Infection Risk in Cancer - What Are the Signs of Infection During Chemotherapy?

A patient about to receive chemotherapy and their doctor discuss infection risk and prevention. The most important determinant during cancer treatment is the medicines given according to cancer type. In general, infection risk is higher during treatment of blood and bone marrow (hematological) cancers because immune cell counts fall much more markedly. Some hematological cancers directly arise from immune cells becoming cancerous, and treatment temporarily suppresses the immune system completely.

During treatment of solid-organ cancers (such as lung, breast and colorectal cancer), infection risk also varies with the medicines used, whether precautions against immunosuppressive treatment are taken, previous treatment-related infections, age and general condition.

How can you protect yourself in potentially risky situations despite reduced white blood cells, which fight infections? Can normal life continue in this respect? Does enjoying activities or close contact with loved ones put you at risk? What should you consider regarding pets? Let us examine these questions together.

Why Should You Pay Close Attention to Infection Risk During Chemotherapy?

There are several answers;

1. During chemotherapy, fighting infection becomes harder for your body, and infection can grow and spread easily. Antibiotics may help, but your immune system plays a greater role.
2. When the immune system is suppressed, viruses or bacteria that normally do not cause disease may cause infections. This is called an opportunistic infection . Even outside illness, we are constantly exposed to microorganisms in daily life, but we develop fewer infections because our immune system can perform its functions. When weakened by cancer or treatment, microorganisms can cause illness in our bodies more easily.
3. Infections caused by microorganisms encountered in clinics or hospitals may be harder to treat; these are called nosocomial infections . They are caused by microorganisms that may resist standard antibiotics, making treatment longer and more difficult.
4. Recognizing infection in people with cancer is also difficult. For example, it may not be immediately clear whether a lung cancer patient’s cough comes from cancer or a new infection. In addition, fever, an immune response, may not appear early in infection in a patient whose immune system is already weak.

Situations Posing Infection Risks and Precautions

Sharing crowded spaces with others

Crowded environments are among the situations posing high infection risks during chemotherapy, including buses, airplanes and shopping centers. Avoid them as much as possible, particularly in winter when influenza-like infections are more widespread. People with blood and bone marrow cancers should be especially careful in crowds and may need masks if attending. For solid-organ cancer treatment, less strict precautions may be taken, and routine mask use is unnecessary.

An ill person and infection risk

During cancer treatment, we do not recommend isolation from loved ones or family members or precautions such as separate rooms. If someone in the family has a cold or influenza-like illness, avoid direct physical contact and sharing drinking glasses or cosmetics. The most important and effective precaution is handwashing.

- Related topic: Can patients with cancer receive influenza or pneumonia vaccines?

Food and infection risk

Foodborne infectionsare the most common form of infection worldwide. Recommendations to reduce the risk during chemotherapy include:

• Avoid raw or undercooked animal products. For example, eat red meat well cooked and avoid raw seafood during treatment.
• Eggs should be completely cooked, including the yolk.
• Wash all foods thoroughly with plenty of water.
• Be aware of possible indirect infection risks. For example, do not use the same cutting board for meat or poultry and fruits or vegetables.
• Avoid mold-ripened or aged cheeses.

Precautions Regarding Pets

Pets such as dogs and cats are undoubtedly our best friends. They genuinely have a therapeutic effect during cancer treatment and other difficult times. However, during chemotherapy people become more vulnerable to infections that would not normally affect them. Important precautions include:

• Keep your pets’ vaccinations up to date
• If possible, do not handle cat litter, change aquarium water or clean up after walking dogs yourself. Otherwise, use disposable masks and gloves and change these daily. Pay attention to hygiene.
• Do not acquire a new pet during chemotherapy. It will need more attention and training, while you need plenty of rest.
• Keeping cats indoors reduces their chance of bringing infections from outside.

- Related topic: Our dear companions, pets, are by our side during cancer treatment

Other Recommendations to Prevent Infections

• Bathe daily,
• Use a soft toothbrush,
• Use disposable gloves in all risky situations, including taking out rubbish,
• Wash your hands frequently and thoroughly with only soap and water. Dry them with a clean towel nobody else has used or a paper towel.

Signs of Infection During Chemotherapy

Always tell your doctor if you experience one or more of these symptoms:

• Fever
• Chills 
• Cough
• Shortness of breath 
• Pain during urination or a frequent urge to urinate
• Headache or a stiff neck
• Abdominal pain 
• Diarrhea

Blood Cell-Boosting Injections to Reduce Infection Risk

Especially chemotherapy , but also radiotherapy, immunotherapy or combinations, may lower white blood cell counts, our defense cells.

The general name for white blood cells is leukocyte; among leukocytes, the principal cells fighting bacteria are neutrophils. A leukocyte count below 3000 per cubic millimeter of blood is called leukopenia, and below 1000, severe leukopenia. A neutrophil count below 1500 per cubic millimeter is called neutropenia, and below 500, severe neutropenia. If fever accompanies this condition, it is called febrile neutropenia . Febrile neutropenia is an oncological emergency requiring hospitalization and intravenous antibiotics. To prevent it, your oncologist may include a blood cell growth factor injection called GCSF (such as filgrastim, lenograstim or pegfilgastrim) in treatment. Because chemotherapy regimens differ in their potential to cause leukopenia or neutropenia, these blood cell-boosting injections are not given after every chemotherapy treatment.

In conclusion, infection risk increases because of cancer or as a treatment side effect. However, today, just as we successfully reduce chemotherapy-related nausea , infection risk associated with cancer treatment is usually manageable and preventable.

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