Outcomes, toxicity profiles, and prognostic factors of unresectable head and neck cancer treated with chemoradiotherapy

Introduction: Head and neck cancer (HNC) is a heterogeneous group of neoplasms that can have a poor prognosis when diagnosed in advanced stages. The optimized treatment for locally advanced and unresectable lesions is mainly based on radiotherapy associated with chemotherapy (cisplatin 100mg/m²), however, at the expense of a high toxicity index. Objective: Evaluate whether chemoradiotherapy (CRT) ­ the goldstandard treatment for locally advanced head and neck cancer (HNC) ­ is effective in the study population. Methods: This is a retrospective study aimed at determining the efficacy of definitive CRT in patients with unresectable HNC treated between the 2012 and 2018 in a single institution. The following outcomes were evaluated: objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and toxicity profiles. Results: Fifty-two (52) patients diagnosed with HNC between 2012 and 2018 met the inclusion criteria. The ORR was 84.6%, with 50% showing complete response. Median PFS and OS were 35.3 and 52 months, respectively. Analysis of the toxicity profiles revealed that 69.2% of the patients presented grade 3-4 toxicity. Completion of two or more cycles of cisplatin-based therapy (HR 3.57 [95% CI 1.25­10.25]; p p<0.001), grade 3-4 toxicity (HR 0.27 [95% CI 0.09-0.8] ­ p<0.02), and Charlson comorbidity index (CCI) (HR 3.23 [95% CI 1.26­8.29]; p<0.001) were significantly associated with survival. Regarding toxicity, prophylactic low-level laser therapy (HR 0.48 [95% CI 0.27­0.86]; p<0.001 for those without this practice) and body mass index (BMI) (HR 0.27 [95% CI 0.09­0.76]; p<0.01) showed statistical significance. Conclusion: CRT was effective to treat HNC in the study population, with PFS and OS comparable to those reported in larger sample studies and lower toxicity grade. Some clinical characteristics have been identified as prognostic and/or predictive factors.