Feasibility of the Use of Neutrophil to Lymphocyte Ratio (NLR) as an Adjunct to Cytology to Suggest Malignancy: A Prospective Study

A BSTRACT Introduction: Inflammation is known to be associated with cancer development and progression. Neutrophil to lymphocyte ratio (NLR) is a simple and efficient marker of inflammation in numerous malignancies. Aim and Objective: The study aimed to investigate the usefulness of NLR as an adjunct to fine needle aspiration cytology (FNAC) to suggest malignancy confirmed by histopathological report postoperatively in Bethesda classes III, IV, and V. Materials and Methods: This was a prospective observational study at a tertiary care hospital over 2 years. Preoperative blood samples were collected in the admission ward between 08:00 and 09:00 h and analyzed using Beckman Coulter hematology and immunoassay analyzers for complete blood counts, absolute neutrophil and lymphocyte counts, differential leukocyte count, Thyroid stimulating Hormone (TSH), and free T4. NLR was calculated and compared between the two groups based on postoperative histopathology. Results: NLR in the benign group and malignant group were 1.75 ± 0.23 and 2.19 ± 0.29 (mean ± SD), respectively ( P < 0.001). Area under ROC curve plotted was 0.823 ( P < 0.001), with recommended cut-off of 1.9. Relatively high sensitivity and specificity at 87.5% and 82.5% imply excellent diagnostic accuracy. Conclusion: NLR with a value of 1.9 or higher is recommended as a predictor of malignancy in thyroid nodules.