Thrombosis: The Hidden Risks and What Cancer Caregivers Need to Know

Thrombosis — the formation of blood clots in a vein or artery — can affect anyone. But cancer patients are at higher risk of thrombosis than the general population, so caregivers should be particularly aware. The most common type of thrombosis in cancer patients is deep-vein thrombosis (DVT), which occurs when a clot forms in a vein deep inside the body, usually veins in the leg or arm. These clots may break free and travel through the bloodstream to the lungs — a potentially fatal condition known as pulmonary embolism (PE). Together, DVT and PE are known as venous thromboembolism (VTE).

An estimated 20 percent of VTE occurs in people with cancer. After cancer progression, VTE is the second most common cause of death in cancer patients. Therefore, VTE in cancer patients is a serious condition that caregivers should look out for.

Cancer increases VTE risk through several mechanisms including:

• Decreased blood flow because of decreased mobility or compression of the veins by tumor
• Damage to the vein wall by surgery, venous catheters, or ports used for chemotherapy delivery
• Hypercoagulability of the blood as a result of cancer treatments or clot-promoting substances released from tumor cells

Recognizing VTE

Because cancer increases a person’s VTE risk, caregivers should be especially aware of this condition and how to recognize both of its forms, DVT and PE.

The symptoms of deep vein thrombosis (DVT) include:

• Pain and/or tenderness in the leg or arm
• Swelling of the leg or arm
• Occasionally redness, purple discoloration, or warmth of the leg or arm

DVT often starts in the calf, with persistent cramping and swelling that intensifies over several days. Upper-extremity DVT may cause otherwise unexplained upper arm or neck swelling. A physician who suspects DVT will confirm the diagnosis using a compression ultrasound, wherein an ultrasound probe is placed on the skin over top of the vein and gentle compression is applied. Normal veins compress with pressure whereas veins filled with clot cannot be compressed.

The symptoms of pulmonary embolism (PE) include:

• Shortness of breath on exertion
• Chest pain that is worse with deep breathing
• Rapid heart rate
• Rapid breathing
• Coughing up blood
• Light headedness and/or passing out

Many patients with PE have a vague sense that something is wrong, but often delay seeking medical attention. Physicians recommend that caregivers consider the possibility of PE in any patient with unexplained chest symptoms.

At times, because the symptoms of PE can be vague and non-specific, even medical professionals may mistake PE for anxiety. This is especially understandable in cancer patients, who often experience significant anxiety. In these cases, the input of a caregiver who knows the patient well can help rule out emotional sources for PE symptoms. To establish a diagnosis of PE, a physician will most frequently perform a computed tomography (CT) scan of the chest.

VTE Prevention and Treatment

VTE is a significant health problem, but it can be prevented. Cancer caregivers should be aware of general VTE risk factors in addition to the cancer-specific factors listed above. Caregivers should pay particular attention if a cancer patient:

• Has a family history of VTE
• Has undergone recent surgery
• Has been hospitalized for long periods of time or otherwise faced a prolonged period of immobility (while traveling, for example)
• Has a central venous catheter or port
• Takes medications containing estrogen

If you are a caregiver to someone who has cancer, you should talk to the patient’s doctor about the risk of VTE and ways to decrease it. The best approach depends on things like the type of cancer they have, the cancer treatment they need and whether they are at the hospital or at home. If their risk is high, the doctor may recommend that they:

• Receive medications called anticoagulants or “blood thinners”
• Wear special tight socks called compression stockings that improve blood flow
• Use a device that intermittently squeezes the legs to keep blood moving

The number one tip for cancer caregivers is to be proactive. Know the risk factors that cancer patients in particular face, and take the patient to the hospital if you observe any symptoms of VTE.

For more information about VTE and thrombosis, visit worldthrombosisday.org. The International Society on Thrombosis and Haemostasis (ISTH) observes World Thrombosis Day each year on October 13, the birthday of thrombosis research pioneer Rudolph Virchow, to spread awareness of the condition.