This is a topic worth diving into since there are several types of pancreatic cancers. They are very different with regards to the treatment and the prognosis.
In general, when people discuss pancreas cancer, they mean pancreatic ductal adenocarcinoma. This is a type of cancer that grows out of the glands of the duct of the pancreas.
What is pancreatic adenocarcinoma?
Pancreatic adenocarcinoma, or more accurately pancreatic ductal adenocarcinoma, arises from the pancreatic duct glands. To refresh your memory, the duct is the main channel that runs through the pancreas and collects the pancreatic digestive enzymes.
The glands of the pancreatic duct can over time get injured and go through a process of precancer (PanIN) to full-blown invasive cancer cells. We still don’t know why people develop these precancer changes, or why only some people progress from PanIN to invasive cancer and others don’t. Cysts of the pancreas can also degenerate and lead to pancreatic ductal adenocarcinoma.
More of these pancreatic ductal adenocarcinomas arise in the head of the pancreas (the right side) than the body or tail (left side). Pancreatic head adenocarcinomas classically result in blockage of the bile duct leading to patients developing jaundice (yellowing of the eyes and skin). This is often a useful way to detect pancreatic cancer early, since the other signs (vague abdominal pain, back pain, weight loss) are not specific to pancreatic adenocarcinoma.
Once these lesions are found, additional CT scans or MRIs are needed to better characterize it and evaluate the other organs to look for spread. To confirm the diagnosis of pancreatic adenocarcinoma, biopsies are necessary.
Unfortunately, three quarters of the time when pancreatic adenocarcinoma is found, it has already spread. For such situations, chemotherapy is the only option available for treatment.
In patients with localized pancreas cancer that hasn’t spread outside of the pancreas or lymph nodes, the treatment is typically chemotherapy and surgery.
What are pancreatic neuroendocrine tumors?
The second major type of pancreatic cancers are pancreatic neuroendocrine tumors (PNET). Pancreatic neuroendocrine tumors are completely different from adenocarcinomas.
Pancreatic neuroendocrine tumors arise from hormone producing cells within the pancreas. These normal neuroendocrine cells can start to over-produce leading to a tumor. For pancreatic neuroendocrine tumors, there are certain key distinguishing features such as the grade (appearance of the cells and their rate of division), size and whether they are producing hormones.
Pancreatic neuroendocrine cells produce various GI hormones, and certain tumors can over produce these. The hormones include insulin, glucagon, gastrin, somatostatin and vasoactive intestinal peptide (VIP). An insulin producing tumor, an insulinoma, can lead to severe attacks of low blood sugar that responds to glucose intake. A glucagon producing tumor, a glucagonoma, has an opposing effecting to insulin with high blood sugars and new-onset diabetes. Gastrinomas over-produce gastrin leading to stomach ulcers, diarrhea and sometimes an unexplained rash. Somatostatinomas can have vague symptoms of diabetes, diarrhea and gallstone issues. And lastly, VIPomas cause severe watery diarrhea. As you may expect, the levels of these hormones can be measured through blood tests and used for confirmation.
Generally, any pancreatic neuroendocrine tumor that secretes hormones and causes symptoms should be removed with surgery. For tumors that don’t secrete hormones (nonfunctional tumors), the management is more nuanced, but is generally based on size. Small non-functional tumors (<1 cm) rarely spread or cause problems, so are typically watched with routine imaging. As non-functional tumors grow to 2cm or more, there is a higher risk of spread and so they are generally removed. There is a special type of PET scan, called a Dotatate PET scan, that is very useful in these scenarios.
Other types of tumors
There are certain other rare types of pancreatic tumors. These include tumors such as acinar cell carcinomas and solid pseudopapillary neoplasms (SPN). These are quite rare and should be evaluated by a pancreatic specialist.
Hearing the words ‘pancreatic cancer’ is understandably frightening and worrying. However, the main purpose of this post is to ensure that you know what kind of pancreatic cancer one may be facing: adenocarcinoma or neuroendocrine tumor. The next steps for each of these are different, and the strategies for overcoming them are also different. They are both treatable, but each treatment type is unique. Please stay tuned for more posts that explore these in more detail.