OBJECTIVES: I. Compare, in a phase III setting, overall and disease-free survival with preservation of laryngeal function in patients with stage III/IV squamous cell carcinoma of the glottic and supraglottic larynx treated with cisplatin/fluorouracil (CDDP/5-FU) followed by radiotherapy vs. concomitant radiotherapy plus CDDP vs. radiotherapy alone. II. Compare the tumor response after completion of chemotherapy but prior to initiation of radiotherapy with that following completion of radiotherapy and concurrent chemotherapy. III. Compare the patterns of relapse (local and regional recurrence and distant metastasis) with these treatments. IV. Compare the incidence of second primary tumors in patients treated on these three regimens. V. Compare the acute and chronic adverse effects of these three regimens. VI. Compare the morbidity experienced with neck dissection and/or laryngeal salvage surgery following treatment with these regimens. VII. Compare quality of life of patients with laryngeal preservation vs. patients requiring salvage laryngectomies. VIII. Compare the quality of life of patients receiving radiotherapy alone vs. those receiving chemotherapy as well.