Pancreatic Cancer – Types & Stages

Radiation Oncology Center in Orange County, CA

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Types of Pancreatic Cancer

Pancreatic cancer comes in a number of subtypes, and it’s important to understand the different variations of the condition. Among the most significant types are exocrine and endocrine cancers – these affect exocrine and endocrine cells, respectively, which are two prominent cell types found in the pancreas. Both of these forms of cancers have distinct risk factors, causes, symptoms, diagnostic tests, and treatments.

Pancreatic Exocrine Cancers

Exocrine cancers are the most common form of pancreatic cancer by a significant margin, accounting for more than 95% of all pancreatic cancer cases. Exocrine cancers come in a number of different subtypes:

Pancreatic Adenocarcinoma

Accounting for roughly 95% of pancreatic cancer cases, adenocarcinomas are by far the most common form of pancreatic cancer. They generally begin in the ducts of the pancreas, although they can also develop in the cells that produce pancreatic enzymes. In these cases, they’re called acinar cell carcinomas.

Other Forms of Exocrine Cancer

In addition to adenocarcinomas, exocrine cancers can include adenosquamous carcinomas, squamous cell carcinomas, signet ring cell carcinomas, undifferentiated carcinomas, and undifferentiated carcinomas with giant cells. These forms are all exocrine cancers, but they collectively make up only a small portion of pancreatic exocrine cancer cases.

Ampullary Cancer

Another relatively uncommon form of exocrine cancer, this form starts in the ampulla of the Vater, the area where the bile duct and the pancreatic duct merge and empty into the small intestine. While this condition isn’t technically a form of true pancreatic cancer, treatment is very similar, so it’s often grouped together with pancreatic cancer. Often ampullary cancers block the bile duct while still relatively small, causing jaundice (yellowing of the skin and eyes). While this may seem like a bad thing, it actually leads to more frequent early diagnosis and treatment, giving ampullary cancers a relatively good prognosis in comparison to other forms of pancreatic cancer.

Pancreatic Endocrine Cancers (Neuroendocrine Tumors)

Pancreatic endocrine tumors are extremely uncommon, accounting for less than 5% of all pancreatic cancer cases. These tumors are often also referred to as pancreatic neuroendocrine tumors (NETs) or islet cell tumors.

Pancreatic NETs may form as a benign (noncancerous) tumor or a malignant cancer. Unfortunately, both types look virtually the same under a microscope, so it’s often very difficult to diagnose an NET as benign or malignant. In some cases, doctors may not know if an NET is a cancer until it has spread outside the pancreas, which is a clear sign of malignancy.

While rare, pancreatic NETs come in a number of different types. They form three main subgroups:

Functioning NETs

Functioning NETs are tumors that create hormones and release them into the bloodstream, which can cause a range of symptoms. The different subtypes of functioning NETs are named for the hormones they produce:

  • Gastrinomas: These form from cells that make gastrin. Gastrinomas are roughly 50% benign and 50% cancer.
  • Insulinomas: Most insulinomas are benign, and the form from cells that make insulin. Insulinomas and gastrinomas make up the majority of functioning NETs, with the remaining types being very rare.
  • Glucagonomas: These tumors arise in cells that make glucagon, and most are cancerous.
  • Somatostatinomas: These form in the cells that make somatostatin, and most are cancerous.
  • CIPomas: Formed from cells that make vasoactive intestinal peptide (VIP), most VIPomas are cancers.
  • PPomas: Primarily cancerous, these tumors form from cells that create pancreatic polypeptide.

Nonfunctioning NETs

Nonfunctioning NETs don’t produce the same levels of excess hormones, and thus they display different symptoms. They’re more often cancerous than functioning tumors, and unfortunately, because they don’t produce the same symptoms from excess hormones, they’re often not detected until they’ve grown significantly large.

Carcinoid Tumors

The third form of NET, carcinoid tumors are most common in other parts of the digestive system but may form in the pancreas. Carcinoid tumors produce serotonin (5HT) or its precursor, 5HTP.

