Prevalence of K-RAS Codons 12 and 13 Mutations in Locally Advanced Head and Neck Squamous Cell Carcinoma and Impact on Clinical Outcomes

Background . RAS gene mutations have an impact on treatment response and overall prognosis for certain types of cancer. Objectives . To determine the prevalence and impact of K-RAS codons 12 and 13 mutations in patients with locally advanced HNSCC treated with primary or adjuvant chemo-radiation. Methods . 428 consecutive patients were treated with chemo-radiation therapy and followed for a median of 37 months. From these, 199 paraffin embedded biopsy or surgical specimens were retrieved. DNA was isolated and analyzed for K-RAS mutational status. Results . DNA extraction was successful in 197 samples. Of the 197 specimens, 3.5% presented K-RAS codon 12 mutations. For mutated cases and non-mutated cases, complete initial response to chemoradiation therapy was 71 and 73% ( P = 0.32). LRC was respectively 32 and 83% ( P = 0.03), DFS was 27 and 68% ( P = 0.12), distant metastasis-free survival was 100 and 81% ( P = 0.30) and OS was 57 and 65% ( P = 0.14) at three years. K-Ras codon 13 analysis revealed no mutation. Conclusion . K-RAS codon 12 mutational status, although not associated with a difference in response rate, may influence the failure pattern and the type of therapy offered to patients with HNSCC. Our study did not reveal any mutation of K-RAS codon 13.