Late health effects and changes in lifestyle factors after cancer in childhood with and without subsequent second primary cancers – the KiKme case-control study

VersKiK: Study protocol of an observational registry-based study on the current state of follow-up care and adherence to follow-up guidelines after cancer in childhood or adolescence

BACKGROUND

This article describes the study design of the quantitative part of the VersKiK study, The primary objectives of this study are to examine the occurrence of late effects in survivors of childhood or adolescent cancer (module 1), investigate health-related vulnerabilities and medical service utilization within this survivor group (modules 1 and 3), and assess the alignment between documented follow-up care for cardiological and audiological late effects with guideline recommendations, along with evaluating the extent of adherence among paediatric cancer survivors (module 3).

METHODS

This is a non-interventional retrospective observational cohort study. It is based on stochastically linked insurance claims data from approximately 150,000 statutory insured persons with information concerning around 25,000-30,000 cancer survivors recorded in the German Childhood Cancer Register (GCCR). To explore adherence to selected follow-up guidelines, intention to treat treatment data from clinical study groups for particular diagnostic entities will be additionally included.

DISCUSSION

The growing group of survivors after cancer in childhood and adolescence is representing a special population with an increasing demand for life-long healthcare services through relative high probability of late effects. Currently, there is a limited evidence in Germany on utilization of corresponding medical services and adherence to follow-up guidelines. With this study design, we are aiming to address these gaps and, consequently, suggest improvements to existing follow-up guidelines and follow-up care provision in Germany.

Self-administered questionnaire assessing childhood cancer treatments and associated risks for adverse health outcomes - The KiKme study

Background

Childhood cancer survivors (CCS) are at particularly high risk for therapy-related late sequelae, with secondary primary neoplasms (SPN) being the most detrimental. Since there is no standardized questionnaire for retrospective assessment of associations between prior cancer treatments and late health effects, we developed a self-administered questionnaire and validated it in a cohort of CCS.

Methods

CCS of a first primary neoplasm (FPN, N=340) only or with a subsequent SPN (N=101) were asked whether they had received cancer therapies. Self-reports were compared to participants' medical records on cancer therapies from hospitals and clinical studies (N=242). Cohen's Kappa (κ) was used to measure their agreement and logistic regression was used to identify factors influencing the concordance. Associations between exposure to cancer therapies and late health effects (overweight/obesity, diseases of the lipid metabolism and the thyroid gland, cardiovascular diseases, occurrence of SPN) were analyzed in all participants by applying generalized linear mixed models to calculate odds ratios (OR) and 95% confidence intervals (95%CI).

Results

For CCS of SPN, a perfect agreement was found between self-reports and medical records for chemotherapy (CT, κ=1.0) while the accordance for radiotherapy (RT) was lower but still substantial (κ=0.8). For the CCS of FPN the accordance was less precise (CT: κ=0.7, RT: κ=0.3). Cancer status, tumors of the central nervous system, sex, age at recruitment, vocational training, follow-up time, and comorbidities had no impact on agreement. CCS with exposure to CT were found to be less often overweight or obese compared to those without CT (OR=0.6 (95%CI 0.39; 0.91)). However, they were found to suffer more likely from thyroid diseases excluding thyroid cancers (OR=9.91 (95%CI 4.0; 24.57)) and hypercholesterolemia (OR=4.45 (95%CI 1.5; 13.23)). All other analyses did not show an association.

Conclusion

Our new questionnaire proved reliable for retrospective assessment of exposure to CT and RT in CCS of SPN. For the CCS of FPN, self-reported RT was very imprecise and should not be used for further analyses. We revealed an association between late health outcomes occurring as hypercholesterolemia and thyroid diseases, excluding thyroid cancer, and the use of CT for the treatment of childhood cancer.