Published Online: June 4, 2011. doi:10.1001 /jama.2011.749
Author Contributions: Dr Biagi 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: Biagi, Mackillop, King, Booth.
Acquisition of data: Biagi, Raphael, Booth.
Analysis and interpretation of data: Biagi, Raphael, Mackillop, Kong, King, Booth.
Drafting of the manuscript: Biagi, Raphael, Mackillop, Kong, Booth.
Critical revision of the manuscript for important intellectual content: Biagi, Mackillop, King, Booth.
Statistical analysis: Kong, King.
Obtained funding: Mackillop, Booth.
Administrative, technical, or material support: Mackillop.
Study supervision: Biagi, Mackillop, Booth.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Mackillop reported that in 2009 he provided expert testimony on the relationship between delays in postlumpectomy radiotherapy for breast cancer and the probability of local control in a class action suit in Quebec (Cilinger c Centre Hospitalier de Chicoutimi). No other disclosures were reported.
Funding/Support: This work was supported in part by a grant from the Canadian Institutes of Health Research (W.J.M.). Dr Booth is supported as a Cancer Care Ontario Chair in Health Services Research.
Role of the Sponsor: The sponsors 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.