OBJECTIVES: I. Determine the time to tumor progression in patients with stage III or IV (without distant metastases) head and neck cancer treated with porfiromycin as adjuvant therapy to radiotherapy. II. Determine percentage of patients with locoregional tumor recurrence up to 2 years posttreatment. III. Determine response rate, disease free survival time, and overall survival time in these patients. IV. Evaluate the safety and tolerance of porfiromycin in these patients.