Everyone responds to radiation therapy differently. The location of your cancer, your general health, and other treatments you are receiving such as chemotherapy all play a role in how you will feel during your treatment. Some people notice very few symptoms, whereas others find these symptoms more bothersome.
Radiation therapy is a local treatment, and therefore most symptoms arise in the area that is being treated. In the case of lung cancer, it is the chest. New technology is allowing radiation to be delivered more precisely to tumors, lowering the chance that side effects will occur. Studies are in process to develop further ways to protect healthy cells against radiation.
Short-term side effects often show up within the first few weeks of treatment, and resolve soon after treatment is completed. Long-term side effects can sometimes appear months or even years after treatment. It is good to keep in mind the benefits of treatment when looking at possible side effects, and to discuss these with your radiation oncologist.
Short-Term Side Effects:
Within a few weeks after beginning radiation therapy, your skin overlying the treatment area may become red and irritated. This is sometimes followed by dryness and peeling 2 to 3 weeks later. As your skin heals, it may appear darker, like a suntan. This usually resolves within a few weeks of finishing therapy, although some darkening of your skin may remain. Special care should be given to avoid sunburn. Limiting the use of lotions and creams that may contain irritating chemicals, and avoiding extremes of hot or cold are also important to prevent further irritation to the skin.
Hair loss can occur, but only in the region where radiation is given, usually the chest with lung cancer.
Cough/Shortness of breath
Radiation therapy lowers the level of the lung's surfactant, a substance that helps the lungs expand. This can result in a dry cough or shortness of breath. Occasionally, steroids are given to ease these symptoms.
Most people feel some degree of fatigue during radiation therapy. This usually begins a few weeks after the start of therapy and tends to worsen with time. It usually subsides 6 to 8 weeks after you complete therapy. Many people are able to continue their daily routine during radiation therapy, but it is important to get plenty of sleep at night and allow yourself rest periods during the day as you need.
Since the esophagus (the tube leading from the mouth to the stomach) travels through the chest, radiation to lungs can cause it to become irritated. Pain or difficulty with swallowing, heartburn, or a sensation of a lump in the throat can occur. Symptoms usually occur 2 to 3 weeks into therapy and subside a few weeks after completing treatments.
Long-Term Side Effects:
Radiation pneumonitis is an inflammatory response of the lungs to radiation, which can occur 1 to 6 months following the completion of radiation treatments and is often treated with a short course of steroids. Symptoms include a fever, cough, shortness of breath, and particular changes seen on chest x-rays. Roughly 5% to 15% of individuals develop this symptom, and in most cases, it resolves over time.
Pulmonary fibrosis refers to the formation of scar tissue in the lungs that can occur for many reasons, including radiation therapy for lung cancer. Symptoms include shortness of breath and a decreased ability to exercise.
In some cases, radiation to the chest can cause damage to the heart muscle. This is most common when high doses of radiation are used for tumors and lymph nodes involving the mediastinum, the area between the lungs near the heart.
A potential side effect of radiation therapy is the occurrence of a second cancer down the line due to the cancer-causing effect of radiation. With lung cancer, leukemia can occur rarely as a second cancer 5 to 10 years after completing therapy. Secondary cancers involving the lung or breast can also occur, usually appearing at least 10 years after treatment.
Abratt, O. and G. Morgan. Lung toxicity following chest irradiation in patients with lung cancer. Lung Cancer. 2002. 35:109.
American Cancer Society. Second Cancers Caused By Cancer Treatment. 01/30/12. http://www.cancer.org/Cancer/CancerCauses/OtherCarcinogens/MedicalTreatments/SecondCancersCausedbyCancerTreatment/second-cancers-caused-by-cancer-treatment-intro
National Cancer Institute. Radiation Therapy and You: Support for People With Cancer. Radiation Therapy Side Effects. Updated 04/20/07. http://www.cancer.gov/cancertopics/radiation-therapy-and-you/page6
Prosnitz, R. et al. Cardiac toxicity following thoracic radiation. Seminars in Oncology. 2005. 32(2 Suppl 3):S71-80.