Local control rate of split-course irradiation combined with chemotherapy for head and neck cancer

Between 1976 and 1984, 99 patients were treated with radical external irradiation (RT) for squamous cell carcinoma of the head and neck excluding the glottis and paranasal cavity. Twenty-six out of 55 patients (47%) on chemotherapy (CT) were treated by split-course (split) RT, mainly because of acute mucositis. Only 8 out of 44 patients (18%) not on CT were treated by split RT. Although the group given split RT alone rested for 14 days and received 35 Gy, the split RT + CT group rested for 16 days and received a lower dose (30.5 Gy). The mean total doses for each treatment modality were 64 Gy in the continuous course (contin.) of RT alone, 63 Gy in contin. RT + CT, 67 Gy in split RT, and 62 Gy in split RT + CT. The observed/predicted (by a Radiation Therapy Oncology Group) control ratios of primary lesions at 2 yrs were 61/80 (0.76), 72/83 (0.87), 75/73 (1.03), and 69/71 (0.97), respectively. Among patients with a predicted rate of over 80%, the observed rates were almost identical (72%, 74%, 4/4, and 75%, respectively). However, for patients with predicted rates of 50-80%, the observed rate was 71% (12/17) in the group given combined therapy against 50% (5/10) in RT alone group. Among patients with predicted rates under 50%, the observed rate was 57% (4/7) in split RT + CR and only 25% (1/4) in contin. RT; there were no cases in contin. RT + CT. Split RT + CT is considered to be favorable for patients with poor prognostic factors.