Key Points for This Section

After gastric cancer has been diagnosed, tests are done to find out if cancer cells have spread within the stomach or to other parts of the body. The following stages are used for gastric cancer: Stage 0 (Carcinoma in Situ) Stage I Stage II Stage III Stage IV

After gastric cancer has been diagnosed, tests are done to find out if cancer cells have spread within the stomach or to other parts of the body.

The process used to find out if cancer has spread within the stomach or to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan treatment.

The following tests and procedures may be used in the staging process:

• ¦Â-hCG (beta-human chorionic gonadotropin), CA-125, and CEA (carcinoembryonic antigen) assays: Tests that measure the levels of ¦Â-hCG, CA-125, and CEA in the blood. These substances are released into the bloodstream from both cancer cells and normal cells. When found in higher than normal amounts, they can be a sign of gastric cancer or other conditions.
• Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
• Endoscopic ultrasound (EUS): A procedure in which an endoscope (a thin, lighted tube) is inserted into the body. The endoscope is used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. This procedure is also called endosonography.
• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
• Laparoscopy: A surgical procedure to look at the organs inside the abdomen to check for signs of disease. Small incisions (cuts) are made in the wall of the abdomen and a laparoscope (a thin, lighted tube) is inserted into one of the incisions. Other instruments may be inserted through the same or other incisions to perform procedures such as removing organs or taking tissue samples for biopsy.
• PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radionuclide glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.

The following stages are used for gastric cancer:

Stage 0 (Carcinoma in Situ)

In stage 0, cancer is found only in the inside lining of the mucosal (innermost) layer of the stomach wall. Stage 0 is also called carcinoma in situ.

Stage I

Stage I gastric cancer is divided into stage IA and stage IB, depending on where the cancer has spread.

• Stage IA: Cancer has spread completely through the mucosal (innermost) layer of the stomach wall.
• Stage IB: Cancer has spread:
  • completely through the mucosal (innermost) layer of the stomach wall and is found in up to 6 lymph nodes near the tumor; or
  • to the muscularis (middle) layer of the stomach wall.

Stage II

In stage II gastric cancer, cancer has spread:

• completely through the mucosal (innermost) layer of the stomach wall and is found in 7 to 15 lymph nodes near the tumor; or
• to the muscularis (middle) layer of the stomach wall and is found in up to 6 lymph nodes near the tumor; or
• to the serosal (outermost) layer of the stomach wall but not to lymph nodes or other organs.

Stage III

Stage III gastric cancer is divided into stage IIIA and stage IIIB depending on where the cancer has spread.

• Stage IIIA: Cancer has spread to:
  • the muscularis (middle) layer of the stomach wall and is found in 7 to 15 lymph nodes near the tumor; or
  • the serosal (outermost) layer of the stomach wall and is found in 1 to 6 lymph nodes near the tumor; or
  • organs next to the stomach but not to lymph nodes or other parts of the body.
• Stage IIIB: Cancer has spread to the serosal (outermost) layer of the stomach wall and is found in 7 to 15 lymph nodes near the tumor.

Stage IV

In stage IV, cancer has spread to:

• organs next to the stomach and to at least one lymph node; or
• more than 15 lymph nodes; or
• other parts of the body.