Tumoral thrombosis (also known as tumor thrombus) is a condition that occurs in certain cancers. It happens when a tumor extends into a blood vessel.

Tumoral thrombosis (TT) can significantly worsen a cancer prognosis. It’s a type of thrombosis, which is the formation of a blood clot or blockage in a blood vessel. It can affect any blood vessel but is more common in veins (venous thrombosis).

TT can occur in different types of cancer, such as:

Medical emergency

Complications of tumoral thrombosis can be life threatening. Be sure to get immediate medical attention for the following symptoms of venous thromboembolism:

  • pain, skin discoloration, warmth, and swelling, usually somewhere on a leg or arm
  • chest pain and increased heart rate
  • breathing issues and lightheadedness

Read on to learn more about tumoral thrombosis — its symptoms, diagnosis, treatment, complications, and other important information.

As cancer grows, it can spread into different tissues and organs. If a blood vessel is near the tumor location, there is a chance that the tumor can grow into it, causing TT. TT may restrict and even completely block the blood flow in this vessel.

Cancers that affect certain organs, such as the kidneys and liver, often develop close to large blood vessels. Researchers estimate that 10% to 18% of people with renal cell cancer will develop TT in one of their renal veins. And 4% to 23% of people with this condition may have TT in their inferior vena cava, the largest vein in the body.

Risk factors for TT development include having:

  • certain types of cancer, such as RCC or HCC
  • large tumors
  • cancers at an advanced stage
  • cancers that spread into distant organs (distant metastasis)

TT usually doesn’t have any specific symptoms. But depending on its type and stage, you may experience symptoms of a growing tumor, such as:

TT can have life threatening complications, including venous thromboembolism (VTE) and major bleeding. In a 2022 study involving 86 people who developed the condition due to kidney cancer, 17 later had VTE, while 11 experienced major bleeding.

Venous thromboembolism

VTE includes different conditions, the most common of which are deep vein thrombosis (DVT) and pulmonary embolism (PE).

DVT can happen when there is a blockage in a deep vein, most often in your arms or legs. PE, on the other hand, happens when this blockage (in the case of TT, a piece of tumor) breaks off from its original location, travels through your bloodstream, and gets stuck in a blood vessel in the lungs.

Of all VTE conditions, PE is the most common complication of TT. PE can be fatal if not treated immediately. Symptoms of PE include:

Major bleeding

Major bleeding can cause death or require a blood transfusion. In people with TT, it can often be a complication of blood thinning therapies used to treat blood clots. Distant metastases can also increase your risk of major bleeding.

Bleeding can be external and internal. Symptoms of internal bleeding include:

Treatment of TT depends on the type of cancer. Let’s discuss the treatment of TT in kidney and liver cancers.

Kidney cancer

Surgery to remove the tumor is the most common treatment for TT in the kidneys. It can significantly improve your chances of survival. Doctors sometimes use targeted therapies before surgery to reduce tumor size.

Liver cancer

Doctors don’t usually perform surgery to remove liver cancers with TT. This is because liver cancers usually develop in people with cirrhosis. Surgery may further aggravate liver damage, causing liver failure.

Instead, doctors often use selective internal radiation therapy (SIRT). This procedure involves using high dose radiation delivered precisely to the tumor site. The medications lenvatinib and sorafenib can also help shrink liver tumors with TT.

If you have TT, you’ll likely be under medical observation. Be sure to get immediate medical attention if you notice the following symptoms of VTE, as they can be life threatening:

  • pain, skin discoloration, warmth, and swelling in the affected area
  • shortness of breath
  • chest pain
  • irregular or increased heart rate
  • lightheadedness and decreased consciousness

TT in a tumor can significantly worsen a cancer prognosis. Generally, people that have TT developed in kidney cancers have a better prognosis than those who have TT in liver cancers.

However, your outlook will depend on how far the tumor has spread into the blood vessel and other factors. Be sure to speak with a doctor about your outlook.

TT is a condition when a tumor extends into a blood vessel. It can cause serious complications related to obstructed blood flow. This condition may significantly worsen a cancer prognosis.

TT usually doesn’t have specific symptoms. Doctors typically discover it when performing imaging tests on your tumor. Treatment depends on the type and location of your cancer.