Brachytherapy for T1-T2 floor-of-the-mouth cancers: the Gustave-Roussy Institute experience.

Abstract

In a retrospective analysis, we evaluated the Gustave-Roussy Institute's experience of locoregional control, survival, and complications of low-dose rate brachytherapy for carcinoma of the floor of the mouth. Between 1970 and 1985, 160 patients with previously untreated carcinoma of the floor of the mouth received interstitial brachytherapy as definitive treatment. Of the 160 patients, 79 (49%) had T1 and 81 (51%) had T2 lesions, and 127 (79%) had N0 and 33 (21%) had N1; 84% of tumors arose from the anterior floor of the mouth. Brachytherapy was performed with 192Ir wires, according to the Paris system rules, followed by neck dissection (T2 or N1) or follow-up (T1N0). With a follow-up period of 9-19 years, the observed survival rates were 89% at 2 years and 76% at 5 years, and the local control rates were 93% in T1 and 88% in T2 tumors. A low rate of distant metastases was noticed (5%); 31% of patients developed a second primary cancer. Severe mucosal necrosis was observed in <10% of patients. Any grade of bone necrosis was seen in 18% of cases (only 2.5% had G3 necrosis). This complication occurred more frequently in patients with poor dental status and in those treated without dental protection during implantation (p <0.001). Radical brachytherapy offers excellent local control (89%) and an acceptable rate of complications (<10% severe necrosis) that may be significantly decreased with dental care and the use of protective devices. The high incidence of second malignancies remains a major concern in these patients.