Colorectal Cancer


Colorectal cancers are cancers of the colon and rectum. They are sometimes diagnosed through screening (colonoscopy) and at other times because of symptoms that include abdominal discomfort, change in bowel habits, bloody stools, and unexplained weight loss. Most colorectal cancers are adenocarcinomas, a type of cancer that that originates in a gland or has glandular characteristics. Colorectal cancers are primarily treated through surgical removal, but treatment also involves treating cells throughout the body (systemic therapy), with chemotherapy, and/or with radiation therapy.

Radiotherapy for Colorectal Cancer

Radiotherapy is a treatment that uses targeted, high-energy x-rays from a machine to kill cancer cells. Radiation works by damaging the DNA inside cells, making them unable to divide and grow.

Radiation therapy is often used in the treatment of rectal cancer. It is sometimes given prior to surgical removal of the cancer and sometimes following surgical removal. Treatment sessions are done on an outpatient basis 5 days a week over a period of 5 to 6 weeks. Please see our Guide to Radiotherapy.

Radiotherapy can have side effects, and these vary from person to person. They include:

  • Diarrhea
  • Fatigue
  • Urinary irritation

Your Team

Your treatment at the Precision Radiotherapy Center is led by radiation oncologists who have specific expertise in treating patients with cancers of the colon and rectum.  They are part of a multidisciplinary gastrointestinal team, which also includes colorectal surgeons, gastroenterologists, medical oncologists, diagnostic radiologists and pathologists. This team meets on a weekly basis to discuss cases of newly diagnosed patients and to recommend a treatment strategy.

Patients treated at Precision Radiotherapy may qualify for participation in clinical trials that are exploring promising new treatments.

Learn more