Funding for this research was provided by:
Canadian Institutes of Health Research (130400)
Received: 17 October 2018
Accepted: 28 March 2019
First Online: 29 April 2019
Compliance with ethical standards
: We can confirm that we have observed appropriate ethical guidelines and legislation in conducting the study. The study was approved by the University of Toronto Research Ethics Board (Protocol #29342), and informed consent was not required as there was no direct contact with women and the study falls within the ethical domain of non-consensual research. In addition, Research Ethics Board approval was obtained for each regional cancer centre for medical chart abstraction.
: The authors declare that they have no conflict of interest.