In patients with some forms of rectal and colon cancer, abnormal genes have been found. Genes are markers in cells associated with hereditary traits. Tests are being developed to determine who carries these abnormal genes long before cancer appears. A doctor needs to know the stage of the disease to plan treatment. Stage 0 or carcinoma in situ Stage 0 cancer of the rectum is very early cancer.
Cancer is found only in the top lining of the rectum.
Stage I Cancer has spread beyond the top lining of the rectum to the second and third layers and involves the inside wall of the rectum, but has not spread to the outer wall of the rectum or outside the rectum. Stage I cancer of the rectum is sometimes called Dukes A rectal cancer. Stage II Cancer has spread outside the rectum to nearby tissue, but it has not gone into the lymph nodes. Stage II cancer of the rectum is sometimes called Dukes B rectal cancer. Stage III Cancer has spread to nearby lymph nodes, but it has not spread to other parts of the body.