Diagnostic and prognostic value of serum procalcitonin concentrations in primary lung cancers

• PCT is elevated in neuroendocrine lung tumors in the absence of bacterial infection.
• PCT is elevated in liver metastases in the absence of bacterial infection.
• High PCT value at diagnosis is an independent predictive factor of bad prognosis.

ObjectivesProcalcitonin (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 methodsWe 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.ResultsWe 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 0.15 ng/mL and the presence of metastases and of sepsis at the time of diagnosis were independent factors of unfavorable prognosis.ConclusionsSerum 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.