Evolution in the Presence and Evidence Category of Radiation Therapy Treatment Recommendations in National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology

Abstract

Some perceptions exist regarding potential decline in the utilization of radiation therapy (RT) with expanding systemic therapy options. We sought to understand the recommended utilization of RT across a broad range of solid tumors by examining National Comprehensive Cancer Network (NCCN) Guidelines. We conducted a comprehensive review and categorization of RT recommendations, with their subsequent supporting evidence categories, in NCCN Guidelines from 2000 through 2019.The 2000, 2009, and 2019 versions of NCCN Guidelines were individually examined for RT-specific recommendations among the 10 most common solid tumors. The presence of RT as a recommended modality was recorded for each tumor type, along with the branch of management. Recommendation categories including Category 1, 2A, 2B and 3 were tallied and compared descriptively to examine totals and percentage distributions.3858 recommendations were individually reviewed. The presence of a recommendation inclusive of RT increased by 129% from 2000 to 2009 and by 111% from 2009 to 2019. From 2000 to 2019, RT recommendations overall increased by 206%. In 2019 NCCN Guidelines, the most Category 1 RT recommendations were found within small cell lung (13%), non-small cell lung (5%), breast (5%), bladder (2%), rectal (2%) and non-Hodgkin lymphoma (1%). Pancreatic, uterine, prostate, melanoma, kidney, and colon cancer guidelines had no Category 1 RT recommendations. Of note, rectal cancer had 31 (27%) preferred recommendations. The majority (89%) of 2019 RT recommendations were for initial therapy, while 9% were specific to salvage therapy. Tumor sites with the highest proportion of RT Category 1 evidence were small cell lung (29%), non-small cell lung (24%), and breast cancer (24%).The frequency of RT recommendations in NCCN Guidelines has increased over the past 20 years among the 10 most common solid tumors. A majority of recommendations remain Category 2A, and this proportional percentage of 2A recommendations is increasing. Consideration of evidence categories by solid tumor type is highly relevant to identify areas in need of expanded prospective, randomized, evidence regarding the use of RT.