[1] Stanford Canc Inst, Dept Radiat Oncol, Stanford, CA USA
[2] Stanford Ctr Hlth Policy, Palo Alto, CA USA
[3] Stanford Ctr Primary Care & Outcomes Res, Palo Alto, CA USA
[4] Stanford Canc Inst, Stanford, CA USA
[5] Stanford Sch Med, Palo Alto, CA USA
[6] Univ Michigan, Ann Arbor, MI 48109 USA
[7] Stanford Univ, Dept Radiat Oncol, Sch Med, Stanford, CA 94305 USA