Radiation Therapy for Colorectal Tumors

  • Garin Tomaszewski, MD, part of the colorectal radiology team at RPCI, works with the latest in cutting-edge technology and treatments.

Colon cancer is typically treated with surgery and chemotherapy, however radiation therapy (or radiotherapy) may be an important part of the treatment plan for some patients with advanced disease. Radiotherapy treatments may also be used as palliative care, to ease cancer symptoms.

The Roswell Park Department of Radiation Medicine offers the latest in cutting-edge technology and treatments, some of which are unavailable elsewhere in Western New York. We have a full-time multidisciplinary staff of radiation oncologists, dosimetrists, physicists, radiation therapists and more.

Radiation therapy uses high-energy x-rays to kill cancer cells. The radiation overwhelms cancer cells with oxidizing molecules that disrupt important cell functions and damage the cancer cells’ DNA so that the cells’ functions are out of balance and they die. Because normal cells are better able to make antioxidants that neutralize the oxidation and detoxify themselves, they are more resistant to the radiation.

Radiation therapy for colorectal cancers may be delivered in different ways, including:

  • External Beam Radiation Therapy (EBRT): This is the most common method of delivering radiation for treatment of colorectal cancer. Radiation is usually delivered over 25-28 treatments and can be done in several ways, each with their own advantages.
  • 3-Dimensional Conformal Radiation Therapy (3D CRT): This is a form of EBRT where a few shaped radiation beams are aimed at the cancer target from different directions.
  • Volumetric Modulated Arc Therapy (VMAT): A more precise form of EBRT than 3D CRT, where the radiation dose is given and the field shape is changed continuously as the treatment machine moves, or arcs around the patient. This treatment helps to spare more normal tissue.