[1] St Louis Vet Affairs Med Ctr, Res Serv, St Louis, MO 63103 USA
[2] Washington Univ, Sch Med, Div Oncol, St Louis, MO 63110 USA
[3] Washington Univ, Sch Med, Div Publ Hlth Sci, St Louis, MO 63110 USA
[4] Washington Univ, Sch Med, Dept Internal Med, St Louis, MO 63110 USA
[5] Advocate Lutheran Gen Hosp, Div Hematol Oncol, Park Ridge, IL 60068 USA
[6] Washington Univ, Sch Med, Div Biostat, St Louis, MO 63110 USA