Author Contributions: Dr Formenti had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Formenti, DeWyngaert, Goldberg.
Acquisition of data: Formenti, DeWyngaert, Jozsef.
Analysis and interpretation of data: Formenti, DeWyngaert, Goldberg.
Drafting of the manuscript: Formenti, DeWyngaert, Goldberg.
Critical revision of the manuscript for important intellectual content: Formenti, Jozsef, Goldberg.
Statistical analysis: Jozsef, Goldberg.
Administrative, technical, or material support: Formenti, DeWyngaert.
Study supervision: Formenti, Goldberg.
Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Formenti reported institutional receipt of payment from the David Geffen School of Medicine at the University of California, Los Angeles, for a presentation at a conference; and institutional receipt of payment for a continuing medical education course offered at New York University. Dr Goldberg reported institutional receipt of a cancer center support grant from the National Cancer Institute at the National Institutes of Health. Drs DeWyngaert and Jozsef did not report any disclosures.
Funding/Support: Federal IDEA grant DAMD17-01-1-0345 from the Department of Defense Breast Cancer Research Program awarded to Dr Formenti enabled the initial feasibility study on prone breast radiotherapy that permitted the current trial.
Role of the Sponsor: The funding agency of the feasibility study on prone breast radiotherapy that permitted the current trial had no role in the design and conduct of the study; in the collection, analysis, and interpretation of the data; or in the preparation, review, or approval of the manuscript.