Staging Pancreatic NETs

When diagnosed with a pancreatic neuroendocrine tumor (NET), most patients are naturally anxious to learn the severity of their disease and the stage of the cancer. The cancer stage gives them an idea of the disease outcome and the types of treatment that may be needed. Being well-informed about the stages of pancreatic NET can help patients prepare for what’s to come physically, mentally and emotionally.

The most common staging system for pancreatic NETs in the United States follows the American Joint Committee on Cancer (AJCC) staging manual. The 8th edition, which is the latest edition of the staging manual, has both clinical and pathological staging systems.

This article covers the staging system for lower-grade tumors (grade 1 or 2), which tend to grow more slowly than high-grade tumors. It is important to note that high-grade pancreatic NETs and other types of pancreatic cancer follow a different staging system.

Learn more: Pancreatic Cancer Stages

The clinical stage is the stage given regardless of the type of treatment. It is based on physical examinations, imaging tests, diagnostic tests and biopsies.

The pathological stage is the stage given after surgery or resection of the tumor, if these treatments are carried out. It is based on information obtained from the surgery, together with any tests done before surgery. The pathological stage tends to be more reflective of the patient’s outlook than the clinical prognosis stage, as it is based on more accurate information on the size and spread of cancer.

Both the clinical stage and pathological stage are based on:

• Size of primary tumor
• Nodal involvement
• Presence of distant metastases

The size of the primary tumor, nodal involvement and presence of distant metastases are described using the AJCC TNM system.

Primary tumor (T)

This category is based on the size of the tumor, the number of tumors and whether or not the cancer has spread to nearby structures. It is described with the letter ‘T’ followed by ‘X’, 0, 1, 2, 3 or 4.

TX: Size of the tumor cannot be measured.

T0: No tumor is present.

T1: A single tumor limited to the pancreas of 2 cm (about 0.8 inches) or smaller.

T2: A single tumor limited to the pancreas that is larger than 2 cm but no larger than 4 cm (about 1.6 inches).

T3: A single tumor limited to the pancreas that is larger than 4 cm OR a tumor that has grown into the duodenum or the common bile duct.

T4: Any size of tumor or multiple tumors growing into any large blood vessel, or any size of tumor or multiple tumors directly invading adjacent organs.

Nodal involvement (N)

This category looks at how many lymph nodes the cancer has spread to, if any. It is described with the letter ‘N’ followed by ‘X’, 0, 1 or 2. This is a brief and simplified description of nodal involvement:

NX: The lymph nodes cannot be assessed.

N0: No cancer has advanced to regional lymph nodes.

N1: Cancer has spread to no more than 3 regional lymph nodes.

N2: Cancer has spread to 4 or more regional lymph nodes.

Distant metastases (M)

This category determines if the cancer has spread to more distant parts of the body, such as the lungs or liver, after imaging tests, physical examination or biopsy. It is described with the letter ‘M’ followed by 0 or 1.

M0: Cancer has not advanced to other parts of the body.

M1: Cancer has advanced to distant organs.

Depending on the TNM assessment, the cancer is clinically staged according to the categories below.

In addition to TNM staging, the biomarker Ki-67 is also used as a prognostic tool for pancreatic neuroendocrine tumors. Ki-67 is a protein that is present in rapidly-dividing cancer cells and can be detected via a biopsy of the affected tissue.

Tumors that exhibit a higher proportion of Ki-67-positive cells tend to be more aggressive. Proportions of Ki-67-positive cells relate to tumor aggressiveness as given below.

Your doctor may share the Ki-67 value of your tumor with you, or you may see this number on the pathologist’s report. Either way, it is an essential component of staging the pancreatic NET and will be used to inform therapeutic decision-making on your journey.

Learning your pancreatic cancer NET stage and prognosis can be a challenging and emotional experience, but it is an essential part of your cancer journey. Understanding the stages of pancreatic NETs can give you a greater sense of control and help you feel more prepared for what lies ahead. It's natural to feel a range of emotions after receiving a diagnosis, and having a strong support system to lean on throughout the process can provide some comfort. Rest assured that your healthcare team will be with you every step of the way, answering your questions and providing guidance as you navigate your treatment.