Neuroendocrine cancer of the pancreas is a rare form of cancer originating in the hormone-producing cells of the pancreas. Often called pancreatic neuroendocrine tumors (PNETs), this type differs significantly from the more common pancreatic adenocarcinoma in its behavior, symptoms, diagnosis, and treatment.
Understanding Pancreatic Neuroendocrine Tumors
Pancreatic neuroendocrine tumors (PNETs) develop from the islet cells of the pancreas, which produce hormones like insulin and glucagon that regulate blood sugar. PNETs are far less common than exocrine pancreatic cancers, such as adenocarcinoma, accounting for less than 10% of all pancreatic tumors, sometimes as low as 2%.
PNETs are broadly classified into functional and non-functional types. Functional tumors produce an excess of hormones, leading to specific symptom syndromes. Examples include insulinomas, which secrete insulin, and gastrinomas, which produce gastrin. Non-functional tumors do not produce significant amounts of hormones and cause symptoms due to their growth and pressure on surrounding organs. PNETs often grow more slowly than adenocarcinomas, potentially leading to a better outlook.
Recognizing the Signs
The symptoms of pancreatic neuroendocrine tumors vary widely depending on whether the tumor is functional or non-functional. Functional tumors often present with symptoms related to specific hormone overproduction. For instance, an insulinoma may cause hypoglycemia, leading to sweating, confusion, and a fast heartbeat. A gastrinoma can result in excessive stomach acid production, causing severe stomach ulcers and abdominal pain.
Non-functional tumors, which do not release hormones, cause symptoms as they grow and press on nearby structures. These symptoms can include generalized abdominal pain, unexplained weight loss, or jaundice if the tumor obstructs the bile duct. Many PNET symptoms can be vague and non-specific, making early detection challenging. Some individuals may experience symptoms for up to a year before receiving a diagnosis.
How Pancreatic Neuroendocrine Tumors Are Diagnosed
Diagnosis of pancreatic neuroendocrine tumors begins with an evaluation of symptoms and a physical examination. Initial blood tests may check for elevated levels of general tumor markers like chromogranin A, or specific hormone levels if a functional tumor is suspected. For example, insulin levels are checked for an insulinoma, or gastrin levels for a gastrinoma.
Imaging techniques play a significant role in identifying and locating PNETs. CT scans and MRI are commonly used to visualize the pancreas and detect tumors. Somatostatin receptor scintigraphy, such as a Ga-68 DOTATATE PET/CT scan, is particularly useful as neuroendocrine cells often have somatostatin receptors, allowing these scans to highlight the tumors. A definitive diagnosis and tumor grading require a biopsy, often performed using endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). This procedure allows for tissue sample collection for pathological examination, which helps determine the tumor’s aggressiveness and stage.
Treatment Approaches
Treatment for pancreatic neuroendocrine tumors is individualized, considering factors such as the tumor’s stage, grade, functionality, and the patient’s overall health. Surgical resection is often the preferred approach for localized tumors, aiming to remove the tumor completely. Even in cases where the cancer has spread, surgery may still be considered to remove as much of the tumor as possible, particularly for slower-growing types.
For more advanced or metastatic disease, various systemic therapies are available. Targeted therapies, such as everolimus and sunitinib, interfere with specific pathways that promote tumor growth. Somatostatin analogs like octreotide and lanreotide are frequently used to control hormone-related symptoms in functional tumors and can also help slow tumor growth. Peptide receptor radionuclide therapy (PRRT), specifically using Lutetium-177 dotatate, delivers targeted radiation directly to neuroendocrine cells that express somatostatin receptors. Chemotherapy may be used for more aggressive or rapidly growing PNETs, and for liver metastases, liver-directed therapies such as embolization or ablation can reduce tumor burden and manage symptoms.
Living with Pancreatic Neuroendocrine Tumors
Living with pancreatic neuroendocrine tumors often involves long-term management and ongoing medical observation. Due to the potential for recurrence or progression, regular follow-up care is important. This includes periodic imaging scans and blood tests to monitor for any changes in the tumor’s status.
The prognosis for individuals with PNETs can vary significantly, depending on factors such as the tumor’s grade, stage at diagnosis, and whether it is functional or non-functional. A multidisciplinary team, including oncologists, endocrinologists, and surgeons, often collaborates to provide comprehensive care. This team approach addresses both the physical aspects of the disease and quality of life considerations for the patient.