Statistical analyses current paper
In the current paper, we compared the participants and non-participants by sex, age at diagnosis, type of cancer, attained age (age at invitation), follow-up time since childhood cancer diagnosis until invitation, and for cancer treatment (dichotomous variables for any chemotherapy, any radiotherapy, any surgery and categorical variable for bone marrow/stem cell transplant [no, autologous, allogenic, unknown]). Treatment variables represent cumulative exposures accumulated during treatment for primary tumor, metastases and recurrences, regardless of time since first diagnosis, and captured from original medical files in the treatment centers (e.g. Teepen et al. submitted). Differences in the distributions were tested using a Chi square test.