Listen to the Cancer.Net Podcast: When to Call the Doctor, adapted from this content.

Cancer and cancer treatments may cause side effects that require the immediate attention of your doctor and health care team. But knowing when to call the doctor during treatment is difficult. For example, it’s hard to know when you might have a common cold versus a more serious infection. In this article, learn about the signs and symptoms of infections, deep vein thrombosis (a potentially life-threatening blood clot), and tumor lysis syndrome (a condition that can cause organ failure)—all of which require an immediate call to your doctor. Plus, learn ways to prevent these side effects and get tips on communicating with your health care team about them.

Infection

An infection occurs when bacteria, viruses, and less commonly, fungi (such as yeast), invade the body’s tissues and the immune system cannot quickly destroy them. Cancer may make it more likely that a person develops an infection. For example, a tumor in the lung might prevent normal secretions in the lung, making it easier to develop pneumonia. Other common sites of infection include the bladder, urinary tract, and gastrointestinal tract (stomach and intestines).

Cancer treatments, such as chemotherapy, may also weaken the immune system, causing an infection. For example, chemotherapy lowers the number of neutrophils (white blood cells that help fight infection).

The signs and symptoms of an infection vary depending on what part of the body is affected and whether it is a bacterial, viral, or fungal infection. However, common symptoms include a fever (a temperature of 100.5°F or higher), chills or sweating, and a general sense of feeling poorly. If you feel fine one day, but then feel poorly the next, monitor your temperature to see if you have a fever. Other possible signs of an infection include a new cough, burning sensation when urinating, change in bowel habits, and/or an ulcer on the skin.

If you show any signs of an infection, call your doctor the same day you start having the symptoms, even if it’s during the weekend. Call the doctor right away, even if you don’t show any other symptoms, if you have a fever seven to 10 days after receiving chemotherapy. Your doctor and other members of the health care team, such as a nurse, will recommend the next steps and will help identify a less serious infection, such as a common cold, from a more serious infection.

You can help prevent infections by getting enough sleep and proper nutrition, exercising and washing your hands regularly, and avoiding contact with people who are ill. Not all infections can be prevented, though. Learn more about an infection.

Deep vein thrombosis

A thrombosis is a blood clot inside a blood vessel. A deep vein thrombosis (DVT) occurs when a blood clot forms inside a deep vein in the extremities, usually in the legs. A DVT becomes life-threatening if the clot travels to the heart and then lodges in the lungs, causing what is called a pulmonary embolism (PE). Signs and symptoms of a PE include shortness of breath, cough, fever, or chest pain that becomes worse if you take a deep breath.

A common sign of a DVT is a swelling in the arm or leg that becomes warm, red, and painful. Contact your doctor as soon as you notice any swelling. A DVT can be treated with drugs called anticoagulants.

Some cancer treatments, including surgery, chemotherapy, and hormone therapy increase your risk of a DVT because the treatments can activate the body’s blood-clotting system. Another risk factor for a DVT is being immobile for a prolonged time, such as staying in bed. As soon as you can, get out of bed and move around after surgery or illness to help prevent a blood clot. Sitting in a seat for an extended time while traveling also increases the risk of a DVT. Periodically get up from your seat and flex your muscles during the trip. If you have had a DVT before, ask your doctor about wearing compression stockings while traveling or taking blood-thinning medication before the trip.

Other risk factors for a DVT include a family history of blood clotting disorders, a recent surgery, and other conditions, such as heart disease and lung disease. The risk also increases with age.

Ask your doctor what your risk is of developing a blood clot or DVT, and what you can do to help prevent them. Read more about bleeding and clotting problems and the American Society of Clinical Oncology’s (ASCO’s) guideline on preventing and treating blood clots.

Tumor lysis syndrome

Tumor lysis syndrome (TLS) occurs due to the rapid death of cancer cells in response to treatment. When tumor cells die, they release their contents, including potassium, phosphate, and parts of the tumor’s DNA into the bloodstream, which may disrupt the body’s metabolism and concentration of electrolytes (salts in the body that conduct electricity and help the body function properly). These imbalances can damage organs, including the heart, liver, and kidneys, and may cause seizures, loss of muscle control, and death.

TLS usually occurs after finishing chemotherapy for a fast-growing cancer, such as some types of leukemia or lymphoma (cancers of the blood), and is detected by blood and laboratory tests. Signs of TLS may include nausea and vomiting, shortness of breath, irregular heartbeat, cloudy urine, and lethargy (lack of energy), and/or pain in the joints.

The risk factors for TLS include having a type of cancer in which the tumor cells divide rapidly, mainly cancers of the blood, such as Burkitt lymphoma (occurs mostly in children but also adults), large-cell lymphoma (type of non-Hodgkin lymphoma), acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), and chronic lymphocytic leukemia (CLL). Rarely does TLS develop in people with solid tumors (colorectal and breast tumors, for example). Other risk factors for TLS include having an elevated level of white blood cells and uric acid before treatment, kidney problems, and dehydration.

TLS usually occurs within 48 hours after starting chemotherapy. Although rare, TLS may occur before starting chemotherapy. Patients at the greatest risk of TLS receive chemotherapy in the hospital so that doctors can monitor them after starting treatment and deliver intravenous (IV) fluids to help prevent it. Medications such as allopurinol (Zyloprim) and rasburicase (Elitek) are also given to help lower the level of uric acid in the body and to prevent TLS.

Communicating with the doctor and health care team

Because each type of cancer and cancer treatment causes different side effects, there may be other serious complications besides an infection, DVT, and TLS, so ask your doctor about what other conditions to watch out for. It’s also a good idea to set up some “ground rules” with your doctor for contacting him or her and members of the staff during your treatment. Ask your doctor the following questions:

• What are the possible side effects of my treatment, and which ones are considered an emergency?
  
  
• Under which other situations should I call your office during my treatment?
  
  
• Who are the key members of your staff, who should I call for what, and what are their telephone numbers?
  
  
• What number should I call after normal business hours?
  
  
• What can I expect for a callback time?
  
  
• Under what situations should I use e-mail to communicate with you and your staff?
  
  
• When should I go straight to the emergency room?

More Information

Managing Side Effects

Managing Your Care

Additional Resources

National Cancer Institute: Managing Chemotherapy Side Effects: Infection (PDF)

National Heart, Lung, and Blood Institute: What is Deep Vein Thrombosis?

University of Florida Shands Cancer Center: Tumor Lysis Syndrome

Last Updated: October 12, 2009