Diagnostic role of the neutrophil-to-lymphocyte ratio and the platelet-to-lymphocyte ratio in breast cancer: A systematic review and meta-analysis

Neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and lymphocyte-to-monocyte ratio (LMR) may be indicative of breast cancer (BC); however, this remains inconclusive. With the aim to assess the current literature to evaluate the diagnostic roles of NLR PLR and LMR in BC, a systematic literature search was performed using the PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, Wanfang Database, VIP database and China Biology Medicine disc databases up to August 29, 2023. The standardized mean deviation and 95% confidence intervals (CI) for each outcome was reported, and heterogeneity and publication bias were assessed. Overall, 39 studies were included in the present study. Pooled analysis with the random-effects model demonstrated that patients with BC had significantly higher NLR and PLR, and a lower LMR, compared with non-BC subjects. The pooled sensitivities of the NLR and PLR were 0.68 (95% CI, 0.59-0.75) and 0.55 (95% CI, 0.36-0.72), respectively, and the pooled specificities of the NLR and PLR were 0.75 (95% CI, 0.68-0.81) and 0.80 (95% CI, 0.51-0.94), respectively. However, the limited number of studies included hindered the evaluation of the diagnostic role of LMR. In summary, a higher NLR and PLR and lower LMR were associated with the presence of BC. NLR and PLR may be potential blood-based biomarkers for the differentiation of BC. Despite these findings, further studies are needed to validate their clinical applicability and practicality. International Prospective Register of Systematic Reviews registration no. CRD42024522226.