Target Volume Determination 2015

• Under the new AJCC classification system, N staging is based on the number of positive nodes (N1 = 1-6 nodes; N2 = 7-15 nodes; N3 > 15 ) (This approach differs from the previous classification system, which was based on anatomic location) • Several studies have confirmed the superiority of number of positive nodes in the estimation of prognosis , but anatomic nodal location remains a valuable criterion because the D classification, a description of the extent of lymphadenectomy, is determined according to the level of lymph node dissection (D1–D4).