Blood clotting is also called coagulation. It is a normal process. It prevents excessive blood loss when you have a cut or an injury. Platelets combine with special blood proteins called clotting factors to form clots. This stops the bleeding at the injured site. Small clots dissolve after an injury heals. People who have an abnormally low level of clotting factors or platelets have a higher risk of bruising and excessive bleeding. This is especially true after an injury or surgery.

The following are some causes of cancer-related bleeding disorders:

• Antiangiogenesis drugs prevent the growth of new blood vessels that feed tumors. They can increase the risk of bleeding.
• Certain cancers can increase the risk of bleeding. Cancer in the liver can decrease the production of clotting factors. This is the case with either a primary liver tumor or cancer that has spread to the liver from elsewhere in the body.

If you already have a condition that decreases the production of clotting factors or platelets, it can also increase your risk of bleeding. Some bleeding disorders run in families. Many are not diagnosed until one or more family members experience bleeding problems due to surgery or trauma.

Thrombocytopenia

Another common type of bleeding disorder is called thrombocytopenia. Thrombocytopenia is a dangerous drop in the number of platelets in the blood. This decrease can increase the risk of bleeding.

Thrombocytopenia occurs in people without cancer as well. However, it is a common side effect of cancer treatment. It may occur because chemotherapy drugs can damage bone marrow, which is where platelets are made. The drugs may also speed up the destruction of platelets in the bloodstream, liver, or spleen.

Hematologists at Memorial Sloan Kettering are experts in the diagnosis and management of thrombocytopenia. We can help whether it is due to a side effect of cancer treatment or another cause.

Symptoms of Bleeding Disorders

Many people who have a bleeding disorder — regardless of whether it is caused by an underlying condition, cancer, or cancer therapy — do not notice symptoms until they are injured or until a doctor detects excessive bleeding in the operating room. Some people may have symptoms such as increased bruising or blood in their vomit or stool. Tell your doctor if you notice any of these symptoms.

Treating Bleeding Disorders

If you have an underlying bleeding disorder or you have been given anticoagulant or thrombolytic medications to prevent blood clots, our hematologists and nurses will monitor your blood. We will determine if you are at risk of excessive blood loss during surgery or other procedures. If your blood does not have enough clotting factors, your doctor may recommend infusions of clotting factors, blood plasma, or platelets from donated blood.

An immune condition called idiopathic thrombocytopenic purpura can cause a low platelet count. In that case, our doctors will develop an individualized treatment plan. We use state-of-the-art treatments and will tailor the plan to this specific condition.

Before your treatment, our blood specialists work with your cancer care team to screen for bleeding problems. We look for inherited conditions, such as Von Willebrand disease and hemophilia. We also look for acquired disorders.