Colorectal cancer develops in several stages, and prognosis strongly depends on the stage at which the disease is discovered.
Stages of colorectal cancer
Stage 0
Cancer cells are only in the innermost layer of the bowel wall (in situ).
Stage I
The tumor has grown into the bowel wall but has not penetrated the muscle layer.
Stage II
The tumor has penetrated the entire bowel wall but has not affected lymph nodes.
Stage III
Cancer has spread to regional lymph nodes.
Stage IV
Cancer has formed metastases in other organs.
