The most commonly used staging systems include the TNM system and the AJCC Cancer Staging Manual. The TNM system classifies cancer based on three main components:
T (Tumor): Size and extent of the primary tumor. N (Nodes): Involvement of regional lymph nodes. M (Metastasis): Presence of distant metastasis.
The AJCC system is an extension of the TNM system and is often used for more detailed staging.