ESTRO 2024 - Abstract Book

S5166

Radiobiology - Immuno-radiobiology

ESTRO 2024

2. Horsman MR, Wittenborn TR, Nielsen PS, Elming PB. Tumors Resistant to Checkpoint Inhibitors Can Become Sensitive after Treatment with Vascular Disrupting Agents. Int J Mol Sci. 2020 Jul 6;21(13):4778.

1193

Digital Poster

Cytokines modulation by pelvic RT with simultaneous hypofractionated boost in prostate cancer

Fiorella D'Auria 1 , Teodora Statuto 2 , Luciana Valvano 2 , Giovanni Calice 3 , Vittoria D'Esposito 4 , Serena Cabaro 4 , Pietro Formisano 4 , Antonio Traficante 1 , Grazia Lazzari 5 , Luciana Rago 5 1 Centro di Riferimento Oncologico della Basilicata (IRCCS-CROB), Laboratory of Clinical Pathology, Rionero in Vulture, Italy. 2 Centro di Riferimento Oncologico della Basilicata (IRCCS-CROB), Laboratory of Clinical Research and Advanced Diagnostics, Rionero in Vulture, Italy. 3 Centro di Riferimento Oncologico della Basilicata (IRCCS-CROB), Laboratory of Preclinical and Translational Research, Rionero in Vulture, Italy. 4 Università degli Studi di Napoli "Federico II", Department of Translational Medical Sciences, Napoli, Italy. 5 Centro di Riferimento Oncologico della Basilicata (IRCCS-CROB), Radiotherapy Unit, Rionero in Vulture, Italy

Purpose/Objective:

Many recent studies have investigated the effects of radiotherapy (RT) on the immune system (1-9) as well as the possibility of combining RT with immunotherapy (10-13). With these assumptions, our study aims to monitor the trend of a group of 10 serum cytokines over time in the peripheral blood of prostate cancer patients undergoing pelvic irradiation with a simultaneous hypofractionated prostate boost. Furthermore, we analyzed whether there was a correlation between serum cytokine levels and acute and late genitourinary (GU) and gastrointestinal (GI) toxicity.

Material/Methods:

Thirty-eight prostate cancer patients were prospectively enrolled in our single-institutional study between April 2020 and November 2021. The study was examined and approved by the local ethics committee. All enrolled patients were treated according to our Institutional guidelines. In particular, 17 patients underwent definitive moderately hypofractionated RT (66-69 Gy/25-27 fractions) and 21 patients underwent post-operative moderately hypofractionated RT (66-70 Gy/25-28 fractions). Both groups were treated by Volumetric Modulated Arc therapy. Target volumes were: prostate + seminal vesicles + pelvis for definitive RT; prostate bed + pelvis for post-operative RT. For both RT treatment, patients received a daily dose of 180 cGy to the pelvis and simultaneously a boost of 250-270 cGy to the prostate/prostate bed. Peripheral blood was collected before RT (PRE-RT), at the end of RT (END-RT), at follow-up time of 3 (FUP 3mo), 6 (FUP 6mo) and 12 months (FUP 12mo) after the end of RT for each patient. Serum samples were tested to quantify 9 human cytokines (IFN-α, IFN-β, IFN-γ, IL-1β, IL-2, IL-6, IL-8, IL-10, TNF-α) with Multiplex Luminex assay kit (R&D Systems) on Luminex 200 System and TGF-β1 by ELISA (R&D Systems). For the statistical analysis, we evaluated the differences among groups by non-parametric tests Kruskal Wallis and Wilcoxon on the occurrence. All analyses were performed by R environment and CRAN packages.

Results:

Patients characteristics are reported in Table 1. After a median follow-up time of 30.5 months (IQR 25.2 – 36.0) only 2 patients experienced biochemical relapse (5.2%). Toxicity was graded by Common Terminology Criteria for