RADIOTHERAPY OF STAGE-I AND STAGE-II CARCINOMAS OF THE MOBILE TONGUE AND/OR FLOOR OF THE MOUTH

From 1977 to 1990, 94 evaluable patients were treated with iridium-192 implantation in the Centre Claudius Regaud for a Stage I (52 patients) or a Stage II (42 patients) squamous cell carcinoma of the mobile tongue and/or the floor of the mouth. Interstitial brachytherapy was associated with external irradiation in 68 patients (group 1; mean dose, 48 Gy for external irradiation, 26 Gy for brachytherapy) or was exclusive in 26 patients (group 2; mean dose, 66 Gy). The mean follow-up was 44 months. Eleven acute complications were noted during or immediately after the implant (1 lethal myocardial infarction, 6 hematomas of the tongue which spontaneously resolved, 3 local sepsis). The mean duration of the mucositis was 9 weeks (from 4 to 20 weeks). Ten patients (17%) experienced a late complication (8 in group 1, 2 in group 2): 3 bone necroses requiring hemimandibulectomy (1 post-operative death), 1 tongue necrosis treated by a transoral mucosal excision, 6 bone expositions which recovered after medical treatment. Local control rates for T1 and T2 tumors were 75% (39/52) and 51% (21/41), respectively. Sixteen patients (17%) presented a nodal relapse which was associated in 6 cases with a concomitant local relapse. The local control rate of T1 tumors was 64% (23/36) in group 1 versus 100% (16/16) in group 2 (p < 0.01). For T2 tumors, these figures were 45% (14/31) and 70% (7/10), respectively (p > 0.3). The influence of 13 parameters on the local control was studied in analysis. In the one model analysis, a cox regression tumor size was significantly predictive of actuarial local recurrence (p < 0.001). The therapeutic modality was close to the significance level (p = 0.06). The other variables (age, sex, anatomic site, macroscopic aspect of the tumor, pathologic differentiation, technique of implant, intersource spacing and dose rate) had no significant influence. This retrospective study suggests that exclusive brachytherapy is the best modality in terms of local control and functional results.