Purpose: To evaluate the results, techniques, indications and complications of interstitial brachytherapy in the management of squamous cell carcinomas of the tonsil and soft palate, we reviewed the Stanford University Medical School experience with this modality.
Methods and materials: Between May 1975 and January 1990, 37 patients with squamous cell carcinomas of the Tonsillo-Palatine region were treated with a combination of external beam irradiation and a removable Iridium-192 interstitial implant. The mean age of these patients was 56. Twenty-two were males and 15 were females. The stage distribution included four patients with Stage I, 5 with Stage II, 10 with Stage III, and 18 with Stage IV cancers. Thirty-two percent (12/37) of these patients had T3 or T4 lesions. Forty-nine percent (18/37) had stage N2 or N3 cervical lymphadenopathy. All 37 patients received initial external beam irradiation to the primary, bilateral necks, and supraclavicular region (mean dose: 5400 cGy, range 4000-6600). Eighteen patients (49%) also received neck dissections. All 37 patients received an interstitial Irridium-192 implant using a combination intraoral swage and external looping technique. The mean dose was 2700 cGy (range 2000-4000 cGy) to an average volume of 24 cc (range 5-81).
Results: Local control was obtained in 95% (35/37) of the patients. Eighty-seven percent (32/37) of the patients have remained disease-free in the neck. Nine patients have developed second primary lesions, and one developed pulmonary metastasis. Fifteen patients have died (6 succumbed to their cancers, 6 to second primaries, 2 to intercurrent disease, 1 from an unknown cause). The actuarial freedom from relapse is 75%, and overall survival is 64% at 5 years, with a mean follow up of 43 months (range 5-110). Complications were limited to one case of osteoradionecrosis of the mandible and one tonsillar ulcer. Functional and esthetic integrity was preserved in most of these patients.
Conclusion: Iridium-192 interstitial implant boost combined with external beam radiation therapy is a safe and effective therapy in the management of locally advanced carcinomas of the tonsil and soft palate.