Assessment of selection bias in clinic‐based populations of childhood cancer survivors: A report from the childhood cancer survivor study

Abstract

Background It is not known to what extent prevalence estimates of late effects among childhood cancer survivors derived from clinic based samples represent the actual estimates that would be derived if the entire population of childhood cancer survivors was recruited and evaluated for a particular outcome. Procedure In a large retrospective cohort study of childhood cancer survivors, the Childhood Cancer Survivor Study (CCSS), the prevalence of chronic health conditions among participants who reported being seen in a cancer center or long-term follow-up clinic was compared to the prevalence of chronic conditions in the entire cohort. Results When compared to survivors who had no medical care in the previous two years, survivors accessing medical follow-up were significantly more likely to have chronic health conditions. Relative risks of reporting a chronic health condition were 1.4 (95% CI 1.3 – 1.5) if seen in a cancer center or long-term follow-up clinic and 1.2 (95% CI 1.1-1.3) if seen in a general medical care setting. Estimates derived from only those childhood cancer survivors who were seen in a cancer center or long term follow-up clinic overestimate the prevalence of any chronic disease by 9.3% (95% CI: 7.0-11.6%). Conclusions Applying chronic condition prevalence estimates from a clinical population to the general population of childhood cancer survivors must be undertaken with caution. Survivorship research must maintain a high level of scientific rigor to ensure that results reported in the literature are interpreted within the appropriate context.

Evaluation of traditional and novel measures of cardiac function to detect anthracycline-induced cardiotoxicity in survivors of childhood cancer.

“…Our study sample was recruited from patients attending our local survivor clinic who might be more likely to participate in research. [38] However, this should not particularly effect comparisons between the various echocardiocraphic measures. While the study was adequately powered to detect a 1.0 standard deviation difference in radial displacement, the small sample limited our ability to perform more detailed multiple variable regression and the cross-sectional nature of the study inhibits conclusions concerning long-term changes in the myocardium.…”

Risk factors for subsequent endocrine-related cancer in childhood cancer survivors

“…Another source for selection bias may be the nature of the cohort. This is illustrated by Ness et al, who observed an overestimation of the prevalence of long-term adverse health conditions by 9.3% (95% CI: 7.0-11.6) in childhood cancer survivors ascertained in a hospital-compared with a population-based setting (Ness et al 2009). Future studies on secondary endocrine-related malignancies after childhood cancer could be prospective, based on national registries, and use objective methods to collect data on secondary malignant neoplasms.…”

Strategy for Long-Term Surveillance at the German Childhood Cancer Registry - an Update

“…The emphasis is usually on the complete follow-up of a population-based cohort [22] . Grabow working groups are involved in long-term follow-up and surveillance: " Late Eff ects Surveillance System " (LESS), " Registry for the evaluation of side eff ects after radiotherapy in childhood and adolescence " (RiSK), the working group " Quality of Life " , and the German Childhood Cancer Registry (GCCR) (described in detail elsewhere; [6] ).…”