The document discusses cancer of the colon and rectum, including treatment options and side effects of treatment. It describes how rectal cancer is staged based on depth of penetration and lymph node involvement. Radiation therapy can help expand the surgical resection volume for some rectal cancers. The document includes images and descriptions of male and female pelvic anatomy, as well as CT, PET, and portal images related to imaging and radiation treatment planning for rectal cancer. It discusses techniques to minimize side effects of pelvic radiation and palliative uses of radiation for recurrent or metastatic disease.