01 What tests are used to see if the cancer cells have spread? After colon cancer has been diagnosed by analyzing polyps that have been removed, tests are done to find out if cancer cells have spread within the colon or to other parts of the body. The process used to find out if cancer has spread within the colon or to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease; this is important to know in order to plan treatment. The following tests and procedures may be used in the staging process:
Computerized Tomography (CT scan, known formerly as Computerized Axial Tomography - CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. A computer that’s linked to an X-ray machine makes the pictures. 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.
Positron Emission Tomography (PET): A nuclear medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body and is useful in the staging of some colorectal cancers. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide (tracer), which is introduced into the body on a biologically active molecule. Three-dimensional images of tracer concentrations within the body are then constructed by computer analysis. In modern scanners, three-dimensional imaging is often accomplished with the aid of a CT X-ray scan that’s performed on the patient during the same session, using the same machine.
Lymph-node biopsy: The removal of all or part of a lymph node. A pathologist views the tissue under a microscope to look for cancer cells.
Carcinoembryonic antigen (CEA) assay: A test that measures the level of CEA in the blood. CEA is released into the bloodstream from both cancer cells and normal cells. When found in higher than normal amounts, it can be a sign of colon cancer or other conditions.
MRI (Magnetic Resonance Imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the colon. A substance called gadolinium is injected into the patient through a vein. This collects around the cancer cells so they show up brighter in the picture. This procedure is also called nuclear magnetic resonance imaging (NMRI).
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 the body and onto film, making a picture of areas inside the body.
Surgery: A procedure to remove the tumor and to see how far it has spread through the colon. Also critical in tracking the disease is a complete blood count (CBC), which is a procedure in which a sample of blood is drawn and checked for the following:
The number of red blood cells, white blood cells, and platelets.
The amount of hemoglobin(the protein that carries oxygen) in the red blood cells.
The portion of the blood sample that is made up of red blood cells.
02 How does cancer spread in the 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 bloodstream to other places in the body.
When cancer cells break away from the primary (original) tumor and travel through the 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 metastatic breast cancer, not bone cancer.
03 How is colon cancer staged? As colon cancer progresses from Stage 0 to Stage IV, the cancer cells grow through the layers of the colon wall and spread to lymph nodes and other organs. Here is a breakdown of how the stages typically progress:
- Stage 0 cells are found in the innermost lining of the colon. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ (CIS). - Stage I colon cancer has formed and has spread beyond the innermost tissue layer of the colon wall and to its middle layers. Stage I colon cancer is sometimes called Dukes A colon cancer. - Stage II colon cancer is sub-divided into stages IIA and IIB. Stage II colon cancer is sometimes called Dukes B colon cancer.
1. Stage IIA: Cancer has spread beyond the middle tissue layers of the colon wall and/or has spread to nearby tissues around the colon or rectum. 2. Stage IIB: Cancer has spread beyond the colon wall into nearby organs and/or through the peritoneum. 3. Stage III colon cancer is also sub-divided into stages IIIA, IIIB, and IIIC. Stage III colon cancer is sometimes called Dukes C colon cancer.
1. Stage IIIA: Cancer has spread from the innermost tissue layer of the colon wall to its middle layers and has spread to as many as three lymph nodes. 2. Stage IIIB: Cancer has spread to as many as three nearby lymph nodes and has spread: 1. Beyond the middle tissue layers of the colon wall; or 2. To nearby tissues around the colon or rectum; or 3. Beyond the colon wall into nearby organs and/or through the peritoneum.
1. Stage IIIC: Cancer has spread to four or more nearby lymph nodes and has spread: 1. To or beyond the middle tissue layers of the colon wall; or 2. To nearby tissues around the colon or rectum; or 3. To nearby organs and/or through the peritoneum.
Stage IV colon cancer may have spread to nearby lymph nodes and to other parts of the body, such as the liver or the lungs. Stage IV colon cancer is sometimes called Dukes D colon cancer. Recurrent colon cancer is cancer that has recurred (come back) after it has been treated. The cancer may come back in the colon or in other parts of the body, such as the liver, lungs, or both.
04 What treatment plans are used? Treatment for colon cancer usually includes surgery followed by chemotherapy. Treatment for rectal cancers (cancers found in the first 12 inches of the colon) usually includes radiation and chemotherapy, followed by surgery, followed by additional chemotherapy.