ESTRO 2024 - Abstract Book

S2288

Clinical - Urology

ESTRO 2024

11

Proffered Paper

Register data on long-term morbidity after prostate ultra-hypofractionation in the HYPO-RT-PC trial

Astrid E Persson 1,2 , Elisabeth Kjellén 1,2 , Hans Garmo 3,4 , Gabriel Adrian 1,2 , Pär Stattin 4 , Anders Widmark 5 , Per Nilsson 1,2 , Adalsteinn Gunnlaugsson 1,2 1 Lund University, Department of Clinical Sciences, Divison of Oncology, Lund, Sweden. 2 Skåne University Hospital, Department of Haematology, Oncology and Radiation Physics, Lund, Sweden. 3 King's College London, Translational Oncology and Urology Research, London, United Kingdom. 4 Uppsala University, Department of Surgical Sciences, Uppsala, Sweden. 5 Umeå University, Department of Radiation Sciences, Oncology, Umeå, Sweden

Purpose/Objective:

HYPO-RT-PC was the first randomised phase III trial to report five-year outcomes of ultra-hypofractionated (UHF) and conventionally fractionated (CF) radiotherapy (RT) in localised prostate cancer (PCa). UHF RT was non-inferior to CF RT in terms of failure-free survival, with similar rates of late toxicity [1]. We compared potentially RT-related medically significant genitourinary (GU) and gastrointestinal (GI) events, as well as mortality associated with these conditions, between the trial arms using routinely-collected health register data in Sweden. Furthermore, we compared the results with a population-based control group.

Material/Methods:

The Scandinavian HYPO-RT-PC trial compares primary UHF (42.7 Gy/7 fractions, 3 fractions/week) and CF (78.0 Gy/39 fractions, 5 fractions/week) RT in localised PCa. Androgen deprivation therapy was not permitted. The trial enrolled 1200 patients with intermediate- or high-risk localised PCa between July 2005 and November 2015. In the current study, we included Swedish residents at trial enrolment. Data were accessed from Prostate Cancer data Base Sweden 5.0, which links the National Prostate Cancer Register with several population-based registers. We used two health administrative registers and one death register. Additionally, we retrieved a population-based control group of men without PCa matched 5:1 with the UHF group on birth year and county of residence. Primary outcomes were medically significant GU and GI events that were considered potentially RT-related, and mortality associated with these conditions. Descriptions of Common Terminology Criteria for Adverse Events version 5 toxicity grades 3 and 4 were mapped to diagnosis and intervention codes from the Swedish version of the International Classification of Diseases 10th Revision and the Classification of Care Measures, respectively, used in Swedish electronic health records. We defined broad code sets to directly and indirectly represent any AE relevant to prostate RT (e.g., acute kidney injury) and narrow code sets to represent AEs strongly related to prostate RT (e.g., proctitis). In-patient episodes of care, interventions and causes of death were identified through the codes and defined events.