[1] No Calif Canc Ctr, Union City, CA USA
[2] Dept Vet Affairs Med Ctr, Minneapolis, MN USA
[3] Univ N Carolina, Dept Med, Div Gastroenterol & Hepatol, Chapel Hill, NC USA
[4] Dept Vet Affairs Med Ctr, Durham, NC USA
[5] NCI, Div Canc Control & Populat Sci, Rockville, MD USA
[6] Univ Calif Los Angeles, Dept Med, Div Gen Internal Med Hlth Serv Res & Hematol Onco, Los Angeles, CA 90024 USA
[7] RAND Corp, Santa Monica, CA USA
[8] Dana Farber Canc Inst, Dept Biostat Sci, Boston, MA 02115 USA
[9] Dana Farber Canc Inst, Dept Med Oncol, Boston, MA 02115 USA
[10] Univ Alabama Birmingham, Dept Med, Div Prevent Med, Birmingham, AL 35294 USA
[11] Harvard Univ, Sch Med, Harvard Pilgrim Hlth Care, Dept Ambulatory Care & Prevent, Cambridge, MA 02138 USA
[12] Univ Iowa, Coll Publ Hlth, Dept Epidemiol, Iowa City, IA USA
[13] Harvard Univ, Sch Med, Dept Hlth Care Policy, Boston, MA 02115 USA
[14] Brigham & Womens Hosp, Dept Med, Div Gen Med, Boston, MA 02115 USA