[1] John Theurer Canc Ctr, Dept Radiat Oncol, Hackensack, NJ USA
[2] Univ Michigan, Ctr Canc Biostat, Ann Arbor, MI 48109 USA
[3] Univ Michigan, Ctr Bioeth & Social Sci Med, Ann Arbor, MI 48109 USA
[4] Univ Michigan, Dept Radiat Oncol, UHB2C490,SPC 5010,1500 E Med Ctr Dr, Ann Arbor, MI 48109 USA