An update on malignant salivary gland tumors treated with neutrons at Fermilab.

One hundred and thirteen cases of recurrent and/or unresectable malignant salivary gland tumors, treated with fast neutron therapy at Fermilab between September 1976 and December 1984, are analyzed for local control, sites of failure, and treatment-related morbidity. Sixty-three patients had major and 55 had minor salivary gland tumors. Local control was achieved in 67% of patients with major and 58% of patients with minor salivary gland tumors. In the subgroup of patients with oropharyngeal and oral cavity lesions, 19/24 (80%) had local control. However, only four of 15 patients with maxillary antrum tumors had successful control of their disease. Seventy-four percent of patients with lesions measuring 5 cm or less and 30% of patients with larger lesions had their local disease controlled. Histology did not influence the local control rate. Both observed and adjusted median survival for patients with major salivary gland tumors was 36 months. Disease-free survival was 31 months. Observed and adjusted median survivals for patients with minor salivary gland tumors are 48 and 57 months respectively. Twenty of 86 patients (23%) had major morbidity; this was directly related to the total dose delivered. In the dose range 20-24 Gy the complication rate was 16%. Most of these complications were successfully managed with minimal functional disability. We have concluded that fast neutron irradiation is an appropriate treatment for malignant salivary gland tumors.