When to Call the Doctor During Cancer Treatment

Approved by the Cancer.Net Editorial Board, 08/2020

Cancer and cancer treatments may cause side effects that need medical attention. It can be hard to know when to call the doctor. Ask your health care team which signs and symptoms to expect and which ones need medical attention right away.

Some serious side effects that need medical attention include the following conditions. Each one is described further in this article.

  • Infection

  • Deep vein thrombosis (DVT), which is a potentially life-threatening blood clot

  • Pulmonary embolism (PE), which is a blood clot in the lung

  • Tumor lysis syndrome (TLS), which is a life-threatening vital organ injury

What are the signs of infection?

Cancer and its treatments weaken the body's immune system. This makes it more likely that you will develop an infection. An infection occurs when bacteria, viruses, or fungi (such as yeast) invade the body.

Common types of infections that need immediate medical attention include:

  • Pneumonia, which starts in the lungs

  • Urinary tract infection, which can start in the bladder or kidneys

  • Infections in the mouth, throat, esophagus, stomach, intestines, or anus

  • Blood infections, which are most common in people with low white blood cell counts or an implanted catheter

  • Signs of a COVID-19 infection

Infection during cancer treatment can be life threatening. Your health care team will help you determine if the infection is serious and how best to manage your symptoms.

What symptoms require immediate care?

Call your health care team right away if you have 1 or more of the signs listed below. These symptoms may mean that you have an infection that needs immediate treatment. If your doctor cannot review your symptoms right away, you may need to go to the emergency room.

  • Fever that is 100.4° F (38° C) or higher

  • Shaking chills

  • Chest pain or shortness of breath

  • Confusion

  • Severe headache with a stiff neck

  • Bloody urine

What symptoms of infection require prompt care?

These symptoms may be safely managed by visiting your doctor’s office:

  • Cough

  • Swelling or redness anywhere, including around a cut, wound, or catheter

  • Sores or a white coating in your mouth or on your tongue

  • Tooth or gum pain

  • Sore throat

  • Ear pain

  • Headache or bad sinus or facial pain

  • Stiff or sore neck

  • Abdominal pain

  • Skin sores or rash

  • Diarrhea

  • Sores near the anus

  • Cloudy urine

  • Pain or burning when urinating

  • Vaginal discharge or itching

  • Any change or something that does not feel normal for you, including a general sense of feeling unwell

How can I protect myself during the COVID-19 pandemic?

As the COVID-19 pandemic continues to spread globally, it is important for people with cancer to take care to protect themselves. People with cancer, especially people who are currently receiving cancer treatment, are at a higher risk of the more severe form of COVID-19. This can lead to hospitalization, be life threatening, and delay cancer treatment.

While the COVID-19 pandemic is ongoing, it is best to follow your doctor's recommendations and public health guidelines, including staying home as much as possible to reduce your exposure to other people. If you must leave your home, keep a distance of at least 6 feet (2 meters) between yourself and other people. Always wear a cloth face covering when you are in public. Wash your hands regularly.

If you think that you have been exposed to COVID-19 or if you have developed symptoms of COVID-19, call your primary care doctor or your oncologist. Visit this website's article on COVID-19 and what people with cancer should know for additional information, including specific symptoms to watch for.

How can I prevent an infection?

The following tips can help prevent infections:

  • Wash your hands well and often with soap and water. If soap and water are unavailable, use antibacterial hand sanitizers. Always clean your hands before eating and after using the restroom.

  • Avoid contact with people who are sick or recently ill. Let your health care team know if you have been around someone who is visibly sick or has had a positive COVID-19 test, even if they are not showing symptoms.

  • Avoid crowds, especially indoors.

  • Wear a cloth face covering or other face mask when you leave your home.

  • Do not share food, drinks, utensils, and personal items.

  • Shower or bathe daily and apply lotion to prevent dry, cracked skin.

  • Clean teeth and gums with a soft toothbrush.

  • Avoid cuts and use an electric razor if possible.

  • Avoid cat litter and handling animal waste.

  • Keep the area around any catheter(s) clean and dry.

Part of preventing an infection is taking care of yourself. Here are some tips for how to stay healthy:

  • Follow food safety guidelines, including ensuring all meats, fish, shellfish, or poultry are fully cooked, and washing all fresh fruits and vegetables.

  • Eat a variety of nutritious foods.

  • Get at least 7 to 8 hours of sleep each night.

  • Get enough physical activity.

  • Drink enough water. Check with your health care team how much water is right for you.

  • Avoid being around people who have just had vaccines for chicken pox, measles, or polio or the mist type of flu vaccine.

  • Check with your health care team before getting any shot or vaccine yourself.

Learn more about infections as a side effect of cancer and its treatment.

Deep vein thrombosis and pulmonary embolism

Thrombosis is a blood clot inside a blood vessel. Deep vein thrombosis (DVT) occurs when a blood clot forms inside a vein deep in the body, usually in a leg. DVT can be treated with drugs called anticoagulants. A blood clot may go away naturally, but a DVT requires anticoagulant treatment because it can become life threatening if the clot travels to the lungs and causes a pulmonary embolism (PE). A PE is a blockage of 1 or more of the lung’s major arteries.

