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Carcinoid cancer is a type of slow-growing neuroendocrine tumors that form (usually) in the lungs and gastrointestinal tract, from the esophagus to the rectum. They are the most common cancer found in the appendix. While typified as a cancer of the elderly, women are more likely than men to develop carcinoid tumors. Additionally, a family history of multiple endocrine neoplasia type I (MEN I), increases the risk of carcinoid tumors. However, this family of cancers, sometimes referred to as neuroendocrine tumors (NETs), do not manifest a single set of symptoms. Rather, carcinoid cancer often comes to light only after an investigation of hormonal changes the cancer induces.  November is Carcinoid Cancer Awareness Month, and it is important to highlight both how this cancer manifests, and the recent treatments for it.

Signs & Symptoms

Carcinoid tumors secrete several substances that are vasoactive; that is, impacts the tone and caliber of blood vessels. In the case of carcinoid cancer specifically, serotonin is the most prominent, but kallikrein (influencing blood pressure, skin peeling, and semen liquefaction) and bradykinin (a very powerful vasodilator) are also produced. Their presence sets off a chain reaction in the body known as carcinoid syndrome.

Occurring in around five percent of carcinoid cancer cases, carcinoid syndrome is a set of seemingly unrelated medical signs and symptoms that are in fact indicators of carcinoid cancer. The most common, and most clinical, is flushing of the head, neck, and chest. Other signs include nausea, edema, vomiting, abdominal pain, diarrhea, and more seriously, constriction of the airways in the lungs (causing wheezing) and carcinoid heart disease (thickening of the lining in the heart chambers, valves and blood vessels, which can lead to heart failure). A sudden onset of these symptoms all at once is called a carcinoid crisis.

Tests & Treatment

Gastrointestinal carcinoid cancer has an excellent five-year survival rate, 98 percent if discovered in the localized stage. If the cancer has spread regionally, the rate falls to 93 percent; the five-year survival rate then falls to 67 percent if the cancer has metastasized to distant parts of the body.

That being said, carcinoid cancer is no less dangerous if left undiagnosed. Scientists at the Universities of North Carolina and Utah have developed a histology expression predictor for the most common types of lung cancer, including carcinoid. This predictor can confirm histologic diagnosis in routinely collected paraffin samples of patients’ tumors and can complement and corroborate pathologists’ findings.

French doctors at the University of Tours found that sirolimus, a drug used to prevent kidney transplant rejection, is also an effective treatment for a rare condition called diffuse idiopathic pulmonary neuroendocrine cell hyperplasia, or DIPNECH syndrome. DIPNECH is a precancerous condition that causes proliferation of neuroendocrine cells in the bronchial wall and the formation of carcinoid tumors. The condition is so rare there are no clinical recommendations to guide care and thus, no proven therapies; the Tours study could be instrumental in treatment.

In other drug news, the FDA recently approved Lutetium Lu 177 dotatate (sold as Lutathera) for adult patients with advanced NETs that affect the pancreas or gastrointestinal tract. The drug consists of a molecule that binds to carcinoid cells that have a molecule called a somatostatin receptor on their surface. The drug then enters these somatostatin receptor−positive tumor cells, and radiation emitted by Lu-177 helps kill the cells. This is the first radioactive drug approved to treat these rare cancers, and offers another option to patients for whom initial treatments have failed.

References:
American Cancer Society. (2019). Survival Rates for Gastrointestinal Carcinoid Tumors. Retrieved from: https://www.cancer.org/cancer/gastrointestinal-carcinoid-tumor/detection-diagnosis-staging/survival-rates.html
American Cancer Society. (2019). What Is a Gastrointestinal Carcinoid Tumor?
Retrieved from: https://www.cancer.org/cancer/gastrointestinal-carcinoid-tumor/about/what-is-gastrointestinal-carcinoid.html
Mayo Clinic. (2019). Carcinoid Tumors. Retrieved from: https://www.mayoclinic.org/diseases-conditions/carcinoid-tumors/symptoms-causes/syc-20351039