Multivariate prediction of the probability of recurrence in patients with carcinoma of the parotid gland

Abstract

BACKGROUND: Parotid gland carcinoma is an infrequent tumor, and series that report on these neoplasms are relatively scarce in the literature. The objective of the current study was to identify prognostic factors in patients with parotid gland carcinoma and to develop a method for defining the probability of recurrence. METHODS: Patients with parotid gland carcinoma who were treated at the authors' institution from January 1981 through December 2004 and who completed treatment constituted the study group. Disease-free survival was calculated by using the Kaplan-Meier method. Logistic regression analysis was employed to define the recurrence-associated prognostic factors. RESULTS: One hundred twenty-seven patients were included (64 men and 63 women); their mean age was 53 years. Mucoepidermoid carcinoma was diagnosed in 34.6% of patients, adenoid cystic was diagnosed in 15.7% of patients, adenocarcinoma was diagnosed in 14.3% of patients, and acinic cell carcinoma was diagnosed in 9.4% of patients. The median disease-free survival was 8.3 years (95% confidence interval [95% CI], 4.3-12.2 years). Logistic regression analysis confirmed tumor classification, facial nerve palsy, grade of tumor differentiation, patient age, and surgical margins as recurrence-associated factors (P < .00001). Using this model, 3 postoperative risk groups were defined-high-risk, intermediate-risk, and low-risk-that had recurrence frequencies of 71.4%, 43.1%, and 8.8%, respectively (P = .0001). The 5-year disease-free survival rates for these groups were 18.7%, 53.9%, and 99.9%, respectively (P = .00001). CONCLUSIONS: In this study, the authors identified several significant prognostic factors. Consequently, they have proposed a prognostic score categorization that allows for a straightforward calculation of the risk of recurrence for a given patient that may help to define therapeutic strategies, target patient counseling, and design future trials.