ESTRO 2025 - Abstract Book

S3963

Radiobiology - Tumour radiobiology

ESTRO 2025

338

Digital Poster Clinical correlation of ERCC4 gene polymorphism with survival outcome and toxicities in post-operative oral cavity cancers Ritusha Mishra 1 , Ekta Prakash 1 , Himanshu Mishra 1 , Pamela Sen 1 , Gopeshwar Narayan 2 , Neville JF 3 , Isha Jaiswal 1 1 Radiotherapy and Radiation Medicine, Institute of Medical Sciences , BHU, Varanasi, India. 2 Department of Molecular Genetics, Institute of Sciences , BHU, Varanasi, India. 3 Department of Surgical Oncology, Institute of Sciences , BHU, Varanasi, India Purpose/Objective: Head and neck cancer(HNC) exerts a significant health burden globally[1] . The multifaceted interplay between genetic susceptibility and environmental exposures underscores the complexity of HNC . The present prospective study was aimed to analyze the Single nucleotide polymorphism(SNP) of ERCC4 gene (member of Nucleotide Excision Repair gene family) in newly diagnosed post-operative cases of oral cavity cancer and its impact on survival outcomes and treatment-related toxicities. Material/Methods: It is a single arm, prospective study conducted from Sep 2022 to June 2024.This study included post-operative squamous cell carcinoma of oral cavity . Prior to initiation of adjuvant treatment(as indicated), 3 mL of blood was collected in EDTA-coated tubes for genetic testing. Genomic DNA was extracted from peripheral blood leukocytes using Phenol Chloroform method. ERCC4 SNP rs1800067 was examined in the extracted DNA samples. The peripheral blood sample of 50 normal healthy individuals of either sex, genetically unrelated to patients was also obtained as control sample. Statistical analysis was done on SPSS version26.0 Results: A total of 126 patients were included. The median age of presentation was 48.5 years with male preponderance. Majority of patients presented in locally advanced stage(86.5%). Adjuvant radiotherapy(RT) ±concurrent chemotherapy(CT) was received by 111 patients. The median RT dose received was 60Gy to high risk volume. Majority were treated by Simultaneous integrated boost with volumetric arc therapy(SIB VMAT). The median follow-up time for the entire cohort was 12 months. The median survival was not reached at the time of analysis. The genotypic distribution of ERCC4rs 180067 showed that the heterozygous genotype (GA) was much more common in patients (93.7%) than in controls (55. 2%).The survival analysis identified a statistically significant difference in overall survival(OS) among the various ERCC4 polymorphism groups. Heterozygous GA variant exhibited a significantly longer(p<0.01) mean survival time (23.5 months) compared to those with the mutant AA (11.2 months) and wild GG variants (9.8 months). This significance persisted even when the mutant and heterozygous groups were combined. These results suggested that polymorphism positively influenced the OS. The toxicity analysis revealed that dysphagia (p=0.057) and hematological toxicity (P=0.067) exhibited a significant association with polymorphism. Table 1:Patient,tumor and treatment characteristics