Diagnosis
Upper endoscopy, as described above, is routinely used for the initial diagnosis and staging of patients with gastric cancer. Using endoscopy, the diagnosis can be obtained in over 95% of cases. Many times, ultrasound during endoscopy is used to attempt to identify how deep into the wall of the stomach the cancer has penetrated. In addition, ultrasound can identify spread to lymph nodes in many cases. Depth of wall invasion and presence of lymph node spread are two very important components of treatment, as the surgeon uses this information to determine if he or she can operate.
Other procedures are needed to determine the stage of the disease. CT scans ("CAT scans") of the abdomen and chest are done, not only to rule out spread to distant organs, like the liver and lungs, but also to determine the spread to lymph nodes close to the stomach that could not be identified by ultrasound. Other tests to rule out abdominal spread of disease outside of the stomach itself are PET scans, which use radioactive solutions to identify tumors, and laparoscopy. Laparoscopy is a surgical procedure that involves puncturing the abdominal cavity with a fiber optic camera and directly viewing the organs and tissues in the stomach's area and the entire abdominal cavity. Although PET scans and laparoscopy are fairly new introductions to the staging of gastric cancer, CT scans, endoscopy, and ultrasound are more generally accepted as required in order to properly identify the extent of disease, and all will likely be done in a patient diagnosed with gastric cancer.
Other, more routine tests done before treatment include blood screening tests, to insure that overall blood counts are within normal limits, and that a patient's liver, kidneys, and overall health are normal.
All of these test are important to determine the extent of the disease which allows the disease to be staged. The stage provides a guideline for the optimal treatment of the gastric cancer as well as the prognosis.
Staging
The staging of a cancer basically describes how much it has grown before the diagnosis has been made, documenting the extent of disease. Unfortunately, gastric cancer often presents as a more advanced disease because of lack of early diagnosis, due mainly to the lack of specific associated symptoms. Before the staging systems are introduced, here’s some background on how cancers grow and spread, and therefore become more advanced in stage.
Cancers cause problems because they spread and can disrupt the functioning of normal organs. One way gastric cancer can spread is by local extension to invade through the stomach wall and into adjacent structures. These surrounding structures include the soft tissues and fat surrounding the stomach as well as other organs such as the spleen, pancreas, large intestine, small intestine, liver, and large blood vessels.
Gastric cancer can also spread by accessing the lymphatic system. The lymphatic circulation is a complete circulation system in the body (somewhat like the blood circulatory system) that drains into various lymph nodes. When cancer cells access this lymphatic circulation, they can travel to lymph nodes and start new sites of cancer. This is called lymphatic spread. Gastric cancers have a propensity to undergo lymphatic spread because there are many small lymphatic vessels contained within the stomach wall. The first lymph nodes that cancer cells spread to are the "perigastric" nodes along the sides of the stomach itself. They can then spread to lymph nodes adjacent to the liver, spleen, pancreas, and aorta.
Gastric cancers can also spread through the bloodstream. Cancer cells gain access to distant organs via the bloodstream and the tumors that arise from these cells are called metastases. Because of the stomach's blood supply, the most common organ it spreads to is the liver, though tumors can also spread to the lung or other organs less commonly.
A fourth way gastric cancer can spread is throughout the entire abdomen, the so-called peritoneal cavity. Although rare, once cancer cells grow outside of the stomach itself, there is nothing stopping cells from spreading to any surface in the entire abdominal cavity.
There are two accepted staging systems in gastric cancer. They both detail the extent of disease by describing the growth of tumor in the stomach itself as well as the presence and extent of spread to the lymph nodes. The TNM systems are used to describe many types of cancers. They have three components: T-describing the extent of the "primary" tumor (the tumor in the stomach itself); N-describing the spread to the lymph nodes; M-describing the spread to other organs (i.e.-metastases).
The "T" stage is as follows:
• Tis-"in-situ cancer"-very superficial tumor, without invasion of the stomach wall
• T1-tumor invades into only the superficial portions of the stomach wall
• T2-tumor invades into the deeper layers of the stomach wall
• T3-tumor extends through the stomach wall into the fat outside of the stomach
• T4-tumor extends outside the stomach wall and invades into other organs
The "N" stage is as follows:
• N0-no spread to lymph nodes
• N1-tumor spread to 1-6 lymph nodes
• N2-tumor spread to 7-15 lymph nodes
• N3-tumor spread to more than 15 lymph nodes
The "M" stage is as follows:
• M0-no tumor spread to other organs
• M1-tumor spread to other organs
The overall stage is based on a combination of these T, N, and M parameters:
• Stage IA-T1N0M0
• Stage IB-T1N1M0 or T2N0M0
• Stage II-T1N2M0 or T2N1M0 or T3N0M0
• Stage IIIA-T2N2M0 or T3N1M0 or T4N0M0
• Stage IIIB-T3N2M0 or
• Stage IV-T4N2M0 or T1-3N3M0 or T4N1-3M0 or any M1
Though complicated, this staging systems help physicians determine the extent of the cancer, and therefore make treatment decisions regarding a patient's cancer. The stage of cancer, or extent of disease, is based on information gathered through various tests done as the diagnosis and work-up of the cancer is being performed.
