The study comprises establishment of two inter-Nordic cohorts (a childhood cancer cohort and a population comparison cohort), planning and executing a late-outcome surveillance system for the two cohorts, and establishing and conducting hypothesis-testing case–cohort studies within the childhood cancer survivor cohort.
Establishment of a childhood cancer cohort and a population control cohort will be the first of six milestones in this 5-year project. This is expected to take 1.25 years and involve the following steps:
At a first joint Nordic meeting of partners, in January 2010, a detailed data collection plan was completed, for:
- final definition of the cohorts of childhood cancer patients and population comparisons
- methods for determining the vital or emigration status of cohort members
- details of registers and data on late outcomes available in each country
- a precise timetable for data extraction and data linkage, and
- coordination of the wording of documents required to obtain study approval in each of the five countries.
Linkage was performed nationally during the period March–November 2010. The coordinating Principal Investigator (Jørgen H. Olsen) and a senior researcher (Jeanette Falck Winther) hired for the study will act as permanent coordinators of this extensive work, in close contact with the five data collection centres. It was anticipated that at least one site visit to each centre was to be arranged, preferably during September–November 2010.
In December 2011, data from the five countries was formatted in accordance with the decisions taken at the beginning of the year, and the individually linked records will be made anonymous.
During January–March 2012, anonymous data will be gathered into one, comprehensive dataset at the Institute of Cancer Epidemiology in Copenhagen. Each variable included will be reviewed and the data harmonized, ready for analysis.
Outcome surveillance system and cohort analyses (second milestone, to be reached by 1 January 2014)
A late outcome surveillance system will be established and the diseases of interest will be addressed one by one, starting with the four themes selected a priori followed by a screening activity:
- cardiovascular and pulmonary diseases (July 2011–December 2012),
- endocrine disorders and adverse reproductive outcome (July 2011–December 2012). Diabetes mellitus is being evaluated in a separate PhD project,
- renal and gastrointestinal disorders (July 2011–December 2012)
Case-cohort studies on selected outcomes (third to sixth milestone, to be reached by July 2014)
This activity includes:
- selection of outcomes and generation of specific working hypotheses,
- selection of sub-cohorts,
- review of medical records for confirmation and subgrouping of outcome and collection of data on childhood cancer treatment, including dosimetry estimations when appropriate, and
The sequence of work is tentatively as indicated in the Gannt Chart below: