Elevated preradiotherapy serum lactate dehydrogenase predicts distant metastasis for lymphoepithelial carcinoma of major salivary gland following postoperative radiotherapy.

BACKGROUND: To evaluate the predicting factors associated with distant metastasis (DM) for lymphoepithelial carcinoma of salivary gland (LECSG) following postoperative radiotherapy (PORT). METHODS: We retrospectively collected 160 eligible patients from two cancer institutions. The DM rate was evaluated using competing risk method. RESULTS: The median follow-up time was 65.6 months. Elevated preradiotherapy serum LDH (ratio >0.5) (p = 0.006) and N classification (N2-3) (p = 0.001) were independently associated with DM for the LECSG. After the risk stratification, the high-risk subgroup was defined as the patients presented higher risk score (score >0), whereas 5-year cumulative incidence of DM in the high- and low-risk group was 30.9% and 6.0%, respectively (p < 0.001). Moreover, a significantly worse overall survival (OS) was observed in the high-risk patients compared with the low-risk subgroup (5-year OS: 83.9% vs. 97.8%, p = 0.006). CONCLUSION: Elevated preradiotherapy serum LDH could serve as a predictive factor for DM in the LECSG following PORT.