IR-192 BRACHYTHERAPY IN THE MANAGEMENT OF 147 T2N0 ORAL TONGUE CARCINOMAS TREATED WITH IRRADIATION ALONE - COMPARISON OF 2 TREATMENT TECHNIQUES

Our purpose is to analyse local control, complications relative to the proportion of total dose delivered by external beam irradiation versus interstitial implant in 147 patients with previously untreated T2N0 squamous cell carcinoma of the oral tongue, managed between 1973 and 1986 (UICC staging system). These T2N0 patients are part of a larger group of 430 patients with oral tongue carcinoma (T1, T2, T3) treated with irradiation alone. Of these 147 T2N0 patients, 70 were treated with interstitial implant alone and 77 with both external beam irradiation and implant. In the group treated with interstitial implant alone, the 5-year local control was 89.8% against 50.6% in those treated with external beam irradiation and interstitial implant (log-rank test, p = 0.00002); 67.6% versus 46.5% for locoregional control (p = 0.029); and 62.2% versus 34.7% for specific survival (p = 0.0015). Since 1980, all the patients treated by iridium implantation were protected with a leaded spacing device between the tongue and the mandible. Soft tissue necrosis and bone exposure following treatment were scored according to the following criteria: minor, moderate or severe. Seven moderate and one severe complications were recorded in the brachytherapy group. None of the patients required surgery. In the combined treatment group, six moderate and two severe complications were observed. Patients treated with interstitial implant alone, and showing moderate or severe complications had received an average brachytherapy dose of 7600 cGy. In the same group, the patients without complications had received an average dose of 6800 cGy. In the combined treatment group, the average external radiation dose and the average brachytherapy dose were not significantly different whether or not the patients had complications, but we noted an improvement in local control when the major part of the dose was delivered by interstitial implant. We currently recommend brachytherapy alone for the initial treatment of T2N0 cancers of the oral tongue, but an elective functional neck dissection is essential for these patients to avoid subsequent neck node metastases.