Procalcitonin and C-Reactive Protein/Procalcitonin Ratio for Distinguishing between Infectious and Neoplastic Fever in Cancer Patients.

Objective: This study aims to investigate the potential of procalcitonin (PCT) levels and the C-reactive protein/procalcitonin (CRP/PCT) ratio as markers for distinguishing between infectious and neoplastic fever among febrile patients with malignant tumors. Methods: A retrospective analysis was conducted on febrile patients admitted to the hospital with malignant tumors. The patients were categorized into an infection group (67 cases) and a non-infection group (73 cases) based on the presence or absence of positive cultures. PCT levels, CRP levels, and CRP/PCT ratios were compared between the two groups. The receiver operating characteristic curve (ROC) was used to identify optimal cut-off values. Results: Data from 140 patients between January 2017 and December 2021 were extracted for analysis. Patients in the infected group showed elevated PCT levels and significantly decreased CRP/PCT ratios compared to the non-infected group (P < .01). The calculated cut-off values for distinguishing infectious and neoplastic fever were 0.52 ng/mL for PCT and 101.80 for CRP/PCT ratio. The ROC curve results revealed good sensitivity for both PCT (74.63%) and CRP/PCT (70.15%), while CRP/PCT demonstrated higher specificity (78.08%) compared to PCT (58.90%). Conclusions: PCT and CRP/PCT are both sensitive markers for identifying infection in patients with malignant tumors, with PCT showing slightly better sensitivity but lower specificity than CRP/PCT. Our findings suggest that CRP/PCT may be more valuable than PCT in distinguishing between infectious fever and neoplastic fever in cancer patients.