Fight Gastrointestinal Cancer
with Laser-like Precision

Proton Therapy for Gastrointestinal Cancer

California Protons’ intensity-modulated pencil beam scanning technology is a highly precise form of cancer radiation treatment that enables our doctors to selectively target gastrointestinal (GI) tumors found in the intricate and sensitive areas of the digestive tract with high-dose radiation.

Compared with older passive-scattering proton therapy treatment, our pencil beam scanning technology precisely delivers radiation treatment for stomach, rectal, anal, colon and other lower GI tumors within 2 millimeters and with the utmost care. We attack tumors layer by layer and minimize harmful exposure to surrounding healthy tissue and organs. This is important as these gastric and colorectal tumors typically require aggressive doses of radiation and are located near healthy tissues and organs that are extremely susceptible to radiation. The reduction of radiation-related toxicity minimizes the side effects of radiation and also increases the likelihood that patients can complete treatment with fewer interruptions or delays.

Gastrointestinal Cancer
Treatment Details

What We Treat

  • Colon cancer
  • Rectal cancer
  • Anal cancer
  • Gastric or stomach cancer
  • Select recurrent cancer and metastatic cancer

What We Do

  • Target the tumor only
  • Protect your bladder, small and large intestine, stomach, kidneys, genitals and spinal cord
  • Maintain your quality of life during treatment
  • Reduce side effects of radiation therapy, including nausea, vomiting, heartburn, cramping, malabsorption (inability to absorb nutrients from food), diarrhea, dehydration and sexual dysfunction
  • Lower the risk of secondary cancer due to radiation

Benefits of Proton Therapy for Gastrointestinal Cancer

  • Our pencil beam scanning technology precisely controls protons to place the Bragg peak—the point at which they deposit their maximum energy—directly in the tumor. This allows us to treat more complex tumor shapes and vary the dose within the tumor.
  • Advanced proton therapy allows doctors to more selectively deliver high-dose radiation to colorectal tumors and cancerous cells found in the digestive tract, and reduce the dose to surrounding healthy tissues and critical organs. In some cases, this has been shown to deliver higher cure rates than X-ray radiation treatment even in some of the most challenging situations.
  • Because proton therapy can better concentrate its radiation dose to the target and limit it elsewhere, doctors can minimize radiation to healthy tissues around the tumor that can affect your ability to digest and metabolize nutrients and rid your system of waste.
  • Specialized techniques can be used with proton therapy to target a moving tumor with great technical precision. This is important for gastrointestinal cancer patients being treated for stomach cancer.
  • Unlike with older technology, the treatment plan can be loaded into the computer and completed within a matter of minutes. Treatments are also noninvasive and convenient so patients can get back to their daily activities quicker.

Proton Therapy
Right for You?


Combined treatments of surgery, chemotherapy and radiation have become the standard treatment for a vast majority of gastrointestinal cancers. Depending on the stage, location and type of cancer, treatment options and risk of side effects may differ. Treatment options are also affected by age, overall health and personal preferences.

Also referred to as gastric cancer, stomach cancers develop in the stomach and are measured by how deep the cancer has spread into the 5 layers of the stomach wall and if there has been spread of disease to the adjacent lymph nodes. Stomach cancer sometimes requires radiation therapy following surgery. Depending on the stage of the tumor, the patient’s overall health status and the extent of surgery, proton therapy can be given concurrently with chemotherapy.

This type of cancer affects parts of the large intestine. Depending on the stage of cancer, radiation therapy for these type of cancers is often given prior to or following surgery. If the cancer has spread widely past the colon wall, proton therapy may be used to shrink tumors widely past the rectal wall or control pain.

Anal cancer is typically a squamous cell carcinoma that arises at the exterior opening of the gastrointestinal tract. This type of cancer is most commonly treated with radiation therapy given concurrently with chemotherapy. Due to its location, chemoradiation is the primary treatment option, instead of surgery, and proton therapy can provide a less toxic radiation treatment that can reduce side effects and damage to surrounding tissues.

Colon cancer forms in your large intestine. Surgery is the most common treatment, especially in stage I and II when the cancer has not yet spread. Chemotherapy is also recommended in more advanced stages of cancer. Proton therapy can also be recommended to help control the cancer.

Treatment for
Recurrent Cancer

Proton therapy is often the best way to treat recurrent tumors in areas that have previously been treated with radiation therapy.

Treating previously irradiated areas can be challenging, especially in the gastrointestinal area. A second round of X-ray radiation treatment could be too dangerous as the healthy tissues around the recurrent tumor do not fully “forget” the previous radiation dose, and any added dose continues to increase the risk of normal tissue injury. Proton beam therapy may enable doctors to better concentrate the dose to the target and limit it elsewhere, allowing re-treatment with radiation in select patients.


Treatment Outcomes &
Long-Term Effects

Proton therapy treatment at California Protons Cancer Therapy Center in San Diego may offer similar outcomes to standard X-ray radiation, while reducing long-term and potentially life-threatening side effects such as ulceration, perforation and internal bleeding due to radiation damage to the digestive tract and pelvis area. It may also lower chances for secondary cancers later in life due to the reduced radiation exposure to your surrounding healthy tissues and organs.

However, all cancer treatments have advantages and disadvantages. Be sure to discuss all of the potential risks, as well as treatment options, with your oncologist.

About Proton Therapy

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