Treatment of carcinoma of the parotid gland: the results of a multicenter study.

Purpose: This study analyzed the prognostic factors for carcinoma of the parotid gland and the role of surgery alone or with radiotherapy in treating these lesions.
Methods: Forty-five patients with malignant parotid tumors were studied retrospectively. Patients were treated by combined surgery and radiation therapy between 1984 and 1995 at the Maxillo-Facial Departments of the General Hospitals of Bologna and Parma. Resection was conservative when possible, depending on the extent of the tumor. The median follow-up time was 54 months. Data regarding incidence, tumor stage and grade, local control, distant metastases (calculated with the Kaplan-Meier method), and survival were analyzed. Cox's multiple linear regression was used to identify patient and tumor characteristics with the greatest prognostic significance.
Results: The actuarial 5- and 8-year disease-free survival rates were 81% and 62%, respectively. Multivariate analysis showed that tumor stage was a more prognostic variable than tumor grade. Residual microscopic disease at the excision margins was also an important prognostic variable. Laterocervical metastases affected 4 patients (9%), and distant metastases appeared in 8 patients (18%).
Conclusions: Postoperative irradiation is indicated for patients with stage III and IV disease, patients with positive excision margins, and for patients with lymph node metastases.