Between 1969 and 1985, 73 patients with maxillary sinus cancers underwent surgical excision and postoperative radiotherapy. The clinical stage distribution by the AJC system was 3T1, 16T2, 32T3, and 22T4. Six patients had palpable lymphadenopathy at diagnosis. Surgery for the primary tumor consisted of partial or radical maxillectomy, and if disease stage indicated it, ipsilateral orbital exenteration. This was followed by radiation treatment delivered through a wedge-pair or three-field technique. All but three patients received 50-60 Gy in 2 Gy fractions to an isodose line defining the target volume. Elective neck irradiation was not routinely given. Clinically involved nodes were treated with definitive radiotherapy (five patients) or combined treatment (one patient). Forty-five patients had no evidence of disease at the last follow-up. The 5-year relapse-free survival for the whole group was 51% The overall local control rate was 78%. Patients with larger tumors, particularly if they also had histological signs of nerve invasion, had a higher recurrence rate than others. The overall nodal recurrence rate without elective neck treatment was 38% for squamous and undifferentiated carcinoma, and only 5% for adenoid cystic carcinomas. Therefore, our current recommendation is to deliver elective nodal irradiation routinely to patients with squamous or undifferentiated carcinoma, except for those who have T1 lesions. Treatment complications were vision impairment, brain and bone necrosis, trismus, hearing loss, and pituitary insufficiency. The incidence of major side effects was determined by disease extent and treatment technique. Many technical refinements were introduced in order to limit the dose to normal tissues in an attempt to reduce the complication rate.(ABSTRACT TRUNCATED AT 250 WORDS)