Chemotherapy is an important treatment for many cancers, working to destroy rapidly dividing cancer cells. While effective, these medications can also lead to various side effects. One serious complication associated with chemotherapy is the increased risk of blood clot formation. Understanding this risk and its management is important for patients and caregivers.
The Link Between Chemotherapy and Blood Clots
Chemotherapy drugs can increase the risk of blood clots. These commonly affect deep veins, a condition known as Deep Vein Thrombosis (DVT). DVT often occurs in the legs, causing pain, swelling, tenderness, and sometimes discoloration.
A more severe complication occurs if a piece of a DVT breaks off and travels through the bloodstream. This traveling clot, an embolus, can lodge in a smaller blood vessel, blocking blood flow. If it reaches the lungs and blocks an artery, it results in a Pulmonary Embolism (PE), a life-threatening condition. Symptoms of a PE include sudden shortness of breath, chest pain, and a rapid heart rate.
How Chemotherapy Increases Clotting Risk
Chemotherapy increases blood clot formation through several mechanisms. Some drugs directly damage the inner lining of blood vessels (endothelium). This damage can initiate clotting as the body attempts repair.
Chemotherapy can also alter blood composition. It may increase clotting factors (proteins involved in coagulation) or decrease natural anticoagulants. Some agents, like cisplatin, release prothrombotic particles that trigger clot formation.
Systemic inflammation, common in cancer patients and exacerbated by chemotherapy, contributes to a pro-clotting state. Reduced mobility, common during treatment, also slows blood flow, allowing blood to pool in veins and increasing clot formation risk. Central venous catheters, used for chemotherapy delivery, can also injure veins and affect blood flow, leading to localized clot formation.
Recognizing Blood Clots and Risk Factors
Recognizing blood clot signs is important for timely medical intervention. Deep vein thrombosis often presents as swelling, pain, tenderness, and warmth or redness in the affected limb, usually a leg. These symptoms usually appear in only one limb. For a pulmonary embolism, symptoms can include sudden shortness of breath, chest pain that may worsen with deep breaths or coughing, and a rapid heartbeat.
Beyond chemotherapy, several factors can increase a patient’s risk of blood clots. Certain cancers, such as pancreatic, stomach, lung, and ovarian, carry a higher clotting risk. Advanced or metastatic cancer also poses a greater risk.
Other factors include older age, obesity, and a personal or family history of blood clots. Immobility, from hospitalization, surgery, or general weakness, also elevates the risk. Some hormone therapies and targeted cancer drugs can further increase clot formation.
Preventing and Managing Chemotherapy-Related Clots
Preventing blood clots during chemotherapy involves several strategies. Staying hydrated helps maintain healthy blood flow. Regular movement is also beneficial; patients should take short walks, exercise leg muscles, and avoid prolonged sitting or lying still.
For high-risk patients, healthcare providers may prescribe anticoagulant medications, also known as blood thinners. These medications help prevent clots from forming or growing larger. Historically, low-molecular-weight heparins (injections) were common, but newer direct oral anticoagulants are also used and may be preferred for ease of use.
If a blood clot is suspected or diagnosed, prompt medical attention is necessary. Treatment typically involves anticoagulant medications to prevent the clot from expanding and allow the body to gradually break it down. Patients must adhere strictly to their doctor’s instructions and report any concerns or side effects immediately to their healthcare team.