Radiation pneumonitis

Radiation pneumonitis is inflammation of the lung caused by radiation therapy to the chest. It most commonly develops 1 to 3 months after treatment is over, but it can happen up to 6 months after treatment. Chronic pneumonitis 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. Certain chemotherapy drugs, such as bleomycin (Blenoxane), cyclophosphamide (Procytox) and carmustine (BiCNU, BCNU), can also increase the risk of developing radiation pneumonitis if given along with radiation therapy.


Symptoms of radiation pneumonitis include:

  • fever
  • cough
  • chest congestion
  • shortness of breath
  • chest pain

If symptoms get worse or don’t go away, report them to your doctor or healthcare team without waiting for your next scheduled appointment.


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

Managing radiation pneumonitis

Your healthcare team may recommend medicines to treat radiation pneumonitis, such as:

  • decongestants
  • cough suppressants
  • bronchodilators
  • corticosteroids to reduce inflammation
  • oxygen therapy

You can also try the following to help manage symptoms:

  • Rest if you feel short of breath.
  • Drink more fluids and use a cool-air vaporizer or humidifier to keep the air moist.
  • Use an extra pillow to raise your head and upper body while resting or sleeping.
  • Avoid the outdoors on hot, humid days or very cold days (which can irritate the lungs).
  • Wear light, loose-fitting tops and avoid anything tight around the neck, such as ties or shirt collars.

Expert review and references

  • Radiotherapy. Cancer Research UK. CancerHelp UK. Cancer Research UK; 2009.
  • Haas ML . Radiation therapy. Varricchio, C., Pierce, M., Hinds, P. S., & Ades, T. B. A Cancer Source Book for Nurses. 8th ed. Sudbury, MA: Jones and Bartlett Publishers; 2004: 8: pp. 131-147.