Baseline Nutritional Status and Early Treatment Response in Oropharyngeal Cancer: A Prospective Cohort Study by HPV Status (FIS 19 Study)

Background/Objectives: Human papillomavirus (HPV) is a well-established prognostic marker in oropharyngeal squamous cell carcinoma (OPSCC); however, the short-term treatment response remains heterogeneous, particularly among HPV-positive patients. Given the high prevalence of malnutrition in head and neck cancer, this study examined whether baseline nutritional status, body composition and functional status were associated with early treatment response in OPSCC according to HPV status. Methods: A prospective observational multicenter cohort study of newly diagnosed OPSCC patients eligible for curative-intent treatment was conducted at three tertiary hospitals in Barcelona, Spain. Baseline assessments comprised anthropometry, computed tomography (CT)-based body composition at L3, functional performance tests, systemic inflammatory biomarkers and nutritional diagnosis by the Patient-Generated Subjective Global Assessment (PG-SGA). Early treatment response, assessed around 12 weeks post-therapy, was classified as complete remission (CR) or non-complete remission (NCR). Classification tree analyses were performed separately by HPV status. Results: Of 101 enrolled patients, 97 completed post-treatment assessment, of whom 51% were HPV-positive. Among HPV-positive patients, PG-SGA score was the main discriminating variable for early response within the classification tree model, with CR achieved in 74% of patients scoring <6 versus 33% of those scoring ≥6 (AUC 0.68, 95% CI 0.55–0.82). Conversely, Eastern Cooperative Oncology Group Performance Status (ECOG PS) and age were the primary discriminating variables in HPV-negative patients (AUC 0.81, 95% CI 0.70–0.93). In both HPV subgroups, body composition and inflammatory markers were not retained in the analysis once nutritional and functional status were considered. Conclusions: PG-SGA-defined nutritional status was associated with early treatment response in HPV-positive patients, while functional status was the main variable retained in HPV-negative patients. These findings support the potential clinical value of standardized nutritional assessment in OPSCC and suggest that early identification of poor nutritional status or functional impairment may help refine supportive care planning at treatment initiation.