Staging is a way of describing where the cancer is located, if or where it has spread, and whether it is affecting the functions of other organs in the body. Doctors use diagnostic tests to determine the cancer's stage, so staging may not be complete until all the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis (chance of recovery). As with Diagnosis , it is important for the staging of pancreatic cancer to be done at a center with experience in staging pancreatic cancer. There are different stage descriptions for different types of cancer.
Doctors use several systems to stage pancreatic cancer. The method used to stage other cancers, the TNM classification, is not often used for pancreatic cancer; however, for completeness, it is discussed below. The more common way to classify pancreatic cancer is to divide it into three categories based on whether it can be removed with surgery and where it has spread:
Resectable. This type of pancreatic cancer can be surgically removed. The tumor may be located only in the pancreas or extends beyond it, but it has not grown into important arteries or veins in the area. There is no evidence that the tumor has spread to areas outside of the pancreas. Approximately 10% to 15% of patients are diagnosed with this stage.
Locally advanced. This type is still located only in the area around the pancreas, but it cannot be surgically removed because it has grown into nearby arteries or veins, or the tumor has grown into nearby organs. There is no evidence of spread to any distant parts of the body. Approximately 35% to 40% of patients are diagnosed at this stage.
Metastatic. The tumor has spread beyond the area of the pancreas and to other organs, such as the liver or distant areas of the abdomen. Approximately 45% to 55% of patients are diagnosed at this stage.
By classifying each cancer into one of these categories, the health care team can plan the best treatment strategy. A fourth category that is sometimes used, which can also be a subcategory of “Locally advanced,” is borderline resectable disease. This refers to a tumor that cannot be surgically removed at the present time, but if chemotherapy and/or radiation therapy is helping to shrink the tumor, it may be able to be removed in the future.
TNM Staging System
Doctors frequently use a tool called the TNM system to stage other types of cancer. Because doctors generally classify a tumor during surgery, and because many patients with pancreatic cancer do not receive surgery, the TNM system is not used as much for pancreatic cancer as it is for other diseases.
The TNM system judges three factors: the tumor itself, the lymph nodes around the tumor, and if the tumor has spread to the rest of the body. The results are combined to determine the stage of cancer for each person. There are five stages: stage 0 (zero) and stages I through IV (one through four). The stage provides a common way of describing the cancer, so doctors can work together to plan the best treatments.
TNM is an abbreviation for tumor (T), node (N), and metastasis (M). Doctors look at these three factors to determine the stage of cancer:
- How large is the primary tumor and where is it located? (Tumor, T)
- Has the tumor spread to the lymph nodes? (Node, N)
- Has the cancer metastasized to other parts of the body? (Metastasis, M)
Tumor. Using the TNM system, the "T" plus a letter or number (0 to 4) is used to describe the size and location of the tumor. This helps the doctor develop the best treatment plan for each patient. Specific tumor stage information listed below.
TX: The primary tumor cannot be evaluated.
T0: No evidence of cancer was found in the pancreas.
Tis: Refers to carcinoma in situ (which is very early cancer that has not spread.)
T1: The tumor is in the pancreas only, and it is 2 centimeters (cm) or smaller in size.
T2: The tumor is in the pancreas only, and it is larger than 2 cm.
T3: The tumor extends beyond the pancreas, but the tumor does not involve the major arteries or veins near the pancreas.
T4: The tumor extends beyond the pancreas into major arteries or veins near the pancreas. A T4 tumor is unresectable (unable to be completely removed during surgery).
Node. The "N" in the TNM staging system is for lymph nodes. Lymph nodes are tiny, bean-shaped organs located throughout the body that normally help fight infection and disease as part of the body's immune system. In pancreatic cancer, regional lymph nodes are those lymph nodes near the pancreas and distant lymph nodes are those lymph nodes in other parts of the body.
NX: The regional lymph nodes cannot be evaluated.
N0: Cancer was not found in the regional lymph nodes.
N1: Cancer has spread to regional lymph nodes.
Distant metastasis. The "M" in the TNM system indicates whether the cancer has spread to other parts of the body.
MX: Distant metastasis cannot be evaluated.
M0: The disease has not spread to other parts of the body.
M1: Cancer has spread to another part of the body, including distant lymph nodes. Pancreatic cancer most commonly spreads to the liver, peritoneum (lining of the abdominal cavity), and lungs.
Cancer stage grouping
Doctors assign the stage of the cancer by combining the T, N, and M classifications.
Stage 0:Refers to cancer in situ, in which the cancer has not yet invaded outside the duct (or tube) in which it started (Tis, N0, M0).
Stage IA:The tumor is 2 cm or smaller in the pancreas. It has not spread to lymph nodes or other parts of the body (T1, N0, M0).
Stage IB:A tumor larger than 2 cm is in the pancreas. It has not spread to lymph nodes or other parts of the body (T2, N0, M0).
Stage IIA:A tumor extends beyond the pancreas, but the tumor has not spread to nearby arteries or veins. It has not spread to any lymph nodes or other parts of the body (T3, N0, M0).
Stage IIB:A tumor of any size has not spread to nearby arteries or veins. It has spread to lymph nodes but not to other parts of the body (T1, T2, or T3; N1; M0).
Stage III:A tumor has spread to nearby arteries, veins, and/or lymph nodes but has not spread to other parts of the body (T4, N1, M0).
Stage IV:Any tumor that has spread to other parts of the body (any T, any N, M1).
Recurrent: Recurrent cancer is cancer that comes back after treatment. If there is a recurrence, the cancer may need to be staged again (called re-staging) using the system above.
Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual, Seventh Edition (2010) published by Springer-Verlag New York, www.cancerstaging.net .