What does TNM mean in cancer staging?

TNM is the most widely used cancer staging system, and most hospitals and medical centers use it as their main method for cancer reporting. You are likely to see your cancer described this way in your pathology report, unless a different system is used for your type of cancer.

In the TNM system:

• T refers to the size and extent of the main (primary) tumor.
• N refers to the number of nearby lymph nodes that have cancer.
• M refers to whether the cancer has metastasized—spread from the primary tumor to other parts of the body.

Numbers after each letter add detail (for example, T3N1M0). A higher T number means a larger tumor or more growth into nearby tissue; a higher N number means more lymph nodes contain cancer; M0 means no distant spread and M1 means the cancer has spread. Your healthcare team can explain what your specific TNM description means.