Sunday, October 16, 2011

Pancreatic Cancer Staging and Survival Rates


Tests and procedures to stage pancreatic cancer are usually done at the same time as diagnosis. For the proper staging of Pancreatic Cancer we should first highlight on how the cancer may spread in the human body.

The three ways that cancer spreads in the body are:
  • Through tissue. Cancer invades the surrounding normal tissue.
  • Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
  • Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.

When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.

Pancreatic Cancer Stages

The following stages are used for pancreatic cancer:

Stage 0 (Carcinoma in Situ)

In stage 0, abnormal cells are found in the lining of the pancreas. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.

Stage I

In stage I, cancer has formed and is found in the pancreas only. Stage I is divided into stage IA and stage IB, based on the size of the tumor.
  • Stage IA: The tumor is 2 centimeters or smaller.
  • Stage IB: The tumor is larger than 2 centimeters.

Stage II

In stage II, cancer may have spread to nearby tissue and organs, and may have spread to lymph nodes near the pancreas. Stage II is divided into stage IIA and stage IIB, based on where the cancer has spread.

  • Stage IIA: Cancer has spread to nearby tissue and organs but has not spread to nearby lymph nodes.
  • Stage IIB: Cancer has spread to nearby lymph nodes and may have spread to nearby tissue and organs.


Stage III

In stage III, cancer has spread to the major blood vessels near the pancreas and may have spread to nearby lymph nodes.

Stage IV

In stage IV, cancer may be of any size and has spread to distant organs, such as the liver, lung, and peritoneal cavity. It may have also spread to organs and tissues near the pancreas or to lymph nodes.
  • Stage IVA: Cancer has spread to organs, such as the stomach, spleen, and colon, that are near the pancreas, but it has not spread to distant organs, such as the liver or lungs.
  • Stage IVB: Cancer has spread to organs, such as the stomach, spleen, or colon, that are near the pancreas or to places far away from the pancreas, such as the liver or lungs.

Recurrent

The cancer has come back (recurred) after it has been treated. It may come back in the pancreas or in another part of the body.

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TNM System

One way to describe the stages of pancreatic cancer is to use the TNM system. This system uses three different codes to describe the size and location of the tumor, whether it has spread to the lymph nodes around the tumor, and whether it can be found in other parts of the body. Because doctors usually classify tumors during surgery and many patients with pancreatic cancer do not have surgery, the TNM system is not used as much with pancreatic cancer as it is for other diseases.

In the TNM system, “T” plus a letter or number (0 to 4) is used to describe the size and location of the tumor. The tumor stages are:
TX - The primary, or original, tumor cannot be evaluated because of incomplete information.
TO - There is no evidence of the primary site.
Tis (carcinoma in situ) - The cancer is present only in the lining of the pancreatic ducts.  
T1 - The cancer has not spread beyond the pancreas and is smaller than 2 centimeters (about ¾ inch).
T2 - The cancer has not spread beyond the pancreas, but is larger than 2 centimeters (about ¾ inch).
T3 - The cancer has spread from the pancreas to surrounding tissues near the pancreas but not blood vessels.
T4 - The cancer has spread from the pancreas into nearby large blood vessels.

The "N" in the TNM system stands for node. Lymph nodes are tiny organs shaped like beans that can be found throughout the body. Lymph nodes help the body fight infections. Regional lymph nodes are near the cervix, while distant lymph nodes are in other parts of the body. Lymph node stages are:
NX - The regional lymph nodes cannot be evaluated because of incomplete information.
N0 - The cancer has not spread into the regional lymph nodes.
N1 - The cancer has spread into the regional lymph nodes.

The "M" in the TNM system is used for cancer that has spread, or metastasized, to other parts of the body. The stages for metastatic pancreatic cancer are:
MX - Distant metastasis cannot be evaluated because of incomplete information.
M0 - The cancer has not metastasized, or spread, to distant lymph nodes (those not near the pancreas) or distant organs.
M1 - The cancer has spread to other parts of the body beyond the pancreas, such as the liver, lungs, or brain.

Stages for Surgery Availability

Determining pancreatic cancer's stage is often tricky. Imaging tests like CT scans and MRIs provide some information, but knowing exactly how far pancreatic cancer has spread usually requires surgery.

Since surgery has risks, doctors first determine whether pancreatic cancer appears to be removable by surgery (resectable). Pancreatic cancer is then described as follows:
  • Resectable: On imaging tests, pancreatic cancer hasn't spread (or at least not far), and a surgeon feels it might all be removable. About 10% of pancreatic cancers are considered resectable when diagnosed.
  • Locally advanced (unresectable): Pancreatic cancer has grown into major blood vessels on imaging tests, so the tumor can't safely be removed by surgery.
  • Metastatic: Pancreatic cancer has clearly spread to other organs, so surgery can't remove it.

If pancreatic cancer is resectable, surgery could extend life and offer a small chance of cure.

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Pancreatic cancer survival by stage

Survival rates are often used by doctors as a standard way of discussing a person's prognosis (outlook). Some patients with cancer may want to know the survival statistics for people in similar situations, while others may not find the numbers helpful, or may even not want to know them. Whether or not you want to read about the survival statistics below for cancer of the pancreas is up to you.

The 5-year survival rate refers to the percentage of patients who live at least 5 years after their cancer is diagnosed. Of course, many people live much longer than 5 years (and many are cured).

Five-year relative survival rates assume that some people will die of other causes and compare the observed survival with that expected for people without the cancer. This is a better way to see the impact of the cancer on survival.

In order to get 5-year survival rates, doctors have to look at people who were treated at least 5 years ago. Improvements in treatment since then may result in a more favorable outlook for people now being diagnosed with cancer of the pancreas.

Survival rates are often based on previous outcomes of large numbers of people who had the disease, but they cannot predict what will happen in any particular person's case. Many other factors may affect a person's outlook, such as the patient's overall health and how well the cancer responds to treatment. Your doctor can tell you how the numbers below may apply to you, as he or she is familiar with the aspects of your particular situation.

The numbers below come from the National Cancer Institute's SEER database and are based on people diagnosed with exocrine cancer of the pancreas between 1988 and 2001.

Exocrine pancreatic cancer (5-year relative survival by stage)
               
Stage IA: 37%
Stage IB: 21%
Stage IIA: 12%
Stage IIB: 6%
Stage III: 2%
Stage IV: 1%

Overall, about 20% of people with pancreatic cancer live at least 1 year after diagnosis, while less than 4% will be alive after 5 years.

The statistics for pancreatic neuroendocrine cancers are not broken down by AJCC stages like cancers of the exocrine pancreas. Instead the statistics are broken down into different stages: localized (only in the pancreas), regional (spread to nearby lymph nodes or tissues), and distant (spread to distant sites, such as the liver). These numbers also come from the National Cancer Institute's SEER database:

Pancreatic neuroendocrine tumors (5-year relative survival by stage)

Localized: 87%
Regional: 70%
Distant: 24%
Overall: 42%


Sources and Additional Information:

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