Liver-Directed Therapies for Metastatic GISTs and Gastric Neuroendocrine Tumors (NETs)

Treatment options for GISTs or gastric NETs may include liver-directed therapies. As you navigate through your treatment plan, your doctors may provide you with a lot of new information, and it’s normal to feel overwhelmed. However, it’s essential to understand what liver-directed therapies are and how they work. By doing so, you can better prepare yourself for treatment and have informed discussions with your cancer care team. This can help you feel more in control of your health and alleviate some of the anxiety that may come with the treatment process.

This image may contain content that could be offensive or disturbing to some individuals. Tap to reveal the image.

One of the most common sites of cancer spread in GISTs and NETs is the liver. If there are only one or two tumors in the liver, they would ideally be removed with surgery. However, if there are more than just a few of them, safely removing these liver tumors may not be possible without endangering your liver or your health. In these situations, your doctors may recommend liver-directed therapies to destroy as much tumor tissue as possible and reduce the tumors’ production of hormones. The latter may occur in the case of gastric NETs that release the hormone histamine, causing symptoms such as atypical flushing and itching.

Liver-directed therapies are generally used for GISTs and NETs that:

• despite previous treatments, have spread to the liver as several small tumors,
• after systemic good systemic control, local therapies can be used to get better control of lesions and consolidate good responses,
• cannot be removed with surgery (unresectable) due to your overall health or the size and number of tumors, and
• are giving rise to symptoms caused by the size of the tumors or the hormones produced by them (carcinoid syndrome).
  

Also called locoregional therapies or interventional radiology (IR) procedures, the aims of these treatments are to slow cancer progression, relieve any symptoms and improve your quality of life. Over the course of your care, you may receive liver-directed therapy many times. In fact, it is normal to even switch among the various types of liver-directed therapies.

There are two broad types of liver-directed therapies used in the treatment of GISTs and gastric NETs that have spread to the liver.

Ablation

Ablation is a treatment technique that uses chemicals or extreme heat or cold to kill cancer cells. Because ablation can destroy some healthy tissue surrounding the tumor, it is typically used to treat tumors that are not located near vital structures such as major blood vessels or ducts in the liver.

> Find out more about the different types of ablation therapy here

Embolization

Embolization is a liver-directed therapy involving the injection of substances into your blood vessels to stop or reduce the blood supply to cancer cells in the liver. This starves the tumor of oxygen and nutrients, which are delivered via the blood vessels, thereby destroying the cancer cells.

Embolization is commonly used for larger tumors located deep in the liver, where your surgeon is unable to remove the tumors without risking the liver’s blood supply.

> Find out more about the various types of embolization here

If you have any questions regarding liver-directed therapies and whether they can help in your treatment, please speak to your doctors and cancer care team. They may run some scans and tests to find out if liver-directed therapies are suitable for you and which type would be most effective in the treatment of your metastatic GISTs and NETs.

Stereotactic Body Radiation Therapy (SBRT)

SBRT is a form of external body radiation therapy that delivers very precise and intense radiation doses to kill cancer cells. It is an important method of treating tumors that have metastasized to the liver.

Radiation oncologists first use computerized systems and imaging scans to map the exact size, shape and location of the liver tumor(s). Subsequently, they develop a customized treatment plan that sets the angles and intensities of the radiation beams to ensure they are tailored to the three-dimensional outline of the tumor(s). In this way, by focusing the radiation on the tumor, SBRT can slow its growth while minimizing damage to nearby healthy tissues and lowering the risk of side effects.

During the procedure itself, you will lie down on a treatment table under a large machine. This machine emits high doses of radiation beams that are precisely directed at the liver, where the tumor(s) is located. Imaging technology on the machine ensures that the targeted area does not shift during the treatment session. SBRT is usually performed in one to five sessions that can be done over one to two weeks, with each session taking about 30 minutes to two hours.