Analysis of the parameters relating to failures above the clavicles in patients treated by postoperative irradiation for squamous cell carcinomas of the oral cavity or oropharynx.

One hundred and two patients with squamous cell carcinoma of the oral cavity or oropharynx were treated from January 1955 through August 1976 with surgical excision followed by irradiation. Twelve patients had T2 lesions and 90 had T3 or T4 lesions. Failures above the clavicles were associated with disease present at the margins of resection, location of the recurrence close to the periphery, or outside of the irradiated portals. Failure in the neck essentially were a result of no elective irradiation. In patients with disease present at the margins of resection, there is a risk both of gross residual disease and hypoxic microscopic disease left behind; 4500 to 5000 rad is not adequate for a significant control rate. In situation where there is definite disease at the margin of resection, 6500 rad, or in specific situations, 7000 rad, should be given through reduced fields.