Targeted Therapy for Gastric Neuroendocrine Tumors

If you’ve been diagnosed with a gastric neuroendocrine tumor and are discussing treatment options with your cancer care team, you may have heard of targeted therapy. Your doctors may even recommend it as part of your treatment plan. While all this new information about targeted therapy can leave you feeling confused and overwhelmed, understanding how this type of treatment works is very useful. Not only will it help you stay on top of medical discussions, but it can prepare you for what to expect during your treatment journey.

Neuroendocrine tumors (NETs) are rare cancers that can occur anywhere in the body. Those that originate from neuroendocrine cells located in the mucosal lining of the stomach are called gastric NETs. These specialized cells produce hormones that control the release of gastric juices and how quickly food moves through the stomach.

Targeted therapy is a type of cancer treatment that uses drugs specifically designed to identify and attack cancer cells while limiting damage to healthy cells. It works by targeting the specific genes, proteins and tissue environments that are unique to NETs and play a vital role in their uncontrolled growth and survival. By inhibiting these targets, drugs used in this type of treatment can interfere with the cancer’s growth and spread within the body.

Thus far, only one targeted drug has been approved for use in the treatment of metastatic gastric NETs: everolimus. Everolimus works by targeting a protein called mechanistic target of rapamycin (mTOR).

mTOR is part of a signaling pathway within the cells. In normal conditions, it is responsible for regulating multiple cellular processes, such as cell growth and survival. However, as a result of mutations (changes or alterations) in the DNA, the mTOR protein is hyperactive in many cancers, including NETs. This encourages tumor angiogenesis and the uncontrolled growth of cancer cells while suppressing cell death. By blocking the cancer-promoting effects of mTOR in the cancerous neuroendocrine cells, everolimus is thus able to slow tumor growth.

Everolimus is usually given in the form of a pill that you take every day.

In the case of gastric NETs, targeted therapy with everolimus is typically used for grade 1 and 2 gastric tumors that are well-differentiated (the cancer cells look similar to normal cells) and advanced (cannot be removed surgically or have spread to other parts of the body).

If your gastric NET has spread to nearby locations such as the lymph nodes, surgery is first done to remove as much tumor tissue as possible. Afterwards, if the entire tumor cannot be removed at the point of surgery, you may receive targeted therapy to control the growth of any remaining cancer cells. If the cancer has spread to distant organs like the liver and cannot be removed with surgery, you may be given targeted therapy in conjunction with other treatments to slow tumor growth and control the course of your condition.

Clinical trials are currently exploring other therapies that can target processes, such as tumor angiogenesis and specific survival pathways, which are implicated in the progression of NETs. This includes small molecule tyrosine kinase inhibitors and other mTOR inhibitors. If you have any questions regarding targeted therapy and how it can help in the treatment of your gastric NET, please talk to your doctors and cancer care team.