[1] Univ Texas Southwestern Med Ctr, Sch Med, Dallas, TX USA
[2] Fred Hutchinson Canc Ctr, Publ Hlth Sci & Clin Res Div, Seattle, WA 98109 USA
[3] Univ Colorado, Childrens Hosp Colorado, Dept Pediat, Denver, CO USA
[4] Univ Washington, Dept Radiat Oncol, Seattle, WA USA
[5] St Jude Childrens Res Hosp, Dept Epidemiol & Canc Control, Memphis, TN USA
[6] Duke Univ, Dept Med, Durham, NC USA