Invitation process
Within the web-based LATER study database, we developed a tool to
automatically support the invitation process and logistics for the
outpatient clinical visit during the period February 2016-February 2020.
A tailor-made study invitation was generated to facilitate the informed
consent for participation to all eligible survivors according to the
outpatient clinic where the survivor was known (Amsterdam University
Medical Center (location VUmc), Leiden University Medical Center,
Erasmus Medical Center, University Medical Center Groningen, Radboudumc
and Princess Máxima Center for Pediatric Oncology). A unique feature of
this application is that the program assigned each survivor to the
appropriate study arms for all 16 sub-studies, based on the
characteristics of the survivor, his/her previous childhood cancer
diagnosis and treatment, and the center from which he or she
participated. If a survivor agreed to participate, study tests were
planned in combination with an already planned outpatient visit. If a
survivor did not respond to the initial invitation, the local center
sent a reminder or attempted to establish contact to the survivor by
phone. To optimize and standardize information for all centres study,
manuals were developed concerning the logistics, data collection
procedure, and storage of material. The study protocol for all LATER 2
sub-studies were approved by the medical ethics boards of all
participating centers.