In this study, we used a population-based, nationally representative sample of adult survivors of childhood cancer and similar individuals without cancer to assess the burden of illness. Adult survivors of childhood cancer were more likely to have diminished health and greater productivity losses compared to similar individuals without cancer, adjusted for the effects of age, gender, race/ethnicity and survey year in multivariate analyses. These findings were consistent across multiple measures of health and productivity. We also found that adult survivors of childhood cancer reported health limitations and productivity loss at multiple times since diagnosis, with the greatest limitations in the initial 4 years and 30 or more years after diagnosis. The prevalence of health limitations and productivity loss in adult survivors over 30 years from diagnosis might reflect earlier childhood cancer treatment patterns that are associated with more morbidities compared to more recent treatments 5
as particularly survivors who were treated in the 1970s and 1980s may have been exposed to a specific treatment or cumulative dose that puts them at particularly high risk for other chronic disease conditions 30
. This population will be an important target for development of interventions to improve functionality and health outcomes.
These high levels of burden, co-morbid conditions, and poorer health status are consistent with other reports of adult survivors of childhood cancer 2, 3, 5, 6, 20, 31
. Studies from the CCSS reported survivors were twice as likely to have performance limitations than their siblings without cancer (19.6% vs. 11.8%) 3
. Additionally, a population-based study in Canada found fewer survivors reported very good or excellent general health compared to controls (62.3% vs. 71.2%) and survivors were more likely to have one or more co-morbid conditions 19
. Because of the potential of selection bias in a clinic-based population, estimates of prevalence of chronic disease may be overestimated 32
and may not reflect care in the community. Our study complements prior studies conducted in academic institutions or cancer centers by providing nationally-representative, population-based estimates of burden of illness in the U.S.
We found significant limitations in workforce participation and productivity in cancer survivors compared to similar individuals without cancer. These findings are consistent with other studies 20, 33
and a recent meta-analysis which reported that cancer survivors were less likely to be employed compared to healthy controls 7
. We also found that adult survivors of childhood cancer were more likely to report having public health insurance without supplemental private or military coverage, which is also consistent with other studies 34
. Having public health insurance can impact access and quality of care as some physicians do not accept patients with public health insurance, patients may not have access to specialty care, or patients may delay care due to cost 21, 35
. Because health insurance is generally obtained through employment in the U.S. and adult survivors of childhood cancer are less likely to participate in the workforce, future work on the inter-relationship between work, health insurance, and health care utilization will be important 36
Clinical guidelines recommend risk-based preventative services to cancer survivors 21, 37, 38
. However, childhood cancer survivors do not always attend follow-up clinics 39
, do not receive appropriate mammography screening 40
, or do not report receiving medical care based on being a cancer survivor 41
. Lack of risk-based care has been reported to be greatest among the oldest survivors 41
, the population with the largest differences in burden of illness in our study. In addition to risk-based care, the development and dissemination of effective interventions specific to childhood cancer survivors and their unique needs as they age to improve quality of life are needed. For example, workplace reintegration programs or other primary prevention programs such as physical activity or tobacco cessation programs, is an important area of research for this population. The costs associated with medical care for adult survivors of childhood cancer are largely unknown and are also an important area of future research.
Despite the strengths of a nationally representative, population-based study with high response rates, there are several limitations to our study. While the weighted number of adult survivors of childhood cancer in the NHIS is a reflection of the size of this population in the U.S., our sample of survivors is relatively small. We excluded a large number of cancer survivors because of possible misinterpretation of the question about age at diagnosis. Approximately 40% of those excluded from the analysis were women who reported they had cervical cancer under the age of 20 years. Because invasive cervical cancer is extremely rare in this age group, it is more likely they were diagnosed with a pre-invasive lesion or had an abnormal Pap smear under the age of 20 or were referring to time since diagnosis. Furthermore, the majority of the cancer sites reported by those excluded were unlikely to be childhood cancer diagnoses (for example, breast and prostate cancer), making it unlikely we excluded any childhood cancer survivors who misinterpreted the question or had cognitive late effects hampering their ability to answer the survey. Although the excluded group was more likely to be female and have lower educational attainment than our sample of adult survivors of childhood cancer, their age distribution, self-reported health status, health limitations, bed days, and days lost from work were similar to the included population. This suggests that excluding this group was unlikely to have impacted our estimates of health limitations and lost productivity. Cancer patients have been found to under-report history of cancer compared to medical records or tumor registries 42
, therefore the possible inclusion of some survivors in the comparison group may understate the differences between the two groups. Although there is also a possibility of recall bias as survivors may be less likely to remember the type of cancer they had as a child, this study focused on reporting of current health rather than prior behaviors. Due to the relatively small size of the general population of adult survivors of childhood cancer in the U.S., the survivors in some of the rare cancer diagnoses groups may not have been represented in this analysis. Finally, burden of illness and late effects in adult survivors of childhood cancer varies by cancer site and treatment 37
, particularly as treatment patterns in this population have changed over time, but we were unable to examine differences due to the absence of treatment data in the NHIS.
In this study, we found adult survivors of childhood cancers had poorer health outcomes than did similar individuals without cancer across several burden and productivity measures. The prevalence of health limitations and lost productivity was highest in survivors in the initial 4 years and 30 or more years after diagnosis. Given the increasing number of adult survivors of childhood cancers, it is important for this population to receive risk-based healthcare and for physicians to be aware of the risks for this population for decades following diagnosis.