The TNM system for pancreatic cancer
The most commonly used system to stage pancreatic cancer is the TNM system. It was developed by the International Union Against Cancer and the American Joint Committee on Cancer (AJCC).
The first step in staging is to find the value for each part of the TNM system. Here is what the letters stand for in the TNM system:
T refers to the size of the tumor in the pancreas and if it has grown into nearby tissues.
N refers to whether any lymph nodes in the area of the original tumor have cancer in them.
M refers to whether the cancer has spread (metastasized) to other, distant organs in the body, such as the liver or lungs.
Numbers or letters after T, N, and M provide more details about each of these factors. There are also 2 other values that can be assigned:
X means the provider does not have enough information to tell the extent of the main tumor (TX), or if the lymph nodes have cancer cells in them (NX).
0 means no sign of cancer, such as no sign of spread to the lymph nodes (N0).
What are the stage groupings of pancreatic cancer?
Stage groupings are determined by combining the T, N, and M values from the TNM system. These groupings give an overall description of your cancer. A stage grouping can have a value of 0 or of Roman numeral I through IV (1 through 4). The higher the number, the more advanced the cancer is. Letters and numbers can be used after the Roman numeral to give more details.
To arrive at the stage of your cancer, your healthcare provider first assigns numbers for the T, N, and M groups. These numbers are then combined in a process called stage grouping to give the cancer an overall stage. The lower the number, the less the cancer has spread. The higher the number, the more the cancer has spread.
These are the stages groupings of pancreatic cancer and what they mean:
Stage 0. The tumor is only in the top innermost layer of cells lining the pancreatic duct. It has not invaded the deeper layers or spread anywhere else. This may be called pancreatic cancer in situ.
Stage I. The cancer has not spread to organs in other parts of the body. This stage is divided into 2 groups:
Stage IA. The cancer is only found inside the pancreas. It’s no larger than 2 cm (centimeters) across.
Stage IB. The cancer is only found inside the pancreas. It’s more than 2 cm but less than 4 cm across.
Stage II. The cancer has not spread to organs in other parts of the body. This stage is divided into 2 groups:
Stage III. The cancer has not spread to organs in other parts of the body. This stage can be any one of the following:
The cancer is only found inside the pancreas. It’s no larger than 2 cm across. It has spread to 4 or more nearby lymph nodes.
The cancer is only found inside the pancreas. It’s more than 2 cm but less than 4 cm across. It has spread to 4 or more nearby lymph nodes.
The cancer is only found inside the pancreas. It’s larger than 4 cm across. It has spread to 4 or more nearby lymph nodes.
The cancer has grown outside the pancreas and into large blood vessels that are nearby. It may or may not have spread to nearby lymph nodes.
Stage IV. The cancer has spread to organs further away from the pancreas. These might include the liver, lining of the abdomen (called the peritoneum), bones, or lungs.
Resectable, borderline resectable, locally advanced, and metastatic cancer
Healthcare providers use the TNM system to formally stage pancreatic cancer. But for practical reasons, they often use a simpler system when trying to decide the best treatment. They may divide cancer into these 3 main groups based on whether they can be removed (resected) with surgery:
These cancers can be surgically removed. This includes many cancers that are still confined within the pancreas or have grown just outside of it.
Borderline resectable cancer
These cancers might be able to be surgically removed. But they are very close to major blood vessels. For these cancers, treatments other than surgery might be tried first to try to shrink the tumor and make it resectable.
These cancers can't fully be removed with surgery:
Locally advanced cancer. These cancers are still only in the area around the pancreas. But they can't be fully removed with surgery. This is often because they’re growing into nearby blood vessels. Surgery may still be done to relieve symptoms, but not to try to cure the cancer.
Metastatic cancer. These cancers have spread to distant parts of the body (stage IV). So they can't be removed completely with surgery. Surgery may still be done. But it's used to relieve symptoms, not to try to cure the cancer.