IR-192 INTERSTITIAL IMPLANT AND EXTERNAL-BEAM RADIATION-THERAPY IN THE MANAGEMENT OF SQUAMOUS-CELL CARCINOMAS OF THE TONSIL AND SOFT PALATE

Purpose: To evaluate the results, techniques, indications and complica tions of interstitial brachytherapy in the management of squamous cell carcinomas of the tonsil and soft palate, we reviewed the Stanford Un iversity Medical School experience with this modality. Methods and Mat erials: Between May 1975 and January 1990, 37 patients with squamous c ell carcinomas of the Tonsillo-Palatine region were treated with a com bination of external beam irradiation and a removable Iridium-192 inte rstitial implant. The mean age of these patients was 56. Twenty-two we re males and 15 were females. The stage distribution included four pat ients with Stage I, 5 with Stage II, 10 with Stage III, and 18 with St age 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 ly mphadenopathy. All 37 patients received initial external beam irradiat ion to the primary, bilateral necks, and supraclavicular region (mean dose: 5400 cGy, range 4000-6600). Eighteen patients (49%) also receive d neck dissections. All 37 patients received an interstitial Irridium- 192 implant using a combination intraoral swage and external looping t echnique. The mean dose was 2700 cGy (range 2000-4000 cGy) to an avera ge volume of 24 cc (range 5-81). Results: Local control was obtained i n 95% (35/37) of the patients. Eighty-seven percent (32/37) of the pat ients have remained disease-free in the neck. Nine patients have devel oped second primary lesions, and one developed pulmonary metastasis. F ifteen patients have died (6 succumbed to their cancers, 6 to second p rimaries, 2 to intercurrent disease, 1 from an unknown cause). The act uarial freedom from relapse is 75%, and overall survival is 64% at 5 y ears, 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 m ost of these patients. Conclusion: Iridium-192 interstitial implant bo ost combined with external beam radiation therapy is a safe and effect ive therapy in the management of locally advanced carcinomas of the to nsil and soft palate.