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

Abstract

To evaluate the predicting factors associated with distant metastasis (DM) for lymphoepithelial carcinoma of salivary gland (LECSG) following postoperative radiotherapy (PORT). We retrospectively collected 160 eligible patients from two cancer institutions. The DM rate was evaluated using competing risk method. 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). Elevated preradiotherapy serum LDH could serve as a predictive factor for DM in the LECSG following PORT.