What happens: A tumor in the pancreas can press on major blood vessels, including the portal vein or inferior vena cava. This pressure can slow blood flow from the legs back to the heart, causing fluid to pool in one or both legs.
More concerning: Pancreatic cancer increases the risk of developing deep vein thrombosis (DVT) —blood clots in the deep veins of the legs. This can cause sudden, painful swelling in one leg.
The link: There’s a well-documented connection between pancreatic cancer and blood clots, known as Trousseau syndrome or Trousseau’s sign of malignancy. In some cases, a DVT can be the first sign of an underlying pancreatic cancer.
2. Blood Clots That Keep Coming Back
What happens: Some people develop recurrent blood clots in their legs or lungs with no obvious risk factors. When clots keep appearing—especially in unusual locations—doctors may look for an underlying cancer.
Why it matters: Pancreatic cancer cells release substances that make blood more likely to clot. This can happen months before other symptoms appear.