Radiation therapy uses high-energy rays (such as x-rays) or particles to kill cancer cells. External beam radiation therapy (EBRT) delivers radiation from outside the body that is focused on the cancer. This is the type of radiation therapy most often used to treat small cell lung cancer.

In small cell lung cancer (SCLC), radiation therapy may be used in several situations:

• It is most often given at the same time as chemotherapy in limited stage disease to treat the tumor and lymph nodes in the chest. After chemotherapy, radiation therapy is sometimes used to kill any small deposits of cancer that may remain.

• It can be used to shrink tumors to palliate (relieve) symptoms of lung cancer such as bone pain, bleeding, trouble swallowing, cough, shortness of breath, and problems caused by brain metastases.

• In limited SCLC, it is often given to the brain after other treatments, to help reduce the chances that the cancer will spread there. (The brain is a common site of metastasis.) This is called prophylactic cranial irradiation.

Before your treatments start, the radiation team will take careful measurements to find the correct angles for aiming the radiation beams and the proper dose of radiation. Radiation therapy is much like getting an x-ray, but the radiation is more intense. The procedure itself is painless. Each treatment lasts only a few minutes, although the setup time -- getting you into place for treatment -- usually takes longer. Most often, radiation treatments are given once or twice daily, 5 days a week for several weeks.

Standard (conventional) EBRT isn't used as much as it used to be. Newer techniques allow doctors to be more accurate in treating lung cancers while lowering the radiation exposure to nearby healthy tissues. These techniques may offer better chances of increasing the success rate and reducing side effects.

Three-dimensional conformal radiation therapy (3D-CRT): 3D-CRT uses special computer programs to precisely map the location of the tumor(s). Radiation beams are shaped and aimed at the tumor(s) from several directions, which makes it less likely to damage normal tissues. Most doctors now recommend using 3D-CRT when it is available.

Intensity modulated radiation therapy (IMRT): IMRT is an advanced form of 3D therapy. It uses a computer-driven machine that moves around the patient as it delivers radiation. Along with shaping the beams and aiming them at the tumor from several angles, the intensity (strength) of the beams can be adjusted to minimize the dose reaching the most sensitive normal tissues. This technique is used most often if tumors are near important structures such as the spinal cord. Many major hospitals and cancer centers are now able to provide IMRT.

Possible side effects of radiation therapy

Side effects of radiation therapy might include sunburn-like skin problems where the radiation enters the body, nausea, vomiting, and fatigue. Often these go away after treatment. Radiation might also make the side effects of chemotherapy worse.

Chest radiation therapy may cause some damage to your lungs, which might eventually cause problems breathing and shortness of breath. Your esophagus, which is in the middle of your chest, may be exposed to radiation, which could cause trouble swallowing during treatment. This usually improves shortly after treatment is over.

Radiation therapy to large areas of the brain can sometimes causes changes in brain function. Some people notice memory loss, headaches, trouble thinking, or reduced sexual desire. Usually these symptoms are minor compared with those caused by a brain tumor, but they can reduce your quality of life. Side effects of radiation therapy to the brain usually become most serious 1 or 2 years after treatment.

For more general information about radiation therapy, please see the separate document, Understanding Radiation Therapy: A Guide for Patients and Families.

Last Medical Review: 10/13/2009
Last Revised: 10/13/2009