The TNM system classifies cancer into three main categories:
T (Tumor): Describes the size and extent of the main tumor. It is usually rated on a scale from T0 (no evidence of primary tumor) to T4 (large tumor that has invaded nearby tissues). N (Node): Indicates whether cancer has spread to the nearby lymph nodes. This ranges from N0 (no lymph node involvement) to N3 (significant lymph node involvement). M (Metastasis): Shows whether cancer has spread to other parts of the body. M0 means no metastasis, while M1 means cancer has spread to other organs.
