Hematological Changes Associated with Thrombotic Events in Cancer Patients: A Retrospective Exploratory Study

Background: Cancer-associated thrombosis is a major cause of morbidity and mortality in oncology patients. Routinely available hematological parameters, including platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW), and neutrophil-to-lymphocyte ratio (NLR), may reflect thrombo-inflammatory alterations accompanying thrombotic events in malignancy. Methods: This retrospective exploratory study included 93 patients with solid malignancies who developed radiologically confirmed thrombotic events between 2006 and 2018. Clinical and laboratory data were retrospectively reviewed. Hematological parameters obtained within seven days before and after thrombotic events were compared using appropriate parametric and non-parametric statistical methods. Results: Thrombotic events were most frequently observed in patients with lung, colorectal, breast, and gastric cancers. Gastrointestinal malignancies accounted for 47.3% of cases. Venous thrombotic events represented the majority of cases (63.4%), whereas arterial thrombosis was observed in a smaller subset of patients (10.7%). Pulmonary embolism was identified in 23.7% of patients. Central venous catheter use was significantly associated with subclavian/femoral vein thrombosis (p < 0.001). PLT significantly decreased following thrombotic events (329.3 × 10³/µL vs. 260.8 × 10³/µL, p < 0.001), whereas MPV increased modestly (9.23 ± 1.57 fL vs. 9.40 ± 1.45 fL, p < 0.001). PDW significantly decreased (14.37 ± 2.78 vs. 13.63 ± 3.24, p = 0.011). NLR increased numerically (3.33 ± 2.32 vs. 4.26 ± 4.74) but did not reach statistical significance (p = 0.089). An inverse correlation was observed between PLT and MPV (r = −0.268, p = 0.009). Conclusions: Routinely available hematological parameters, including PLT, MPV, PDW, and NLR, demonstrated measurable alterations in cancer patients with thrombotic events and may reflect thrombo-inflammatory processes associated with malignancy. However, because of the retrospective design, heterogeneous study population, and absence of a non-thrombotic control group, these findings should be considered exploratory and hypothesis-generating rather than evidence of predictive biomarkers. Larger prospective controlled studies are required to clarify their clinical significance.