Clinical significance of pathologic staging of progression in carcinoma ex pleomorphic adenoma: A comparison with current t classification for salivary cancer

Although pathologic progression stage on the basis of the extent of capsular invasion has been considered to be a useful prognostic indicator for carcinoma ex pleomorphic adenoma (CXPA), this pathologic factor is not adopted in the T-factor of the current TMN classification for salivary cancer. In this study, we examined the pathologic progression stage in 31 cases of CXPA, and evaluated its clinical and prognostic significance in CXPA, with a comparison with the current T-classification. Among the cases in category pT1 and 2, 25% and 50% showed invasion beyond the capsule of preexisting pleomorphic adenoma, 25% and 30% developed distant metastasis after surgery, and 25% and 20% eventually died of cancer, respectively. In contrast, 41.7% of the cases in category pT3 were histopathologically non-invasive carcinoma, and none of them developed local recurrence or distant metastasis. Moreover, noninvasive or minimally invasive CXPAs showed excellent prognoses, regardless of their sizes or strategies for postoperative adjuvant therapy. In addition, pathologic progression stage was a more useful prognostic indicator in CXPA than the current T-classification regarding disease-free and overall survival rates. These results demonstrate that appropriate postoperative treatment and clinical follow-up based on the pathologic progression staging is important for patients with CXPA.