For people with weakened immune systems, such as those with lung cancer, pneumonia can be an even more serious condition. Pneumonia is a pulmonary infection that causes inflammation in the alveoli (small air sacs inside the lungs). Between 50 percent and 70 percent of people with lung cancer also develop pneumonia. Pneumonia can be life-threatening even in healthy people. Seek medical care immediately if you believe you have developed pneumonia.

Common Signs and Symptoms of Pneumonia

The signs and symptoms of pneumonia are often similar to the signs and symptoms of lung cancer. This can make it difficult to detect and diagnose the infection. Some of the similar signs and symptoms may include:

• Shortness of breath (dyspnea)
• Coughing, sometimes with blood
• Phlegm or sputum (phlegm mixed with saliva) when coughing
• Hoarseness or raspiness
• Chest pain when breathing, coughing, and laughing
• Fatigue

Common symptoms of pneumonia may also include having a lower than usual body temperature, fever, sweating, “shaking chills,” loss of appetite, and nausea, vomiting, or diarrhea.

What Causes Pneumonia?

According to the American Lung Association, pneumonia has many different causes. The infection can arise from viral, bacterial, and fungal infections. Your doctor will identify what particular pathogens (infectious agents) have caused your pneumonia in order to prescribe the correct medical treatment.

Several factors can increase a person’s risk of developing pneumonia, such as age. Other risk factors — including underlying health conditions, lifestyle choices, and environmental factors — can also make a person more susceptible to the infection. People with other chronic lung diseases such as cystic fibrosis, ​chronic obstructive pulmonary disease, and bronchiectasis are also more vulnerable.

Health Care-Associated Pneumonia

When a person develops pneumonia in a health care setting, such as in a hospital, it is called health care-associated pneumonia. This is opposed to community-acquired pneumonia, which is spread outside a health care facility. Health care-associated pneumonia can also include ventilator-associated pneumonia. As its name suggests, this form of infection occurs as the result of being put on a ventilator (breathing support device).

Health care pneumonia and community-acquired pneumonia are generally caused by different viruses and bacteria. One cause of community-acquired pneumonia, for instance, is ​streptococcus pneumoniae — a major cause of bacterial pneumonia. One cause of hospital-acquired pneumonia, on the other hand, is staphylococcus aureus (also referred to as a staph infection).

Lung Cancer and Pneumonia Risk

Lung cancer and lung cancer treatments affect the body and immune system in a way that makes it easier to develop infections. People with lung cancer may be more at risk of developing infections due to poor nutrition, cancer treatments, and cancer itself. Having other unrelated health problems — or taking medications taken for those unrelated conditions — can also increase the risk of infection.

The body’s complex immune system tries to resist bacterial or viral infections. Cancer and some cancer treatments change blood cells and how the immune system works. White blood cells (also known as WBCs or leukocytes) protect you from disease and illness. When there are fewer WBCs, the body has a harder time fighting infections.

Mutated immune cells can also prevent the immune system from working properly. Depending on the situation, problems with the lung tissues — such as pneumonitis, an inflammation of the lung tissue — can leave the body more prone to infection. Some of these infections may be fatal if not treated early.

Lung Cancer Treatments and Pneumonia

The development of infections isn’t just determined by the underlying disease. Pneumonia — as well as other lower respiratory infections, like bronchitis — can also occur as the result of certain tests, treatments, medications, and surgeries. These infections (treatment-related infectious syndromes) commonly develop after cancer treatments like radiation and chemotherapy (“chemo”).

Chemo, in particular, is the most common cause of immunodeficiency (weakened immunity) in people undergoing cancer treatments. WBCs are immune cells that play an important role in helping our bodies fight off infections. Chemotherapy can decrease the number of a particular type of WBCs (neutrophils) in the body. This condition (called neutropenia) can decrease a person’s ability to fight off infections like pneumonia.

Radiation therapy, also called radiotherapy, is another common cause of a decrease in WBC counts and a weakened immune system. A low WBC count is one of the most serious side effects of chemotherapy and radiology.

How Dangerous Is Pneumonia With Lung Cancer?

Pneumonia can be serious for anyone — this is true whether they do not have lung cancer, are in remission, are in the middle of treatment, or are in an advanced stage. Because lung cancer affects the lungs, as well, acquiring pneumonia while you have lung cancer — especially in advanced cases of the disease — can be life-threatening.

Possible Complications of Pneumonia in Lung Cancer

Many potential complications may occur with pneumonia, especially if it is untreated. Some of the most common complications include:

• Respiratory failure
• Sepsis
• Lung abscesses

Respiratory Failure

Respiratory failure will require breathing support with a ventilator. It is also possible to develop a more severe form of respiratory failure called acute respiratory distress syndrome.

Sepsis

Sepsis occurs when the immune system begins to turn on the body’s tissues while fighting off an infection. This uncontrolled inflammation can lead to organ failure.

Lung Abscesses

Although uncommon, this is a very serious potential complication of pneumonia. Lung abscesses occur when pus pockets form around or inside a lung. They may need to be drained through surgery.

