Background: To report local long-term morbidity after concomitant boost radiotherapy (AFRT) or alternating chemoradiotherapy (CTRT), we analyzed the toxicity data recorded in 168 patients with advanced head and neck squamous cell carcinoma treated at our institution within phase II-III studies.
Patients and methods: All patients enrolled in three consecutive phase II-III studies and followed for a minimum of three months after the end of treatment were included in the present analysis. Local late reactions were scored prospectively. The actuarial incidence of grade 2 or more (2-4) late local toxicity according to RTOG/EORTC was taken as endpoint. The median follow-up is 32.0 months (range, 3.3-138.1 months). For living patients the minimum and median follow-up are 12.1 and 69.3 months, respectively.
Results: The five-year actuarial incidence of grade 2+ and grade 3+ toxicity are 56.7 +/- 5% and 21 +/- 4%, respectively. At multivariate analysis, acute mucositis grade, complementary surgery, primary site and performance status proved to be independent predictive factors of grade 2+ late toxicity with P values of <0.001, 0.009, 0.022 and 0.033, respectively. No effect was found for treatment itself on the incidence of late toxicity, although patients treated with accelerated radiotherapy had a higher probability of confluent mucositis than patients treated with alternating chemoradiotherapy (68% vs 32%, P <0.01).
Conclusions: A substantial proportion of surviving patients develops late complications, although severe irreversible reactions occur in a minority of patients. Acute local toxicity can be used to predict local late toxicity that arises within five years of the end of treatment.