The neuroendocrine system,Neuroendocrine cells are like nerve cells in some ways and like hormone-making endocrine cells in other ways. Cells in this system don't form actual organs. Instead, they are scattered throughout other organs like the esophagus, stomach, pancreas, intestines, and lungs.
Neuroendocrine cells (sometimes just called endocrine cells) in the pancreas are found in small clusters called islets (or islets of Langerhans). These islets make important hormones like insulin and glucagon (which help control blood sugar levels), and release them directly into the blood.
Functioning neuroendocrine tumors are characterized by inappropriate release of biologically active polypeptides or amines causing the typical clinical presentation.
Therefore, determination of the “hypersecreted” hormone or amine is mandatory.
Both Pancreatic Cancer and Neuroendocrine Cancer are diseases that need maximum publicity, both types of cancer have their own unique situations, thus why the awareness messages can be so vastly different. It’s really important, therefore, that publicity surrounding famous patients be attributed to the correct cancer type in order that the advocate organisations and supporters can gain maximum benefit to forward their causes. Unfortunately, thanks to doctors and media, this very often doesn’t work out in favour of Neuroendocrine Cancer due to the Human Anatomy of Neuroendocrine Cancer.
Neuroendocrine neoplasms (NENs) display variable behaviors based on origin and grade. We assumed that both tumor origin and the location of metastasis may play a role in survival.
Site of metastasis plays an important role in survival of metastatic NEN patients independent of commonly described prognostic factors and should be considered in survival estimates.
Neuroendocrine tumours frequently metastasize to the liver. Although generally slowly progressing, hepatic metastases are the major cause of carcinoid syndrome and ultimately lead to liver dysfunction, cardiac insufficiency and finally death.
Platelet serotonin and chromogranin A are useful biomarkers for detection and follow-up of neuroendocrine tumour. Helical computed tomography and somatostatin receptors are the most sensitive diagnostic modalities.
Surgical debulking is an accepted approach for reducing hormonal symptoms and to establish better conditions for medical treatment, but is frequently impossible due to the extent of disease.
Carcinoids are neuroendocrine tumours that arise from neoplastic proliferation of enterochromaffin or Kulchitsky cells. In 1963, carcinoids were classified according to their embryologic site of origin as foregut carcinoids (respiratory tract, stomach, duodenum, biliary system and pancreas), midgut carcinoids (small intestine, appendix, cecum, and proximal colon), and hindgut carcinoids (distal colon and rectum). According to the WHO classification in 2000, distinction was made between well-differentiated neuroendocrine tumours (benign behaviour or uncertain malignant potential.
Neuroendocrine tumours of the small intestine produce large quantities of serotonin (5-hydroxytryptamine), reflected in raised levels of platelet serotonin and a high urinary excretion of 5-hydroxyindoleacetic acid (5-HIAA) . The platelet serotonin concentration is more sensitive in the detection of carcinoid tumours than urinary 5-HIAA, particularly in tumours with relatively low serotonin production. Circulating free serotonin is removed very rapidly and effectively by the liver. In contrast to urinary 5-HIAA, platelet serotonin is not affected by a serotonin-containing diet. Hence platelet serotonin is the most discriminating marker for detection of most neuroendocrine tumours. However, in hindgut carcinoids, hydroxylase and decarboxylase are absent and no serotonin is produced.
Plasma chromogranin A (CgA) has been claimed to be the most sensitive and specific marker of tumour volume. CgA is a precursor for several peptides and is stored in secretory granules of neuroendocrine tissue . Circulating CgA allows early detection of persistent or recurrent neuroendocrine tumours.
Your symptoms may depend on where your tumor is growing and what kind it is. They show a spectrum of behaviors and this makes their treatment challenging. Some exhibit an indolent, slow growth pattern, while others parallel the more aggressive, rapidly spreading tumors such as small cell lung cancer (SCLC); in between there are neoplasms of intermediate malignant potential.
In general, well- differentiated tumors progress slowly and surveillance may be the best approach in some cases, whereas poorly differentiated neoplasms require urgent aggressive chemotherapy and are associated with markedly shorter survival. Tumors of small bowel origin tend to have a better prognosis compared to NENs originating in the pancreas. The effect of other factors such as age, race, predictability, performance status or even marital status has similarly been examined in several publications. Most medical decisions nowadays consider tumor of origin, staging, but also tumor differentiation.
While it is generally accepted that stage IV (presence of metastasis) portends a poor prognosis for most neoplasms including NENs, there is no consensus on the gravity and importance of metastatic sites, or how they interplay with the primary tumor site when it comes to survival estimates. It has been shown for example that the incidence of certain types of NETs has increased and that the survival of patients has improved over time . This has been partially attributed to treatments such as somatostatin analogues (time to progression prolonged by 8 months), targeted therapies such as everolimus and sunitinib (progression free survival benefit of about 5 months for both), and hopefully pazopanib or peptide receptor radionuclide therapy (PRRT) in the future. With the latest iteration, the SEER database was enriched to include details of general metastatic sites, including lung, liver, bone and brain. This presents a unique opportunity to study the behavior of metastatic neuroendocrine tumors across a range of sites and histologies. We sought to explore the behavior of NENs with regards to the site of origin and metastatic areas and hypothesized that the site of metastasis will carry different prognostic significance depending on tumor grade and tissue of origin.
When completely removing the tumor is not possible, "debulking surgery" is sometimes recommended. Debulking surgery removes as much of the tumor as possible and may provide some relief from symptoms, but it generally does not cure a NET.
It is usually measured in matters of months and may reflect the virulence of the tumor, the severity of CNS dysfunction or the inability of most current therapies to cross the blood brain barrier. In our study, median survival was a mere 7 months and it is worth mentioning that single site brain metastases were more prominent in lung and “other” primary but uncommon in pancreas and small bowel.
The rate of brain metastasis was high. It is usually measured in matters of months and may reflect the virulence of the tumor, the severity of CNS dysfunction or the inability of most current therapies to cross the blood brain barrier.
Treatment options and recommendations depend on several factors, including:
The primary site (where the NET originated)
Whether the tumor is functional
Stage (where the tumor is located in the body)
Grade and degree of differentiation (how fast the cells are dividing)
Pace of growth
Somatostatin receptor status (whether the tumor is bright on 68Ga DOTATATE PET)
Possible side effects
The patient’s preferences and overall health
Site of metastasis plays an important role for survival in metastatic NEN patients and is probably reflective of variable tumor biology, even among NENs of similar origin and grade.
A promising approach is the concept of somatostatin receptor (SSTR)-mediated chemo-or radiotherapy of SSTR-expressing metastatic carcinoid.
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