Serum procalcitonin as a biomarker for differentiation of both radiation pneumonitis and chemotherapy induced pneumonitis from bacterial pneumonia

Abstract

Introduction Procalcitonin is used as a promising biomarker for bacterial infection, especially bacterial pneumonia (BP) in recent years. However, it has not yet been studied about differentiation of BP from non-infectious treatment-related pneumonitis (TRP), that is, both radiation pneumonitis (RP) and chemotherapy induced pneumonitis (CIP) using serum procalcitonin. The purpose of this study was to compare serum procalcitonin levels in patients with BP, RP and CIP, and to assess its diagnostic potential for discrimination of BP from both RP and CIP.

Methods This study was a retrospective observation study. Among adult patients with suspected pneumonia who visited the National Cancer Center Hospital and underwent serum procalcitonin test as an initial pneumonia work-up from May 2012 through May 2013, procalcitonin levels in patients with BP, RP and CIP were compared.

Results Among 220 patients with suspected pneumonia, 98 patients with non-classified pneumonia were excluded. Finally, 84, 29 and 9 patients were classified into BP, RP, CIP, respectively. Serum procalcitonin level in BP (5.64±18.97 ng/mL) was significantly higher than in RP (0.08±0.05 ng/mL) and CIP (0.14±0.12 ng/mL) (BP vs. RP: p<0.001 and BP vs. CIP: P=0.008. respectively, Mann Whitney (MW) test). In ROC curve analysis for discrimination of BP from both RP and CIP, serum procalcitonin had a higher diagnostic accuracy than CRP, fever (≥ 38℃) and BUN (area under the ROC curve (AUC) 0.935 vs. 0.835, 0.805, and 0.655, respectively). With a cut-off value of 0.19ng/mL, serum procalcitonin had a sensitivity of 90.5% and a specificity of 92.1% for discrimination of BP from both RP and CIP.

Conclusions Serum procalcitonin level was very useful for differentiation of BP from both RP and CIP, so it would help avoid misuse of not only antibiotics for both RP and CIP but also steroid for BP.