Concomitant cisplatin chemotherapy and radiotherapy in advanced mucosal squamous cell carcinoma of the head and neck. Long-term results of the Radiation Therapy Oncology Group study 81-17. One hundred twenty-four eligible patients with advanced mucosal squamous cell carcinoma of the head and neck were entered into a pilot study of concomitant cisplatin (100 mg/m2 given every 3 weeks for three doses) and standard irradiation. The initial complete response (CR) was 71% with an additional two cases salvaged by surgery for an overall 73% CR. When no keratin was identified in the histologic specimen (41 patients) the CR was 90%. The nasopharynx showed the best CR (89%) among the sites. At 4 years after treatment, the estimated locoregional tumor control rate was 43% and the survival, 34%. When no keratin was present in the specimen, the estimated locoregional control of tumor was superior (56% versus 38% with keratin identified, P = 0.02) and the estimated survival was also superior (48% versus 26%, P = 0.008). Acute treatment-related toxicities included one death due to renal damage and two patients with life-threatening renal damage. The delivery of radiotherapy was not altered. Late toxicity included necrosis -3%, fibrosis -4%, and one fistula. The results of this study justify a randomized trial for the comparison of this combination of cisplatin and radiotherapy versus radiotherapy alone in advanced mucosal carcinomas of the head and neck. 