ESTRO 2024 - Abstract Book

S2445

Clinical - Urology

ESTRO 2024

Late toxicity is a major issue after radiotherapy (RT) for localized prostate cancer. Radiation-induced CD8 T lymphocyte Apoptosis (RILA) is a test for predicting individual risk of radiation-induced toxicity based on a simple, non-invasive blood sample. To assess the predictive/prognostic role of RILA in radiation induced late complication of prostate cancer, we conducted a prospective multicenter trial.

Material/Methods:

From Oct 13 2006, to June 28 2016, 383 patients were included in this prospective multicenter study evaluating the predictive value of RILA on late toxicity following radiotherapy for localized prostate cancer. RILA was performed to all participants before radiotherapy and results were concealed from the clinicians. Patients received radiotherapy for localized prostate cancer and were prospectively evaluated for toxicity and survival. Outcome measurements and statistical analysis: Gastrointestinal and urinary late complication (GIUlt) was defined by the occurrence at least 3 months after the start of treatment of a grade 2 or more toxicity among the following digestive events (diarrhea and rectitis) and urinary (cystitis, incontinence, stenosis, urinary frequency) events. Impact of RILA on late complication was assessed using a competing risk method.

Results:

RILA was significantly lower in the GIUlt + group than in the GIUlt – group (p=0.012). In the univariate analysis, RILA, Gleason score and baseline urinary symptoms were statistically significant prognostic factors for GIUlt – FS. RILA and baseline urinary symptoms remained prognostic factors of GIUltin a multivariate analysis. The positive predictive value was equal to 40% for RILA ≤15% and the negative predictive value was equal to 78% for RILA >24%. RILA as a continuous variable is a reliable predictor of the risk of GIUlt +.

Conclusion:

Our results show that RILA is a predictive factor of GIUlt after RT for prostate cancer.

Keywords: Prostate, radiotherapy, predictive assay

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Gilles Créhange 1 , Jérôme Rigaud 2 , Nathalie Pello-Leprince-Ringuet 3 , Valérie Perrot 4 , Thierry Lebret 5

1 Institut Curie, Radiation Oncology, Paris, France. 2 CCHU Hôtel-Dieu, 2. Urology department, Nantes, France. 3 Ipsen, Medical affairs, Boulogne-Billancourt, France. 4 Ipsen, Biostatistics, Boulogne-Billancourt, France. 5 Foch hospital, 4. Urology department, Suresnes, France

Purpose/Objective: