ESTRO 2025 - Abstract Book

S1976

Clinical - Urology

ESTRO 2025

Keywords: Prostate cancer, oligometastasis, SBRT

1874

Digital Poster Stereotactic ablative body radiotherapy as an alternative to surgery to control primary kidney cancer Enrico Raggi 1 , Carlo Furlan 1 , Margherita Crespi 2 , Luca Triggiani 3 , Anna Chiara Camilletti 1 , Filippo De Renzi 1 , Fabrizio Tonetto 4 , Eugenia Moretti 5 , Giovanni Liguori 6 , Alessandro Magli 7 1 Radiotherapy, San Martino Hospital, Belluno, Italy. 2 Medical Physics, San Martino Hospital, Belluno, Italy. 3 Radiotherapy, Spedali Civili, Brescia, Italy. 4 Radiotherapy, Ospedale Nuovo, Udine, Italy. 5 Medical Physics, Ospedale Nuovo, Udine, Italy. 6 Urology, Clinica Urologica, Trieste, Italy. 7 Radiotherapy, Ospedale Maggiore, Trieste, Italy Purpose/Objective: investigate retrospectively outcome and toxicity of stereotactic ablative radiotherapy (SABR) in patients medically inoperable or refusing surgery. Material/Methods: we evaluated patients unfit for surgery or refusing surgery treated with SABR for primary kidney cancer. All patients had creatinine tested before starting radiotherapy and during follow-up. Radiation schedules allowed were 39 Gy/3 fractions, 42 Gy/3 fractions, 40 Gy/4 fraction. Follow up combined history and physical examination, blood tests and imaging. Results: seventeen patients were treated with SABR for primary kidney cancer; 13 had sufficient follow up data to be evaluated. Median age of the patients was 74 years (range 48-89). Fourteen patients were male and 3 were females. Seven patients out of 17 had had abdominal surgery before (5 patients had undergone contralateral nephrectomy- partial in 2 patients and total in 3 patients). ECOG performance status was 0 in 6 patients, 1 in 4 patients, whilst it was not specified in 7 patients. Seven patients were biopsied confirming primary kidney cancer. Ten patients had a radiographic diagnosis of cancer. Staging imaging was by computed tomography in all patients but one who was staged by magnetic resonance. Median tumor dimension was 32 millimeters (range 17-52). Median creatinine before SABR was 1,13 mg/dL (range 0.74-1.81). Median creatinine after SABR was 1.51 mg/dL (range 0,94-1,86). Toxicity, assessed by the Common Terminology Criteria for Adverse Events (CTCAE), was less than G3 in all cases and it mainly consisted of pain in the flank/abdomen, diarrhea, asthenia. Median prescribed dose was 42 Gy (range 39-42). Median number of fractions was 3 (range 3-4). Fourteen patients were treated once daily continuously, whilst 3 patients were treated every other day. Image-guided radiotherapy (IGRT) was done by daily cone beam computed tomography (CBCT). Median follow-up was 18 months (range 3-30 months). Eight patients showed no sign of tumor progression. Three patients relapsed (2 patients developed metastastic disease whilst 1 patient had local recurrence). Two patients died of intercurrent disease (COVID infection complications). Four patients were recently treated and their follow-up is still pending. Conclusion: our data support SABR for primary kidney cancer as a valid non-invasive alternative to surgery in terms of outcome with a favourable toxicity profile in patients medically inoperable or declining surgery. No patient required dialysis, not even those patients who had a history of contralateral nephrectomy. This is in line with the TROG 15.03 FASTRACK II trial [1].

Keywords: kidney, stereotactic, ablative