50P - Accuracy of serum/pleural fluid lactate dehydrogenase ratio measurement in patients with malignant pleural effusion

Date 15 April 2016
Event European Lung Cancer Conference 2016 (ELCC) 2016
Session Poster lunch
Topics Thoracic Malignancies
Presenter Franco Lumachi
Citation Journal of Thoracic Oncology (2016) 11 (supplement 4): S57-S166. S1556-0864(16)X0004-4
Authors F. Lumachi1, R. Tozzoli2, F. Mazza3, G.B. Chiara4, S. Basso4
  • 1Department Of Surgery, Oncology & Gastroenterology (discog), University of Padua, School of Medicine, 35128 - Padova/IT
  • 2Clinical Pathology Laboratory, Department Of Laboratory Medicine, S. Maria degli Angeli Hospital, 33170 - Pordenone/IT
  • 3Pneumology, S. Maria degli Angeli Hospital, Pordenone/IT
  • 4Surgery 1, S. Maria degli Angeli Hospital, 33170 - Pordenone/IT

Abstract

Background

Several human tumors release lactate dehydrogenase (LDH) that is involved in anaerobic glycolysis, and LDH serum level usually increases in cancer patients. Unfortunately, both sensitivity and specificity of serum LDH is low and thus not useful for early diagnosis of malignancy. The aim of this study was to evaluate the accuracy of serum LDH measurement and serum/pleural fluid LDH ratio (SPLR) in patients with benign and malignant pleural effusions.

Methods

Serum and pleural LDH was measured in a population (cases) of 117 cancer patients (mean age: 68.2±10.1 years) with malignant pleural effusion. There were 48 non-small-cell lung cancer (NSCLC), 38 patients with lung metastases, and 31 patients with pleural mesothelioma. Controls were 36 age-matched patients (mean age: 69.1±13.5 years; p = 0.67) with confirmed benign pleural effusion. A standard commercially available colorimetric LDH activity assay kit was used.

Results

Serum/pleural fluid LDH ratio was lower in patients with lung metastases (0.63±0.14) with respect to those with NSCLC (0.90±0.71, p = 0.042) and pleural mesotheliomas (1.08±0.66, p = 0.0004). Overall, serum LDH and SPLR (cases vs. controls) were 260.8±243.6 vs. 371.6±607.4 IU/L (p = 0.11) and 0.90±0.60 vs. 1.23±1.14 (p = 0.024), respectively. For SPLR, a cut-off level of 0.5 showed 93.1% sensitivity and 97.22% specificity. The table reports the other results. 50PT1

ParameterResults95% CI
Sensitivity93.16%88.68–97.76
Specificity97.22%91.85–98.71
Positive predictive value99.09%95.00–99.84
Negative predictive value81.40%67.38–90.26
Diagnostic accuracy94.12% 
Pre-test probability (prevalence)76.47% 
Likelihood ratio for positive test result33.54 
Likelihood ratio for negative test result0.07 
Pre-test odds3.25 
Post-test odds109.00 
True-positive/false-negative ratio13.25 

Conclusions

The measurement of SPLR represents an accurate and low-cost laboratory method, especially useful when metastatic or non-small-cell lung cancer are suspected, and should be suggested in all patients with pleural effusions.

Legal entity responsible for the study

University of Padua

Funding

University of Padua

Disclosure

All authors have declared no conflicts of interest.