SALVAGE SPLIT COURSE BRACHYTHERAPY FOR TONSIL AND SOFT PALATE CARCINOMA - TREATMENT TECHNIQUES AND RESULTS

From December 1981 to October 1990, 28 patients with prior irradiation of the oropharynx underwent salvage brachytherapy for a squamous cell carcinoma of the tonsil and/or the soft palate. The patients were fre e of cervical nodes and without metastatic disease. There were 4 immed iate failures of radiotherapy, 14 local recurrences, and 10 new malign ancies. The mean size of the lesion was 2.7+/-1.7 cm (range, 0.5 to 7 cm). The initial irradiation had delivered 40 to 80 Gy (mean, 69 Gy) t o the oropharynx with a mean interval between external therapy and sal vage treatment of 22+/-28 months. Salvage brachytherapy consisted of t wo split course implants done 1 month apart, delivering 35 and 30 Gy, respectively. Fifteen patients (46.5%) were clinically disease-free be fore the second implant and 23 (82%) were clinically disease free at t he end of treatment. Five local failures have been observed without an y influence of the tumor size, the topographic site of the tumor, or t he histological differentiation. Of the 4 patients who previously had failed with external beam therapy, 3 were disease-free after salvage b rachytherapy. Among the 23 patients in complete remission, 4 (17%) pre sented a local recurrence within a mean time of 5 months. The overall local control rate was 68% with a mean follow-up of 41+/-29 months. Th e overall actuarial survival was 25% and 19% at 2 and 5 years, respect ively; it was 30% at 5 years for the patients presenting with lesions less than or equal to 3 cm. Tolerance was acceptable. Among the 23 pat ients who achieved complete remission, subsequent soft-tissue necrosis was observed in 4 cases. For these 4 patients, the interval between p revious radiation therapy and salvage treatment was short (mean, 7 mon ths). Interstitial split course brachytherapy offers an effective and reasonable option for salvage therapy in patients with recurrent and s econd cancers occurring in the tonsillar region and in the soft palate , even when the tumor arises in a zone that has previously received hi gh-dose irradiation.