A group of 381 patients with squamous cell carcinoma of the oral cavity and naso-and oropharynx treated with definitive radiotherapy were analyzed with respect to the incidence and precipitating factors of mandibular osteonecrosis. Elective dental extraction prior to therapy increased the incidence, and dental conservation decreased it. Spontaneous osteonecrosis did not occur with doses less than 6,000 rads in 6 weeks, and was uncommon (1.8%) at doses under 7,000 rads in 7 weeks. At doses over 7,000 rads, osteonecrosis developed in 9%. The incidence was greater in patients with tumors near bone (9.4%) than in those with tumors not next to bone (2.1%).

From 1954 through 1971, 47 patients with malignant tumors of the nasal cavity and paranasal sinuses were treated with an entire eye included in the tumor dose volume. All patients were treated with megavoltage radiation and received approximately 6,000 rads in 30 fractions in six weeks. Two thirds of the patients treated by irradiation alone had no problems with vision or difficulties related to treatment of the eye. When 5-fluorouracil (5-FU) was used in conjunction with high-dose radiotherapy, loss of vision was much more frequent and all patients had either visual loss or major clinical difficulties.

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Between January 1954 and August 1971, 174 patients with squamous cell carcinoma of the base of the tongue were treated with megavoltage external beam using conventional treatment times. Since the cumulative recurrence rate was 90% by 2 years, patients surviving 2 years without primary recurrences are considered to have no evidence of disease (NED) at the primary site. The primary control rate for T1 lesions is over 90% for doses of 6000 rads in 6 weeks to 6500 rads in 6 1/2 weeks. The control rate for T2 and T3 lesions is in excess of 80% with 7500 rads in 7 1/2 weeks. The slope of a hand-drawn exclusion line for T2 and T3 lesions is 0.38. For T4 lesions no significant pattern of dose, time, and primary control could be elicited. Of the 15 mandibular necroses, only six ultimately required mandibular resection. There was a signficant relationship (p = 0.03) between the development of mandibular necroses and extension of the primary onto the mucosa covering the mandible. A plot of ret dose versus area suggested a direct relationship between the portal area (volume irradiated) and the development of mandibular necroses.