The Khorana risk score estimates a cancer patient's risk of developing venous thromboembolism during chemotherapy, based on factors including tumor site, pre-treatment platelet and white blood cell counts, hemoglobin level, and body mass index. It is applied before chemotherapy initiation to identify patients who may warrant closer monitoring or preventive measures. This score has been validated across multiple cancer types and treatment settings.

Cancers of the stomach and pancreas are typically assigned the highest risk category within the Khorana scoring system, reflecting their strong association with cancer-associated thrombosis. Other cancer types are assigned to intermediate or standard risk categories based on their relative thrombotic risk. Healthcare professionals should use the specific cancer type alongside other score components for accurate risk stratification.

A high Khorana score identifies patients at elevated risk who may benefit from primary thromboprophylaxis, but the decision should also weigh individual bleeding risk and clinical judgment rather than relying on the score alone. Guidelines generally recommend considering prophylaxis in higher-risk ambulatory cancer patients starting chemotherapy. Healthcare professionals should reassess risk periodically as treatment and clinical status evolve.