Levels of Evidence for Radiation Therapy Recommendations in the National Comprehensive Cancer Network (NCCN) Clinical Guidelines

Miguel Angel Noy; Benjamin J Rich; Ricardo Llorente; Deukwoo Kwon; Matthew Abramowitz; Brandon Mahal; Eric A Mellon; Nicholas G Zaorsky; Alan Dal Pra

doi:10.1016/j.adro.2021.100832

Levels of Evidence for Radiation Therapy Recommendations in the National Comprehensive Cancer Network (NCCN) Clinical Guidelines

Adv Radiat Oncol. 2021 Oct 29;7(1):100832. doi: 10.1016/j.adro.2021.100832. eCollection 2022 Jan-Feb.

Authors

Miguel Angel Noy¹, Benjamin J Rich², Ricardo Llorente², Deukwoo Kwon³, Matthew Abramowitz², Brandon Mahal², Eric A Mellon², Nicholas G Zaorsky^{4

5}, Alan Dal Pra²

Affiliations

¹ Florida International University, Miami, Florida.
² Department of Radiation Oncology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida.
³ Division of Biostatistics, Department of Public Health Sciences, Sylvester Biostatistics and Bioinformatics Shared Resource, University of Miami Leonard M. Miller School of Medicine, Miami, Florida.
⁴ Department of Radiation Oncology, Penn State Cancer Center, Hershey, Pennsylvania.
⁵ Department of Public Health Sciences, Penn State College of Medicine, Hershey, Pennsylvania.

Abstract

Purpose: The National Comprehensive Cancer Network (NCCN) clinical guidelines influence medical practice, payor coverage, and standards of care. The levels of evidence underlying radiation therapy recommendations in NCCN have not been systematically explored. Herein, we aim to systematically investigate the NCCN recommendations pertaining to the categories of consensus and evidence (CE) for radiation therapy.

Methods and materials: We evaluated the distribution of CE underlying current treatment recommendations for the 20 most prevalent cancers in the United States with at least 10 radiation therapy recommendations in the NCCN clinical guidelines. For context, the distribution of evidence in the radiation therapy guidelines was compared with that of systemic therapy using a χ² test. The proportion of category I CE between radiation and systemic therapy was compared using a 2-proportion, 2-tailed z-test in total and for each disease site. A P value of < .05 was considered significant.

Results: Among all radiation therapy recommendations, the proportions of category I, IIA, IIB, and III CE were 9.7%, 80.6%, 8.4%, and 1.3%, respectively. When analyzed by disease site, cervix and breast cancer had the highest portion of category I CE (33% and 31%, respectively). There was no radiation therapy category I CE for hepatobiliary, bone, pancreatic, melanoma, and uterine cancers. There was a significant difference in the distribution of CE between the systemic therapy recommendations and the radiation therapy recommendations (χ² statistic 64.16, P < .001). Overall, there was a significantly higher proportion of category I CE in the systemic therapy recommendations compared with the radiation therapy recommendations (12.3% vs 9.7%, P = .043).

Conclusions: Only 9.7% of radiation therapy recommendations in NCCN guidelines are category I CE. The highest levels of evidence for radiation therapy are in breast and cervical cancers. Despite major advances in the field, these data underline that the majority of NCCN radiation therapy recommendations are based on uniform expert opinion and not on higher level evidence.