Diagnostic accuracy of neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios in differentiating thyroid tumors: A systematic review and meta-analysis

Background: Thyroid neoplasms include a range of lesions, most of which are benign, though some may progress to or present as malignant. Diagnostic tools like FNAB, ultrasound, and hormone analysis are commonly used, though they have limitations. Recently, peripheral blood markers have been explored for their potential in differentiating thyroid lesions, despite controversy evidence. This review evaluates the diagnostic utility of NLR and PLR in thyroid lesions. Methods: We systematically searched all relevant articles on PubMed, Science Direct, Cochrane Library, and gray literature, including Google Scholar, for studies on the diagnostic utility of platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) in thyroid lesions. Two researchers independently screened articles, and study quality was assessed using the QUADAS 2 tool. A random-effects model calculated pooled sensitivity and specificity, while the area under the HSROC curve summarized diagnostic accuracy. Heterogeneity was evaluated with Higgins’ I² statistic, and publication bias was assessed using the MIDAS command. Subgroup analyses by sample size, gender distribution, cutoff values, and carcinoma types explored sources of heterogeneity. Results: A total of 12 studies were included in the final meta-analysis, with 9 focusing on NLR and 6 on PLR. Most of these studies were retrospective in design. The pooled sensitivity and specificity of NLR were 75% (95% CI: 65–82%) and 62% (95% CI: 42–75%), respectively. For PLR, the overall sensitivity and specificity were 70% (95% CI: 61–78%) and 57% (95% CI: 46–66%), respectively. The diagnostic accuracy, based on the area under the HSROC curve (AUC), was 0.75 (95% CI: 0.71–0.79) for NLR and 0.69 (95% CI: 0.65–0.73) for PLR. These results indicate that NLR has better diagnostic accuracy than PLR in distinguishing between benign and malignant thyroid lesions. Conclusion: While the NLR demonstrates better diagnostic utility than the PLR in distinguishing between benign and malignant thyroid lesions, its standalone diagnostic accuracy remains moderate. Therefore, we recommend using these markers as complementary tools alongside other standard diagnostic modalities until further studies provide more definitive evidence.