Upper endoscopy, as described above, is routinely used for the initial diagnosis and staging of patients with gastric cancer. Using endoscopy, the diagnosis can be obtained in over 95% of cases. Many times, ultrasound during endoscopy is used to attempt to identify how deep into the wall of the stomach the cancer has penetrated. In addition, ultrasound can identify spread to lymph nodes in many cases. Depth of wall invasion and presence of lymph node spread are two very important components of treatment, as the surgeon uses this information to determine if he or she can operate.
Other procedures are needed to determine the stage of the disease. CT scans ("CAT scans") of the abdomen and chest are done, not only to rule out spread to distant organs, like the liver and lungs, but also to determine the spread to lymph nodes close to the stomach that could not be identified by ultrasound. Other tests to rule out abdominal spread of disease outside of the stomach itself are PET scans, which use radioactive solutions to identify tumors, and laparoscopy. Laparoscopy is a surgical procedure that involves puncturing the abdominal cavity with a fiber optic camera and directly viewing the organs and tissues in the stomach's area and the entire abdominal cavity. Although PET scans and laparoscopy are fairly new introductions to the staging of gastric cancer, CT scans, endoscopy, and ultrasound are more generally accepted as required in order to properly identify the extent of disease, and all will likely be done in a patient diagnosed with gastric cancer.
Other, more routine tests done before treatment include blood screening tests, to insure that overall blood counts are within normal limits, and that a patient's liver, kidneys, and overall health are normal.
All of these test are important to determine the extent of the disease which allows the disease to be staged. The stage provides a guideline for the optimal treatment of the gastric cancer as well as the prognosis.
Staging
The staging of a cancer basically describes how much it has grown before the diagnosis has been made, documenting the extent of disease. Unfortunately, gastric cancer often presents as a more advanced disease because of lack of early diagnosis, due mainly to the lack of specific associated symptoms. Before the staging systems are introduced, here’s some background on how cancers grow and spread, and therefore become more advanced in stage.
Cancers cause problems because they spread and can disrupt the functioning of normal organs. One way gastric cancer can spread is by local extension to invade through the stomach wall and into adjacent structures. These surrounding structures include the soft tissues and fat surrounding the stomach as well as other organs such as the spleen, pancreas, large intestine, small intestine, liver, and large blood vessels.
Gastric cancer can also spread by accessing the lymphatic system. The lymphatic circulation is a complete circulation system in the body (somewhat like the blood circulatory system) that drains into various lymph nodes. When cancer cells access this lymphatic circulation, they can travel to lymph nodes and start new sites of cancer. This is called lymphatic spread. Gastric cancers have a propensity to undergo lymphatic spread because there are many small lymphatic vessels contained within the stomach wall. The first lymph nodes that cancer cells spread to are the "perigastric" nodes along the sides of the stomach itself. They can then spread to lymph nodes adjacent to the liver, spleen, pancreas, and aorta.
Gastric cancers can also spread through the bloodstream. Cancer cells gain access to distant organs via the bloodstream and the tumors that arise from these cells are called metastases. Because of the stomach's blood supply, the most common organ it spreads to is the liver, though tumors can also spread to the lung or other organs less commonly.
A fourth way gastric cancer can spread is throughout the entire abdomen, the so-called peritoneal cavity. Although rare, once cancer cells grow outside of the stomach itself, there is nothing stopping cells from spreading to any surface in the entire abdominal cavity.
There are two accepted staging systems in gastric cancer. They both detail the extent of disease by describing the growth of tumor in the stomach itself as well as the presence and extent of spread to the lymph nodes. The TNM systems are used to describe many types of cancers. They have three components: T-describing the extent of the "primary" tumor (the tumor in the stomach itself); N-describing the spread to the lymph nodes; M-describing the spread to other organs (i.e.-metastases).
The "T" stage is as follows:
• Tis-"in-situ cancer"-very superficial tumor, without invasion of the stomach wall
• T1-tumor invades into only the superficial portions of the stomach wall
• T2-tumor invades into the deeper layers of the stomach wall
• T3-tumor extends through the stomach wall into the fat outside of the stomach
• T4-tumor extends outside the stomach wall and invades into other organs
The "N" stage is as follows:
• N0-no spread to lymph nodes
• N1-tumor spread to 1-6 lymph nodes
• N2-tumor spread to 7-15 lymph nodes
• N3-tumor spread to more than 15 lymph nodes
The "M" stage is as follows:
• M0-no tumor spread to other organs
• M1-tumor spread to other organs
The overall stage is based on a combination of these T, N, and M parameters:
• Stage IA-T1N0M0
• Stage IB-T1N1M0 or T2N0M0
• Stage II-T1N2M0 or T2N1M0 or T3N0M0
• Stage IIIA-T2N2M0 or T3N1M0 or T4N0M0
• Stage IIIB-T3N2M0 or
• Stage IV-T4N2M0 or T1-3N3M0 or T4N1-3M0 or any M1
Though complicated, this staging systems help physicians determine the extent of the cancer, and therefore make treatment decisions regarding a patient's cancer. The stage of cancer, or extent of disease, is based on information gathered through various tests done as the diagnosis and work-up of the cancer is being performed.
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