Retrospective Assessment of Neutrophil/Lymphocyte Ratio and CRP Value Correlation with Infections in Cancer Patients

Recent studies have pointed out that CRP and NLR levels are important in determining the prognosis for cancer and diagnosis of infection, but there are few studies on cut‐off levels in patients with solid tumours. In this study, the relationship between CRP cut‐off levels with infection and NLR with infection has investigated in adult solid organ cancer patients receiving inpatient treatment. Patients with solid cancer hospitalised in ZBEU Oncology and Infectious Diseases between 2013 and 2018 were included to study retrospectively. Patients were separated into 2 groups: 240 patients with clinical and radiological or microbiological evidence of infection as group 1 and 240 patients with no signs of infection as group 2. Both groups were subdivided into patients with metastatic cancer and nonmetastatic cancer. The mean CRP at admission and 24th hour in the group 1 (170.0 and 157.5 mg/L, respectively) were found to be statistically higher than group 2 (51.0 and 47.5 mg/L, respectively) ( p < 0.001 and p < 0.001). The best cut‐off value of CRP at admission was found to be 108 mg/L with %72.08 sensitivity, %75.42 specificity ( p < 0.001) and 88 mg/L 24th hour CRP ( p < 0.001). Mean values of NLR on admission and 24th hour were significantly higher in group 1 than in group 2 ( p < 0.001 and p < 0.001). The best NLR cut‐off value was found to be 7.823 at admission ( p < 0.001) and 8.4 at 24th hours ( p < 0.001). Although both tests are used to detect infection in patients with solid cancer, it is important to know that the cut‐off values are high. In patients with solid cancer who do not have clinical signs of infection, unnecessary antibiotherapy should not be performed because of high CRP or NLR.