Inflammatory indexes as prognostic biomarkers in advanced triple negative breast cancer patients

Background: The immune system is known to be involved in the microenvironment of triple negative breast cancer (TNBC). Immune ratios such as the neutrophil-to-lymphocyte ratio (NLR), the platelet-to-lymphocyte ratio (PLR), the monocyte-to-lymphocyte ratio (MLR), and the systemic immune-inflammation index (SII) may reflect the functional status of the immune system in these patients and the involvement of circulating immune cells in cancer progression. Methods: We conducted a retrospective-prospective, observational multicenter analysis to investigate the association between inflammatory indexes (NLR, PLR, MLR, and SII), clinical characteristics and survival outcomes in patients with metastatic TNBC in the first-line setting. Results: Data from 114 consecutive patients with a diagnosis of metastatic TNBC were evaluated. At a median follow-up of 28 months, median PFS in the overall patient population was 8.6 months (95% CI 6.5-9.6), while median OS was 17.7 months (95% CI 13.7-23.9). All high inflammation-based scores evaluated at the diagnosis of metastatic disease were significantly associated with lower PFS, particularly high NLR (≥3), high MLR (≥0.34), high PLR (≥210), and high SII (≥836) (p <0.0001, p <0.0001, p = 0.0002, p <0.0001, respectively). Similarly, all indexes appeared to be significantly associated with lower OS, particularly NLR (≥3), SII (≥836), PLR (≥210), and MLR (≥0.34) (p <0.0001, p = 0.001, p = 0.002, and p = 0.0006, respectively). In multivariable analysis for predictors of OS, the number of metastatic sites, NLR, SII, and MLR remained significant. Conclusions: NLR, PLR, SII, and MLR are associated with PFS and OS in metastatic TNBC. Although our results require validation in larger prospective studies and contemporary cohorts treated with chemoimmunotherapy and novel agents, inflammatory ratios may represent feasible prognostic biomarkers in metastatic TNBC.