ESTRO 2023 - Abstract Book

S1226

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ESTRO 2023

hormone therapy have, more fatigue and insomnia, and worse quality of life, physical function, role function and social function than those not receiving HT.

Conclusion Patients with localized prostate cancer referred to radiotherapy already show Q&L deterioration in relation to their presenting comorbidities. RT treatment significantly deteriorates Q&L, some symptoms and functions and the deterioration is greater in those receiving HT.

PO-1508 Urinary toxicity after prostate cancer stereotactic reirradiation : frequency and predictors

M. BATY 1 , R. DE CREVOISIER 1

1 Centre Eugene Marquis, Department of Radiation Oncology, RENNES, France

Purpose or Objective The aim of this study was to describe urinary toxicity after salvage stereotactic body radiation therapy (SBRT) for local prostate cancer recurrence after radiotherapy. Materials and Methods We retrospectively reviewed a total of 108 medical records of patients treated with salvage SBRT for prostate cancer recurrence, between July 2015 and February 2021 in our institution. Patients who had initial radical prostatectomy were excluded. The median time interval between the two radiation treatments was 9 years (range, 3-20 years). Local recurrence was to be proven by biopsies, without distant lymph node or metastasis. The salvage treatment consisted in SBRT at a total dose of 36 Gy in six fractions delivered every other day, associated with androgen deprivation therapy in 44% of patients. Urinary toxicities after salvage SBRT were described according to the CTCAE v 4.03 classification. Clinical and dosimetric predictors of toxicities were searched by Cox analysis. Results Median follow-up was 19.6 months (range, 2.3-67 months). The acute grade 2 and 3 overall GU toxicity rates were 22% and 2%, respectively. The 2 year grade ≥ 2 and ≥ 3 overall GU toxicity rates were 55% (95% CI: 44-66%) and 5% (95% CI: 0-10%), respectively. The acute and late GU toxicity rates by symptoms are provided in the Table. One patient experimented a grade 4 GU toxicity (bladder necrosis requiring a cystectomy) 8 months after SBRT. Predictors of grade ≥ 2 late overall GU toxicity in multivariate analysis were anticoagulant treatment (RR=2.2, p=0.01) and V37 in the bladder wall (in cc) (RR=1.8, p=0.01).