Analysis of the results of combined therapy for maxillary carcinoma

BACKGROUND: Maxillary sinus carcinomas usually are locally advanced. A wide variety of modalities, including surgery, radiation therapy, and intraarterial chemotherapy, alone or in combination, have been used. However, there is still much controversy with regard to the optimum treatment. METHODS: From 1972 to 1986, 108 patients with squamous cell carcinoma of the maxillary sinus were treated at the Department of Radiology, University of Tokyo Hospital. From 1972 to 1974 (the first period), the treatment consisted of operation for reduction of tumor volume, daily cleaning of the maxillary antrum, 20 Gy of postoperative radiation therapy, and intraarterial infusion of 1500 mg of 5-fluorouracil (5-FU) and 3000 mg of 5-bromodeoxyuridine (BUdR). From 1975 to 1979 (the second period), the radiation dose was reduced to 10 Gy, and intraarterial infusion of 5-FU and BUdR was not performed. Surgery for reduction of tumor volume and daily cleaning of the antrum played a major role in this period. From 1980 to 1982 (the third period), daily cleaning of the antrum was not performed. Instead, the dose of radiation was increased to 50-60 Gy. From 1983 to 1986 (the fourth period), more extensive surgery to resect the tumor en bloc was introduced. The radiation dose was increased to 70 Gy. Intraarterial infusion of 3750 mg of 5-FU and 120 mg of cisplatin also was administered. RESULTS: The 5-year survival rate was 46% in the first period, 24% in the second period, 7.2% in the third period, and 53% in the fourth period. In the third period, there were more cases in which death resulted from a cause other than local failure, such as distant metastasis, pneumonia, or secondary primary cancer. Since 1984, we planned treatment with computed tomography (CT) and used the linear accelerator with a multileaf collimator to treat patients with an irregular field of irradiation. These have made it possible to administer radiation therapy in doses as high as 70 Gy without severe complications and improve the survival rate, especially for T4 disease. CONCLUSIONS: Radiation plays an important role in sterilizing malignant cells that cannot be removed by operation. The dose of radiation should be determined according to the volume of residual tumor. Careful treatment planning is required to irradiate the tumor adequately and reduce complications.