Gastric lymph node contouring atlas: A tool to aid in clinical target volume definition in 3-dimensional treatment planning for gastric cancer

To develop a contouring atlas of the gastric lymph node stations to be used in defining and planning clinical target volumes in 3-dimensional treatment planning for gastric cancers.Four physicians, including 2 radiation oncologists, a diagnostic radiologist, and a surgical oncologist specialized in gastric cancer, convened over the course of multiple meetings. Four patients were identified as representative cases, including 3 gastric cancer patients treated with differing surgical approaches (total gastrectomy, Ivor-Lewis esophagogastrectomy, and distal gastrectomy) and 1 patient with intact gastric anatomy. Radiographic delineation of lymph node stations was established for each case to highlight differences between intact anatomy and different postoperative anatomy.Consensus was achieved among physicians in order to create a computed tomographic-based contouring atlas of gastric lymph node stations. Detailed radiographic lymph node station delineation for both intact gastric anatomy and post-surgical anatomy are discussed.This report serves as a template for the delineation of gastric lymph node stations to aid in the definition of elective clinical target volumes to be used in conformal treatment planning.