Radiation therapy uses high energy X-rays to help kill cancer cells, but in most cases, it isn’t as effective as a stand-alone therapy. For that reason, it’s often used in combination with chemotherapy and surgical options. It can be given before surgery (neoadjuvant therapy) to shrink the size of a tumor and preserve the sphincter, or after surgery (adjuvant therapy) to destroy any remaining cancer cells and decrease the risk of tumor recurrence.
Progressive radiation treatments include:
- Proton beam cancer treatment (proton therapy) – an advanced form of radiation therapy that delivers higher doses of radiation directly to the tumor. This results in more precise treatment and fewer side effects. Loma Linda University Health was the first hospital-based treatment center in the world to offer proton therapy.
- Proton-based stereotactic body radiotherapy (SBRT) – used to deliver more precise radiation, while saving healthy surrounding tissue. SBRT is also used when there is a recurrence of cancer, where standard radiation treatment could not be used again.
- Intensity-modulated radiation therapy (IMRT) – used to precisely target lower GI tumors. IMRT delivers high-dose radiation to the tumor and reduces damage to healthy tissues in the small bowel, bladder, genitalia, skin and bone marrow.
How does radiation therapy work?
Radiation therapy uses a machine like the one below to find and destroy cancer in your body.

Our radiotherapy system allows us to locate, target and shrink tumors with pinpoint precision. Based on the location of your tumors, we create a custom radiation treatment plan, optimized by advanced computer software. The colorful image below shows an example of a treatment plan near a patient's pelvis. The red lines represent bullseyes close to the tumors and correspond with more intense radiation treatment. The blue-green areas on the outer edges of the pelvis will receive less intense radiation.

With an optimized plan, we use radiation treatment to kill the cancer cells inside your tumors. Using radiation beams finely tuned to your body and each tumor, our radiotherapy system delivers accurate, high-dose treatment. Because the system is so precise, we can avoid damage to the healthy tissues around a tumor. The end result is powerful, fast and comfortable radiation therapy that helps you fight colorectal cancer.