Diagnosing Neuroendocrine Neoplasms (NENs).

 It’s no secret that Neuroendocrine Neoplasms (NENs) can be difficult to diagnose, particularly well differentiated slow growing types (NETs) which can sometimes be difficult to see.  Plus, many patients present with relatively routine day to day symptoms suggesting a myriad of day-to-day illnesses seen daily in every GP/PCP practice. 

But conversely, many are found incidentally while checking for something else, or in reaction to a visit to the ER/A&E or as a referral by primary care physicians for further checks at secondary facilities.  A few examples:

1. Most appendiceal NETs are found when patients present with pain in the right lower quadrant i.e. symptoms of appendicitis.  The resulting appendectomy will find the tumour. However, it’s true to say that most appendectomies will be connected to appendicitis with no NET involvement.  Nonetheless, the number of NETs discovered this way is significant, but most will be removed with curative intent.  They rarely metastasise at the lower grades. 

2.  Many Gastric NETs are found when investigating symptoms of heartburn/acid reflux issues.  They are almost always found by simple endoscopy checks using cameras and needle biopsies.  They rarely metastasise at the lower grades. 

3. Many Rectal NETs are being found via colonoscopies when investigating symptoms of abdominal issues plus (e.g.) as a follow up to abnormal tests on faecal immunochemical test (FIT) as part of regular government cancer screening initiatives. Like appendiceal NETs, most of these will be removed with curative intent. They rarely metastasise at the lower grades. 

4.  More and more small intestine NETs are being found via extended colonoscopies (based on the common location of the terminal ileum) plus as a follow up to abnormal tests on faecal immunochemical test (FIT) as part of regular government cancer screening initiatives. 

5. More and more pancreatic NETs are being found a combination of endoscopy examinations and conventional imaging. 

6. Diagnoses of Lung NETs can be triggered by simple x-rays checking for things such as chest infections. 

7. Often, doctors move straight to imaging where abnormalities can be spotted which warrants further and deeper investigation. 

Most of the above can also be applied to Neuroendocrine Carcinomas (NECs), a poorly differentiated type of NEN. 

Despite what you see in patient groups and statistics pushed out by certain organisations, most NETs are localised (i.e. low stage) and grade 1. These statistics can be seen in the SEER US NET study published in 2017 (based on data up to 2012) – this document can be found in my “Not as rare as you think” blog post here.  When you consider the game changers below, this should hopefully confirm/improve this situation when new statistics come out in this new era of better imaging and earlier diagnoses.  An update to the above SEER dataset is due sometime in 2025 (in fact it’s well overdue).