Radiation Therapy for Rectal Cancer

Our radiation oncology team uses radiation therapy to eliminate rectal tumors. This form of treatment uses high-energy beams or radioactive seeds to kill cancer cells. We use sophisticated, highly precise tools to deliver powerful doses of radiation directly to tumors while avoiding damage to healthy tissues.

Your treatment team can use radiation therapy to treat rectal cancer in variety of ways, including:

  • to shrink tumors before surgery, making it easier for the surgeon to remove them
  • in place of surgery for patients who aren’t good candidates for it
  • to relieve symptoms such as pain and blockage in the intestines in advanced metastatic rectal cancers

Our radiation oncologists work closely with our medical physicists to plan each radiation treatment. This ensures that the correct radiation dose is delivered precisely where it’s needed. Advanced technology makes it possible to eliminate rectal tumors while limiting damage to nearby healthy tissue. Depending on your condition, your treatment team can recommend a number of radiation therapies:

External-beam radiation therapy (EBRT) delivers a highly focused beam of radiation directly to the tumor. EBRT is the most common type of radiation therapy for rectal cancer treatment. It is proven to reduce the chance that the tumor will regrow in the pelvis after surgery. Newer radiation techniques can reduce radiation exposure to the pelvic bones, decreasing the risk of osteoporosis.

Intensity-modulated radiation therapy (IMRT) uses sophisticated software and 3-D images from CT scans to target tumors with greater precision than EBRT. Our radiation oncologists use IMRT to treat patients with anal cancer, low-lying rectal cancers, or rectal cancer that has come back after surgery. Anal and rectal cancer patients may also receive chemotherapy drugs that make radiation more effective.

Image-guided radiation therapy (IGRT) uses advanced imaging techniques. First, small markers are implanted in the body. Their locations are then verified using a CT scanner just before treatment, guiding the radiation delivery. IGRT is an effective treatment for recurrent cancer patients who previously had pelvic radiation therapy. Because IGRT is highly focused, therapy can take as few as three treatments.

Intraoperative radiation therapy (IORT) occurs during rectal cancer surgery. It delivers a single, concentrated dose of radiation therapy directly to the affected area using radioactive seeds. This allows your doctor to deliver an intense and highly focused dose of radiation while avoiding nearby healthy tissues. Some patients who receive IORT have already received a full dose of EBRT, so they therefore cannot safely receive more EBRT. Your treatment team may use IORT if your rectal cancer has come back in your pelvis after initial surgery and radiation therapy.

Endorectal brachytherapy involves temporarily placing radioactive material in your rectum. The highly targeted treatment minimizes radiation exposure to nearby healthy tissue. This treatment is now an option for some MSK patients whose cancer has come back but aren’t candidates for surgery.

If you qualify, your treatment team may be able to recommend one of our clinical trials as part of your overall plan of care. Clinical trials may give you access to new or experimental radiation therapies.