The role of radiotherapy in the management of adenoid cystic carcinoma of the head and neck.

Sixty-eight patients with adenoid cystic carcinoma (ACC) of the head and neck treated by radiation with or without surgery were reviewed. The tumors were located in the major salivary glands in 15 patients and in the minor glands of various sites, mostly in the palate and/or upper gum, in 53. The local control rate was naturally better in the patients with elective postoperative radiation and those with recurrent disease who underwent radiation after repeated surgery for the purpose of tumor reduction than in patients with residual and/or inoperable tumors. For localized tumors in the oral cavity or maxillary sinus, local control was excellent using brachytherapy or "trimodal" combined therapy (radiation, drugs, and minor surgery). The effectiveness of radiation seemed to be more significantly related to the size of the tumor than the dose of radiation. The prognosis of the patients with a predominantly "solid" histologic pattern was apparently worse and presented fulminating progression of the disease. Among patients with a histologically typical cribriform pattern and/or undetermined pattern, although distant metastasis developed frequently, the majority survived a relatively long period without functional or cosmetic disturbance to their normal activities associated with slow progression of the disease. In minor gland tumors, as long as the lesion was localized and a solid histologic pattern was unlikely, radical radiation could be considered an effective choice with the advantage of enhancing the quality of life for the patients.