Contouring inguinal and femoral nodes; how much margin is needed around the vessels?

Circumferential margins around femoral vessels required to adequately cover this nodal region were >2 cm in most directions. Contouring the inguinal lymph nodes as a compartment defined by the anatomic landmarks suggested above may be more reproducible. Physicians should exercise caution in extrapolating pelvic nodal contouring guidelines to inguinal lymph nodal contouring.