A spotlight on NENs - Types - Ronny Allan - Living with Neuroendocrine Cancer

Category: A spotlight on NENs – Types

Neuroendocrine cells are found in almost every organ of the body and are also dispersed among other epithelial cells throughout the gastrointestinal and bronchopulmonary systems (the diffuse neuroendocrine system). The cells contain dense, core secretory granules, which synthesise, store and secrete serotonin and numerous other hormones/bioactive peptides with various functions in the gut, including nutrient sensing, gut secretions and motility, hormone release, and energy balance and appetite.

Neuroendocrine neoplasms (NENs) are uncommon tumours that derive from these neuroendocrine cells. They range in phenotype from poorly differentiated neuroendocrine carcinomas (NECs) to well-differentiated neuroendocrine tumours (NETs).

NENs (but mostly NETs) uniquely express cell-surface peptide hormone receptors, including somatostatin (SST) receptors (SSTRs). SST is a regulatory peptide hormone with a predominantly inhibitory function, inhibiting hormone secretion and cell proliferation and/or growth through five SSTR subtypes (SSTR1–5). The presence of SSTRs on NETs can be exploited to facilitate imaging and treatment of these tumours with somatostatin analogues (SSAs) and peptide-receptor radionuclide therapy (PRRT); and allow more detailed imaging output via SSTR PET.

07Jun 2023 by Ronny Allan No Comments

A spotlight on duodenal Neuroendocrine Neoplasms (dNENs)

A spotlight on NENs - Types

What are Duodenal Neuroendocrine Neoplasms (dNEN)? The duodenum is technically part of the small intestine, and you can find that in most anatomy-based descriptions. One of the research references I used was titled "Somewhere between the pancreas and the small intestine" and in the case of Duodenal NENs (dNENs), I can understand why they adopted that unconventional anatomy description. I suspect they contextually meant that they are not like either of these organs, but they share some similarities. They are not normally treated like small intestine NETs (SI NETs) or pancreatic NETs (pNETs) but they share some relationships, particularly with the latter. They are also closely aligned to the stomach (Gastric NENs) in terms of symptoms and syndromes that they sometimes present. Although they are a type of NEN (i.e. dNENs),…

12May 2023 by Ronny Allan No Comments

A spotlight on Rectal Neuroendocrine Neoplasms

A spotlight on NENs - Types, Awareness, Patient Advocacy

What are Rectal NENsRectal Neuroendocrine Neoplasms (NENs) (rNENs) account for approximately 1-2% of all primary cancers in the rectum. The other main cancer types found in the rectum are regular adenocarcinomas (the vast majority) and some other rare types including Gastrointestinal stromal tumors (GIST) and Lymphoma. The vast majority of rNENs will be well differentiated, i.e. rectal Neuroendocrine Tumours (rNETs) and are mostly indolent tumours treated effectively with surgical procedures if less than 1cm in size. Above that size there are different scenarios. Most will be found incidentally upon presentation of classic rectal symptoms or via colonoscopy screenings and faecal tests which lead to colonoscopy follow ups. They are typically diagnosed in older patients but the incidence in younger patients is on the increase, see author's note below in epidemiology section. Poorly differentiated…

26Mar 2023 by Ronny Allan No Comments

A spotlight on Appendiceal Neuroendocrine Neoplasms

A spotlight on NENs - Types, Awareness, Patient Advocacy, Spotlight on NENs - Types Series

What are Appendiceal NENsAppendiceal Neuroendocrine Neoplasms (NENs) account for approximately 60% of all primary cancers in the appendix. The other main cancer types found in the appendix are regular adenocarcinomas (including signet ring cell and goblet cell) and mucinous neoplasms such as Pseudomyxoma Peritonei (PMP) or Low-Grade Mucinous Neoplasms (LAMD). Appendiceal neuroendocrine tumours (aNET) (i.e. well differentiated) account for 75% of all aNENs, are mostly indolent tumours treated effectively with simple appendectomy. In fact, most are incidentally found upon presentation of right lower quadrant (RLQ) pain in keeping with appendicitis. They are typically (but not exclusively) diagnosed in younger patients. Poorly differentiated appendiceal Neuroendocrine Carcinomas (aNEC) resemble small-cell or large-cell neuroendocrine carcinomas of the lung, have aggressive behaviour, and usually present with metastatic disease at diagnosis.Mixed neuroendocrine-non-neuroendocrine neoplasms (MiNEN) are possible, particularly…

