title: Prognostic value of cystatin C in patients with nasopharyngeal carcinoma: a retrospective study of 1063 patients.
abstract: OBJECTIVE
  Patients with nasopharyngeal carcinoma experience highly variable outcomes despite receiving similar therapeutic regimens. Identifying biomarkers that predict survival and guide individualized therapy is urgently needed. Cystatin C has been explored as a valuable prognostic marker in several malignancies. We retrospectively assessed the relationship between serum cystatin C levels and nasopharyngeal carcinoma prognosis in a large cohort of nasopharyngeal carcinoma patients receiving long-term follow-up.
  
  
  METHODS
  A total of 1063 consecutive patients diagnosed with nasopharyngeal carcinoma from June 2006 to December 2010 were retrospectively analyzed. The serum levels of cystatin C at the time of diagnosis were collected. Receiver operating characteristic curve analysis, the Kaplan-Meier method and multivariate analyses using a Cox regression model were performed to assess the correlation of cystatin C levels with overall survival, progression-free survival, distant metastasis-free survival and loco-regional recurrence-free survival.
  
  
  RESULTS
  The median follow-up duration was 68.3 months. The optimal cut-off value of cystatin C levels for predicting death was 0.945 mg/L. Compared with the low cystatin C group, the high cystatin C group experienced significantly shorter overall survival (hazard ratio=1.47, p=0.050), progression-free survival (hazard ratio=1.65, p=0.004), distant metastasis-free survival (hazard ratio=2.37, p<0.001) and loco-regional recurrence-free survival (hazard ratio=2.40, p=0.002). Based on multivariate analysis, a high cystatin C level was identified as a significant and independent negative predictor of overall survival (hazard ratio=1.47, p=0.050), progression-free survival (hazard ratio=1.65, p=0.004), distant metastasis-free survival (hazard ratio=2.37, p<0.001), and loco-regional recurrence-free survival (hazard ratio=2.40, p=0.002).
  
  
  CONCLUSIONS
  Cystatin C levels are associated with the prognosis of nasopharyngeal carcinoma patients. A high cystatin C level is an independent indicator of poor prognosis for nasopharyngeal carcinoma patients.
authors.affiliation: Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer Medicine, Department of Experimental Research, Guangzhou, Guangdong, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Yuan
authors.affiliation: Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer Medicine, Department of Experimental Research, Guangzhou, Guangdong, China.
authors.forename: Miao
authors.initials: M
authors.lastname: Xu
authors.affiliation: The First Affiliated Hospital of Zhengzhou University, Department of Medical Oncology, Zhengzhou, Henan, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer Medicine, Department of Experimental Research, Guangzhou, Guangdong, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.affiliation: Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer Medicine, Department of Experimental Research, Guangzhou, Guangdong, China.
authors.forename: Li-Zhen
authors.initials: LZ
authors.lastname: Chen
authors.affiliation: Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer Medicine, Department of Experimental Research, Guangzhou, Guangdong, China.
authors.forename: Qi-Sheng
authors.initials: QS
authors.lastname: Feng
authors.affiliation: Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer Medicine, Department of Experimental Research, Guangzhou, Guangdong, China.|Beijing Hospital, Beijing, China.
authors.forename: Yi-Xin
authors.initials: YX
authors.lastname: Zeng
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D002277:Carcinoma / Q000097:blood*; D055316:Cystatin C / Q000097:blood*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000097:blood*; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis; D013997:Time Factors
chemical_list: D014408:Biomarkers, Tumor; D055316:Cystatin C