Purpose: To examine the function of serum lactic dehydrogenase (SLDH) level after intensity-modulated radiotherapy (IMRT) as a predictive factor for and loco-regional relapse free survival (LRFS), distant metastasis-free survival (DMFS), disease free survival (DFS), and overall survival(OS) among patients with in-situ nasopharyngeal carcinoma (NPC).
Results: Compared with the normal pt-SLDH group, elevated pt-SLDH demonstrated significant lower DMFS (46 versus 66 months, hazard ratio (HR) 4.07, 95% CI 2.43-6.80, p < 0.001), DFS (46 versus 63 months, HR 2.78, 95% CI 1.70-4.53, p < 0.001), and OS (54 versus 66 months, HR 2.93, 95% CI 1.65-5.23, p < 0.001). Distant metastasis were observed in 32.8% (20/61) patients with elevated pt-SLDH, and 8% (54/678) in normal SLDH (odds ratio (OR) 6.13, 95% CI 3.35-11.18, p < 0.001). COX regression showed that pt-SLDH was an independent prognostic factors for OS (HR 2.91, 95% CI 1.57-5.41, p < 0.001), DMFS (HR 4.21, 95% CI 2.51-7.07, p < 0.001), LRFS (HR 2.53, 95% CI 1.22-5.24, p < 0.001), and DFS (HR 2.81, 95% CI 1.72-4.59, p < 0.001).
Materials and methods: The records of 739 in-situ NPC patients admitted to Zhejiang Cancer Hospital between January 2007 and May 2012 were retrospectively reviewed. The relationships between post-treatment SLDH (pt-SLDH) and LRFS, DMFS, DFS, and OS were analyzed.
Conclusions: Our finding indicated that elevated pt-SLDH could be a simple available prognostic indicator for distant metastasis and survival for in-situ NPC patients.
Keywords: intensity-modulated radiation therapy; metastasis; nasopharyngeal carcinoma; prognostic factor; serum lactic dehydrogenase.