Neuroendocrine tumors (NETs), or sometimes referred as islet cells, are
abnormal growths in the endocrine glands. Since endocrine glands produce
hormones, tumors of endocrine glands may also produce hormones. These
hormones are often produced in excessive amounts by endocrine tumors and
then released into the bloodstream, which can result in profound effects
on the body.
Neuroendocrine tumors can be found all over the body. They are most commonly
found in the abdomen, and are sometimes further classified as pancreatic
neurendocrine tumors (PNET), when found in the pancreas. PNETs are NETs
that arise in the pancreas. They tend to have a slightly worse prognosis
in comparison to NETs. Both PNETs and NETs tend to be slow growing tumors
that are treatable even after they have metastasized.
Although NETs are much less common than most GI malignancies, SEER data
(from 1973-2004) shows a dramatic 5-fold increase in diagnosed cases.
Diagnosed incidence of NETs is predicted to continue rising at a faster
rate than most other malignancies.
Neuroendocrine tumors can be benign or malignant. Whether benign or malignant,
it is recommended to have all abdominal NETs surgically removed. At the
time of resection/following surgery, the distinction of a benign or malignant
tumor will be determined.
A way of classifying Neuroendocrine tumors is by the secretion of hormones
from the tumor:
Non-functioning NETs: Patients with non-functioning tumors do not have any symptoms from excess
secretion of pancreatic hormones since the tumor does not secrete any
hormones into the blood.
Functional NETs: These tumors produce dramatic symptoms because of excess secretion of
various different hormones such as insulin, gastrin, or glucagon.
Risk Factors for Neuroendocrine Tumors
Generally, the causes of neuroendocrine tumors are unknown. However, certain
types of rare family syndromes have a higher risk of developing NETs, such as:
- Multiple endocrine neoplasia type 1
- Neurofibromatosis type 1
- Von Hippel-Lindau syndrome (VHL)
Symptoms of Neuroendocrine Tumors
Symptoms of neuroendocrine tumors depend on the type of tumor and it’s
location, whether it produces excess hormones, how aggressive it is and
whether it has spread to other structures in the body. NETs can be very
difficult to diagnose and may take many years to grow to a size larger
enough to be seen in imaging scans or produce symptoms.
Up to half of all neuroendocrine tumors produce excess amounts of hormones
that produce symptoms in the affected patient. For example, in patients
with insulin producing NETs of the pancreas, excessive insulin decreases
blood sugar levels so that symptoms of severe hypoglycemia develop. Whereas,
excessive hormones caused by others NETs may cause symptoms such as flushing,
diarrhea, asthma and heart valve problems.
Because there are a whole host of unusual symptoms that can be associated
with neuroendocrine tumors, it’s important to speak with your physician
if you’re experiencing any unusual symptoms, or have a family history
of neuroendocrine tumors.
If neuroendocrine tumors are suspected, it’s important to seek proper
evaluation and treatment from a healthcare expert experienced in the
treatment of gastrointestinal issues.
Expert Care You Can Trust!
The Hoag Digestive Disease Center, in alliance with USC Norris Comprehensive
Cancer Center, continues to lead the way in complex hepatobiliary and pancreatic cancer
care, providing access to a highly specialized surgical team that works
collaboratively with Hoag-affiliated gastroenterologists and medical oncology
specialists to provide academic-level care. Hoag’s committed to
accurate diagnosis, combined with
progressive therapeutic options enables Hoag patients to achieve some of the highest clinical outcomes
in the nation.
To schedule a comprehensive diagnostic evaluation, or a second-opinion
consultation with a Hoag hepatobiliary and pancreatic expert, visit
Meet the Team, or call us at: 949-764-5350.