[1] Univ Autonoma Barcelona, Hosp Santa Creu & St Pau, Inst Invest Biomed St Pau, Oncol Dept, Carrer St Quint 89, Barcelona 08041, Spain
[2] Brigham & Womens Hosp, Prog Ram Regulat Therapeut & Law, 75 Francis St, Boston, MA 02115 USA
[3] Harvard Med Sch, Boston, MA 02115 USA
[4] Hosp Santa Creu & Sant Pau, Dept Epidemiol, Barcelona, Spain
[5] Univ Autonoma Barcelona, Barcelona, Spain
[6] Princess Margaret Canc Ctr, Dept Med, Div Med Oncol & Hematol, Toronto, ON, Canada
[7] Univ Toronto, Toronto, ON, Canada