Long-term results of local excision and radiotherapy in pleomorphic adenoma of the parotid

Three hundred and eleven patients with primary pleomorphic salivary adenoma of the parotid gland seen between 1950 and 1971 are reviewed. All were managed by a combination of surgery, usually local excision, and irradiation. The minimum follow-up is 10 years. Recurrence rates at 0-5 years and 5-10 years were 1 and 1.5%, respectively, and all recurrences in this period were histologically or clinically benign. This recurrence rate is similar to those reported after superficial parotidectomy. After 10 years, however, the recurrence rate rose, becoming maximal at 15-20 years (4%) and yielding a cumulative risk of recurrence of 8.0% at 20 years. The late recurrences were predominantly malignant tumors. One tumor was probably radiation-induced; the remainder were compatible with spontaneous malignant transformation of benign pleomorphic adenoma, although radiation may have increased the incidence. In the absence of a comparable purely surgical series, this cannot be determined. The recommendation is made that the management of these tumors should be primarily surgical with irradiation reserved for patients presenting surgical difficulties. In addition, prolonged follow-up is necessary since there is a significant incidence of late recurrence and such recurrence may be more likely to be malignant regardless of the primary form of management.