ESTRO 2022 - Abstract Book

S1156

Abstract book

ESTRO 2022

found for pre-NCRT haemoglobin value and PLR with TRG 1-2 versus TRG 3-4 (p= 0.930 and p=0.710, respectively). Furthermore, no significant correlation was obtained between pre-NCTR values and clinical outcomes. We also evaluated post-NCRT blood values but none of them resulted in a significant correlation with TRG neither outcomes.

Conclusion Conclusion: The prognostic significance of systematic inflammation values, as haemoglobin, NLR and PLR, is an interesting argument and it has been explored in several neoplasms. In our study a higher (2.0 - 3.3) pre-NCRT NLR resulted as a predictor of poor pathological tumor response. The study is still ongoing in order to be validated in a larger number of patients. This could be helpful to define predictive models for treatments personalization, allowing the possibility of an intensified therapy, especially in poor-responders’ patients.

PO-1362 Genetic variability of homologous recombination repair genes and radiotherapy cardiotoxicity

T. Marinko 1 , F. Dugar 2 , V. Dol ž an 3 , K. Gori č ar 4

1 Institute of Oncology Ljubljana, Radiotherapy department, University of Ljubljana, Faculty of Medicine, Ljubljana, Slovenia; 2 University of Ljubljana, Faculty of Medicine, Ljubljana, Slovenia; 3 University of Ljubljana, Faculty of Medicine, Institute of Biochemistry and Molecular Genetics, Pharmacogenetics Laboratory, Ljubljana, Slovenia; 4 Faculty of Medicine, University of Ljubljana, Institute of Biochemistry and Molecular Genetics, Pharmacogenetics Laboratory, Ljubljana, Slovenia Purpose or Objective Despite the significant impact of adjuvant radiotherapy (RT) on the survival of HER2-positive early breast cancer patients, they may also experience treatment-related adverse events. The homologous recombination repair (HRR) pathway is involved in the repair of double-strand breaks, the most cytotoxic DNA lesions caused by radiation. Genetic variability of DNA repair genes could contribute to the interindividual variability in the occurrence of adverse events. Therefore, the study aimed to evaluate the association of polymorphisms in HRR genes on the occurrence of RT cardiotoxicity in breast cancer patients. Materials and Methods Our study included 101 HER2-positive early breast cancer patients treated with adjuvant radiotherapy. Markers of cardiotoxicity investigated in the study were LVEF reduction, serum NT-proBNP concentration, and NYHA grade. DNA was isolated from buccal swab samples. All patients were genotyped for eight single nucleotide polymorphisms ( NBN rs1805794, rs709816, and rs1063054, RAD51 rs1801320, rs1801321, and rs12593359, XRCC3 rs1799794 and rs861539) using competitive allele-specific PCR. Logistic regression was used to evaluate the association with cardiotoxicity. Results Median time after adjuvant RT was 4.0 (2.6-5.4) years. LVEF reduction was observed in 9 (8.9%) patients, increased NT- proBNP in 36 (25.6%) patients, while 17 (16.8%) patients had NYHA grade 2. Among clinical parameters, hyperlipidemia and