3 genitourinary and gastrointestinal toxicity events were reported. Questionnaires showed that overall QoL patients was satisfactory at last follow-up. Conclusion These updated data about efficacy and late toxicity of this extreme hypofractionated schedule with concomitant boost on the DIL confirm our previously published findings that it is a safe and effective approach. The increasing dose to the DIL does not worsen the RT toxicity and consequently does not affect patients' QoL, thus questioning the possibility of an even more escalated treatment. Purpose or Objective Propensity score-matching (PSM) based long-term outcome and toxicity comparison of EBRT versus EBRT plus HDR brachytherapy boost (HDR-BT boost). Materials and Methods 744 prostate cancer patients were treated with either EBRT alone (n = 406) or EBRT plus HDR-BT boost (n=338) between 2002 and 2019 and were retrospectively compared in this monocentric study. PSM was performed including age, Gleason score, initial PSA value, tumor stage, use of ADT, and risk group according to D´Amico. After PSM, 258 patient pairs (n = 516) were included into the final analysis. For EBRT alone, 33 fractions were applied using VMAT with a simultaneous integrated boost of 60 Gy (D 95 ) / 76.23 Gy (D mean ). For combined EBRT and HDR brachytherapy, EBRT was delivered in 46 Gy (D Mean ) in conventional fractionation, followed by two fractions HDR-BT boost with 9 Gy (D 90% ) two and four weeks after EBRT. Genitourinary (GU) and gastrointestinal (GI) toxicity was evaluated utilizing the Common Toxicity Criteria for Adverse Events (version 5.0) and biochemical failure was defined according to the Phoenix definition. Toxicities were calculated for the total group without PSM. For all statistical analyses, R software environment for statistical computing and graphics (version 4.1; The R Foundation for Statistical Computing, Vienna, Austria) was used. All tests were two-sided with a level of significance set at p < 0.05. Results The median follow-up was 95.3 months (range 0.5-230.7 months) in the propensity score-matched cohort (n = 516). 36 / 190 / 290 patients had low- / intermediate- / high-risk prostate cancer, respectively. Additive androgen deprivation therapy was given in 52.7% of the patients. Biochemical relapse-free survival (bRFS), metastasis-free survival (MFS), and overall survival (OS) for both groups were not statistically different after PSM. The estimated 10-year bRFS was 82.0% versus 76.3% (p = 0.075) for EBRT versus EBRT + HDR brachytherapy, respectively. The estimated 10-year MFS was 82.9% versus 87.4% (p = 0.19) and the 10-year OS was 65.7% versus 68.9% (p = 0.30). EBRT, compared to EBRT + HDR-BT boost, showed significantly MO-0552 Propensity score-matched analysis comparing prostate EBRT versus EBRT + HDR brachytherapy J. Tamihardja 1 , I. Lawrenz 1 , P. Lutyj 1 , J. Kraft 1 , M. Zimmermann 1 , S. Weick 1 , M. Flentje 1 , B. Polat 1 1 University of Wuerzburg, Department of Radiation Oncology, Wuerzburg, Germany