What’s New in Gastrointestinal Carcinoid Tumor Research?

Research is always going on in the field of gastrointestinal (GI) carcinoid tumors. Scientists keep looking for the causes of, and new ways to prevent, diagnose, and treat these tumors.

Genetics

Researchers hope finding the causes of GI carcinoid tumors can be used to help prevent or treat them in the future. For example, the IPMK gene (the gene associated with a small intestinal neuroendocrine tumor that runs in families) has now been found in people with GI carcinoid tumors who might not have a family history of small intestinal neuroendocrine tumors. Other genetic changes that seem to make tumors more aggressive are now being explored as well.

Diagnosis and staging

Because the outlook and treatment of GI carcinoid tumors and other cancers of the digestive tract are very different, accurate diagnosis is important. Tests that can detect specific substances found in the cells of carcinoid tumors are being developed. Most of these tests treat tissue samples with special, man-made antibodies. The antibodies are designed to recognize specific parts of proteins that appear only in certain types of tumors.

In the past few years, a new imaging test called a Gallium-68 PET/CT Dotatate scan has been approved to look for GI carcinoid tumors in the body. This scan appears to find carcinoid tumors better than the Octreoscan. Researchers are now looking at other imaging methods to see if they can detect carcinoid tumors early.

Treatment

Surgery is the main treatment for carcinoid tumors that can be removed. Sometimes, removing the bulk of the carcinoid can also reduce the severity of the carcinoid syndrome. But better approaches are needed when surgery can’t remove all of the tumors. Chemotherapy has had limited success. New chemotherapy drugs and combinations of drugs are being studied, but true advances are likely to come from other approaches.

Targeted therapy

Several newer types of drugs, known as targeted therapies, are now being studied for use against neuroendocrine tumors. Targeted therapy are drugs or other substances that identify and attack cancer cells while doing little damage to normal cells. These therapies attack the parts of cancer cells that make them different from normal, healthy cells. Each type of targeted therapy works differently, but all can change the way a cancer cell grows, divides, repairs itself, or interacts with other cells.

Bevacizumab (Avastin^®) is a type of targeted drug that attacks a tumor’s blood supply. It is already being used against some types of cancer and is being studied for carcinoid tumors.

Other targeted therapies block the molecules that increase the growth of cancer cells. Some of these (such as erlotinib, temsirolimus, and sorafenib) are used in other types of cancer and are now being tested for use against carcinoids.

Netazepide is new drug that blocks the hormone gastrin. In early studies of patients who have carcinoid tumors of the stomach and high gastrin levels, this drug helped the tumors shrink. More studies are planned.

Immunotherapy drugs are showing promise in many cancer types. A new immune checkpoint inhibitor, RRx-001, is a next generation immunotherapy drug that affects many parts of the immune system to kill cancer cells and is being studied in people with carcinoid tumors.

The FDA has approved a newer, more improved radionuclide treatment for patients with advanced, worsening GI carcinoid tumors that have the somatostatin protein. This treatment takes Lu-177-Dotatate (a radioactive substance) which attaches to carcinoid tumors with the somatostatin protein and then releases small doses of radiation to kill the cancer cells.