The side effects depend mainly on the type of radiation therapy, the dose of radiation, and the part of your body that is treated. External radiation therapy to the chest may harm the esophagus, causing problems with swallowing. You may also feel very tired. In addition, your skin in the treated area may become red, dry, and tender.

After internal radiation therapy, a person may cough up small amounts of blood.

Educational information provided by The National Cancer Institute (NCI) Internet site.