Comparing initial PET/CT and expression of p16 (INK4a) and human papillomavirus in locally advanced head and neck cancer treated by radiochemotherapy

Purpose. - The overexpression of p16 and HPV status are now well established as independent prognostic factors in head and neck squamous cell carcinoma (HNSCC). It was suggested that some parameters derived from initial ¹⁸F-FDG PET are also independent prognostic factors. Our purpose was to study the correlation between virology and pretreatment PET/CT in locally advanced HNSCC treated by radio-chemotherapy. Methods. - Forty HNSCC patients with tumor volumes > 3 cm³ were prospectively recruited. All patients underwent initial ¹⁸F-FDG PET/CT, from which metabolic volume, intensity (SUV), overall activity, heterogeneity and shape parameters were extracted. The correlation of these parameters with virological data extracted from pre treatment biopsy, including p16 expression, DNA HPV 16 and HPV status (p16 + DNA HPV 16) was subsequently studied. Results. - P16 + tumors exhibited higher SUV_max (P = 0.028) and SUV_mean (P = 0.02). P16+ tumors were also more heterogeneous, albeit with a lower correlation (P = 0.004 for local heterogeneity). In addition, P16+ and HPV+ tumors were characterized by less complex shapes (P = 0.03). Conclusion. - Locally advanced HNSCC show specific PET characteristics in case of P16+ tumors. The relationship between those different biological characterization approaches and overall patient outcome needs to be investigated. (authors)