Kidney disease in very long-term survivors of Wilms tumor: A nationwide cohort study with sibling controls.

BACKGROUND: Survival after Wilms tumor has significantly increased and focus on late effects has become increasingly important. However, knowledge about long-term renal function in survivors of Wilms tumor is missing. Our aim was to investigate evidence of kidney disease in 20- or more-year survivors of Wilms tumor in a clinical setting, with siblings as comparisons. METHODS: In this cross-sectional study, we established a cohort of Danish 20-plus-year survivors of Wilms tumor and siblings as controls. Participants answered a comprehensive health questionnaire supplemented by measurements of estimated glomerular filtration rate (eGFR), urine albumin-to-creatinine ratio, and blood pressure and were categorized according to the chronic kidney disease classification. Multiple linear regression analysis, taking family membership into account, was used to describe the differences in eGFR. Logistic regression analysis was performed to describe risk factors for the development of kidney disease. RESULTS: We included 99 survivors of Wilms tumor and 38 sibling controls with a median of 37 years of follow-up. The eGFR of Wilms tumor survivors was 13 ml/min/1.73 m2 (95% CI -20; -5) lower when compared to sibling control. Evidence of kidney disease, with risk factors as hypertension and diabetes, was found in 19% of the Wilms tumor survivors and 2% developed end-stage renal disease. Ninety-two percent of the Wilms tumor survivors had an eGFR >60 ml/min/1.732 . CONCLUSION: Long-term Wilms tumor survivors have on average a significantly decreased renal function along with the increased prevalence of kidney disease and end-stage renal disease when compared to sibling controls. Still, most survivors had kidney function within the normal range.

Disease-specific hospitalizations among 5-year survivors of Wilms tumor: A Nordic population-based cohort study.

BACKGROUND: With modern therapy, over 90% of Wilms tumor patients can expect to become long-term survivors, and focus on morbidity and late effects become increasingly important. We provide a novel evaluation and insight to subsequent hospitalizations in 5-year survivors of Wilms tumor. METHODS: As part of the Adult Life after Childhood Cancer in Scandinavia (ALiCCS) study, we identified 5-year survivors of Wilms tumor. Based on stratified random sampling, we constructed a population comparison cohort. Outcomes of interest were overall hospitalizations; hospitalizations for specific organ systems and disease-specific categories. Standardized hospitalization rate ratios (SHRR) and absolute excess risks (AER) were calculated. RESULTS: We included 913, 5-year survivors of Wilms tumor and 152 231 population comparisons. Survivors of Wilms tumor had an increased overall risk of being hospitalized (SHRR 1.8; 95% confidence interval (CI) 1.7-2.0). The hospitalization risk was increased within all major organ systems: urinary and genital organs (SHRR 2.5; 95% CI 2.1-3.0), endocrine (SHRR 2.5; 95% CI 1.9-3.3), cardiovascular (SHRR 2.2; 95% CI 1.7-2.9), and gastrointestinal (SHRR 1.5; 95% CI 1.3-1.8). Risks for specific diseases are reported in the study. CONCLUSIONS: Survivors of Wilms tumor had higher risks than population comparisons for a wide range of diseases, with the highest risks seen for urinary, endocrine, and cardiovascular disorders. Five to 20 years after the Wilms tumor diagnosis, 43% of survivors had been hospitalized at least once versus 29% of population comparisons. The overall AER was 2.3, which translates into 0.2 extra hospitalizations in 10 years for every Wilms tumor survivor.

Measuring childhood cancer late effects: evidence of a healthy survivor effect.

INTRODUCTION: Given considerable focus on health outcomes among childhood cancer survivors, we aimed to explore whether survivor bias is apparent during long-term follow-up of childhood cancer survivors. METHODS: We identified all 1-year survivors of cancer diagnosed before 20 years of age in Denmark, Finland, Iceland, and Sweden. From the general population, we randomly sampled a comparison cohort. Study individuals were followed for hospitalizations for diseases of the gastroenterological tract, endocrine system, cardiovascular system, or urinary tract from the start of the cancer registries to 2010. We estimated cumulative incidence with death as competing risk and used threshold regression to compare the hazards of the diseases of interest at ages 20, 40, 60, and 75 years. RESULTS: Our study included 27,007 one-year survivors of childhood cancer and 165,620 individuals from the general population. The cumulative incidence of all four outcomes was higher for childhood cancer survivors during early adulthood, but for three outcomes, the cumulative incidence was higher for the general population after age 55 years. The hazard ratios (HRs) decreased for all outcomes with increasing age, and for two of the outcomes, the hazards were higher for the general population at older ages (endocrine diseases: age-specific HRs = 3.0, 1.4, 1.0, 0.87; Cardiovascular diseases: age-specific HRs = 4.1, 1.4, 0.97, 0.84). CONCLUSIONS: Our findings provide empirical evidence that survivor bias attenuates measures of association when comparing survivors with the general population. The design and analysis of studies among childhood cancer survivors, particularly as this population attains older ages, should account for survivor bias to avoid misinterpreting estimates of disease burden.

Long-term inpatient disease burden in the Adult Life after Childhood Cancer in Scandinavia (ALiCCS) study: A cohort study of 21,297 childhood cancer survivors.

