['To determine whether the application of two courses of cisplatin simultaneously with hyperfractionated radiotherapy improves the outcome in locally advanced and/or node-positive nonmetastatic carcinomas of the head and neck, compared with hyperfractionated radiotherapy alone.', 'From July 1994 to July 2000, 224 patients with squamous cell carcinomas of the head and neck (excluding nasopharynx and paranasal sinus) were randomly assigned to hyperfractionated radiotherapy (median dose, 74.4 Gy; 1.2 Gy twice daily) or the same radiotherapy combined with two cycles of concomitant cisplatin (20 mg/m2 on 5 days of weeks 1 and 5). The primary end point was time to any treatment failure; secondary end points were locoregional failure, metastatic relapse, overall survival, and late toxicity.', 'There was no difference in radiotherapy between both treatment arms (74.4 Gy in 44 days). The full cisplatin dose was applied in 93% and 71% of patients during the first and second treatment cycles, respectively. Acute toxicity was similar in both arms. Median time to any treatment failure was not significantly different between treatment arms (19 months for combined treatment and 16 months for radiotherapy only, respectively) and the failure-free rate at 2.5 years was 45% and 33%, respectively. Locoregional control and distant disease-free survival were significantly improved with cisplatin (log-rank test, P = .039 and .011, respectively). The difference in overall survival did not reach significance (log-rank test, P = .147). Late toxicity was comparable in both treatment groups.'] Does concomitant cisplatin significantly improve locoregional control in advanced head and neck cancers treated with hyperfractionated radiotherapy?