Local control of squamous carcinoma of oral cavity and oropharynx with 3 VS 5 treatment fractions per week

The local control at a minimum of 18 month followup of 3 vs 5 fractions per week was compared in squamous carcinoma of the oral cavity and oropharynx. The records of 132 patients at The Medical College of Wisconsin affiliated hospitals, who had completed external beam irradiation alone, were selected for review. Excluded were 38 patients with local control of the primary, but who died before 18 months of intercurrent disease, nodal recurrence, or metastatic disease. The patients were distributed relatively equally in each fractionation scheme by stage and site of primary; local control of the primary in 94 evaluable patients was significantly lower (p less than 0.005) with 3 fractions per week. With all stages combined, 37/63 (59%) patients achieved local control with 5 fractions per week, while only 4/31 (12%) did so with 3 fractions per week. A similar trend was observed for each stage and site evaluated separately. The authors emphasize that caution should be used in applying the Ellis' formula, which is based on radiation tolerance of normal connective tissue, to predictions of tumor lethal dose, when using unusual fractionation schemes in treatment of carcinomas of the oral cavity and oropharynx.