The AJCC staging system is a classification system developed by the American Joint Committee on Cancer for describing the extent of disease progression in cancer patients.It utilizes in part the TNM scoring system: Tumor size, Lymph Nodes affected, Metastases. The AJCC staging system is a classification system developed by the American Joint Committee on Cancer for describing the extent of disease progression in cancer patients.It utilizes in part the TNM scoring system: Tumor size, Lymph Nodes affected, Metastases.