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Carcinoma ex pleomorphic adenoma (CXPA) is an uncommon malignant tumor with aggressive behavior but the treatment outcome and prognostic factors are rarely reported. 

From April 2008 to January 2021, 22 patients with pathologically proven CXPA were collected. The treatment modality contained surgery alone (2), surgery plus adjuvant radiotherapy (13) or chemoradiotherapy (5), and definitive chemoradiotherapy (2). We analyze the associations between clinical characteristics and treatment outcomes.

After a median follow-up of 46.5 months (range 13-114), we observed 8 relapses (distant metastasis predominantly) and 5 deaths (all due to uncontrolled tumor). The 5-year overall survival (OS), relapse-free survival (RFS), locoregional-free survival (LRFS) and distant metastasis-free survival (DMFS) were 71.7%, 64.2%, 76.3% and 64.6%, respectively. Kaplan-Meier survival curve analysis revealed only tumor origin was a significant factor for OS. The 5-year rates of OS for the tumor arising from parotid gland and submandibular gland were 88.9% and 26.7%, respectively (P=0.011). Univariate analysis identified some potential biomarkers in predicting worse survivals- OS, submandibular vs. parotid origin (P=0.029); RFS, clinical regional lymph nodes positive vs. negative (P=0.061); LRFS, age>50 vs. ≦50 (P=0.083) and clinical regional lymph nodes positive vs. negative (P=0.069); DMFS, submandibular vs. parotid origin (P=0.095). When we focused on 20 patients who received surgery, invasiveness (invasive subgroup vs. minimal invasive/non-invasive subgroups) and pathological T-stage (T4 vs. T1-3) were two important prognostic factors on survivals.