LAUSR

14 Background: National Comprehensive Cancer Network (NCCN) guidelines are the most comprehensive and widely used standard for clinical care in oncology by clinicians and payors in the US. The level of scientific evidence in NCCN guidelines has not been studied since it’s last review in 2010. We describe the categories of evidence and consensus (EC) among the 10 most common cancers in the US as of 2019 and compare them with 2010 guidelines. Methods: We obtained the 2019 version of NCCN guidelines. The definitions for various categories of EC used were: Category 1 (high level evidence such as randomized controlled trials with uniform consensus), 2A (lower level of evidence with uniform consensus), 2B (lower level of evidence without a uniform consensus but with no major disagreement) and 3 (any level of evidence but with major disagreement). We compared our results with previously published results from 2010 guidelines. Results: Total recommendations increased by 77% from 1023 (2010) to 1818 (2019). Of the 1818 recommendations, Category 1, 2A, 2B and 3 EC were 7%, 87%, 6% and 0% while in 2010 they were 5%, 85%, 9% and 1% respectively. Recommendations with category 1 EC were found in lung (13%), prostate (11%), melanoma (8%), breast (7%), NHL (5%), kidney (2%), bladder (2%) and colorectal (2%) guidelines. Pancreatic and uterine cancer guidelines had no recommendations with category 1 EC. 19% of therapeutic recommendations were category 1 EC with the majority (65%) pertaining to initial therapy. Guidelines with highest proportions of therapeutic recommendations with category 1 EC were breast (30%), lung (10%), and kidney (10%) cancers. No category 1 EC recommendations existed in screening or surveillance. Although we found an increase in the total number of recommendations, the distribution of different types of categories of EC are largely similar to 2010. Conclusions: Recommendations in 2019 NCCN guidelines are largely derived from lower levels of evidence with uniform expert opinion. Despite the major advances in oncology in the past decade, this is largely unchanged. Our study underscores the urgent need and available opportunities to expand the current evidence base in oncology which forms the platform for clinical practice guidelines.