Table of ContentsView AllTable of ContentsDefinition and TypesSymptomsDiagnosisTreatment (High-Grade)Treatment (Intermediate/Low-Grade)PrognosisScreening
Table of ContentsView All
View All
Table of Contents
Definition and Types
Symptoms
Diagnosis
Treatment (High-Grade)
Treatment (Intermediate/Low-Grade)
Prognosis
Screening
Neuroendocrinelung tumors, also known as neuroendocrine tumors (NETs) of the lungs, are a rare spectrum of cancers that arise in the lung’s neuroendocrine cells. These growths account for only around 2% of all lung tumors.
Treatments vary depending on the specific type of tumor. The long-term prognosis for someone with a neuroendocrine tumor in the lung is generally good compared to other forms of lung cancer.
Types of Neuroendocrine Lung Tumors
Neuroendocrine cells are specialized cells responsible for repairing tissues that line the airways, intestines, and other surfaces of the body. They function as neurons (nerve cells) and endocrine cells (responsible for the secretion of hormones).
There are four different types of lung neuroendocrine tumors (NETs), and they can vary widely in terms of cell type, aggressiveness, response to treatment, and prognosis. The one common feature among them is that they usually develop in the central airways, called thebronchi, located nearer to the middle of the chest.
Neuroendocrine lung tumors tend to affect the large airways, so they typically cause symptoms of airway obstruction.
Commonsymptomsinclude:
As lung cancer progresses, people also often experienceunexplained weight loss.
Hormonal Complications
Because of the role of neuroendocrine cells in producing hormones, NETs secrete excessive amounts of hormones as they grow. This can sometimes lead to the following complications:
Risk Factors
While the exact cause of neuroendocrine tumors is unclear, several factors make people more likely to get them:
The diagnosis of neuroendocrine tumors typically involves a combination of blood tests, imaging studies, and a lung biopsy.
Blood Tests
Blood tests cannot confirm neuroendocrine tumors, but they can help distinguish subtypes and, hence, the grade of the disease. TheKi67 proliferation indexis a blood marker test used to differentiate between high-grade and low-grade tumors. It can also be used to estimate the likelihood of recurrence.
A generalblood chemistry panelcan reveal hypercalcemia and other abnormalities. A healthcare provider may also order blood tests to measure levels of adrenocorticotropic and growth hormone since hormone levels tend to be excessively high when neuroendocrine lung cancer is advanced.
Imaging Studies
Achest X-rayis often the first test done when lung cancer is suspected, but it can miss as many as nine of every 10 lung malignancies in the earlier stages.
If neuroendocrine cancer is suspected, your healthcare provider will more likely order other imaging studies:
Lung Biopsy
A lung biopsy is considered the gold standard for a lung cancer diagnosis. There are several ways that a healthcare provider can obtain a sample of tissue for evaluation:
Lung Cancer Staging
Once neuroendocrine lung cancer is diagnosed, it is staged to denote the severity of the disease, direct the appropriate treatment, and predict the prognosis.
LCC and carcinoid tumors arestagedin the same way as non-small cell lung cancers, with five stages ranging from stage 0 to stage 4. Stages 0, 1, 2, and 3A are considered early-stage lung cancer, whereas stages 3B and 4 are advanced. The staging is based on the TNM classification system which characterizes the malignancy based on the size of the tumor (T), whether lymph nodes are involved (L), and whether the malignancy has metastasized (M).
Small cell lung cancers have two stages:
Treatments
Treatments for neuroendocrine lung cancer vary depending on the tumor type, cancer stage, tumor location, and the general health of the individual.
SCLC and LCLC treatment may include any, or a combination of, the following:
Treatment of Low- and Intermediate-Grade NETs
Low- to intermediate-grade carcinoid tumors do not respond to newer targeted therapies and immunotherapies for certain non-small cell lung cancers. Even chemotherapy and radiation therapy are not used in quite the same way with carcinoid tumors and have different degrees of efficacy.
With that said, carcinoid tumors are responsive to surgery and other medications not commonly used in lung cancer therapy.Since relatively few studies have looked at the best treatment options for advanced carcinoid tumors, there is currently no standardized approach for them.
Surgery to Remove Carcinoid Tumors
With early-stage carcinoid tumors, surgery is the treatment of choice because it can be curative. Depending on the size of the tumor, a healthcare provider may recommend one of the following surgeries:
Surroundinglymph nodesmay also be removed as they often contain cancer cells. These include lymph nodes situated where the bronchi enter the lungs (hilar lymph nodes) and/or lymph nodes between the lungs (mediastinal lymph nodes).
Drug Treatments for Carcinoid Tumors
Thetreatment of carcinoid tumorsis more challenging once the disease is advanced, but it may involve one of these drugs:
Chemotherapy and Radiation Therapy
Carcinoid tumors are not very responsive to standard chemotherapy drugs. Even so, chemotherapy may be used for tumors that are not responsive to other forms of therapy, especially those that have a high Ki67 proliferation index.
Radiation therapy may be an option for early-stage tumors when surgery is not possible. Specialized techniques such asstereotactic body radiosurgery (SBRT)deliver high doses of radiation to a focused area, and can sometimes provide similar results to those attained with surgery.
Carcinoid tumor screening is not recommended for the general public, but some healthcare providers will routinely screen people with multiple endocrine neoplasia type 1 given their increased risk of the disease. For these individuals, chest CT scans may be performed every three years starting at age 20. Unfortunately, there is little evidence that screening increases survival time.
Adults at high risk of smoking-related lung cancer should undergo routine screening. The U.S. Preventive Services Task Force currently recommendslung cancer screeningfor adults ages 50 to 80 who have a 20pack-yearhistory and either currently smoke or have quit within the past 15 years.If you think you should be screened and it has not yet been recommended to you, speak with your healthcare provider.
Summary
Neuroendocrine lung tumors are a rare type of cancer that originate in the neuroendocrine cells of the lungs. Their exact cause is unknown, but they are more likely to occur in smokers and people who were exposed to pollutants.
Surgery is often the first treatment for neuroendocrine lung tumors. Depending on the type of tumor, chemotherapy, radiation, and drug therapies may also be used. If you’re at a high risk of lung cancer, talk to your healthcare provider about regular screenings for the disease.
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