What are the other Names for this Condition? (Also known as/Synonyms)

• G Cell Tumor of Pancreas
• Pancreatic Gastrin-Producing Tumor
• Ulcerogenic Islet Cell Tumor of Pancreas

What is Gastrinoma of Pancreas? (Definition/Background Information)

• Gastrinoma of Pancreas is a malignant tumor of G-cells that produce the gastrin hormone. They are considered to be functionally-active tumors, because they secrete gastrin. They may be found in the pancreas or duodenum (part of the small intestine)
• These pancreatic tumors generally occur in adults, especially in men. They can occur as part of Zollinger-Ellision syndrome
• Due to the secretion of gastrin, there is ulceration of the stomach and intestines, with many other associated signs and symptoms. The malignant tumors may infiltrate into local tissue or even metastasize (which happens frequently)
• There are various treatment modalities available to address Gastrinoma of Pancreas; although, a complete surgical excision is the preferred mode of treatment. In cases of metastasis, a combination of chemotherapy, radiation therapy, and surgical procedures may be used
• The prognosis of Gastrinoma of Pancreas depends upon many factors including the stage of the tumor and overall health of the individual. it also depends upon the severity of the underlying conditions such as Zollinger-Ellision syndrome or multiple endocrine neoplasia 1

The pancreas is an important organ of the digestive system.

• Based on function of the pancreas, it can be functionally divided into 2 parts, namely:
  • Exocrine pancreas, which produces digestive enzymes, and
  • Endocrine pancreas that produces hormones such as insulin, glucagon, and somatostatin. Insulin and glucagon helps with controlling sugar levels in blood
• 95% of the pancreas is exocrine portion and 5% is endocrine portion. Pancreatic tumors (both benign and malignant) can arise from both the exocrine and the endocrine part
• Based upon anatomy of the pancreas, it can be divided into 3 main parts, namely the:
  • Head,
  • Body, and
  • Tail
• Pancreatic tumors can affect the head, body, and tail region of the pancreas. Some tumors can affect one area of the pancreas more than the other areas.

Hence, localizing the tumor site can guide the healthcare provider to arrive at a probable diagnosis.

Who gets Gastrinoma of Pancreas? (Age and Sex Distribution)

• Pancreatic Gastrinoma is tumor that typically affects adults in the 30-50 years age group
• It can affect both males and females, though a preference for males is observed (male-female ratio is 2:1)
• The condition can occur worldwide; individuals of all racial and ethnic background may be affected

What are the Risk Factors for Gastrinoma of Pancreas? (Predisposing Factors)

The risk factors for Gastrinoma of Pancreas include the following:

• Zollinger-Ellision syndrome (ZES): A condition in which a high level of gastrin hormone is produced due to the formation of tumors called Gastrinomas
• Multiple endocrine neoplasia type 1 (MEN 1) which is an inherited genetic disorder
• A family history of Pancreatic Gastrinoma or other pancreatic tumors/cancers

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Gastrinoma of Pancreas? (Etiology)

The exact cause of Gastrinoma of Pancreas development is unknown.

• Many of these tumors are associated with Zollinger-Ellision syndrome to a greater extent, and to multiple endocrine neoplasia type 1 to a lesser extent
• However, Pancreatic Gastrinomas can also occur in individuals not diagnosed with either ZES or MEN 1
• Research scientists believe that the cause of the condition is mostly due to molecular or genetic mutations, which results in tumor formation

What are the Signs and Symptoms of Gastrinoma of Pancreas?

The signs and symptoms of Gastrinoma of Pancreas depend upon the size and location of the tumor. Most tumors occur in the duodenum, while some occur in the pancreas. During the initial stages, small tumors may not cause any signs and symptoms that are readily recognized. Hence, these tumors are only detected incidentally, when being worked-up for other conditions (i.e., diagnostic tests and exams undertaken for other health conditions).

