Abstract
BACKGROUND: This study aimed to show the incidence of distant metastases (DM) in salivary gland cancer as well as the types of histology most commonly associated with it and to identify factors predictive of DM. METHODS: The study identified 301 patients who underwent surgery for cancer of the major salivary glands at Memorial Sloan-Kettering Cancer center between 1985 and 2009. Clinical, tumor, and treatment characteristics were recorded. Tumors were categorized as low-, intermediate-, and high-risk pathology based on histologic subtype and grade. Factors predictive of distant recurrence-free probability (DRFP) were determined by uni- and multivariable analyses. RESULTS: The primary tumor was parotid in 266 patients (88 %), and 96 tumors (32 %) were clinical T3/T4. For 57 patients (18.9 %), DM developed with a 5-year DRFP of 72.7 %. The most common site of metastasis was the lung (50 %). The clinical predictors were male gender, cT4 stage, cN+ stage, and clinical overall stage. The multivariable analysis of clinical variables showed male gender (p = 0.018), cT4 stage (p < 0.001), and cN+ stage (p = 0.004) to be significant. The pathologic predictors were high-risk and high-grade pathology, vascular invasion, perineural invasion, positive margins, pT4 stage, pN+ stage, and overall stage. The multivariable analysis of pathologic variables showed high-grade pathology (p < 0.001), perineural invasion (p = 0.005), and pN+ stage (p = 0.002) to be significant. CONCLUSIONS: Distant metastases developed in approximately 20 % of the patients with salivary gland cancer. The most common site of metastases was the lung. The significant predictors of DM were cT4, cN+, male gender, high-grade pathology, perineural invasion, and positive nodal disease.