Brachytherapy is as effective as surgery for tumor control, with better functional and cosmetic results. When the primary treatment includes radiation therapy, however, a second malignancy (SM) may develop in the previously irradiated area. The present study investigated the incidence and treatment results of SM in the oral cavity after brachytherapy for tongue cancer.

A retrospective study was performed using medical records from our institution’s database.

A retrospective review of 281 patients who had been treated with brachytherapy for stage I or II tongue cancer between 1965 and 2000 was performed. All of the patients had been followed-up for more than 10 years at the Department of Diagnostic Radiology and Oncology, Tokyo Medical and Dental University Hospital.

SM of the oral cavity occurred in 26 (9.3%) of the 281 patients between 8 and 32 years after brachytherapy. Twenty of these patients underwent surgery, and their 4-year overall survival rate was 94.4%. Four patients received a second brachytherapy treatment because of the presence of inoperable and/or unresectable lesions, but all of these treatments failed;　3 of the patients died of SM at a median of 1.8 years after the diagnosis. One patient received laser treatment and another patient received chemotherapy, but both of these patients died of uncontrolled SM at 2 months and 5 months after the diagnosis of SM. 

SM can occur in the oral cavity after brachytherapy for tongue cancer during a long-term follow-up period. In such cases, surgery is the only successful salvageable treatment.

tongue cancer, treatment results, brachytherapy