[1] McMaster Univ, Dept Surg, Hamilton, ON, Canada
[2] McMaster Univ, Dept Hlth Res Methods Evidence & Impact, Hamilton, ON, Canada
[3] McMaster Univ, Ontario Clin Oncol Grp, Hamilton, ON, Canada
[4] McMaster Univ, Dept Oncol, Hamilton, ON, Canada
[5] Univ Toronto, Dept Surg, Toronto, ON, Canada
[6] Sunnybrook Hlth Sci Ctr, Odette Canc Ctr, Div Gen Surg, Toronto, ON, Canada
[7] Univ Hlth Network, Dept Surg, Toronto, ON, Canada
[8] Mem Sloan Kettering Canc Ctr, Dept Surg, 1275 York Ave, New York, NY 10021 USA