Colorectal Cancer: Open Access

Stages

Staging is a way of describing where the cancer is located or where it has spread, and whether it is affecting other parts of the body. There are different stage descriptions for different types of cancer.

The earliest stage colorectal cancers are called stage 0 (a very early cancer), and then range from stages I (1) through IV (4). As a rule, the lower the number, the less the cancer has spread. A higher number, such as stage IV, means cancer has spread more. And within a stage, an earlier letter means a lower stage. Although each person’s cancer experience is unique, cancers with similar stages tend to have a similar outlook and are often treated in much the same way.

1. TNM staging system

Where T means tumour, N means node, M means metastatis

The extent (size) of the tumor (T): How far has the cancer grown into the wall of the colon or rectum? These layers, from the inner to the outer, include:

The inner lining (mucosa), which is the layer in which nearly all colorectal cancers start. This includes a thin muscle layer (muscularis mucosa).

The fibrous tissue beneath this muscle layer (submucosa)

A thick muscle layer (muscularis propria)

The thin, outermost layers of connective tissue (subserosa and serosa) that cover most of the colon but not the rectum

The spread to nearby lymph nodes (N): Has the cancer spread to nearby lymph nodes?

The spread (metastasis) to distant sites (M): Has the cancer spread to distant lymph nodes or distant organs such as the liver or lungs?

Numbers or letters after T, N, and M provide more details about each of these factors. Higher numbers mean the cancer is more advanced. Once a person’s T, N, and M categories have been determined, this information is combined in a process called stage grouping to assign an overall stage. For more information see Cancer Staging.

colorectal cancer screening:

Screening is used to look for cancer before you have any symptoms or signs. Scientists have developed, and continue to develop, tests that can be used to screen a person for specific types of cancer before signs or symptoms appear. The overall goals of cancer screening are to:

1. Lower the number of people who die from the disease, or eliminate deaths from cancer altogether

2. Lower the number of people who develop the disease

The tests used to screen for colorectal cancer are:

1. Colonoscopy

2. Computed tomography (CT or CAT) colonography

3. Sigmoidoscopy.

4. Fecal occult blood test (FOBT) and fecal immunochemical test (FIT).

5. Double contrast barium enema (DCBE).

6. Stool DNA tests.

Some of benefits and limits of colorectal cancer screening tests are:

Fecal immunochemical test (FIT):

Benefits: No direct risk to the colon, No bowel prep, No pre-test diet or medication changes needed,Sampling done at home.

Limits: Can miss many polyps and some cancers, Can have falsepositive test results, Needs to be done every year

Colonoscopy;

Benefits: Can usually look at the entire colon, Can biopsy and remove polyps,Done every 10 years

Limits: Can miss small polyps,Full bowel prep needed,Costs more on a one-time basis than other forms of testing

CT colonography:

Benefits: Fairly quick and safe, Can usually see the entire colon, Done every 5 years

Limits: Can miss small polyps, Full bowel prep needed, Some falsepositive test results.

Colorectal cancer survival rate:

For colon cancer, the overall 5-year survival rate for people is 63%. If the cancer is diagnosed at a localized stage, the survival rate is 90%. If the cancer has spread to surrounding tissues or organs and/or the regional lymph nodes, the 5-year survival rate is 71%. If colon cancer has spread to distant parts of the body, the 5-year survival rate is 14%.

For rectal cancer, the overall 5-year survival rate for people is 67%. If the cancer is diagnosed at a localized stage, the survival rate is 89%. If the cancer has spread to surrounding tissues or organs and/or the regional lymph nodes, the 5-year survival rate is 71%. If the cancer has spread to distant parts of the body, the 5-year survival rate is 15%.