ABSTRACT
The unique nature of cancer biology impacts therapeutic strategy. The tissue of origin (often referred to as the “primary site”) of a cancer can usually be determined by the pattern of growth or spread and then confirmed by pathologic or molecular evaluation. Attention to the primary site of cancer is important because it often correlates with disease course and treatment sensitivity. Clinical staging of cancer takes into consideration clinical characteristics of the tumor (T), the involvement of lymph nodes (N) by the tumor, and the presence of metastasis (M) to other locations within the body. A compilation of these parameters (TNM) forms the basis of the most commonly used staging system by the American Joint Committee on Cancer (AJCC).
