How is pancreatic cancer staged?
The stage of a pancreatic cancer (extent of disease at diagnosis) is the most important factor in choosing treatment options and predicting a patient’s outlook. Pancreatic cancer is staged based on the results of exams, imaging tests, endoscopies, and biopsies, which are described in “How is pancreatic cancer diagnosed?”
The American Joint Committee on Cancer (AJCC) TNM staging system
A staging system is a standard way for doctors to sum up how far a cancer has spread. The main system used stage cancers of the pancreas is the American Joint Committee on Cancer (AJCC) TNM system. The TNM system is based on 3 key pieces of information:
- T describes the size of the main (primary) tumor and whether it has grown outside the pancreas and into nearby organs.
- N describes the spread to nearby (regional) lymph nodes.
- M indicates whether the cancer has metastasized (spread) to other organs of the body. (The most common sites of pancreatic cancer spread are the liver, lungs, and the peritoneum — the space around the digestive organs.)
Numbers or letters appear after T, N, and M to provide more details about each of these factors.
TX: The main tumor cannot be assessed.
T0: No evidence of a primary tumor.
Tis: Carcinoma in situ (the tumor is confined to the top layers of pancreatic duct cells). (Very few pancreatic tumors are found at this stage.)
T1: The cancer is still within the pancreas and is 2 centimeters (cm) (about ¾ inch) or less across.
T2: The cancer is still within the pancreas but is larger than 2 cm across.
T3: The cancer has grown outside the pancreas into nearby surrounding tissues but not into major blood vessels or nerves.
T4: The cancer has grown beyond the pancreas into nearby large blood vessels or nerves.
NX: Nearby (regional) lymph nodes cannot be assessed.
N0: The cancer has not spread to nearby lymph nodes.
N1: The cancer has spread to nearby lymph nodes.
M0: The cancer has not spread to distant lymph nodes (other than those near the pancreas) or to distant organs such as the liver, lungs, brain, etc.
M1: The cancer has spread to distant lymph nodes or to distant organs.
Stage grouping for pancreatic cancer
Once the T, N, and M categories have been determined, this information is combined to assign an overall stage of 0, I, II, III, or IV (sometimes followed by a letter). This process is called stage grouping.
Stage 0 (Tis, N0, M0): The tumor is confined to the top layers of pancreatic duct cells and has not invaded deeper tissues. It has not spread outside of the pancreas. These tumors are sometimes referred to as pancreatic carcinoma in situ or pancreatic intraepithelial neoplasia III (PanIn III).
Stage IA (T1, N0, M0): The tumor is confined to the pancreas and is 2 cm across or smaller (T1). It has not spread to nearby lymph nodes (N0) or distant sites (M0).
Stage IB (T2, N0, M0): The tumor is confined to the pancreas and is larger than 2 cm across (T2). It has not spread to nearby lymph nodes (N0) or distant sites (M0).
Stage IIA (T3, N0, M0): The tumor is growing outside the pancreas but not into major blood vessels or nerves (T3). It has not spread to nearby lymph nodes (N0) or distant sites (M0).
Stage IIB (T1-3, N1, M0): The tumor is either confined to the pancreas or growing outside the pancreas but not into major blood vessels or nerves (T1-T3). It has spread to nearby lymph nodes (N1) but not to distant sites (M0).
Stage III (T4, Any N, M0): The tumor is growing outside the pancreas into nearby major blood vessels or nerves (T4). It may or may not have spread to nearby lymph nodes (Any N). It has not spread to distant sites (M0).
Stage IV (Any T, Any N, M1): The cancer has spread to distant sites (M1).
Other prognostic factors
Although not formally part of the TNM system, other factors are also important in determining prognosis (outlook).
Tumor grade: The grade of the cancer (how abnormal the cells look under the microscope) is listed on a scale from G1 to G3 (or sometimes G1 to G4), with G1 cancers looking the most like normal cells and having the best outlook.
The details of grading are a little different for exocrine cancers and NETs. For NETs, measures of how many of the cells seem to be dividing is an important part of grading. This can be determined by counting mitoses (cells that have started to split into two new cells) under a microscope or with a Ki-67 test that recognizes cells that are almost ready to start splitting.
Extent of resection: For patients who have surgery, another important factor is the extent of the resection — whether or not all of the tumor is removed:
- R0: All visible and microscopic tumor was removed.
- R1: All visible tumor was removed, but lab tests of the removed specimen show that some small areas of cancer were probably left behind.
- R2: Some visible tumor could not be removed.
Resectable versus unresectable pancreatic cancer
The AJCC staging system provides a detailed summary of how far the cancer has spread. But for treatment purposes, doctors use a simpler staging system, which divides cancers into groups based on whether or not they can likely be removed (resected) with surgery. These groups are called resectable, borderline resectable, and unresectable (either locally advanced or metastatic).
These terms are used more often to describe exocrine pancreatic cancers than pancreatic neuroendocrine tumors.
If the cancer is only in the pancreas (or has spread just beyond it) and the surgeon believes the entire tumor can be removed, it is called resectable. (In general, this would include most stage IA, IB, and IIA cancers in the TNM system.)
It’s important to note that some cancers might appear to be resectable based on imaging tests such as CT scans, but once the surgeon starts the operation it might become clear that not all of the cancer can be removed. If this happens, only a sample of the cancer may be removed to confirm the diagnosis (if a biopsy hasn’t been done already), and the rest of the planned operation will be stopped to help avoid the risk of major side effects.
This term is used to describe some cancers that might have just reached nearby blood vessels, but which the doctors feel might still be removed completely with surgery. This would include some stage III cancers in the TNM system.
These cancers can’t be removed entirely by surgery.
Locally advanced: If the cancer has not yet spread to distant organs but it still can’t be removed completely with surgery, it is called locally advanced. Often the reason the cancer can’t be removed is because it has grown into or surrounded nearby major blood vessels. (In general, this would include stage IIB and most III cancers in the TNM system.)
Surgery to try to remove these tumors would be very unlikely to be helpful and could still have major side effects. Some type of surgery might still be done, but it would be a less involved operation with the goal of relieving symptoms or problems like a blocked bile duct or intestinal tract, not of curing the cancer.
Metastatic: If the cancer has spread to distant organs, it is called metastatic. These cancers can’t be removed completely. Surgery might still be done, but the goal would be to relieve symptoms, not to cure the cancer.
Last Medical Review: 06/11/2014
Last Revised: 06/11/2014