1. Leiden University Medical Center, Leiden, the Netherlands (M.K.V., O.M.D., E.K.)
2. University Medical Center Utrecht, Utrecht, the Netherlands (K.P.S.)
3. Maastricht University Medical Center, Maastricht, the Netherlands (M.J.A.)
4. Zuyderland Medical Center, Sittard-Geleen, the Netherlands (F.W.V.)
5. Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, the Netherlands (C.U.B., J.B.H.)
6. Radboud University Medical Center, Nijmegen, the Netherlands (M.J.B.)
7. Dutch Institute for Clinical Auditing, Leiden, and Cancer Center Amsterdam, Amsterdam University Medical Center, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands (J.V.)
8. Cancer Center Amsterdam, Amsterdam University Medical Center, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands (A.J.V.)
9. Isala Oncology Center, Isala, Zwolle, the Netherlands (J.W.B.)
10. University Medical Center Groningen, Groningen, the Netherlands (G.A.H.)
11. Medisch Spectrum Twente, Enschede, the Netherlands (D.P.)
12. Medical Center Leeuwarden, Leeuwarden, the Netherlands (R.S.V.)
13. Amphia Ziekenhuis, Breda, the Netherlands (A.J.T.)
14. Erasmus Medical Center Cancer Institute, Rotterdam, the Netherlands (A.A.V.)
15. Maxima Medical Center, Veldhoven, the Netherlands (G.V.)
16. Dutch Institute for Clinical Auditing, Leiden, the Netherlands (M.C.V.)
17. Dutch Institute for Clinical Auditing, Leiden, and Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, the Netherlands (M.W.W.).