PIK3CA mutation in HPV-associated OPSCC patients receiving deintensified chemoradiation
Menée sur 77 patients atteints d'un carcinome épidermoïde de l'oropharynx lié au papillomavirus humain et inclus dans des essais de phase II évaluant une chimioradiothérapie d'intensité réduite, cette étude examine l'association entre la présence d'une mutation sur le gène PIK3CA et la survie sans maladie à 3 ans
PIK3CA is the most frequently mutated gene in HPV-associated oropharyngeal squamous cell carcinoma (OPSCC). Prognostic implications of such mutations remain unknown. We sought to elucidate the clinical significance of PIK3CA mutations in HPV-associated OPSCC patients treated with definitive chemoradiation (CRT). Seventy-seven patients with HPV-associated OPSCC were enrolled on two phase II clinical trials of de-intensified CRT (60 Gy intensity-modulated radiotherapy with concurrent weekly cisplatin). Targeted next-generation sequencing was performed. Nine of 77 patients had disease recurrence (2 regional, 4 distant, 3 regional and distant). Thirty-four patients had mutation(s) identified; 16 had PIK3CA mutations. Patients with wild-type-PIK3CA had statistically significantly higher 3-year disease-free survival than PIK3CA-mutant patients (93.4% [95% CI 85.0-99.9%] vs. 68.8% [95% CI 26.7-89.8%]; p = 0.004. On multivariate analysis, PIK3CA mutation was the only variable statistically significantly associated with disease recurrence (HR 5.71 [95% CI 1.53, 21.3], p = 0.01). PIK3CA mutation is associated with worse disease-free survival in a prospective cohort of newly diagnosed HPV-associated OPSCC patients treated with de-intensified CRT.
Journal of the National Cancer Institute , résumé, 2018