1 Department of Radiation Oncology, University of Toronto, Toronto, ON M5S 1A1, Canada; Harvard School of Public Health, Harvard University, Boston, MA 02115, USA.
2 Department of Radiation Oncology, University of Toronto, Toronto, ON M5S 1A1, Canada; Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada, Toronto, ON M5G 2M9, Canada.
3 Harvard School of Public Health, Harvard University, Boston, MA 02115, USA.
4 Harvard Global Equity Initiative, Harvard University, Boston, MA 02115, USA; Mexican Health Foundation, AC México, Mexico.
5 Department of Radiation Oncology, University of Toronto, Toronto, ON M5S 1A1, Canada; Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada, Toronto, ON M5G 2M9, Canada. Electronic address: mary.gospodarowicz@rmp.uhn.on.ca.