[1] Deutsch Krebsforschungszentrum DKFZ, Radiat Oncol, Heidelberg, Germany
[2] Netherlands Canc Inst NKI, Radiat Oncol, Amsterdam, Netherlands
[3] Univ Hos, GROW Res Inst, Maastricht Radiat Oncol MAASTRO, Radiat Oncol, Maastricht, Netherlands
[4] Massachusetts Gen Hosp, Boston, MA 02114 USA
[5] Harvard Med Sch, Radiat Oncol, Boston, MA USA