EXTERNAL AND INTERSTITIAL RADIOTHERAPY IN THE TREATMENT OF OROPHARYNGEAL SQUAMOUS-CELL CARCINOMA

The records of 165 patients with squamous cell carcinoma of the oropha rynx treated at our hospital with external and/or interstitial radioth erapy between 1971 and 1990 were reviewed to evaluate the treatment re sults, focusing on primary control and complications. All cancers were restaged according to the UICC 1987 TNM staging system. Of these 165 patients, 11% were in Stage I, 55% in Stage II, 24% in Stage III and 8 .5% in Stage IV. Local control and complications were analysed in 140 patients. The remaining 25 patients died of intercurrent or metastatic disease during the first 2 years following treatment and were exclude d from the analysis. 70 patients were treated by interstitial implant using permanent implant seeds (Rn-222 in eight patients, Au-198 in 62 patients) with or without external radiation. 56 other patients receiv ed external irradiation alone and another 14 patients received pre-ope rative external irradiation plus surgery. 2-year recurrence-free rates were 73% (100% for T1, 76% for T2, 36% for T3 tumours) in the patient s who received interstitial implant with or without external radiation and 36% (67% for T1, 48% for T2, 13% for T3 tumours) in the patients treated by external irradiation alone. The incidence of soft-tissue or bone complications requiring long-term treatment was 14%. Based on th ese findings, it is believed that an interstitial implant using Au-198 grains combined with external beam irradiation is a useful treatment modality for small lesions of the oropharynx.