The signs and symptoms of a blood clot might stem from the clot itself or a pulmonary embolism. Some people are not aware of a deep vein clot until they develop signs and symptoms the clot has moved to the lungs.

See your doctor right away if you have signs or symptoms of either condition. Both DVT and PE can cause serious, possibly life-threatening problems if not treated. Signs and symptoms of a DVT may include 1 or more of these:

  • Swelling of the leg or along a vein in the leg or arm

  • Pain or tenderness in the leg, which you may feel only when standing or walking

  • Pain or tenderness in the arm that limits movement

  • Increased warmth in the part of the leg or arm that is swollen or painful

  • Red or discolored skin on the leg or arms

Signs and symptoms of a PE may include 1 or more of these:

  • Unexplained shortness of breath

  • Pain in the chest, sides, or back with deep breathing

  • Coughing up blood

  • Fast breathing rate

  • Fast heart rate

There are certain factors that may increase your risk of developing a DVT or a PE:

  • Surgery

  • Chemotherapy

  • Hormonal therapy

  • Not being able to move for a long time

  • Diagnosis of adenocarcinoma, pancreatic cancer, lymphoma, or myeloma

  • Personal or family history of blood clotting disorders

  • Medical conditions such as heart disease or lung disease

  • Older age

  • Smoking

  • Having a long-term catheter in a vein

To help prevent blood clots:

  • Get out of bed and move around as soon as you can after surgery or illness.

  • Get up from your seat and flex your muscles periodically when traveling or sitting for a long period of time.

  • If you have had a DVT before, ask your doctor about wearing compression stockings. These are worn while traveling and/or taking blood-thinning medication before a trip.

Also ask your doctor about your risk of developing a blood clot or DVT and what you can do to help prevent them. Learn more about bleeding and clotting problems.

Tumor lysis syndrome

Tumor lysis syndrome is a life-threatening medical emergency. It usually occurs after chemotherapy for a fast-growing cancer, such as some types of leukemia or lymphoma. TLS is less likely to develop in people with solid tumors, with the exception of small cell lung cancer. Talk with your health care team about your risk of TLS.

The rapid death of cancer cells due to cancer treatment may cause TLS. As tumor cells die, they break apart and spill their contents into the blood. Tumor cell contents include potassium, phosphate, and tumor DNA. This sudden release causes a change in certain electrolytes and other chemicals in the blood. This concentration of chemicals can damage organs, including the kidneys, heart, liver, and nervous system. The result can be loss of muscle control, seizures, kidney or heart failure, or even death.

TLS is usually linked with chemotherapy, but other types of cancer treatment may also lead to TLS. Rarely, this syndrome may occur before starting any cancer treatment or after a biopsy of a tumor. People with the highest risk of TLS must stay in the hospital for their cancer treatment. This is so doctors can monitor them and deliver intravenous fluids and medications that lower uric acid, such as rasburicase (Elitek), to help prevent TLS. This syndrome can be found through blood tests and other laboratory tests and specific physical signs and symptoms (see below).

Types of cancers most commonly linked with TLS include:

  • Burkitt lymphoma

  • Large-cell lymphoma (types of non-Hodgkin lymphoma)

  • Acute lymphocytic leukemia

  • Acute myeloid leukemia

  • Chronic lymphocytic leukemia

  • Small cell lung cancer

The following factors may also increase a person’s risk of TLS during cancer treatment:

  • High white blood cell level

  • High blood uric acid level

  • Kidney problems

  • Dehydration

  • Later-stage cancer

  • Large tumor size

The signs and symptoms of TLS include:

  • Nausea and vomiting

  • Diarrhea

  • Swelling

  • Shortness of breath

  • Irregular heartbeat

  • Low blood pressure

  • Cloudy or bloody urine

  • Low urine output

  • Back pain behind the lower ribs

  • Weakness or low energy

  • Seizures

  • Muscle spasms or cramps

  • Pain in the joints

  • Sudden death

Questions to ask your health care team

Each type of cancer and its treatment causes different side effects. Ask your health care team what side effects you should watch for. Consider asking the following questions:

  • What are the possible symptoms and side effects of my cancer? What are the possible side effects of my cancer treatment?

  • Which side effects should be considered an emergency? Where should I go to seek out medical care if this happens?

  • Which of these side effects should I call the doctor's office about?

  • Are there other situations when I should call the doctor right away during my cancer treatment?

  • When should I contact other members of the health care team? What is their contact information?

  • What telephone number should I call if I have a problem after normal business hours?

  • When can I expect a return call from the doctor, the health care team, or the after hours on-call provider? What should I do if I don't hear back?

  • When should I use email to communicate with my health care team?

Related Resources

Food Safety During and After Cancer Treatment

A Simple Way You Can Prevent Infection and Illness

Coronavirus and COVID-19: What People with Cancer Need to Know

Common Questions About COVID-19 and Cancer: Answers for Patients and Survivors

More Information

National Cancer Institute: Infection and Neutropenia During Cancer Treatment (PDF)

Centers for Disease Control and Prevention (CDC): Preventing Infections in Cancer Patients

CDC: Cancer and Flu

National Heart, Lung, and Blood Institute: Venous Thromboembolism