Prognostic factors affecting the clinical outcome of carcinoma ex pleomorphic adenoma in the major salivary gland

BACKGROUND Carcinoma ex pleomorphic adenoma (CXPA) is an uncommon malignant tumor with highly aggressive biological behavior. Our goal was to investigate the prognosis of CXPA in the major salivary glands and factors influencing it. METHODS We retrospectively reviewed 51 patients diagnosed with CXPA of the major salivary glands between 1999 and 2006, comprising 36 males and 15 females, aged from 23 to 86 years. All patients underwent surgery with curative intention, and 21 received postoperative radiation therapy. RESULTS Of the 51 patients, 39.2% developed locoregional recurrence and 27.5% developed distant metastases. Median follow-up was 54 months. At the time of analysis, 29 (56.9%) patients were deceased. Overall survival was 62.7% at 3 years and 50.3% at 5 years. Tumor-specific survival was 64.4% at 3 years and 53.5% at 5 years. Using chi-squared tests, invasiveness, T stage, lymph node involvement and clinical stage were found to be significantly associated with locoregional recurrence. Histological grade, invasiveness, lymph node involvement and perineural invasion were associated with distant metastases (P < 0.05). Cox analysis showed that T stage, lymph node involvement, histological grade and perineural invasion were independent prognostic factors for overall survival. CONCLUSION T stage, lymph node involvement, histological grade, perineural invasion and extent of invasion are important prognostic factors of CXPA in the major salivary glands. Surgery is the primary treatment modality for CXPA and postoperative radiation therapy may be used in patients with factors for poor prognosis.