Treatment Options for Carcinoid Tumors

Management of Metastatic Disease in Carcinoid Tumor

A significant percentage of carcinoid tumor metastases occur in the liver and these usually arise from midgut tumors since the blood supply connects directly from the small intestines to the liver via the portal vein. There are several types of surgery that may be performed in order to control the intensification of metastases to the liver. These include:

Liver Resection and Liver Transplantation

Liver resection surgery (partial hepatectomy), during which the tumor is debulked (reduced in size), may be either curative or palliative. It is associated with frequent tumor recurrence and is performed for slow growing tumors if the patient has severe symptoms due to hormonal expression of the tumor. Relief from symptoms is usually brief. There is a high rate of mortality associated with liver surgery due to infection or bleeding.

Liver transplantation has been reported to increase survival as well as control symptoms related to hormonal expression of the tumor.

Hepatic Artery Embolization

In this procedure, the branch of the hepatic artery, which supplies the affected portion of the liver with blood, is sealed or occluded with a special embolizing material that is injected directly into the hepatic artery. By cutting off the blood supply to the area of the liver where the metastasis is located, the tumor is deprived of its blood supply and shrinks. This procedure has the advantage of not involving major surgery and is a less invasive procedure than hepatic resection surgery.

Chemoembolization

Chemoembolization is a method of delivering cancer treatment directly to a tumor in the liver. During this procedure, a small catheter is inserted into an artery in the groin and the tip of the catheter is advanced into the hepatic artery in the liver that supplies blood flow to the tumor. A chemotherapeutic drug such as doxorubicin or cisplatin is injected through the catheter into the tumor together with particles that embolize or block the flow of blood to the diseased tissue.

Chemoembolization works to attack the cancer in two ways. First, it delivers a very high concentration of chemotherapy directly into the tumor, without exposing the entire body to the effects of those drugs. Second, the procedure cuts off blood supply to the tumor, depriving it of oxygen and nutrients, and trapping the drugs at the tumor site to enable them to be more effective.

Some studies indicate that changes following chemoembolization include:

• Slowing or cessation of tumor growth for up to approximately 3 years
• Improvement of symptoms related to hormonal levels

Side effects of chemoembolization may include:

• Nausea
• Vomiting
• Mild fever
• Abdominal pain
• Elevated liver enzyme levels

Radiofrequency Ablation

Radiofrequency ablation is a procedure that is sometimes used to destroy tumors in the liver. The goal of this procedure is to ablate (destroy) the tumor with heat that is generated with a radiofrequency electrode. This procedure is usually done during laparotomy (a surgical incision created in the abdomen) or laparoscopy (a procedure in which a small, lighted instrument called an endoscope or laparoscope is inserted through an abdominal incision). During this procedure, a special needle electrode is placed in the tumor under the guidance of an imaging method such as ultrasound, CT scan, or MRI. A radiofrequency current then is passed through the electrode to heat the tumor tissue ablate (destroy) it. In general, radiofrequency ablation causes only minimal discomfort and may be done as an outpatient procedure without general anesthesia. Admission to the hospital is not usually necessary.

Cryosurgery

Cryosurgery is a technique that involves destroying the liver tumor by freezing the cells with liquid nitrogen. Success rates reflecting a reduction of levels of hormone-like substances related to the carcinoid tumor using this procedure are reported to be up to 80-90%.

Other Approaches

Other approaches that may be utilized to treat metastases which occur outside of the liver include:

• Chemotherapy
• Octreotide therapy

Chemotherapy

Chemotherapy is a form of drug therapy that uses anticancer drugs, also called cytotoxic or antineoplastic drugs, to destroy cancer cells. The choice of drug(s) given depends upon the specific type of cancer. In many types of cancers, a combination of anticancer drugs is administered at the same time (combination chemotherapy). Some anticancer drugs may be given orally while others are administered intravenously (IV).

Common side effects of cancer chemotherapy may include:

• Hair loss
• Mucositis - swelling, irritation, and ulceration of the mucosal cells that line the digestive tract. It can occur anywhere along the digestive tract from the mouth to the anus.
• Increased susceptibility to infections
• Fatigue and general loss of energy
• Nausea and vomiting
• Loss of appetite
• Increased susceptibility to bleeding and bruising

It is important to note that the side-effects of chemotherapy are temporary and usually disappear after the chemotherapy has been stopped. A variety of strategies are available to help better control the common side-effects of cancer chemotherapy and patients should discuss the various options available to reduce or eliminate the side-effects with their oncologist.

Octreotide Therapy

Octreotide is the most effective drug used in the treatment of carcinoid syndrome. Some studies report that up to 80% of patients report improvement in their symptoms while on a regimen of octreotide.

Some of the palliative properties of octreotide include:

• Inhibition of the synthesis and release of hormones from the cancer cells.
• Improvement of the absorption of fluid in the GI tract which reduces the symptoms of diarrhea.

Another application for the use of octreotide involves its ability to deliver targeted radiotherapy to carcinoid cells. This technique involves the administration of radiolabeled octreotide which is attracted to the receptors on the cells of carcinoid tumors. A newer version of radiolabeled octreotide, Yttrium 90-DOTA Octreotide, has been developed and appears to:

• Improve survival rates and
• Reduce tumor associated pain