The role of neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio as venous thromboembolism predictors in breast cancer patients pre- and post-therapy.

Objectives: Breast cancer (BC) accounts for 12.3% of all cancer-associated venous thromboembolism (VTE). Platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) are recognized inflammatory biomarkers but have not been incorporated into thrombosis risk stratification models. We evaluated NLR and PLR as predictive biomarkers for VTE in BC patients to determine their optimal predictive cutoffs and net predictive value before and after treatment.

Methods: We conducted a prospective pilot study that involved 56 women with BC, recruited prior to treatment (chemotherapy and immunotherapy) initiation with at least 6-month monitoring for VTE. NLR and PLR were assessed pre and posttreatment.

Results: Five patients (8.9%) developed VTE. NLR and PLR increased significantly posttreatment (P = 0.001). Post, not pretreatment, NLR (P = 0.029) and PLR (P = 0.033) were significantly associated with VTE occurrence. Receiver Operating curve analysis indicated enhanced predictive capacity for VTE postimmunotherapy. Optimal posttreatment cutoffs were 3.6 for NLR and 280 for PLR, aligning with existing literature, with slightly elevated NLR.

Conclusions: Posttreatment NLR and PLR have higher predictability for VTE in patients receiving immunotherapy compared to chemotherapy. NLR outperforms PLR, particularly postimmunotherapy. This data holds promise for thrombosis risk stratification in the context of immunotherapy but requires evaluation in larger studies.