UNDERSTANDING THE BIG PICTURE
Where is it, and has it spread?
Each panel is a separate, simplified example. These are broad colon-cancer stage groups, not an inevitable sequence or a tool for assigning a stage.
Within the lining
Into the bowel wall
Through the wall
Nearby lymph nodes
A distant site
Simplified cross-sections, not to scale. Substages, tumour deposits, TNM criteria, and differences between colon and rectal cancer require a clinician’s explanation. Stage III and IV are defined by spread, not the illustrated wall depth. Source: National Cancer Institute. Independent clinical review pending.
Stage describes extent
Staging describes where cancer is and how far it has spread. Clinicians combine scans, tissue findings, and other information. A colonoscopy alone does not establish the full stage.
The broad categories
- Stage 0: abnormal cells are confined to the innermost lining.
- Stage I: cancer involves inner layers of the bowel wall.
- Stage II: cancer extends farther through the wall, without nearby lymph-node involvement.
- Stage III: cancer involves nearby lymph nodes.
- Stage IV: cancer has spread to distant sites.
Substages and TNM categories add detail. Ask your team to explain your exact terminology.
Stage and grade differ
Grade describes how cells look under a microscope. Neither label alone gives a complete treatment plan or an individual prognosis.
This is general education for U.S. readers, not a diagnosis or a personal screening plan. Talk with your clinician about your own history and symptoms. Follow your clinic’s instructions.