Neuroendocrine Tumors

April 6, 2018

Name:

Neuroendocrine tumors.

Childhood Cancer Name:

Neuroendocrine tumors, carcinoid tumors, NET.

Explanation:

Neuroendocrine cells are distributed throughout the body (pancreas, gut, lungs), and therefore neuroendocrine tumors can arise in different organs in the body. Affecting cells that release hormones into the bloodstream (neuroendocrine cells). Neuroendocrine tumors can be cancerous (malignant) or non-cancerous (benign). NETs are relatively rare in pediatric and young adult populations. However, they do occur.

Characteristics:

These tumors are usually small, slow-growing, and benign. Some neuroendocrine tumors are malignant (cancer) and spread to other places in the body. The cause of neuroendocrine tumors not known, some are related to familial syndromes.

Biology:

The cell of origin of most neuroendocrine tumors is the neuroendocrine system, regardless of organ site, these neuroendocrine cells most of the times secrete bioactive substances and proteins (such as somatostatin, insulin, gastrin, serotonin, chromogranins, and synaptophysin).

These types of tumors recur locally or metastasize to liver and bone if not completely excised early in their course of development.

Main types:

Appendiceal NETs or Appendix carcinoids (a pouch that sticks out from the first part of the large intestine near the end of the small intestine) his is the most common neuroendocrine tumor in children.
Lung NETs or Bronchial carcinoids
Small bowel NETs
Large bowel NETs
Pancreatic NETs
Gastric NETs
Pheochromocytoma (tumors of the adrenal gland)
Paraganglioma (head, neck, thorax, and abdomen)
High-grade neuroendocrine carcinoma (fast-growing and aggressive)

The stages: The World Health Organization has provided a recent classification of NETs, to include 5 major categories:

- Well-differentiated endocrine tumors (benign or low-grade malignancy)
- Well-differentiated endocrine carcinomas
- Poorly differentiated endocrine carcinomas (small cell carcinomas),
- Mixed exocrine and endocrine carcinomas, and tumor-like lesions.

Special cases:

Although most tumors occur in a sporadic way, some neuroendocrine tumors are related hereditary syndromes like: multiple endocrine neoplasia type 1 (MEN1), neurofibromatosis type 1 and Von Hippel-Lindau syndrome (VHL). For more information follow this link: http://mychildscancer.org/more-about-neuroendocrine-tumors/

Note: Referral for genetic counseling should be made at the time of tumor diagnosis.

Childhood Cancer Localization:

NETs are a rare type of cancer that most commonly occurs in the pancreas, lung or stomach.

Childhood Cancer Noticeable Symptoms:

Symptoms associated are related to the location, size, and extent of spread of the tumor. A tumor in the lung can cause wheezing or a persistent cough. A tumor in the digestive system can cause diarrhea, constipation or tummy pains. Some neuroendocrine tumors release hormones and other substances and can cause symptoms such as diarrhea, flushing, cramps, wheezing, low blood sugar (hypoglycemia), and changes in blood pressure and heart problems known as carcinoid syndrome. Some kids can present with a weight loss of 3 to 14 kg over a period of weeks to months.

If the tumor spread to the liver, high amounts of hormones are released and cause a group of signs and symptoms called carcinoid syndrome.

Carcinoid syndrome caused by the hormone somatostatin may cause any of the following signs and symptoms: Redness and a warm feeling in the face and neck, fast heartbeat, trouble breathing, sudden drop in blood pressure and diarrhea.

Childhood Cancer Diagnostic method:

blood tests, urine tests, scans and a biopsy.

The clinical presentation of an appendiceal NET is similar to acute appendicitis (no specific symptoms), and usually, the child is diagnosed during the appendectomy or other surgical procedures.

if carcinoid syndrome or a carcinoid tumor is suspected based on clinical symptoms or imaging studies, it is best to obtain several laboratory studies before proceeding with surgical biopsy or resection.

Bronchial carcinoid tumors are likely to be discovered on computed tomography (CT) or magnetic resonance imaging (MRI).
Rectal or gastric carcinoids are most likely to be visualized directly by endoscopy procedure unless they are large enough in size to be detected by more routine imaging.
Small intestinal tumors are the most difficult to localize by imaging studies and are usually only found in this manner after they have metastasized to other regions.

Fortunately, the majority of pediatric and young adult carcinoid tumors are found incidentally during appendectomy or evaluation for other diseases.

