Radiation Therapy for Rectal Cancer

Radiation Therapy for Rectal Cancer

Our radiation oncology team uses radiation therapy to deliver high-energy beams or seeds to eliminate rectal tumors. 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
  • using radiation therapy instead of surgery for patients who aren’t good candidates for surgery
  • 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 to the tumor from a source outside your body. EBRT is the most common type of radiation therapy for rectal cancer treatment. It’s also an important treatment for patients whose rectal cancer comes back after getting radiation therapy as part of their initial treatment. 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) is a radiation therapy that uses advanced imaging techniques. Small markers are implanted in the body, whose locations are 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), which occurs during rectal cancer surgery, delivers a concentrated electron radiation beam to the affected area using a machine called a linear accelerator, allowing your doctor to use a higher, more effective radiation dose, protecting nearby healthy tissues (patients receiving IORT usually get EBRT before the operation). Your treatment team can use IORT to help patients whose rectal cancer has come back in their pelvis after initial surgery and radiation therapy.

Endorectal brachytherapy, which involves temporarily placing radioactive material in your rectum, giving you a highly targeted treatment that minimizes radiation exposure to nearby healthy tissue (this treatment is now an option for some Memorial Sloan Kettering 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.