[1] Princess Maxima Ctr Paediat Oncol, Lundlaan 6, NL-3584 EA Utrecht, Netherlands
[2] Erasmus MC, Dept Gen Practice, Rotterdam, Netherlands
[3] Erasmus MC Sophia Childrens Hosp, Dept Paediat Oncol Haematol, Rotterdam, Netherlands
[4] Erasmus MC, Dept Publ Hlth, Rotterdam, Netherlands
[5] Univ Southampton, Fac Hlth Sci, Southampton, Hants, England