Management of minor salivary gland carcinomas

To assess the role of radiotherapy alone or in combination with surgery in the treatment of patients with malignant minor salivary gland carcinomas.

Between October 1964 and November 1992, 95 patients with minor salivary gland carcinomas of the head and neck received radiotherapy with curative intent. Eighty-seven patients were previously untreated, and 8 were treated for postsurgical recurrence. Fifty-one patients were treated with radiotherapy alone, and 44 were treated by surgical resection plus radiotherapy. Patients were staged according to the 1983 American Joint Committee on Cancer (AJCC) staging criteria for squamous cell carcinomas.

The 20-year actuarial rate of local control was 57% with no significant difference according to histologic type. When tumor stage was taken into consideration, there were no significant differences in local control according to tumor site. The 12-year actuarial probability of distant metastases was 40% (19% as the only site of failure). In multivariate analyses, local control was significantly affected only by tumor stage and treatment type (combined therapy better than radiotherapy alone); tumor stage was a significant predictor of cause-specific survival and freedom from relapse. Freedom-from-relapse rates were higher for patients who received combined treatment (p = 0.068).

Treatment of minor salivary gland carcinomas is usually by combined surgery and radiotherapy, but there are situations where surgery alone or radiotherapy alone may be used. The ability to control these tumors with radiotherapy alone is not widely recognized. In the present series, the tumor was locally controlled in 20 patients with previously untreated primary lesions after radiotherapy alone (2.5 to 21 years) and in 4 other patients who were treated by radiotherapy alone for postsurgical recurrent tumor (3.5 to 14 years after radiotherapy). Contrary to the widely held belief that local recurrence after radiotherapy eventually develops in all patients with adenoid cystic carcinoma, local control has been maintained in 13 patients after radiotherapy alone; 5 of the 13 patients have been observed for 10 to 17 years.