Tests To Diagnose Pneumonia

There are several common tests to determine whether a person has pneumonia or another lung infection, such as bronchitis. Some of the most common tests used for this purpose include:

• Blood tests and blood cultures
• Pulse oximetry
• Arterial blood gases
• Bronchoscopy
• Lung biopsy
• Thoracentesis
• Chest X-ray or computerized tomography scan

Blood Tests and Blood Cultures

Blood testing can be used to determine which specific organisms are present in the bloodstream. Blood cultures can identify harmful bacteria, in particular.

Pulse Oximetry

This test measures the amount of oxygen in the blood. This can help determine whether a person’s lung function has been impaired by an infection like pneumonia.

Arterial Blood Gases

In this test, a sample of blood is drawn from an artery to measure levels of oxygen and carbon dioxide in the blood. Like pulse oximetry, arterial blood gases can help assess how well a person’s lungs are functioning.

Bronchoscopy

A bronchoscopy is an endoscopic procedure that allows a doctor to view the lungs and air passages (bronchial tubes) from inside. During this procedure, a doctor can clear any obstructions (blockages) and take mucus, fluid, or tissue samples for analysis.

Lung Biopsy

In a lung biopsy, a doctor will obtain a piece of lung tissue and analyze it for signs of certain diseases or conditions.

Thoracentesis

In this test, fluid is obtained from the sac surrounding the lungs called the pleural space. This fluid can then be checked for pulmonary infections and cancer.

Chest X-Ray or Computerized Tomography Scan

These tests can be used to produce detailed images of the body’s structures (in this case, those in the chest).

Preventing Pneumonia With Lung Cancer

There’s no guaranteed way to prevent pneumonia. However, there are some steps a person with lung cancer can take to help reduce their chances.

Discuss options with your doctor. There are many things to take into consideration while trying to prevent another condition, including the lung cancer stage, the state of your immune system, and what lung cancer treatments you are undergoing.

Keep Up With Vaccinations

Certain vaccines are highly recommended for people with lung cancer. However, before you receive any vaccines, speak with your oncology care team. Some vaccines may be more harmful than helpful. A discussion with an oncologist about the risks and benefits of all vaccines needs to be clearly understood.

A few of the most common vaccines that can help prevent pneumonia with lung cancer are listed below.

COVID-19 Vaccines

These vaccines are generally recommended for people with any type of cancer to prevent infection with COVID-19. Keep in mind, discussion with a health care professional is crucial before making a decision. These vaccines may be less effective for individuals during chemotherapy, radiation (or radiotherapy), and other cancer treatments.

Flu Vaccine

It’s unknown whether people with lung cancer and lung cancer survivors are more likely to catch the flu than other individuals. What is known, however, is that people with cancer have an increased risk of developing complications if they get the flu. These complications may be serious, so doctors usually advise people with cancer to receive this vaccine.

Pneumonia Vaccine

The pneumonia vaccine helps fight off certain bacterial infections, making them particularly helpful for individuals with weakened immune systems. One or more shots of this vaccine may be needed, depending on the doctor’s recommendation.

Generally, the Centers for Disease Control and Prevention (CDC) recommends that most adults with cancer receive pneumonia vaccinations (pneumococcal vaccines). There are two types of pneumonia vaccine available in the United States: the PCV13 (pneumococcal conjugate) vaccine and the PPSV23 (pneumococcal polysaccharide) vaccine.

The CDC recommends that a person with cancer receive one dose of PCV13, then a first dose of PPSV23 at least eight weeks later. A second dose of PPSV23 should be administered at least five years after the first PPSV23 dose.

As with any other vaccine, medication, or treatment, a discussion with your doctor is necessary to be sure you receive the best medical advice for your condition.

Wash Your Hands

Frequent hand-washing is always important to protect against illness. Wash your hands thoroughly with warm, soapy water before cooking or eating and after using the bathroom or blowing your nose.

Wear a Mask

Wearing a face covering decreases the risk of spreading disease. Masks help lower the incidence of disease for both the person wearing the mask and for those the person comes into contact with.

Don’t Smoke

People who smoke have a higher risk of catching pneumonia than non-smokers. This is because the damage tobacco does to the lungs makes it more difficult for the body to fight off infections.

Keep Up Your General Health

Getting plenty of rest, eating a healthy diet, and exercising regularly may help ward off some illnesses. Keeping up with all doctor appointments and discussing signs or symptoms of pneumonia (or other illnesses) is also extremely important.

What Comes Next

Because pneumonia, other infections, chemotherapy, and radiation therapy greatly affect WBC counts, your doctor may need to stop or delay certain treatments when an infection is detected. They will take into account your type of cancer — for example, whether you have non-small cell lung cancer or small cell lung cancer — and where you are in your cancer treatment, among other factors.

Your doctor will discuss with you the best course of action for pneumonia treatment or prevention. This may include antibiotic therapy, catching you up with your vaccines, and any other crucial steps to stop your infection as fast as possible. Report any changes in your health status and any new or worsened signs or symptoms. The earlier a doctor discovers an infection or other issues, the better chance a person has of a positive outcome.

Find Your Team

Talking to other people who understand what you are going through can be a great source of emotional support. MyLungCancerTeam is the social network for people with lung cancer. On MyLungCancerTeam, more than 4,900 members come together to ask questions, give advice, and share their stories with others who understand life with lung cancer.

Have something to add to the conversation? Share your experiences and thoughts in the comments below or by posting on MyLungCancerTeam.