22Feb 2023 by Ronny Allan 2 Comments

A spotlight on Gastric Neuroendocrine Neoplasms

A spotlight on NENs - Types, Awareness, Patient Advocacy, Spotlight on NENs - Types Series, Treatment

What are Gastric NENsUnlike other anatomical types, the word Gastric is used to indicate a tumour (NET) or carcinoma (NEC) in the stomach. The stomach lies at the bottom of your oesophagus and connects to the first part of the small intestine (the duodenum). Clearly a key part of the gastrointestinal system, it processes food on its journey downwards.The stomach produces strong acid. This kills many microorganisms that might have been swallowed along with the food. It also contains special chemicals called enzymes. These are important for breaking down the food so it can be absorbed by the body. After it leaves the stomach, the partially digested food passed into the intestines where it begins to be absorbed.The main parts of the stomach are shown below (often this can give…

03Mar 2022 by Ronny Allan No Comments

A Spotlight on Lung Neuroendocrine Neoplasms

A spotlight on NENs - Types, Awareness, Patient Advocacy, Spotlight on NENs - Types Series

WHO Classification of Tumours, 5th Edition, Volume 5: Thoracic TumoursThe aim of this spotlight is to provide a summary of the latest information on Lung Neuroendocrine Neoplasms (NEN) including the latest terminology, epidemiology data, and guidelines. This follows the publication of the Thoracic WHO classification 5th edition (2021): terminology and criteria for neuroendocrine neoplasms (Blue Book). This book has been anticipated to see if the panel compiling this follows the lead of the Gastroenteropancreatic Neuroendocrine Neoplasms (GEPNEN) editions issued in 2017 (Endocrine) and 2019 (Digestive systems) by removing the antiquated misnomer term ''Carcinoid" in line with the recommendations made by senior NEN doctors in 2020 to have commonality across all blue books. Neuroendocrine neoplasm update: toward universal nomenclature © 2020 Society for Endocrinology 2020, Guido Rindi and Frediano Inzani.I can tell…

09May 2019 by Ronny Allan 5 Comments

A spotlight on Grade 3 (High grade) Neuroendocrine Neoplasms

A spotlight on NENs - Types, Awareness, Patient Advocacy

Reviewed and updated 30th May 2023High Grade Neuroendocrine Neoplasms - the forgotten patient group?When reading articles in the mainstream media, found in medical publications; and even listening to doctors speak about my disease, it's clear that the focus is on the term "Neuroendocrine Tumours" or NET for short. Many websites of advocate foundation organisations and specialist scientific organisations, all still use the term "NET" in their naming. I too am guilty of having a large Facebook site falling into this category. It's little wonder that those with high grade disease can often feel like the forgotten patient group. Clearly all the aforementioned organisations support all patients regardless of grade, but it's true to say that the naming and general use of terminology continues to fall behind. It's also true that…

14Dec 2016 by Ronny Allan 4 Comments

Neuroendocrine Tumours: a spotlight on Pheochromocytoma and Paraganglioma

A spotlight on NENs - Types, Awareness, Patient Advocacy, Spotlight on NENs - Types Series

Updated 19th November 2023I spend a lot of time talking about the most common forms of Neuroendocrine Tumours (NETs), but what about the less well-known types? As part of my commitment to all types of NETs, I'd like to shine a light on two less common tumour types known as Pheochromocytomas and Paragangliomas - with an incidence rate of approximately 8 per million per year. They are normally grouped together, and the definitions below will confirm why. If you think it's difficult to diagnose a mainstream NET, this particular sub-type is a real challenge.So, let's get definitions out of the way:Pheochromocytomas (Pheo for short)Pheochromocytomas are tumours of the adrenal gland that produce excess adrenaline. They arise from the central portion of the adrenal gland, which is called the adrenal medulla…