From City of Hope Comprehensive Cancer Center, Duarte (A.F.H., M.G.M., J.Y.S.), University of California Davis Comprehensive Cancer Center, Sacramento (J.M.T.), and Children's Hospital Los Angeles, Los Angeles (C.F., A.D., A.K.) - all in California; SWOG Statistics and Data Management Center, Fred Hutchinson Cancer Center, (M.L., H.L.) and Seattle Children's Hospital (A.L.) - both in Seattle; Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta (S.M.C.), and Winship Cancer Institute and Emory University Hospital (K.A.B.), Atlanta; Weill Cornell Medicine (S.C.R., J.P.L.), Memorial Sloan Kettering Cancer Center (P.T.), and New York University Langone (L.K.S.), New York, Wilmot Cancer Institute, University of Rochester, Rochester (C.C., L.S.C., J.W.F.), and Roswell Park Comprehensive Cancer Center, University at Buffalo, Buffalo (K.M.K.) - all in New York; Rutgers Cancer Institute of New Jersey, New Brunswick (A.M.E.); McGill University Health Centre, Montreal (K.D.), and SickKids Hospital (Angela Punnett) and Princess Margaret Cancer Centre (D.H., Anca Prica, M.C.), Toronto - all in Canada; Reid R. Sacco AYA Cancer Program, Tufts Medical Center (S.K.P.), and Dana-Farber Cancer Institute (M.A.S.) - both in Boston; M.D. Anderson Cancer Center, Houston (S.A.), and University of Texas Health Science Center at San Antonio, San Antonio (S.K.) - both in Texas; Siteman Cancer Center, Washington University, St. Louis (N.L.B., B.K.); Medical University of South Carolina, Charleston (B.T.H.), and Prisma Health Cancer Institute - Eastside, Greenville (S.C.) - both in South Carolina; Carolinas Medical Center, Levine Cancer Institute, Charlotte, NC (R.J.); Moffitt Cancer Center, Tampa (H.S.), and Sylvester Comprehensive Cancer Center, University of Miami, Miami (C.M.) - both in Florida; Huntsman Cancer Institute, University of Utah, Salt Lake City (B.H.); University of Alabama at Birmingham, Birmingham (G.G.); Illinois CancerCare, Peoria (P.K.), and University of Chicago, Chicago (S.M.S.); Cancer and Hematology Centers of Western Michigan, Grand Rapids (B.B.), and University of Michigan, Ann Arbor (A.M.P.); the Department of Hematology and Oncology, Geisinger Community Medical Center, Scranton, PA (N.S.); Fairview Ridges Hospital, Minnesota Oncology, Burnsville (A.S.); SWOG Cancer Research Network, Teaneck, NJ (H.D.); and the National Cancer Institute, Cancer Therapy Evaluation Program, Bethesda, MD (R.F.L.).