In cancer patients retrospective assessment of neutrophil/lymphocyte ratio and CRP value correlation with infections

İntroduction and purpose: C-reactive protein (CRP) is an acute phase reactant with rapidly increasing serum levels in many conditions such as inflammation, malignancy and autoimmune diseases. Neutrophil / lymphocyte ratio (NLR) is also used as an indicator of systemic inflammation. 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 tumors. In this study, the relationship between CRP cut-off levels with infection and NLR with infection has investigeted in adult solid organ cancer patients receiving inpatient treatment. Materials and Methods: Patients with solid cancer hospitalized in ZBEU Oncology and Infectious Diseases between 2013-2018 were included to study retrospectively. Patients seperated into 2 groups; 240 patients with clinical and radiological or microbiological evidence of infection as group 1, 240 patients with no signs of infection as group 2. Both groups were subdivided into patients with metastatic cancer and non-metastatic cancer. Results: The mean CRP at admission and 24th hour in the group 1(170,0 mg/ L and 157,5 mg/L, respectively) were found to be statistically higher than group 2 (51,0 mg/L and 47,5 mg/L, respectively), (p<0,001 and p<0,001). The best cut-off value of CRP at admission was found 108 mg/L with %72,08 sensitivity, %75,42, specificity (p<0,001) and 24th hour CRP was found 88 mg/L (p<0,001). Mean values of NLR on admission and 24th hour were significantly higher in group 1 than 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). Conclusion: 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.