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An Overview of Gastrointestinal and Colorectal Cancer

Purpose of the Gastrointestinal Organs

The organs of the gastrointestinal tract are primarily involved in digestion, which is the conversion of food into energy. Digestion begins with the mixing of food and saliva in the mouth. The food travels from the mouth to the stomach through the esophagus, a hollow, muscular tube that passes through the neck. Chemical breakdown of food into smaller molecules takes place in the stomach and small intestines. The liver and pancreas secrete chemicals called enzymes that assist with this process. The gallbladder stores bile, one of the enzymes created by the liver. The large intestine, which consists of the colon and rectum and ends in the anus, is responsible for the removal of solid waste, which is created as a byproduct of digestion.

A view of the gastrointestinal organs
A view of the gastrointestinal organs (click to enlarge)

Cancer in the Gastrointestinal System

Cancers in this system are referred to as either gastrointestinal cancers or colorectal cancers, depending on where they originate and include:

Two genetic diseases that are considered precursors to colon cancer are:

Stanford's Expertise in Gastrointestinal and Colorectal Cancer

The Stanford Gastrointestinal Cancer Program of the Stanford Cancer Center offers a treatment expertise and a multi-specialty team approach for patients with all of these cancers.

Team Approach to Care: Tumor Boards

The Gastrointestinal (GI) Cancer Program offers focused expertise in radiology, interventional radiology, radiation oncology, medical oncology, pathology, and gastroenterology (including hepatology). As part of Stanford's team approach to care, Stanford's physicians participate in a multi-specialty GI Cancer Tumor Board, and a multi-specialty Liver Tumor Board. These weekly meetings allow experts to provide a thorough and collaborative review of patient records, laboratory studies, radiographs, and pathology.

Advanced Technology

Stanford's physicians in the GI Cancer Program are leaders in their subspecialty fields and have access to the most advanced technologies available. Stanford's programs and expertise include:

Diagnostic Radiology

Virtual endoscopy (including virtual colonoscopy and virtual bronchoscopy) allows doctors to explore internal structures in non-invasive ways using advanced imaging technology and computer algorithms.

Multislice CT scanner (computerized tomography) scanner takes four simultaneous images and facilitates

3-D reconstruction for ultra fast and sensitive tumor imaging.

PET/CT which can increase sensitivity in accurate diagnosis and disease staging.

3T MRI, which uses a magnet twice the size of standard for imaging with high resolution that can allow precise preoperative treatment planning.

Radiation Oncology

Intensity modulated radiation (IMRT) reduces the dose of radiation received by healthy tissue and can allow doctors to deliver radiation to difficult-to-reach areas.

3-D conformal radiation, a technology in some ways similar to IMRT, uses computer-guided radiation to precisely deliver high doses of radiation with fewer side effects.

Intraoperative radiotherapy (IORT) that allows doctors to deliver a high dose of radiation to the tumor site while a patient is still in the operating room during surgery. One-time IORT is more convenient than traditional radiotherapy and reduces the exposure of healthy tissues to radiation. In addition, the precision of IORT allows us to treat tumors that are considered inoperable.

Stereotactic Body Radiation Therapy (SBRT) evolved from work pioneered at Stanford, including the development of stereotactic radiation techniques using CyberKnife, Trilogy, and TrueBeam linear accelerators. These are advanced stereotactic radiosurgery devices that use computer technology to deliver radiation therapy with unprecedented precision.


GI surgical oncologists provide skilled management of rare or complex cases where coordination of services and good communication among subspecialists is critical. This is especially important for newly diagnosed patients requiring involvement of surgeons as well as radiation and medical oncologists.

In addition, the GI Program offers the most advanced laparoscopic procedures, including laparoscopic esophageal and colorectal surgery. These minimally-invasive procedures cause patients less pain and provide faster recovery times.

Targeted Therapies

Stanford's medical oncologists have been instrumental in developing "targeted" therapies for cancer. Unlike treatments such as radiation and chemotherapy, targeted therapies are engineered to preferentially target and kill cancerous cells, minimizing toxicity to healthy tissue.

The very first monoclonal antibody (Rituxan®) was administered to a cancer patient at Stanford.

We also designed and participated in several of the key trials that led to the widespread use of targeted therapies for different gastrointestinal cancers, including:

We are currently conducting trials of targeted agents in gastroesophageal, colorectal, pancreatic, GI stromal, and neuroendocrine tumors.

We are expanding our immunotherapy program and are conducting trials which harness the body’s natural tumor surveillance mechanisms as anti-cancer therapy.

Genetic Analysis and Counseling

Gastrointestinal cancers sometimes runs in families and is caused by alteration of genes. If multiple people in a patient's family have been diagnosed with these cancers, it is standard to refer for evaluation by genetic counselors that specialize in specific genetic mutations or syndromes (e.g., familial adenomatous polyposis syndrome (FAP), hereditary non-polyposis colorectal cancer (HNPCC, Lynch).

If one of these syndromes is identified, his or her treatment plan will be tailored, often with specific treatments and monitoring schedules.

Learn More about Treatment for Specific Diseases at Stanford

Learn more about innovative treatments at Stanford:

See Also:

Clinical Trials and Research in Gastrointestinal Cancer


Stanford Medicine Resources:

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