The goal of radiation therapy for colorectal cancer is to destroy or disrupt the growth of cancerous cells. For treating rectal cancer, radiation therapy is commonly used in conjunction with chemotherapy, which can make radiation more effective, either before or after surgery. When administered before surgery, it can reduce the size of a tumor to facilitate removal; when given after surgery, it can help prevent cancer recurrence. Radiation therapy is used less often for the treatment of colon cancer, unless the cancer has spread to the stomach lining or another nearby organ, or has metastasized to the bones or brain (this is rare). Additionally, it may be used to help control inoperable cancers or ease symptoms caused by tumors, such as intestinal blockages.
Moffitt Cancer Center offers several different types of radiation therapy for colorectal cancer, including:
External beam radiation therapy – Using a machine called a linear accelerator, which is located outside a patient’s body, a radiation oncologist focuses high-energy beams using predetermined measurements and angles to ensure precise delivery and an accurate dosage. The procedure is virtually painless, and each treatment lasts only a few minutes. Treatments are typically given five days a week for several weeks.
Brachytherapy (internal radiation therapy) – A catheter containing small radioactive seeds or pellets is placed at or near a cancer site. Because the radiation travels only a short distance, damage to surrounding healthy tissue is minimized. This can be performed as a one-time procedure, or a few times a week over the course of several weeks.
Novalis® radiosurgery – High-energy beams are precisely shaped around a tumor, allowing for the delivery of high dosages while protecting the surrounding healthy tissue from the side effects of radiation therapy.
Endocavitary radiation therapy – Mainly used for treating small rectal tumors, this type of treatment involves the insertion of a small device through the anus into the rectum to deliver high-intensity beams to a tumor for a few minutes. Because the radiation can reach the rectum without passing through skin or abdominal tissue, the risk of side effects is reduced. Treatment is typically administered in four sessions scheduled at two-week intervals.
Radioembolization – To reduce the flow of blood to cancerous cells in the liver, which is what causes tumor growth, small beads coated with yttrium-90 are injected into the hepatic artery. The beads become lodged in the blood vessels near the tumor and emanate small amounts of radiation for several days.
Moffitt also has a robust clinical trials program through which we evaluate groundbreaking new therapies that are not yet available in other settings, and our patients can be among the first to benefit from these promising treatment options. In addition to being nationally recognized for leading-edge research, Moffitt is well known and respected for developing highly individualized cancer treatment plans that improve patient outcomes and quality of life.
If you’d like to learn more about colorectal cancer radiation therapy, the experts at Moffitt can help. Call 1-888-663-3488 or complete a new patient registration form online. No referrals are required.