[1] Inst Curie, Paris, France
[2] Eur Org Res & Treatment Canc, Brussels, Belgium
[3] MCHaaglanden, The Hague, Netherlands
[4] Inst Verbeeten, Tilburg, Netherlands
[5] Univ Hosp Gasthuisberg, Leuven, Belgium
[6] Univ Hosp St Luc, Woluwe St Lambert, Belgium
[7] Charite, Comprehens Canc Ctr, Dept Radiat Oncol & Radiotherapy, Berlin, Germany
[8] Georges Francois Leclerc Canc Ctr, Dijon, France
[9] Radiotherapiegrp, Deventer, Netherlands
[10] Univ Med Ctr Utrecht, Utrecht, Netherlands
[11] Gustave Roussy, Dept Radiat Therapy, Villejuif, France
[12] German Canc Res Ctr, Heidelberg & German Canc Consortium DKTK, Partner Site Tubingen, Tubingen, Germany
[13] Acad Med Ctr, Dept Radiat Oncol, Amsterdam, Netherlands
[14] Univ Hosp Zurich, Zurich, Switzerland
[15] Rambam Hlth Care Campus, Haifa, Israel
[16] Netherlands Canc Inst, Amsterdam, Netherlands