A Systematic Review of Contouring Guidelines in Radiation Oncology: Analysis of Frequency, Methodology and Delivery of Consensus Recommendations

Abstract Purpose Objectives: Clinical trials have described variation in radiotherapy plan quality, of which contour delineation is a key component, and linked this to inferior patient outcomes. In response, consensus guidelines have been developed to standardize contour delineation. This investigation assesses trends in contouring guidelines and examines the methodologies used to generate and deliver recommendations. Material Methods We conducted a literature search for contouring guidelines published after 1995. Of 11,124 citations, 332 were identified for full-text review to determine inclusion. We abstracted articles for intent of consensus process, key elements of the methodology, and mode of information delivery. Fisher’s Exact Test was used to identify elements that differ between guidelines generated for clinical trials and routine care. Results Overall, 142 guidelines were included, of which 16 (11%) were developed for a clinical trial. There was an increase in guideline publication over time (0 from 1995-1999 vs 65 from 2015-2019; p=0.03), particularly among recommendations for stereotactic radiation and brachytherapy. The most common disease sites were head and neck (24%), gastrointestinal (12%), and gynecologic (12%). Methods used to develop recommendations included literature review (50%) and image-based methods (45%). Panels included a median of 10 physicians (IQR 7-16), and 70% of panels represented multidisciplinary expertise. Guidelines developed for a clinical trial were more likely to include an image-based approach with quantitative analysis of contours submitted by the panel members, and to publish a full set of image-based recommendations (p Conclusions This review highlights an increase in consensus contouring recommendations over time. Guidelines focus on disease sites with evidence supporting a correlation between treatment planning and patient outcomes, such as head and neck, but variation exists in the approach to the consensus process. Elements that may improve guideline acceptance (i.e. image-based consensus contour analysis) and usability (i.e. inclusion of a full image set) are more common in guidelines developed for clinical trials.