Retrospective study of results of interstitial radiotherapy for cancer of the tongue

Abstract

Background: This retrospective study was carried out to clarify whether interstitial radiotherapy is effective in the management of carcinoma of the tongue. Methods:The subjects were 65 previously untreated patients with invasive squamous cell carcinoma of the anterior two-thirds of the tongue who received mainly interstitial radiotherapy using 137Cs needles with or without external irradiation between 1977 and 1993. Results:The local control rate was 80% for T1, 73% for T2, 57% for T3 and 73% overall. Thirteen of 16 patients for whom local control failed achieved good control by salvage surgery. The local control rates were slightly lower with combined radiotherapy (64%) than with the interstitial radiotherapy alone (78%), but there was no significant difference between external radiation (< 30 Gy) and external radiation (> 30 Gy). Cervical lymph node metastases developed in 26% of patients with T1-3 NO. Neck control was achieved in 20 (74%) of 27 patients in whom pathologically positive nodes were found. Twentytwo patients developed soft tissue or/and mandibular complications for a total of 28 cases. Soft tissue complications were more likely to occur in patients who received interstitial radiotherapy alone. On the other hand, mandibular complications were l ikelyto occur in patientswho received external irradiation. The cumulative 5-year survival rate was 92% for T1,72% for T2 and 33% for T3. The 5-year survival rate of patients with subsequent cervical node metastases was 41%, whereas in patients without subsequent cervical node metastases it was 89% (P < 0.001). Conclusions:Interstitial radiotherapy with or without external irradiation has useful implications in the local control of newly diagnosed cases of tongue cancer. If local recurrence develops, it is possible to control the primary lesion and prolong survival by salvage surgery. The most effective treatment modality for neck control and survival could not be determined from this study.