[1] Univ Toronto, Princess Margaret Hosp, Dept Med Oncol, Toronto, ON M5G 2M9, Canada
[2] BC Canc Agcy Vancouver Clin, Vancouver, BC, Canada
[3] London Hlth Sci Ctr, London, ON, Canada
[4] Odette Canc Ctr, Toronto, ON, Canada
[5] Queens Univ, NCIC Canada Clin Trials Grp, Kingston, ON, Canada
[6] NCI, Rockville, MD USA