Sex Differences in Cancer-Associated Thrombosis.

Cancer-associated thrombosis (CAT) is a major cause of morbidity and mortality in oncology, arising from complex interactions between tumor biology, host factors, and anticancer therapies. Growing evidence indicates that biological sex and gender-related factors modulate both thrombotic risk and clinical expression of venous thromboembolism (VTE) in patients with cancer. In this narrative review, we summarize current epidemiological, biological, and clinical data on sex- and gender-related differences in CAT across solid and hematologic malignancies. Men generally exhibit a higher overall incidence of VTE, whereas women may experience earlier, treatment-associated thrombotic events, with variability according to cancer type, stage, and therapy. Biological factors linked to coagulation and inflammation differ between sexes and may contribute to these patterns, although mechanistic evidence remains incomplete. Sex-related disparities also emerge in treatment-associated complications, including bleeding risk and abnormal uterine bleeding in anticoagulated women of reproductive age. In contrast, evidence for sex differences in oncohematology-associated thrombosis is limited and inconsistent. Gender-related inequalities in clinical trial participation further constrain the interpretation of available data. Overall, current evidence supports sex as a clinically relevant modifier of CAT risk, underscoring the need for systematic sex- and gender-informed research, to improve mechanistic understanding, and sex-stratified reporting to advance precision medicine in thrombosis and oncology.