Common Symptoms of Radiation Pneumonitis

Overview

Radiation pneumonitis is an inflammation of the lungs due to radiation therapy or stereotactic body radiotherapy (SBRT) for cancer. This side effect of radiation therapy occurs in roughly a fourth of people who go through radiation therapy for lung cancer but can also result from radiation to the chest for breast cancer, lymphomas, or other cancers

Symptoms most commonly occur between one and six months after completing radiation therapy. With treatment (and this is important), most people recover without any lasting effects.

Symptoms

It is important to be aware of radiation pneumonitis, because symptoms can be very similar to those caused by lung cancer alone, or can be mistaken for an infection such as pneumonia. Many people simply tolerate these symptoms as expected, yet radiation pneumonitis is a good reminder that you should talk to your oncologist about any symptoms you note: Common symptoms include:

• Shortness of breath that is usually more notable with exercise.
• Chest pain, especially chest pain which worsens with breathing (pleuritic chest pain.)
• A Cough which can be dry or produce mucus. Since many people with lung cancer have a cough at times, it's important to note any change in your cough, whether it is more frequent, harsher, or more uncomfortable.

• Low-grade fever.

In some cases, no symptoms are present, and the diagnosis is made by the appearance of inflammation on a chest x-ray alone.

Who Is at Risk?

Some people are more at risk than others of developing radiation pneumonitis. Conditions which increase the risk include:

• Concurrent (meaning at the same time) radiation therapy and chemotherapy. Radiation pneumonitis (RP) is more common in people receiving concurrent radiation and chemotherapy than those receiving sequential (at different times) radiation and chemotherapy. If this is alarming it's important to look at factors other than this complication.  In a 2009 study, researchers found that people with stage 3 lung cancer who received concurrent radiation and chemotherapy had double the survival after 5 years. Other studies have also suggested improved survival when the treatments are used together.

• People who have other lung diseases, such as COPD, are at an increased risk.
• Older patients are more likely to develop radiation pneumonitis than younger patients.
• The amount of tissue treated. The risk of radiation pneumonitis increases with the area of the chest that is treated.  It is also more common when the middle and lower lobes of the lungs are treated than with treatment of upper lobe lung cancers.
• People who receive the chemotherapy drugs Paraplatin (carboplatin) and Taxol (paclitaxel.)

Cause

Radiation causes the lungs to produce less of the substance surfactant. Surfactant works to keep the lungs expanded when we exhale and increases the surface area of the lungs available for the exchange of oxygen and carbon dioxide. It is the lack of surfactant in premature babies which often results in respiratory distress.

Diagnosis

Lab tests may show signs of inflammation, such as an increased white blood cell count. Results of a test that looks for inflammation, called a sed-rate, may show non-specific elevations above normal. A chest x-ray can show the characteristic appearance of radiation pneumonitis and may suggest that you need to be treated, even if you are not having any symptoms.

Treatment

Treatment is aimed at decreasing the inflammation. Corticosteroids, such as prednisone, are given until the inflammation subsides and then slowly decreased over time. Other treatments may be used depending upon the location. For example, with radiation esophagitis, medications such as proton pump inhibitors, changes in diet, and local anesthetics to help with pain may be used.

Prognosis

Radiation pneumonitis usually resolves with treatment and is only rarely fatal. If it goes untreated or persists, it can lead to pulmonary fibrosis (scarring of the lungs), one of the possible long-term side effects of radiation therapy.

Prevention

Research is ongoing looking for ways to reduce the risk of radiation pneumonitis among people going through radiation for lung cancer. Thus far it appears that the intake of soy isoflavone (eating soy-based foods such as tofu) may decrease the risk of radiation pneumonitis. The way this occurs is through decreasing inflammation, so it's unlikely that the intake of soy-based foods would interfere with the purpose of radiation therapy—eliminating cancer cells—but it's important to talk to your radiation oncologist about this, and any other suggestions she may have about lowering your risk.

Bottom Line

Radiation pneumonitis is very common in people who are treated for cancers such as lung cancer and breast cancer. Thankfully, with treatment, the condition often resolves without going on to cause radiation fibrosis. The most important thing you can do is be aware of the possible symptoms, and talk to your doctor if you experience any of these. As a final note, many of the symptoms may overlap with symptoms of your cancer or side effects of other treatments. Always talk to your doctor about any symptoms and be your own advocate for your cancer care. You are not being a whiner or a problem patient to bring up these concerns, and your doctor will recognize, instead, that you are being an active and involved participant in your care.

Sources:

Abernathy, L. et al. Soy Isoflavones Promote Radioprotection of the Normal Lung Tissue by Inhibition of Radiation-Induced Activation of Macrophages and Neutrophils. Journal of Thoracic Oncology. 2015. 10(12):1703-12.

Hillman, G. et al. Radioprotection of lung tissue by soy isoflavones. Journal of Thoracic Oncology. 2013. 8(11):1356-64.

Kong, F. et al. Non-small cell lung cancer therapy-related pulmonary toxicity: an update on radiation pneumonitis and pulmonary fibrosis. Seminars in Oncology. 2005. 32(2 Suppl 3):S42-54.

Okubo, M., Itonaga, T., Saito, T. et al. Predicting Risk Factors for Radiation Pneumonitis after Stereotactic Body Radiation Therapy for Primary or Metastatic Lung Tumors. The British Journal of Radiology. 2017 Feb 14. (Epub ahead of print).

Palma, D. et al. Predicting esophagitis after chemoradiation for non-small cell lung cancer: an individual patient meta-analysis. International Journal of Radiation Oncology, Biology, and Physics. 2013. 87(4):690-6.

Palma, D. et al. Predicting radiation pneumonitis after chemoradiation therapy for lung cancer: an international individual patient data meta-analysis. International Journal of Radiation Oncology, Biology, and Physics. 2013. 85(2):444-50.

Yazbeck, V. et al. Management of normal tissue toxicity associated with chemoradiation (primary skin, esophagus, and lung). Cancer Journal (Sudbury, Mass). 2013. 19(3):231-7.