Risk factors for distant metastases from carcinoma of the parotid gland

Distant metastases (DM) have become an increasingly common cause of death in cancer patients because of the increasing therapeutic control of locoregional disease. However, little data exist regarding the role of clinical factors in predicting the likelihood of DM in patients with carcinoma of the parotid gland.

To analyze the incidence of DM and the factors involved in developing DM, the authors retrospectively studied clinical and survival data from 124 consecutive patients with parotid gland carcinoma who were surgically treated at the Institute of Otolaryngology of the University of Florence.

DM occurred in 33 of 124 patients (26.6%). Patients with high grade carcinoma had a higher occurrence of DM than those with low grade disease (30.6% vs. 17.9%; P = 0.033). The presence or absence of tumor positive cervical lymph nodes in dissection specimens significantly influenced the occurrence of DM (68.2% vs. 23.7%) (P = 0.007), as well as the number of histologically positive cervical lymph nodes (P = 0.014). Clinical signs of local tumor extension, particularly facial nerve impairment, were found to be associated with a higher rate of DM (P = 0.008). Moreover, tumor size (P = 0.0216) and clinical stage (P = 0.010) were prognostically significant in predicting the incidence of DM. Interestingly, locoregional tumor failure (P = 0.096) did not affect the risk of DM. Multivariate Cox proportional hazards analysis showed that clinical stage and facial nerve infiltration were the most important factors in predicting the risk of DMs (P = 0.010; hazard ratio [HR]: 3.75; 95% confidence interval [CI]: 1.14-13.05 and P = 0.041; HR: 2.75; 95% CI: 1.04-7.30, respectively).

Tumor stage and local aggressiveness were found to be the major prognostic factors in predicting the risk of distant failure in patients with carcinoma of the parotid gland.