Phase III trial of high- vs. low-dose-rate interstitial radiotherapy for early mobile tongue cancer

Purpose: Early mobile tongue cancer can be controlled with interstitial rad iotherapy (ISRT). We carried out a Phase III trial to compare the treatment results of low-dose-rate (LDR) ISRT and high-dose-rate (HDR) ISRT for earl y mobile tongue cancer. Methods and Materials: From April 1992 through October 1996, 59 patients wi th cancer of the early mobile tongue were registered in this Phase III stud y. Eight patients were excluded from the evaluation because of violations o f the requirements for this study. Of 51 eligible patients, 26 patients wer e treated with LDR-ISRT (70 Gy/4-9 days) and 25 patients with HDR-ISRT (60 Gy/10 fractions/1 week). For the hyperfractionated HDR-ISRT, the time inter val between 2 fractions was more than 6 h. Results: Five-year local control rates of the LDR and HDR groups were 84% a nd 87% respectively. Nodal metastasis occurred in 6 patients in each group. Five-year nodal control rates of the LDR and HDR groups were 77% and 76%, respectively. Conclusion: Hyperfractionated HDR-ISRT for early mobile tongue cancer has t he same local control compared with continuous LDR-ISRT. Hyperfractionated HDR-ISRT is an alternative treatment for continuous LDR-ISRT. (C) 2001 Else vier Science Inc.