According to research published in the National Library of Medicine, blood naturally moves more slowly through the deep veins of the legs than in many other parts of the body. This happens because gravity works against the upward flow of blood and because the legs are located far from the heart. As a result, this region is particularly vulnerable to the development of blood clots.
When abnormal clotting signals circulate throughout the body, the legs are one of the most frequent locations where a blockage can develop. As a clot begins to form, it disrupts normal blood flow and quickly leads to swelling and inflammation in the affected area. Some individuals may also notice pain, warmth, or redness, but for many patients the only visible warning sign is swelling in the leg.
Statistical Risks: The Khorana Score
Clinical evidence consistently confirms a strong relationship between pancreatic cancer and disorders involving blood clots. Among all cancers, pancreatic cancer ranks second for the risk of developing venous thromboembolism (VTE), a condition that includes both deep vein thrombosis (DVT) and pulmonary embolism.
Recent estimates from 2024 and 2025 suggest that roughly 20% to 40% of people with advanced pancreatic cancer will experience a clotting event at some point during the course of their illness. This makes clotting disorders one of the most frequent complications associated with the disease.
The Khorana Risk Score
To determine which cancer patients face the highest likelihood of developing blood clots, clinicians often rely on a predictive tool known as the Khorana Risk Score. This model assesses several factors, including the type of cancer involved, platelet levels, hemoglobin concentration, and body mass index.
Each cancer type is assigned a baseline score based on its known risk of causing clotting problems. Pancreatic cancer automatically receives two points, placing patients directly into the high-risk category even before other risk factors are taken into account.
Prognostic Significance
For individuals with pancreatic cancer, blood clots are not merely a complication of the disease—they may also provide insight into how severe the cancer is. Research connected to the COMPASS trial in 2025 suggests that the early appearance of clots may be linked to particularly aggressive tumor subtypes.
When venous thromboembolism occurs within the first three months after diagnosis, it is often associated with tumors that have biological characteristics promoting faster growth and poorer survival outcomes. Because of this connection, doctors view sudden or unexplained leg swelling as a possible warning sign that the disease may progress more aggressively.
