Pneumonitis and Stage 3 Lung Cancer: A Side Effect of Chemo, Radiation, and Immunotherapy
If you have stage 3 lung cancer, you likely already know all lung cancer treatments have potential risks and side effects. Though your doctor will try to minimize their occurrence, it’s important to understand how to recognize treatment side effects should they develop. One possible, and potentially serious, side effect of lung cancer treatment is pneumonitis, a condition characterized by inflammation in your lungs. Certain substances, such as chemicals you breathe in or medications you take, can cause the air sacs in your lungs to become irritated and inflamed. This makes it hard for your lungs to enrich your blood with oxygen, leading to symptoms such as shortness of breath, dry cough, weakness, fatigue, fever, and weight loss.
Pneumonia is actually a type of pneumonitis. But often, pneumonia is used to refer to inflammation in your lungs caused by a viral or bacterial infection, while pneumonitis is used to describe lung inflammation that’s not related to an infection.
Which stage 3 lung cancer treatments can cause pneumonitis?
Some of the commonly used stage 3 lung cancer treatments—radiation, chemotherapy, and immunotherapy—can lead to pneumonitis as an adverse effect. Radiation therapy aims high-powered beams at your chest to kill cancer cells and shrink tumors, but it can also damage healthy tissue around it, causing inflammation.
Similarly, chemotherapy is used to destroy fast-growing stage 3 lung cancer cells. These strong drugs can impair normal lung cells as well, leading to inflammation and breathing problems. And immunotherapy, which boosts your immune system’s ability to fight cancer, can sometimes mount an unintended attack on the noncancerous cells in your lungs; this also brings inflammation.
Pneumonitis can be tricky to diagnose since it may not develop until months after your cancer treatment and can mimic other lung conditions (even lung cancer itself). But if pneumonitis goes unrecognized or untreated, it can cause permanent lung damage, called pulmonary fibrosis. So, it’s important to let your doctor know if you develop any symptoms to avoid further complications.
How is pneumonitis treated?
Since pneumonitis can range in severity from mild to life-threatening, treatment can vary. You may be prescribed corticosteroids to help reduce the inflammation in your lungs. Supplemental oxygen may be needed in some cases to make breathing easier. Medication to ease your coughing and help open up your airways may be given as well.
Your doctor may also temporarily pause your lung cancer treatment until your symptoms improve. Very significant pneumonitis may require your cancer treatment to be changed or stopped altogether.
Most cases of pneumonitis will resolve with treatment, but for some, it can have long-lasting effects on breathing and lung function.
What factors increase the risk of pneumonitis from stage 3 lung cancer treatments?
We know some people have a higher risk of developing pneumonitis. Associated factors include:
Combination of radiation and chemotherapy as cancer treatment
Certain chemotherapy drugs, such as paclitaxel (Taxol) or docetaxel (Taxotere)
Co-existing lung disease, including emphysema and chronic obstructive pulmonary disorder (COPD)
High doses of radiation
Large areas of tissue exposed to radiation
Researchers are also studying whether certain genetic and molecular markers can be identified in patients who are more likely to develop pneumonitis.
Armed with this knowledge, we are learning how to more safely administer lung cancer treatments while minimizing side effects. For example, newer methods of radiation therapy, such as intensity-modulated radiation therapy, deliver precise radiation to the tumor with less exposure to normal tissue. Better identification of high-risk individuals can help guide future treatment decisions as well.