The signs and symptoms may include the following:

Majority of them (90%) have ulcers in either the duodenum or stomach

• Over 50% of the affected individuals have diarrhea
• Symptoms of low glucose level in blood, such as sweating, dizziness/confusion, blurring of vision, and even loss of consciousness
• Nausea and vomiting
• Abdominal pain, back pain
• Loss of appetite, weight loss
• Indigestion
• Yellowing of skin (jaundice)
• Dark-colored urine
• Fatigue (getting tired easily)
• Signs and symptoms of any underlying disorder, such as ZES or MEN 1

General features of Pancreatic Gastrinoma include:

• The tumors are usually a few millimeters to a few centimeters in size. Sometimes the tumors are missed, because of their small size
• They can arise from the endocrine portion of the pancreas
• The tumors may be single, while sometimes multiple tumors are observed

How is Gastrinoma of Pancreas Diagnosed?

Frequently, pancreatic tumors are difficult to detect/diagnose in the early stages. The signs and symptoms can be very similar to other conditions. Since the pancreas is located in the peritoneum, behind many organs, there is a lot of space for the tumor to grow (often unnoticed).

The following are the diagnostic methods that may be used to detect Gastrinoma of Pancreas:

• A thorough physical examination and a complete medical history is very important
• Fasting serum gastrin levels
• Glucagon provocative test
• Pancreatic arteriography to detect small tumors
• Radiological studies that include:
  • Upper GI endoscopy: The use of an endoscope to visualize the gastrointestinal tract (esophagus, stomach, etc.)
  • Abdominal ultrasound: A procedure where high-frequency sound waves are used to produce real-time images
  • Endoscopic ultrasound: It is a minimally-invasive procedure that uses high-frequency sound waves to obtain detailed images of the pancreas
  • CT scan of abdomen: It may be helpful in detecting recurrences, or if metastasis to other organs has occurred
  • MRI scan of abdomen: It helps produce high-quality pictures of certain body parts including the tissues, muscles, nerves, and bones
• Additionally, the following magnetic resonance imaging procedures may be used particularly in individuals suspected of having pancreatic tumor/cancer:
  • MR cholangio-pancreatography (MRCP)
  • MR angiography (MRA)
• Positron emission tomography (PET) scan: It is particularly helpful in visualizing the spread of the cancer to other body parts (metastasis) and/or recurrence
• Somatostatin scintigraphy (helps to localize the tumor)
• Gastrin level testing using selective transhepatic portal venous sampling. In this test, the gastrin levels from various parts of the portal system is measured to localize the tumor
• Tissue biopsy: A tissue biopsy is performed and sent to a laboratory for a pathological examination to the pathologist, who examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

The tissue for diagnosis can be procured in multiple different ways, and they include:

• Fine needle aspiration (FNA) biopsy of the pancreatic tumor:
  • A FNA biopsy may not be helpful, because one may not be able to visualize the different morphological areas of the tumor. Hence, a FNA biopsy as a diagnostic tool has certain limitations, and an open surgical biopsy is preferred
• Core biopsy of the pancreatic tumor
• Open biopsy of the pancreatic tumor

Other tests to diagnose Gastrinoma of Pancreas may include the following:

• Blood test to check for serum amylase levels
• Complete blood count with differential
• Blood tests that may involve tumors markers, such as:
  • Carcinoembryonic antigen (CEA)
  • CA 19.9
  • CA 15.3
  • Alpha fetoprotein
• Percutaneous transhepatic cholangiography (PTC): A contrast material is injected into the bile ducts to visualize the structure
• Endoscopic retrograde cholangio-pancreatography (ERCP): This technique is used when symptoms of pancreatic cancer are present in the individual. A special equipment and dye injections are used to obtain a series of images. If required, a biopsy sample may also be collected during the procedure
• Invasive diagnostic procedures such as:
• Laparoscopy: A special device is inserted through a small hole into the abdomen, to visually examine it. If necessary, a tissue sample is obtained for further analysis. Exploration of the abdomen using a laparoscope is called ‘exploratory laparoscopy’
• Laparotomy: The abdomen is opened through an incision for examination, and if required, a biopsy sample obtained. Exploration of the abdomen using laparotomy procedure is called ‘exploratory laparotomy’

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Gastrinoma of Pancreas?

