Twice-a-day radiation therapy for cancer of the head and neck.

Experience with the twice-a-day (BID) radiation therapy program for carcinomas of the head and neck areas is presented. The program consists of 1.6 Gy per fraction, two fractions per day with 4 hours between fractions, for 12 days, 5 days a week. After 38.4 Gy, the patient is given a 2-week break for symptoms of acute mucositis to subside and then twice-a-day radiation therapy is resumed with similar fraction size, two fractions a day for an additional 8 days to bring the total dose to 64 Gy. In some instances the primary site was boosted to an additional BID day with a maximum of 67.2 Gy. The spinal cord dose was limited to 38.4 Gy. A subset of 321 patients with squamous cell carcinoma of the oral cavity (61 patients), oropharynx (74 patients), and larynx (186 patients) treated by this program is reported. Marked improvement in local control rate at 36 months was observed for advanced tumors (T3 and T4) and with nodal disease by BID radiation therapy program as compared to conventional once-a-day (QD) radiation therapy program. The improvement in local control for early lesions, T1 and T2 when treated with BID radiation therapy was not noted to reach a statistically significant level. However, the successful results are quite different when compared to QD radiation therapy program, with a trend suggesting that significant difference might exist if additional patients had been entered into the studies. Acute mucosal reactions are generally more severe than those produced by QD continuous radiation therapy, but the duration of symptoms is shorter. Late effects on the normal tissues, as observed during the 4-year follow-up period, show no undue subcutaneous or mucosal reactions nor an increase in chondronecrosis or osteoradionecrosis. With the dose limited to 38.4 Gy in 2.5 weeks to the spinal cord, no case of radiation myelitis has been encountered.