Treatment modification in radiation therapy was not associated with altered risk from COVID-19 in lower-risk scenarios, according to a simulation model created from a retrospective analysis of prepandemic clinical trials, according to the results of a recent study published in JAMA Network Open.

The study authors simulated COVID-19 risk associated with radiation treatment for cancer across different pandemic scenarios, varying infection risk per fractions (IRFs) and case fatality rates (CFRs). A simulation model was build based on individual patient–level data extracted from published survival figures from 8 randomized clinical trials across oncology. The clinical trials selected included rectal, breast, and prostate cancer (3 common sites) with published, high-quality trials of different radiation fractionation approaches. The primary study outcome was overall survival.

Data from a total of 14,170 patients was included in the analysis. When low COVID-19 risk was modeled using an IRF of 0.5% and CFRs of 5%, fractionation was not significantly associated with altered outcomes. However, in high COVID-19 risk scenarios, more aggressive hypofractionation were associated with improved survival, but moderate hypofractionation was not.


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“Our results suggest minimal mortality risk with standard treatment regimens when infection control measures can keep daily infection risk at or below 0.5% and support the delivery of standard evidence-based cancer care in most settings when appropriate precautions are taken,” the study authors wrote. “We demonstrate that the benefits of treatment modification vary based on the local pandemic scenario and degree of treatment shortening.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Tabrizi S, Trippa L, Cagney D, et al. Assessment of simulated SARS-CoV-2 infection and mortality risk associated with radiation therapy among patients in 8 randomized clinical trials. JAMA Netw Open. Published online March 29, 2021. doi:10.1001/jamanetworkopen.2021.3304