OBJECTIVES:Procalcitonin (PCT) is widely used for the diagnosis of bacterial infections. The aim of this study was to evaluate PCT as a tumor and as a prognostic marker in patients with primary lung cancer.
DESIGN AND METHODS:We retrospectively performed a PCT dosage in the frozen serum samples of 147 patients with pulmonary neoplasia for whom a test of neuron-specific enolase (NSE) had been conducted at the time of diagnosis.
RESULTS:We show that a PCT serum level above 0.15 ng/mL was independently linked to the presence of a neuroendocrine component in the tumor (HR=5.809 95% CI [1.695-19.908] p: 0005). Thus, median PCT serum levels were significantly more elevated in small-cell lung cancers than in pulmonary adenocarcinomas: 0.33 ng/mL versus 0.07 ng/mL (p<0.001). However, the diagnostic value of serum PCT levels for diagnosing carcinoma with a neuroendocrine component remains low (sensitivity 63.8%; specificity 71.9%). In this series, serum PCT levels were significantly more elevated in the presence of liver metastases: 0.37 ng/mL versus 0.09 ng/mL in the absence of liver metastasis (p<0.001). In uni- and multivariate analyses, a serum PCT level above 0.15n g/mL and the presence of metastases and of sepsis at the time of diagnosis were independent factors of unfavorable prognosis.
CONCLUSIONS:Serum PCT is elevated in patients with lung cancer with neuroendocrine component or with liver metastases. As a consequence, in this population, PCT has a poor specificity for bacterial infection. At diagnosis, an elevated serum PCT is an independent predictive factor of bad prognosis.