DNA repair- and apoptosis-pathways to regulate response to chemo-radiotherapy (CRT) in patients (p) with locally advanced head and neck cancer (HNC).

e17025 Background: Platinum-based CRT is preferred standard of care for locally advanced HNC. However, survival benefit is small, with substantial toxicity and biomarkers of CRT resistance could guide treatment selection and spare morbidity. Increased DNA repair in solid tumors may contribute to cancer cells’ ability to survive in genotoxic stress environments afforded by therapy. Apoptosis may also play an important role in determining response to chemotherapy. Methods: We assessed mRNA expression levels of DNA-repair-related genes BRCA1, RAP80, 53BP1 and RNF8 as well as apoptosis-related genes BIM and Mcl-1. We correlated our findings with response and overall survival (OS) in 72 HNC p treated with weekly carboplatin AUC 2 and radiotherapy. Results: Median age 65; 70.2% male; 84.7% smokers and alcohol users; 97.2% squamous carcinoma; 90.3% stage IV; 44.4% complete response (CR) to CRT; 10.5 months (m) median OS. P with CR to CRT or with second primary tumors had significantly longer OS compared to p wit...