[1] Washington Univ, Sch Med, Div Oncol, Dept Med, St Louis, MO 63110 USA
[2] Univ Chicago, Dept Med, Sect Hematol & Oncol, Chicago, IL 60637 USA
[3] Univ Chicago, Ctr Comprehens Canc, Chicago, IL 60637 USA
[4] Washington Univ, Sch Med, Alvin J Siteman Canc Ctr, St Louis, MO 63110 USA
[5] Washington Univ, Sch Med, Div Biostat, St Louis, MO 63110 USA
[6] Univ Chicago, Dept Hlth Studies, Chicago, IL 60637 USA