GI NET Treatments
GI neuroendocrine tumors (NETs), the most common type being carcinoid tumors, are diagnosed in an estimated 11,000 to 12,000 people each year in the U.S. and can arise in the stomach, small intestine, rectum, colon and liver.
Carcinoid tumors are rare, slow-growing tumors that originate in cells of the diffuse neuroendocrine system. They occur most frequently in tissues derived from the embryonic gut. Fore-gut tumors, which account for up to 25 percent of cases, arise in the lung, thymus, stomach, or proximal duodenum. Mid-gut tumors, which account for up to 50 percent of cases, arise in the small intestine, appendix, or proximal colon. Hind-gut tumors, approximately 15 percent of cases, arise in the distal colon or rectum. Other sites of origin include the gallbladder, kidney, liver, pancreas, ovary and testis.
There are four standard therapies: surgery, chemotherapy, radiation therapy and hormone therapy.
Surgery and Other Procedures
Treatment of GI carcinoid tumors usually includes surgery. One of the following procedures may be used:
Endoscopic resection: Surgery to remove a small tumor that is on the inside lining of the GI tract. An endoscope is inserted through the mouth and passed through the esophagus to the stomach and sometimes, the duodenum. An endoscope is a thin, tube-like instrument with a light, a lens for viewing, and a tool for removing tumor tissue and a small amount of normal tissue around it.
Resection: Surgery to remove part or the entire organ that contains cancer. Nearby lymph nodes may also be removed.
Cryosurgery: A treatment that uses an instrument to freeze and destroy carcinoid tumor tissue. This type of treatment is also called cryotherapy. The doctor may use ultrasound to guide the instrument.
Radiofrequency ablation: The use of a special probe with tiny electrodes that release high-energy radio waves (similar to microwaves) that kill cancer cells. The probe may be inserted through the skin or through an incision in the abdomen.
Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer. The way the radiation therapy is given depends on the type and stage of the cancer being treated.
Radiopharmaceutical therapy is a type of radiation therapy. Radiation is given to the tumor using a drug that has a radioactive substance, such as iodine I 131, attached to it. The radioactive substance kills the tumor cells.
Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping the cells from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the cerebrospinal fluid, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy).
Chemoembolization of the hepatic artery is a type of regional chemotherapy that may be used to treat a gastrointestinal carcinoid tumor that has spread to the liver. The anticancer drug is injected into the hepatic artery through a catheter (thin tube). The drug is mixed with a substance that embolizes (blocks) the artery, and cuts off blood flow to the tumor. Most of the anticancer drug is trapped near the tumor and only a small amount of the drug reaches other parts of the body. The tumor is prevented from getting the oxygen and nutrients it needs to grow, while the liver continues to receive blood from the hepatic portal vein, which carries blood from the stomach and intestine.
Hormone therapy with a somatostatin analogue is a treatment that stops extra hormones from being made. GI carcinoid tumors are treated with the drug, which are injected under the skin or into the muscle, and may help stop tumor growth.
Different combinations of therapies may be used depending on the stage of the cancer and the health of the patient. New combinations of therapies are always being tested in clinical trials and are available at Siteman Cancer Center before other places may have access to them. Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells without harming normal cells. Several types of targeted therapy are being studied in the treatment of GI carcinoid tumors.