[1] Maastricht Univ, Med Ctr, GROW Sch Oncol & Dev Biol, Dept Med Oncol, Peter Debyelaan 25, NL-6229 HX Maastricht, Netherlands
[2] Zuyderland Med Ctr, Dept Internal Med, Henri Dunantstr 5, NL-6419 PC Heerlen Geleen, Netherlands
[3] Maastricht Univ, Dept Family Med, Peter Debyelaan 1, NL-6229 HX Maastricht, Netherlands
[4] Katholieke Univ Leuven, Dept Gen Practice, Kapucijnenvoer 33,PB 7001, B-3000 Leuven, Belgium
[5] Maxima Med Ctr, Dept Internal Med, Run 4600, NL-5504 DB Veldhoven, Netherlands
[6] Hgsk Amsterdam, Fac Hlth, Tafelbergweg 51, NL-1105 BD Amsterdam, Netherlands
[7] Univ Queensland, Sch Med, Discipline Gen Practice, Royal Brisbane & Womens Hosp, Bldg 16-910, Herston, Qld 4029, Australia