What Is a Neuroendocrine Tumor?

Neuroendocrine tumors are tumors that originate from neuroendocrine cells. Neuroendocrine cells are a large class of cells with a neuroendocrine phenotype in the body that can produce a variety of hormones.

Basic Information

Visiting department

Gastroenterology, Gastrointestinal Surgery, Oncology

Common locations

Stomach, intestine, pancreas

Common causes

still not clear

Contagious

no

Causes of neuroendocrine tumors

Most neuroendocrine tumors are sporadic, and the exact etiology is unknown. However, the occurrence of a small number of neuroendocrine tumors is related to genetic factors, involving the deletion and mutation of some genes, such as multiple endocrine adenomas (MEN), von Hippel-lindausyndrome (VHLsyndrome).

Clinical manifestations of neuroendocrine tumors

Neuroendocrine tumors are classified into non-functional (approximately 80%) and functional (approximately 20%) two types according to whether the tumor has hormone secretion function and the presence or absence of clinical symptoms caused by hormones. Non-functional gastrointestinal and pancreatic neuroendocrine tumors are mainly manifested as non-specific gastrointestinal symptoms or local space occupying symptoms, such as progressive dysphagia, abdominal pain, bloating, diarrhea, abdominal mass, jaundice or mela Gut and pancreatic neuroendocrine tumors are mainly clinical symptoms related to biologically active hormones secreted by the tumor, such as skin flushing, sweating, asthma, diarrhea, hypoglycemia, refractory peptic ulcer, and diabetes. Functional gastrointestinal pancreatic neuroendocrine tumors are mainly pancreatic neuroendocrine tumors, including insulinoma, somatostatin tumor, glucagon tumor, and gastrinoma.

Neuroendocrine tumor examination

Tumor marker examination

Neuroendocrine tumors have a very important tumor marker called ChromograninA (CgA), which is the most valuable universal marker for neuroendocrine tumors (whether functional or non-functional neuroendocrine tumors). . Detection of serum or plasma chromaffin A levels can indicate whether a patient has a neuroendocrine tumor, or track the patient's response to treatment, or even assess the patient's prognosis. Serum or plasma chromogranin A detection has a diagnostic sensitivity and specificity between 60% and 95%. In addition to chromaffin A, a universal tumor marker, functional neuroendocrine tumors can also be diagnosed by detecting the secretion of special hormones. For example, gastrinoma can detect serum gastrin levels, and insulinoma can detect serum insulin levels. .

2. Imaging examination

Various imaging examinations, including endoscope, endoscopic ultrasound, ultrasound, CT, PET-CT, MRI, Somatostatin Receptors Cinigraphy (SRS), etc. are important means for the localized diagnosis of neuroendocrine tumors.

3. Pathological examination

The final diagnosis of neuroendocrine tumors depends on pathological examination.

The main points of pathological diagnosis of neuroendocrine tumors include: first, determine whether the tumor is a neuroendocrine tumor by immunostaining the neuroendocrine markers Synaptophysin (Syn) and chromogranin A; secondly, determine the tumor classification according to the tumor's proliferative activity. Tumor proliferative activity was assessed by mitotic figures or Ki-67 positive index.

Gastrointestinal and pancreatic neuroendocrine tumors are classified according to the tumor's proliferative activity: G1 (low grade, 1/10 mitotic figures, high magnification field or Ki 67 index 2%), G2 (medium grade, mitotic figures 2 20 / 10 high-power field of view or Ki-67 index of 3% to 20%), G3 (high level, mitotic image number> 20/10 high-power field of view or Ki-67 index> 20%). Based on the above,

Gastrointestinal pancreatic neuroendocrine tumors are classified as follows:

(1) Neuroendocrine tumor (NET) is a highly differentiated neuroendocrine tumor, classified as G1 and G2.

(2) Neuroendocrine carcinoma (NEC) is a poorly differentiated and highly malignant tumor classified as G3.

(3) Mixedadenoendocrinecarcinoma (MANEC) is a special type of neuroendocrine cancer. Morphologically, it includes two components of adenocarcinoma and neuroendocrine cancer. Any one of the two components accounts for at least 30%.

Neuroendocrine tumor diagnosis

According to the corresponding clinical manifestations, tumor marker detection, imaging examination and pathological examination, the diagnosis of neuroendocrine tumors is performed. The complete diagnosis includes tumor location, grade, stage, and functional status.

Neuroendocrine tumor treatment

The treatment methods for neuroendocrine tumors include endoscopic surgery and surgical treatment, radiation intervention therapy, radionuclide therapy, chemotherapy, biological therapy, molecular targeted therapy, etc. The choice of treatment method depends on the grade, stage, Occurrence site and whether it has the function of secreting hormones.

For localized tumors, radical resection can be performed; for patients with advanced tumors, palliative treatment can also be performed through surgical cytoreductive surgery; for patients with liver metastases only, local treatment for liver metastases can be selected, including Various ablation, hepatic artery embolism, radioactive particle implantation, and even liver transplantation; for metastatic neuroendocrine tumors, nuclide-labeled somatostatin analogs can also be used for peptide receptor-mediated radionuclide therapy, referred to as PRRT (PeptideRadioReceptorTherapy, PRRT).

Drug therapy for neuroendocrine tumors includes chemotherapy, biological therapy, and molecular targeted therapy. The goal of drug therapy is to control the symptoms caused by the excessive secretion of functional neuroendocrine tumor hormones, and to control the growth of tumors. The choice of drug also depends on the location, functional status, pathological grade, and tumor stage of the tumor. Traditional cytotoxic chemotherapy drugs are still the first-line treatment for poorly differentiated G3 neuroendocrine cancer, but well differentiated G1 and G2 neuroendocrine tumors are not sensitive to chemotherapy. Biological therapy and targeted therapy are the main drug treatments for G1 and G2 neuroendocrine tumors. The current drugs used in the biological treatment of neuroendocrine tumors are mainly somatostatin analogs, including octreotide and lanreotide; targeted drugs include mammalian rapamycin target protein inhibitor everolimus and receptor tyrosine kinase Inhibitor sunitinib. The selection of drugs is summarized in the following table:

drug	Primary tumor site	Features	Grading
Octreotide / lanreotide	Anywhere	+/-	G1-2
Streptozotocin + 5-FU	pancreas	+/-	G1-2
Temozolomide + capecitabine	pancreas	+/-	G1-2
Everolimus or sunitinib	pancreas	+/-	G1-2
Etoposide + cisplatin	Anywhere	+/-	G3
Octreotide / lanreotide	Anywhere	+	G1-G3

Prognosis and follow-up of neuroendocrine tumors

The factors affecting the prognosis of neuroendocrine tumors include tumor size, location, grade, and stage. The survival time of poorly differentiated G3 neuroendocrine cancer is about 10 months. Well-differentiated G1 and G2 neuroendocrine tumors usually progress slowly, with survival ranging from 3 to 20 years.

The follow-up and review of patients with neuroendocrine tumors need to communicate closely with the doctor. The doctor will formulate different review and follow-up plans according to the tumor size, location, grade and stage. Common follow-up methods include serum chromaffin A detection, CT, MRI and internal medicine. Mirror and other imaging examinations.