Thermochemoradiotherapy for advanced or recurrent head and neck cancer. Analysis of clinical results and background variables

Eighteen patients with 25 unresectable advanced or recurrent head and neck cancers (squamous cell carcinomas) received thermochemotherapy in combination with radiotherapy. The total radiation dose ranged from 50 to 82 Gy (mean, 65.6 Gy). Patients received thermochemotherapy twice a week, for a total number of 8.8 sessions, on average. The temperature in the tumor, as a result of the hyperthermia, was over 42 deg C in 185 (84.5%) of the 219 treatments. Three kinds of heating systems were used: a 13.56-MHz radiofrequency system, a 2450-MHz microwave system, and a radiofrequency interstitial system. The total amount of administered CDDP ranged from 40 to 300 mg (mean, 110 mg), combined with PEP and/or 5FU. Background factors (tumor factors and treatment factors) were investigated in detail, and the clinical results (tumor response and the 5-year cumulative focal control rate) were evaluated. The relationship between these two results was then analyzed using univariate and multivariate statistics. The clinical results of patients with a WHO histological classification of grade 3 were poor compared with patients with a classification of grade 1 or 2. The difference between these two results was significant when analyzed using univariate statistics, but not significant when analyzed using multivariate statistics. The clinical results of patients with primary lesions surrounded by bony tissues were slightly poor compared with those of patients whose lesions were surrounded by soft tissues, but the difference between these two results was not significant. Successful treatment of refractory recurrent tumors, large tumor masses, and diffuse invasive carcinomas was not affected by the treatment factors (heating systems, heating sessions, radiation dose, and CDDP dose and drug combination). These results suggest that refractory recurrence, proximity to bony tissues, tumor size, and histological malignancy might not be prognostic variables for thermochemoradiotherapy strategy in patients with advanced or recurrent head and neck cancers. (author)