Radiation pneumonitis

Last medical review:

Radiation pneumonitis is inflammation of the lungs caused by radiation therapy to the chest. It often starts in the first few months after treatment is over, but it can start up to 12 months after treatment. If you have chronic pneumonitis, which means the inflammation lasts for a long time, it can lead to permanent scarring of the lungs (called pulmonary fibrosis).


Radiation pneumonitis is more likely to happen when high doses of radiation are used or a large area of the lung is treated with radiation. Combining radiation therapy with certain chemotherapy drugs, immunotherapy, or targeted therapies can make the lung tissue more sensitive to radiation and increase the risk of radiation pneumonitis.


Symptoms of radiation pneumonitis include:

  • fever
  • cough
  • a general feeling of discomfort or illness (called malaise)
  • shortness of breath
  • chest pain

Tell your doctor or healthcare team about any symptoms you have. The sooner you tell them of any symptoms, the sooner they can suggest ways to help manage them.


Your doctor will try to find the cause of your symptoms. You may need to have the following tests:

  • physical exam
  • chest x-ray
  • chest CT scan
  • pulmonary function test
  • bronchoscopy

Managing radiation pneumonitis

Your healthcare team may recommend different treatments for radiation pneumonitis. These include:

  • cough suppressants to lessen your cough

  • bronchodilators to help open your airways

  • corticosteroids to reduce inflammation

  • oxygen therapy to improve your breathing

You can also try the following to help manage symptoms:

  • Rest if you feel short of breath.
  • Use an extra pillow to raise your head and upper body while resting or sleeping.
  • Avoid being outside on hot, humid days or very cold days. Extreme temperatures can irritate the lungs.
  • Wear light, loose-fitting tops. Avoid anything tight around the neck, such as ties or shirt collars.

Expert review and references

  • Srinivas Raman, MD, MASc, FRCPC
  • Jain V, Berman AT. Radiation Pneumonitis: Old Problem, New Tricks. Cancers. MDPI; 2018: 10(7): 222.
  • Rahi MS, Parekh J, Pednekar P, Parmar G, Abraham S, Nasir S, Subramaniyam R, Jeyashanmugaraja GP, Gunasekaran K.. Radiation-Induced Lung Injury—Current Perspectives and Management. Clinics and Practice. MDPI; 2021: 11(3):410-429.
  • American Cancer Society. Radiation Therapy Side Effects. 2020: https://www.cancer.org/. Friday, October 27, 2023.
  • OncoLink. Radiation Pneumonitis. 2023: https://www.oncolink.org/. Friday, October 27, 2023.

Medical disclaimer

The information that the Canadian Cancer Society provides does not replace your relationship with your doctor. The information is for your general use, so be sure to talk to a qualified healthcare professional before making medical decisions or if you have questions about your health.

We do our best to make sure that the information we provide is accurate and reliable but cannot guarantee that it is error-free or complete.

The Canadian Cancer Society is not responsible for the quality of the information or services provided by other organizations and mentioned on cancer.ca, nor do we endorse any service, product, treatment or therapy.

1-888-939-3333 | cancer.ca | © 2024 Canadian Cancer Society