OBJECTIVES: To explore the risk factors of laryngo-esophageal dysfunction-free survival and nutritional support dependence over 12 months in patients with unresectable locally advanced head and neck carcinomas who received chemoradiotherapy in a phase II trial of JCOG0706 (UMIN000001272). METHODS: Forty-five patients received radiation therapy for a total of 70 Gy/35fr concurrently with S-1 and cisplatin. Risk factors of laryngo-esophageal dysfunction-free survival and nutritional support dependence over 12 months were analyzed using Cox regression models and logistic regression models, respectively, with consideration to patient laboratory data just before chemoradiotherapy. Radiation fields were reviewed to analyze the relationship between the extent of the irradiated field and functional outcome. RESULTS: With a median follow-up period of 3.5 years, 3-year laryngo-esophageal dysfunction-free survival was 48.9%. For laryngo-esophageal dysfunction-free survival, hazards ratio of 2.35 in patients with nutritional support at registration (vs. without nutritional support; 95% confidence interval 0.96-5.76). For nutritional support dependence over 12 months, odds ratio was 6.77 in patients with hemoglobin less than the median of 13.4 g/dl (vs. higher than or equal to the median; 95% confidence interval 1.24-36.85) and was 6.00 in patients with albumin less than the median of 3.9 g/dl (vs. higher than or equal to the median; 95% confidence interval 1.11-32.54). Primary sites in disease-free patients with nutritional support dependence over 12 months were the oropharynx (N = 2) or hypopharynx (N = 1), and all pharyngeal constrictor muscles were included in irradiated fields with a curative dose. CONCLUSIONS: This supplementary analysis showed that pretreatment severe dysphagia requiring nutritional support, anemia and hypoalbuminemia might have a negative prognostic impact on long-term functional outcomes after curative chemoradiotherapy in head and neck cancer.