- How cancer has spread (metastasized) to other organs of the body (M)
- M0 – Malignancy has not spread to other regions of the body.
- M1 – Cancer has progressed to other organs, such as the liver or lungs.
For instance, your diagnosis could be “T3N1M0.” This indicates that cancer has migrated from the bowel’s outer lining to up to three surrounding lymph nodes, but not to other areas of the body.
Furthermore, the TNM staging report is occasionally written with a lower case letter in front of it. cTNM denotes that the report is based on clinical data. This is based on scans and biopsies performed before to the start of treatment. On the other hand, pTNM indicates that the report is based on the complete findings of both the pre-treatment and post-surgery investigations. It may also include some pathological assessments of tissue under the microscope.
Colorectal Cancer Staging: Number Staging
The system also determines what stage the cancer is in — the earliest stage of colorectal cancer which is 0, or any of the other four primary stages. Substages that fall under some of the main stages (like stage 2A or 2B) describe specific features. It may also suggest the locality of the cancer cells.
Stage 0 (Carcinoma in Situ)
During this early stage, abnormal cells are discovered in the mucosa (innermost layer) of the colon wall. These abnormal cells may develop into cancer and spread to other normal tissues nearby. Carcinoma in situ is another term for stage 0 cancer.
The next stage directs progression to the submucosa (tissue layer adjacent to the mucosa) or the muscle layer of the colon wall.
Colon cancer in stage 2 is classified into three stages: 2A, 2B, and 2C.