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Like many cancers, there are four stages of colon cancer, says John Rioux, MD, of Fawcett Memorial Hospital. In this video, he explains the differences between the four stages.
Colon cancer is staged with four stages, says Joseph Thornton, MD, a colorectal surgeon at Sunrise Hospital. In this video, he describes what each stage means for treatment.
Colorectal cancer is staged according to the depth of tumor invasion into the bowel wall and nearby structures, involvement of lymph nodes, and extent of spread throughout the body.
Stage 1-involvment of the more superficial layers of the bowel wall, no lymph node involvement, no distant spread of the cancer
Stage 2-involvement of the deeper layers of the bowel wall or nearby structures, no lymph node involvement, no distant spread of the cancer
Stage 3-involvment of any layer of the bowel wall or nearby structures, lymph node involvement, no distant spread of the cancer
Stage 4-spread of the cancer to other distant organs in the body
With early detection, colorectal cancer can be prevented and may even be curable. That is why colonoscopy screenings are generally recommended beginning at age 50.
Colon cancer ranges from stages 0 to IV, with 0 being the least severe and IV being the most serious. In stage 0, the cancer is contained within the inner layer of the colon. In stage I, the cancer is grown through the inner layer, but hasn't spread beyond the colon. In stage II, the cancer has grown into or through the colon wall, and in stage III, the cancer has spread to the nearest lymph nodes. In stage IV, the cancer has spread far outside the colon to other organs.
The following are the stages of colon cancer:
- Stage 1: Spreads into mucus layer of colon
- Stage 2: Spreads to outer colon layers
- Stage 3: In colon muscle; lymph involvement
- Stage 4: In one or more distant organs
The stages of colon cancer are based on a classification system called TNM, for Tumor, Nodes, and Metastasis. Each of the three are assigned numbers, with higher numbers for worse stages. Small letters are also assigned to further distinguish the staging.
"T," or tumor invasion, is assigned a number between 0 and 4, depending on the extent of invasion into surrounding tissues. For example, T0 means no tumor is found, while a T4b means the tumor has invaded other organs/structures.
"N" is for lymph node invasion, and a number between 0 and 2 is assigned, based on the extent of spread to lymph nodes.
"M" is for metastasis, which means "spread" to distant areas. For example, M0 means no spread and M1b means the cancer has spread to more than one organ.
Physical exam and tests such as CT scans are used to "stage" colon cancer.
Stage 0 (Carcinoma in Situ): In stage 0, abnormal 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.
Stage I: In stage I, cancer has formed and spread beyond the innermost tissue layer of the colon wall to the middle layers. Stage I colon cancer is sometimes called Dukes A colon cancer.
Stage II: Stage II colon cancer is divided into stage IIA and stage IIB:
Stage IIA: Cancer has spread beyond the middle tissue layers of the colon wall or has spread to nearby tissues around the colon or rectum. Stage IIB: Cancer has spread beyond the colon wall into nearby organs and/or through the peritoneum.
Stage II colon cancer is sometimes called Dukes B colon cancer.
Stage III: Stage III colon cancer is divided into stage IIIA, stage IIIB, and stage IIIC:
Stage IIIA: Cancer has spread from the innermost tissue layer of the colon wall to the middle layers and has spread to as many as 3 lymph nodes. Stage IIIB: Cancer has spread to as many as 3 nearby lymph nodes and has spread: beyond the middle tissue layers of the colon wall; or to nearby tissues around the colon or rectum; or Beyond the colon wall into nearby organs and/or through the peritoneum. Stage IIIC: Cancer has spread to 4 or more nearby lymph nodes and has spread: to or beyond the middle tissue layers of the colon wall; or to nearby tissues around the colon or rectum; or To nearby organs and/or through the peritoneum.
Stage III colon cancer is sometimes called Dukes C colon cancer.
Stage IV: In stage IV, cancer may have spread to nearby lymph nodes and has spread to other parts of the body, such as the liver or lungs. Stage IV colon cancer is sometimes called Dukes D colon cancer.
This answer is based on source information from National Cancer Institute.
There are a number of staging systems, but generally 1-4 would be a traditional scale for colon cancer. Stage 1 is confined to the colon lining, stage 2 and 3 deeper through the lining, and stage 4 spread to distant organs.
This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.