The complications due to Gastrinoma of Pancreas may include the following:

• Gastrointestinal and biliary tract obstruction causing jaundice
• Severe ulcer formation resulting in signs and symptoms, such as GI bleeding, nausea and vomiting, abdominal pain, and intestinal perforation
• Compress adjoining organs if the tumor size is large, which may cause the organs to dysfunction or function abnormally
• Severe hypoglycemia can cause brain damage
• Malignant tumors can cause local invasion or distant metastasis; up to 50% of the individuals may have metastasis at the time of diagnosis
• Complications may arise due to the presence of the underlying genetic disorder (ZES or MEN type 1)

How is Gastrinoma of Pancreas Treated?

The treatment of Gastrinoma of Pancreas depends upon a set of factors that include the following:

• If the tumor is benign or malignant
• Stage of the tumor (how far the tumor has spread from the pancreas)
• Whether it is a single tumor, or there are multiple tumors
• Whether the tumor is associated with a syndrome (such as ZES or MEN 1)
• Overall health status of the individual
• Location of the tumor in the pancreas (head, body, or tail)
• Size of the tumor

The treatment measures available for Pancreatic Gastrinoma include the following:

• In most cases, a surgical resection of the entire tumor is the preferred treatment option
• In some cases, a portion of the pancreas may have to be removed
• If the tumor has metastasized, then a combination of chemotherapy, radiation therapy, and invasive procedures may be used to treat the tumor. This is often based upon the individual’s specific circumstance
• Proton pump inhibitor medication
• Other treatment options may include:
  • Radiofrequency ablation of the tumor
  • Cryotherapy
  • Selective internal radiotherapy
  • Transarterial chemoembolization (TACE)
  • If the above measures are not effective, chemotherapy may be considered
• Treatment of the underlying ZES or MEN type 1 (if any present)
• Post-operative care is important: One must maintain minimum activity levels, until the surgical wound heals
• Follow-up care with regular screening and check-ups are important and encouraged

How can Gastrinoma of Pancreas be Prevented?

Currently, there are no specific methods or guidelines to prevent Gastrinoma of Pancreas. However, the condition may be avoided through the following measures:

• Genetic testing in individuals with a family history of pancreatic tumors or underlying genetic conditions associated with pancreatic tumors (such as ZES or MEN type 1)
• Regular medical screening at periodic intervals with blood tests, scans, and physical examinations for those who have already endured the tumor

What is the Prognosis of Gastrinoma of Pancreas? (Outcomes/Resolutions)

• Gastrinoma of Pancreas is a malignant tumor and its prognosis depends upon a set of several factors, which include:
  • Stage of tumor: With lower-stage tumors, when the tumor is confined to site of origin, the prognosis is usually excellent with appropriate therapy. In higher-stage tumors, such as tumors with metastasis, the prognosis is poor
  • The surgical respectability of the tumor (meaning, if the tumor can be removed completely) 
  • Overall health of the individual: Individuals with overall excellent health have better prognosis compared to those with poor health
  • Age of the individual: Older individuals generally have poorer prognosis than younger individuals
  • Whether the tumor is occurring for the first time, or is a recurrent tumor. Recurring tumors have a poorer prognosis compared to tumors that do not recur
  • Response to treatment: Tumors that respond to treatment have better prognosis compared to tumors that do not respond so well to treatment
• An early diagnosis and prompt treatment of the malignant tumor generally yields better outcomes than a late diagnosis and delayed treatment
• In case of underlying genetic syndromes, such as Zollinger-Ellision syndrome or multiple endocrine neoplasia 1, the prognosis is further dependent upon the severity of the syndrome
• Regular follow up visits with the healthcare provider are important

Additional and Relevant Useful Information for Gastrinoma of Pancreas:

It is estimated that the average lifetime risk of developing pancreatic cancer is about 1.5%.