[1] Acad Med Ctr, Dept Med Psychol, Amsterdam, Netherlands
[2] Netherlands Fdn, Detect Hereditary Tumours, Leiden, Netherlands
[3] Leiden Univ, Med Ctr, Dept Gastroenterol, Leiden, Netherlands
[4] Antoni Leeuwenhoek Hosp, Netherlands Canc Inst, Dept Psychosocial Res & Epidemiol, Amsterdam, Netherlands