Background
Expert consensus contouring atlas. Four physicians — 2 radiation oncologists, 1 diagnostic radiologist, 1 surgical oncologist specializing in gastric cancer — from Massachusetts General Hospital and Brigham and Women's Hospital. Developed through multiple consensus meetings. Goal: provide a CT-based reference standard for delineating gastric lymph node stations in 3D treatment planning for postoperative gastric cancer radiation.
Interventions and follow up
Arm A: N/A — contouring atlas development, not a clinical trial
Arm B: N/A
Primary endpoint: Consensus CT-based lymph node station delineation for 4 representative case
mFollow up: N/A
Arm B: N/A
Primary endpoint: Consensus CT-based lymph node station delineation for 4 representative case
mFollow up: N/A
Results
Atlas coverage: Includes intact gastric anatomy + 3 postoperative anatomies (total gastrectomy, Ivor-Lewis esophagogastrectomy, distal gastrectomy). Covers all major gastric lymph node stations (perigastric stations 1–6 and nodal groups 7–16) with CT-based boundaries for each surgical scenario.
Adverse events
Main adverse events: N/A
Conclusions
Provides a standardized CT-based contouring template for gastric lymph node stations applicable to all major surgical resection types, enabling consistent and reproducible clinical target volume (CTV) definition in 3D conformal planning for adjuvant gastric cancer radiation.
Key Limitations
Key Limitations: Consensus among 4 physicians at 2 institutions — inter-institutional variability not assessed. Atlas does not account for all anatomic variants or tumor locations. Derived from non-randomized case selection. Predates widespread IMRT for gastric cancer; updated atlases may be needed for modern dose distribution goals.
Clinical Context
Standard reference used alongside RTOG 9904 and INT-0116 contouring guidance for adjuvant gastric radiation therapy CTV definition. Complements the INT-0116 nodal coverage recommendations (para-aortic, splenic hilar, celiac, porta hepatis nodes depending on primary location and surgery type). Enables more consistent nodal target delineation across practitioners when delivering the 45 Gy adjuvant dose established by INT-0116.
References