RTOG Chest Wall Contouring Guidelines for Post-Mastectomy Radiation Therapy: Is It Evidence-Based?

Abstract

Adoption of 3-dimensional planning has brought a great renaissance in radiation oncology; however, its use in breast radiation therapy has lagged substantially. Recently, Radiation Therapy Oncology Group published an invaluable atlas describing consensus recommendations based on expert opinion for chest wall contouring. Although the atlas represents an important step toward 3-dimensional planning, continued reappraisal is essential, especially because the atlas guides ongoing protocols. Prior to opening Radiation Therapy Oncology Group (RTOG) study 1304 within our large comprehensive cancer network, a pretreatment review encountered a discrepancy in the recommended posterior border for the chest wall clinical target volume (CTV) relative to conventional clinical field boarders. This discrepancy significantly increases heart (mean V10Gy increase of 3%4%) and lung (mean V20Gy increase of 4%-11%) irradiation relative to the traditional techniques (1). Although chest wall recurrence accounts for 60% to 80% of locoregional recurrences after mastectomy, detailed information for the anatomic location of chest wall recurrences should guide CTV design. As such, we instituted a publications search to identify locations of chest wall recurrences to better guide CTV contouring. Querying electronic databases (PubMed), bibliographies for studies published since 1952, and Brand & Copeland’s textbook The Breast using search terms including