Classifying Pancreatic Tumors

Staging systems provide a standardized way for doctors to diagnose the size of a cancer, how far it has spread, and how generally dangerous it is. As with most types of cancer, pancreatic cancer is staged using a TNM system, which relies on 3 key elements:

  • Tumor: This describes the size of the primary tumor. Tumor size is graded on the literal size of the tumor as well as if it has grown outside the pancreas.
  • Node: This describes if the cancer has spread to nearby lymph nodes. Cancers frequently spread to these bean-sized collections of immune cells, and through the lymph system, they can provide a gateway to the rest of the body.
  • Metastasis: This indicates if the cancer has spread (metastasized) to other organs or regions of the body. Commonly, pancreatic cancer will metastasize to the liver, lungs, and peritoneum, which is a lining surrounding the organs in the abdomen.

In the TNM staging systems, numbers or letters appear after each variable to classify how advanced the cancer is. Generally, the higher the number, the more serious and advanced the cancer.

Tumor Staging Classifications

  • TX: Can’t assess the main tumor.
  • T0: No apparent evidence of a primary tumor.
  • Tis: Carcinoma in situ, meaning the tumor is confined only to the top layers of the pancreatic duct cells. It’s very rare to find a cancer at this stage.
  • T1: The cancer is less than 2cm across and has not grown outside the pancreas.
  • T2: Than cancer is larger than 2cm but still combined to the pancreas.
  • T3: The tumor has spread outside the pancreas but still hasn’t hit any major nerves or blood vessels.
  • T4: The cancer has spread past the pancreas and infected nearby nerves and large blood vessels.

Node Staging Classifications

  • NX: We cannot assess the nearby (regional) lymph nodes.
  • N0: The tumor hasn’t infected any lymph nodes.
  • N1: The cancer has spread to regional lymph nodes.

Metastasis Staging Classifications

  • M0: The cancer has not meaningfully metastasized to distant lymph nodes or organs.
  • M1: The cancer has metastasized, meaning it has spread to distant lymph nodes or distant organs. These are among the most serious cancers.

Stages of Pancreatic Cancer

Based on the T, N, and M categories of the tumor, your cancer doctor will determine the holistic stage of your cancer – whether stage 0, I, II, III, or IV. Pancreatic cancer stages go as follows:

  • Stage 0 – Tis, N0, M0: These tumors are only present in the top layers of the pancreatic duct cells and haven’t yet invaded any deeper tissues or spread outside the pancreas.
  • Stage IA – T1, N0, M0: These tumors are confined to within the pancreas and are less than 2cm across. No lymph nodes or distant tissues are infected.
  • Stage IB – T2, N0, M0: While larger than 2cm across, these tumors are still confined to the pancreas and have not spread to lymph nodes or other tissues.
  • Stage IIA – T3, N0, M0: These tumors have spread beyond the pancreas, but they haven’t hit any major nerves or blood vessels, grown into lymph nodes, or metastasized to distant sites.
  • Stage IIB – T3, N1, M0: At this stage, the tumor may still be entirely confined to the pancreas or have grown outside it but not yet into major nerves and blood vessels. In any case, the cancer has spread to regional lymph nodes but has not yet spread to distant sites.
  • Stage III – T4, Any N, M: Stage III tumors have spread beyond the pancreas and infected nearby nerves or major blood vessels. The cancer may or may not have infected regional lymph nodes, but it has not yet spread to distant sites.
  • Stage IV – T4, Any N, M1: The most serious stage of pancreatic cancer, these tumors have spread to distant sites.

Schedule a Cancer Treatment Consultation in Orange County

Pancreatic cancer is among the most serious forms of cancer at any stage, but no matter how bleak things look, there’s always hope. Call us today at 714.962.7100 to learn more about the world-class radiation oncology treatments we have to offer, or contact OC CyberKnife online to see how we can help you beat cancer. Together, we’ll create a treatment plan that attacks your cancer head on and gives you the best possible chance at reclaiming a normal, healthy life.