How is pancreatic cancer staged?
The staging of pancreatic cancer is an assessment of how far the cancer has spread. Pancreatic cancer can be staged using imaging such as computerized tomography, or it can be done pathologically based on tissues that are removed at the time of surgery. Staging is done for two reasons. First, it is used to guide therapy. Cancers that are low stage (confined to the pancreas) are often best treated surgically, while cancers that are high stage (which have spread to organs outside of the pancreas) are typically best treated with chemotherapy and/or radiation therapy. Second, staging is often used to provide prognostic information. While no two patients are alike, staging can provide a rough estimate of the typical life expectancy for patients with similar cancers. It should absolutely be noted that there are always exceptions, and that some patients live much longer than one would have predicted from their stage, while others succumb to their disease faster than one would have predicted from their stage.
The staging provided below is the Seventh Edition Staging from the American Joint Committee on Cancer. More details can be found at: http://www.cancerstaging.org/
The staging of tumors of the pancreas uses the TNM staging system.
“T” in this system designates the extent of the primary tumor in the pancreas.
T0 No evidence of a primary tumor
Tis Carcinoma in situ (a precancerous lesion, such as an intraductal papillary mucinous neoplasm with high-grade dysplasia)
T1 Tumor limited to the pancreas and 2 cm or less in size
T2 Tumor limited to the pancreas and greater than 2 cm in size
T3 Tumor extends beyond the pancreas but it does not involve the blood vessels of the celiac axis or the superior mesenteric artery (two blood vessels that run close to the pancreas)
T4 Tumor involves the blood vessels of the celiac axis or the superior mesenteric artery (two blood vessels that run close to the pancreas)
“N” in the staging system designates whether or not the cancer has spread (metastasized) to lymph nodes in the region of the pancreas (regional lymph nodes)
NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastases (cancer has not spread to the lymph nodes)
N1 Regional lymph node metastases (cancer has spread to the lymph nodes)
The “M” of TNM designates spread to other organs beyond the pancreas, also known as distant metastasis.
M0 No distant spread (no distant metastasis)
M1 Distant spread (distant metastasis)
Once the T, the N and the M designations are established for a given patient, they can be combined to determine the stage of the patient’s cancer using the chart below.
Stage 0 Tis N0 M0
Stage IA T1 N0 M0
Stage IB T2 N0 M0
Stage IIA T3 N0 M0
Stage IIB T1, T2 or T3 N1 M0
Stage III T4 Any N M0
Stage IV Any T Any N M1
As noted earlier, this staging system is important because it helps determine the best way to treat a patient, and as will be discussed in the next blog, it can be used to provide general prognostic information. For example, patients with stage IA and Stage IB disease are often best treated surgically, while patients with stage IV disease are usually best treated with chemotherapy. Patients with Stage IIA, IIB and Stage II disease are often best managed by a multi-disciplinary team, such as the multi-disciplinary clinic at Johns Hopkins (http://pathology.jhu.edu/pancreas/ChooseMDT.php).