Final report of RTOG 9610, a multi-institutional trial of reirradiation and chemotherapy for unresectable recurrent squamous cell carcinoma of the head and neck

Background. Our objectives were to determine the incidence of acute and late toxicities and to estimate the 2-year overall survival for patients treated with reirradiation and chemotherapy for unresectable squamous cell carcinoma of the head and neck (SCCHN). Methods. Patients with recurrent squamous cell carcinoma or a second primary arising in a previously irradiated field were eligible. Four weekly cycles of 5-fluorouracil 300 mg/m² IV bolus and hydroxyurea 1.5 g by mouth were used with 60 Gy at 1.5 Gy twice-daily fractions. Toxicity was scored according to Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer (RTOG/EORTC) criteria. Results. Seventy-nine of the 86 patients enrolled were analyzable. The worst acute toxicity was grade 4 in 17.7% and grade 5 in 7.6%. Grade 3 and 4 late toxicities were found in 19.4% and 3.0%, respectively. The estimated cumulative incidence of grade 3 to 4 late effects occurring at >1 year was 9.4% (95% confidence interval [CI]: 0, 19.7) at 2 and 5 years. The 2- and 5-year cumulative incidence for grade 4 toxicity was 3.1% (95% CI: 0, 9.3). The estimated 2- and 5-year survival rates were 15.2% (95% CI: 7.3, 23.1) and 3.8% (95% CI: 0.8, 8.0), respectively. Patients who entered the study at >1 year from initial radiotherapy (RT) had better survival than did those who were <1 year from prior RT (median survival, 9.8 months vs 5.8 months; p = .036). No correlation was detected between dose received and overall survival. Three patients were alive at 5 years. Conclusion. This is the first prospective multi-institutional trial testing reirradiation plus chemotherapy for recurrent or second SCCHN. The approach is feasible with acceptable acute and late effects. The results serve as a benchmark for ongoing RTOG trials.