T Categories
TX: The main tumor cannot be assessed
T0: No evidence of a primary tumor
Tis: Carcinoma in situ (very few tumors are found at this stage)
T1: The cancer has not spread beyond the pancreas and is smaller than 2 cm (about ¾ inch) across.
T2: The cancer has not spread beyond the pancreas but is larger than 2 cm across.
T3: The cancer has spread from the pancreas to surrounding tissues near the pancreas but not to blood vessels.
T4: The cancer has extended further beyond the pancreas into nearby large blood vessels.
N Categories
NX: Regional lymph nodes cannot be assessed
N0: Regional lymph nodes (lymph nodes near the pancreas) are not involved.
N1: Cancer has spread to regional lymph nodes.
M Categories
MX: Spread to distant organs cannot be assessed
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: Distant metastasis is present.
Stage Grouping for Cancer of the Pancreas
After the T, N, and M categories of the cancer have been determined, this information is combined to assign a stage, which expressed in Roman numerals I through IV. The process of assigning a stage number based on TNM stages 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 less than 2 cm in size. It has not spread to nearby lymph nodes or distant sites.
Stage IB (T2, N0, M0): The tumor is confined to the pancreas and is larger than 2 cm in size. It has not spread to nearby lymph nodes or distant sites.
Stage IIA (T3, N0, M0): The tumor is growing outside the pancreas but not into large blood vessels. It has not spread to nearby lymph nodes or distant sites.
Stage IIB (T1-3, N1, M0): The tumor is either confined to the pancreas or growing outside the pancreas but not into nearby large blood vessels. It has spread to nearby lymph nodes but not distant sites.
Stage III (T4, Any N, M0): The tumor is growing outside the pancreas into nearby large blood vessels. It may or may not have spread to nearby lymph nodes. It has not spread to distant sites.
Stage IV (Any T, Any N, M1): The cancer has spread to distant sites.
