The Voice
What Are Neuroendocrine Tumors? Why Are They Important?
Neuroendocrine cells specialize in repairing tissues that line important organs, like the lungs. Within the lungs, they produce hormones that regulate air flow and blood flow. Neuroendocrine cells across the body can develop tumors, including the neuroendocrine cells in the lungs. These are known as pulmonary neuroendocrine tumors. Neuroendocrine tumors are classified based on how fast they grow, where they are located in the lungs, and whether or not they release hormones. Neuroendocrine tumors can also grow at very different rates, depending on what type of tumors they are. Some types are very aggressive, and others grow slowly.
One classification system for neuroendocrine growths measures the tumor, the nodes and metastasis. Doctors measure how large the tumor is, look at the nearby lymph nodes , whether cancer has spread to them or not and whether the tumor has spread (or metastasized) to other parts of the body. Neuroendocrine tumors can also be classified in stages between 1 and 4, based on how many centimeters the tumor measures and whether it has spread to nearby lymph nodes or not. Stages 0, 1, 2 and 3A are considered early-stage cancers, while anything after stage 3A is considered a more advanced stage cancer.
Symptoms of neuroendocrine tumors include shortness of breath, a cough that won’t go away, a hoarse voice, fatigue, recurring bronchitis or chest infections and chest pain or coughing up blood. Neuroendocrine tumors that release hormones can cause different conditions in the body, each with their own set of symptoms. One, called hypercalcemia, increases the amount of calcium in the blood, which leads to muscle cramps, confusion and can make the heartbeat irregular. Patients with carcinoid tumors sometimes produce too many prostaglandins and too much serotonin, which leads to symptoms similar to asthma, facial flushing or lesions and diarrhea. Neuroendocrine tumors can also lead to acromegaly, or an excess of growth hormone that make the face, hands and feet grow too much. This type of tumor can also cause Cushing’s Syndrome, which causes excessive hair growth, weight gain and darkening skin.
One major type of neuroendocrine tumors are carcinoid tumors. Like other neuroendocrine tumors, carcinoid tumors are classified in various ways. One classification system describes where the tumors grow, and whether they form near the center of the lungs (central carcinoids) or further away from central air vessels (peripheral carcinoids). Most carcinoid tumors grow slowly and are unlikely to spread beyond the lungs. Some atypical carcinoid tumors are usually found in smokers, and are more likely to spread from the lungs. Most carcinoid tumors are found in people between the ages of 45 and 55. Doctors diagnose between 2,000 and 4,000 carcinoid tumors each year in the US. They have found that these tumors do not respond as well to new treatments, like immunotherapies or targeted therapy, but that they respond well to surgical intervention and a certain set of medications.
Small-cell lung cancer tumors are the most common type of neuroendocrine tumors. This type of lung cancer is much more aggressive than carcinoid tumors and is usually not diagnosed until it has already spread beyond the lungs. Doctors refer to the condition as limited stage small-cell lung cancer if it remains in the area of the lung where it first developed, and extensive-stage small-cell lung cancer if it has spread to other parts of the lungs. Although small-cell lung cancer responds well to treatment, it often recurs. Many smokers develop small-cell lung cancer.
Sources:
Neuroendocrine Tumor Stages and Survival Rate | City of Hope
Learn About Lung Neuroendocrine Tumors (NETs) | Neuroendocrine Tumor Research Foundation
8 Common Signs of Neuroendocrine Lung Tumors | Verywell Health
Lung Carcinoid Tumor | Lung Neuroendocrine Tumor | American Cancer Society
If You Have a Lung Carcinoid Tumor | American Cancer Society
Spotlight on Small-Cell Lung Cancer and Other Lung Neuroendocrine Neoplasms | ASCO