Long-term functional outcome of brachytherapy for carcinoma of the mobile tongue: focus on the atrophic change of irradiated tongue

OBJECTIVE: To assess tongue atrophy and long-term functional outcome of mobile tongue cancer patients after interstitial radiotherapy. METHODS: Of 493 patients whose squamous cell carcinoma of the mobile tongue had been treated with low dose rate brachytherapy, there were 57 patients evaluated between July 2002 and April 2004 whose tongue had not been modified by surgical procedures and who had no primary recurrence. The median time from treatment to evaluation was 96 months (range: 9-214 months). Almost all of the patients belonged to the early stage tongue cancer (T1/T2/T3/T4=30:24:3:0), and all had received interstitial radiotherapy with a single-plane implant. To evaluate the deformity of the tongue, we used a grading system that classified the atrophic changes of the tongue into four categories (G0-G3). RESULTS: Thirty-nine patients (70%) showed mild tongue hemiatrophy (G1 or G2) in the irradiated side. However, no patients showed severe atrophy where the tongue cannot be made to protrude beyond the incisors (G3). The length of time after brachytherapy was >72 months and the age of the patients at brachytherapy had the same statistical significance (P=0.0366). As for functional outcome, understandability of speech and a normal diet were preserved for almost all patients. CONCLUSION: The progression of atrophic change in the irradiated tongue occurred over a long term after brachytherapy. However, most patients could maintain their activities of daily life without severe restriction.