The AJCC Cancer Staging Manual is a comprehensive guide used by healthcare professionals to classify the extent of cancer in patients. It provides a standardized system for staging various types of cancer, which helps in determining the prognosis and treatment options. The manual includes detailed criteria for assessing tumor size, lymph node involvement, and the presence of metastasis, which are crucial for accurate staging. Developed by the American Joint Committee on Cancer (AJCC), this manual is regularly updated to reflect new research and advancements in cancer treatment. It serves as an essential resource for oncologists, pathologists, and other medical professionals involved in cancer care, ensuring consistent communication and understanding of cancer stages across different institutions.