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

PURPOSE: 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.

METHODS AND MATERIALS: 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.

RESULTS: 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.

CONCLUSIONS: 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.