Can radiation therapy cause bleeding?

It's possible: The side effects of radiation are dependent on the area of the body that is being treated. It is possible that radiation could cause some bleeding long term, for example, from the rectum following prostate radiation. However, with newer radiation techniques such as imrt this risk is very small now.

Yes: Often radiation is used to stop bleeding, such as coughing up blood from a lung cancer, or bleeding from the vagina from a cervix or vaginal cancer. However if the skin in an area peels excessively or the linings of the oral or intestinal tract such as the rectum can bleed temporarily and often heal. However long term changes can lead to periodic bleeding from an area such as the rectum.