OBJECTIVES: I. Compare the efficacy and safety of iseganan HCl oral solution vs placebo in patients undergoing radiotherapy with or without chemotherapy for head and neck cancer. II. Compare the effects of these treatments on mouth pain, ability to swallow, weight loss, and the distribution of oral mucositis in these patients.

OUTLINE: This is a randomized, double-blind, placebo-controlled, multicenter study. Patients are stratified according to radiotherapy (conventional fractionating radiotherapy vs hyperfractionating or concurrent boost radiotherapy) and concurrent chemotherapy (yes vs no). Patients are randomized to 1 of 3 arms. Arm I: Patients rinse with iseganan HCl oral solution 6 times daily. Treatment continues for the duration of the scheduled radiotherapy. Arm II: Patients rinse with oral placebo 6 times daily. Treatment continues for the duration of the scheduled radiotherapy. Arm III: Patients receive standard-of-care supportive treatment. Oral cavity pain, ability to swallow, and weight loss are assessed twice weekly and on follow-up days 28 and 56. Patients are followed on days 28 and 56.

PROJECTED ACCRUAL: A total of 504 patients (252 for arm I, 168 for arm II, and 84 for arm III) will be accrued for this study.

DISEASE CHARACTERISTICS: Histologically confirmed malignancy of the head and neck, including cancer of the oral cavity, oropharynx, nasopharynx, hypopharynx, or salivary glands Undergoing or planning to undergo radiotherapy to the head and neck involving: Bilateral treatment with either conventional, hyperfractionated, or concurrent boost external beam radiotherapy Minimum total radiation dose of 60 Gy to at least 3 sites within the oral cavity Total scheduled administration of no more than 8 weeks No oral mucositis already present Ulceration related to head and neck malignancy or prior surgery allowed

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Not specified Life expectancy: Not specified Hematopoietic: Not specified Hepatic: Not specified Renal: Not specified Other: Must be able to orally rinse with study drug Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: Concurrent chemotherapy allowed Endocrine therapy: No concurrent topical corticosteroids to oral cavity Radiotherapy: See Disease Characteristics Surgery: See Disease Characteristics Other: At least 30 days since prior investigational agent for prevention and/or treatment of mucositis No prior participation in this study No concurrent topical anesthetics, such as lidocaine or dyclonine hydrochloride, within 30 minutes before or 15 minutes after study agent No concurrent oral rinses within 15 minutes of study agent