Somatostatin-based imaging/ Octreoscan:Neuroendocrine tumors often absorb a substance called octreotide. A small amount of octreotide is ‘labeled’ with a radioactive tracer to make it glow on scan pictures (single-photon emission computed tomography/CT). The octreotide is then injected into the bloodstream and taken up by NETs, wherever they are.

A Complete pathologic characterization, including grade, stage, and biomarkers, are critical for defining the treatment and follow-up.

Octreoscan combined with a single-photon emission computed tomography (SPECT) imaging should also be obtained before biopsy.

Laboratory test:

Some of these laboratories are of more benefit than others, depending on the location of the tumor and the patient’s symptoms at presentation.

24 Hour Urine test (u-5HIAA): This test looks for raised levels of 5HIAA in your urine in a 24-hour period. Serotonin is broken down by the liver into a chemical called 5HIAA and then passed out of the body in the urine. This test is mandatory in patients with carcinoid syndrome but not as useful in patients with bronchial, gastric, rectal and pancreatic NETs.
- Certain foods, drinks and medicines can raise the levels of 5HIAA. You may be asked to avoid these for a few days before and during the urine collection.
Chromogranin A: elevated in as many as 80% of patients with carcinoid cancer, tend to be highest in metastatic cancer, particularly in the liver.
Pancreastatin: It has been shown to be an effective marker in the follow-up of patients who require hepatic artery chemoembolization and for those patients who may have metastatic disease.
Ki-67: Which refers to the number of cells dividing in a certain amount in a certain amount of cancer tissue.

Genetic counseling:

Genetic counseling is of relevance in this group of patients.

Childhood Cancer Treatment:

Treatment depends on where the NET started, its size, whether it has spread, how the cells look under a microscope and your symptoms, but invariably all these tumors need some sort of surgical resection and in some cases somatostatin analogues (such as octreotide or lanreotide), that stop the body from making lots of hormones and consequently reducing the symptoms of carcinoid syndrome.

The majority of these patients will be cured completely by surgical resection. There are no consensus guidelines for treatment of NET in children, and most physicians follow adult guidelines. For those with a more extensive metastatic disease at presentation, aggressive treatment of their tumors with surgical resection when possible, somatostatin analogs, hepatic chemoembolization, and perhaps novel therapeutic agents such as radioactive analogs may be indicated.
Types of treatment:

Somatostatin analogs:has shown to be of some help in patients with residual disease and significant symptoms of carcinoid syndrome. The most commonly used somatostatin analogs are octreotide (Sandostatin®, Sandostatin Lar®) and lanreotide (Somatuline® LA, Somatuline Autogel®).
Chemotherapy:to kill cancer cells, in general, is relatively unhelpful for patients with carcinoid tumors, tumors with higher levels of Ki-67 may respond better to chemotherapy than those with Ki-67 levels <2%.
Target therapy: target specific molecules to stop the growth and spread of cancer cells.
Radiation therapy:can be used when NETs have spread to other parts of the body, it can be radionuclide therapyorexternal beam radiation therapy.
Hepatic arterial embolization:blocks or slows down the flow of blood through the liver so liver tumors do not receive the oxygen and nutrients they need to grow. Sometimes chemotherapy drugs are used during the embolization (called chemoembolization).
Radiofrequency ablation (RFA): uses heat to destroy cancer cells.

Follow up, late effects:

Patients of all ages, who have carcinoid syndrome, are at risk for carcinoid heart disease and should be monitored appropriately. Especially so for patients with metastatic disease.
Why? Sometimes these tumors secret vasoactive substances (agents that cause contraction or distention of blood vessels), which are usually inactivated by the liver. However, when a patient has the disease in the liver itself, the vasoactive substances are not inactivated and are allowed to reach the systemic circulation reaching and damaging the heart.
In the absence of any evidence of metastatic disease, observation, screening for tumor markers, and imaging are recommended 3 to 6 months, or till disease shows up.

Parents tips:

It is crucial to find a physician specialized in this field for a successful surgery and follow up.
You will need to have regular follow-up visits, especially in the first 5 years after treatment has concluded.
Many patients diagnosed with a neuroendocrine tumor claimed that this video helped them to learn and understand deeply about their condition. For this reason, we want to share with you this lecture about Neuroendocrine Tumors (NETs) from the Royal Free London NHS Foundation Trust given by Dr. Christos Toumpanakis and Jorge Garcia-Hernandez.
https://youtu.be/bOTAYyZ8R6s
Eventhoug is not specifically directed to childhood cancer, since Neuroendocrine Tumors are rare in children and young adults, we believe that this information can really help parents of kids diagnosed with NETs to understand in a very detailed level about this tumors.