BACKGROUND: Survivors of childhood cancer are at increased risk for a wide range of late effects. However, no large population-based studies have included the whole range of somatic diagnoses including subgroup diagnoses and all main types of childhood cancers. Therefore, we aimed to provide the most detailed overview of the long-term risk of hospitalisation in survivors of childhood cancer. METHODS AND FINDINGS: From the national cancer registers of Denmark, Finland, Iceland, and Sweden, we identified 21,297 5-year survivors of childhood cancer diagnosed with cancer before the age of 20 years in the periods 1943-2008 in Denmark, 1971-2008 in Finland, 1955-2008 in Iceland, and 1958-2008 in Sweden. We randomly selected 152,231 population comparison individuals matched by age, sex, year, and country (or municipality in Sweden) from the national population registers. Using a cohort design, study participants were followed in the national hospital registers in Denmark, 1977-2010; Finland, 1975-2012; Iceland, 1999-2008; and Sweden, 1968-2009. Disease-specific hospitalisation rates in survivors and comparison individuals were used to calculate survivors' standardised hospitalisation rate ratios (RRs), absolute excess risks (AERs), and standardised bed day ratios (SBDRs) based on length of stay in hospital. We adjusted for sex, age, and year by indirect standardisation. During 336,554 person-years of follow-up (mean: 16 years; range: 0-42 years), childhood cancer survivors experienced 21,325 first hospitalisations for diseases in one or more of 120 disease categories (cancer recurrence not included), when 10,999 were expected, yielding an overall RR of 1.94 (95% confidence interval [95% CI] 1.91-1.97). The AER was 3,068 (2,980-3,156) per 100,000 person-years, meaning that for each additional year of follow-up, an average of 3 of 100 survivors were hospitalised for a new excess disease beyond the background rates. Approximately 50% of the excess hospitalisations were for diseases of the nervous system (19.1% of all excess hospitalisations), endocrine system (11.1%), digestive organs (10.5%), and respiratory system (10.0%). Survivors of all types of childhood cancer were at increased, persistent risk for subsequent hospitalisation, the highest risks being those of survivors of neuroblastoma (RR: 2.6 [2.4-2.8]; n = 876), hepatic tumours (RR: 2.5 [2.0-3.1]; n = 92), central nervous system tumours (RR: 2.4 [2.3-2.5]; n = 6,175), and Hodgkin lymphoma (RR: 2.4 [2.3-2.5]; n = 2,027). Survivors spent on average five times as many days in hospital as comparison individuals (SBDR: 4.96 [4.94-4.98]; n = 422,218). The analyses of bed days in hospital included new primary cancers and recurrences. Of the total 422,218 days survivors spent in hospital, 47% (197,596 bed days) were for new primary cancers and recurrences. Our study is likely to underestimate the absolute overall disease burden experienced by survivors, as less severe late effects are missed if they are treated sufficiently in the outpatient setting or in the primary health care system. CONCLUSIONS: Childhood cancer survivors were at increased long-term risk for diseases requiring inpatient treatment even decades after their initial cancer. Health care providers who do not work in the area of late effects, especially those in primary health care, should be aware of this highly challenged group of patients in order to avoid or postpone hospitalisations by prevention, early detection, and appropriate treatments.

Gastrointestinal and liver disease in Adult Life After Childhood Cancer in Scandinavia: A population-based cohort study.

Survival after childhood cancer diagnosis has remarkably improved, but emerging evidence suggests that cancer-directed therapy may have adverse gastrointestinal late effects. We aimed to comprehensively assess the frequency of gastrointestinal and liver late effects among childhood cancer survivors and compare this frequency with the general population. Our population-based cohort study included all 1-year survivors of childhood and adolescent cancer in Denmark, Finland, Iceland, Norway and Sweden diagnosed from the 1940s and 1950s. Our outcomes of interest were hospitalization rates for gastrointestinal and liver diseases, which were ascertained from national patient registries. We calculated standardized hospitalization rate ratios (RRs) and absolute excess rates comparing hospitalizations of any gastrointestinal or liver disease and for specific disease entities between survivors and the general population. The study included 31,132 survivors and 207,041 comparison subjects. The median follow-up in the hospital registries were 10 years (range: 0-42) with 23% of the survivors being followed at least to the age of 40 years. Overall, survivors had a 60% relative excess of gastrointestinal or liver diseases [RR: 1.6, 95% confidence interval (CI): 1.6-1.7], which corresponds to an absolute excess of 360 (95% CI: 330-390) hospitalizations per 100,000 person-years. Survivors of hepatic tumors, neuroblastoma and leukemia had the highest excess of gastrointestinal and liver diseases. In addition, we observed a relative excess of several specific diseases such as esophageal stricture (RR: 13; 95% CI: 9.2-20) and liver cirrhosis (RR: 2.9; 95% CI: 2.0-4.1). Our findings provide useful information about the breadth and magnitude of late complications among childhood cancer survivors and can be used for generating hypotheses about potential exposures related to these gastrointestinal and liver late effects.

Hospital contacts for endocrine disorders in Adult Life after Childhood Cancer in Scandinavia (ALiCCS): a population-based cohort study.

BACKGROUND: The pattern of endocrine disorders in long-term survivors of childhood cancer has not been investigated comprehensively. Here, we aimed to assess the lifetime risk of these disorders in Nordic survivors of childhood cancer. METHODS: From the national cancer registries of Denmark, Finland, Iceland, Norway, and Sweden, we identified 31,723 1-year survivors of childhood cancer, notified since the start of registration in the 1940s and 1950s. From the national population registries, we randomly selected a comparison cohort of people matched by age, sex, and country. Study participants were linked to the national hospital registries, and observed numbers of first-time hospital contacts for endocrine disorders in survivors of childhood cancer were compared with the expected numbers derived from the population comparison cohort. We calculated the absolute excess risks attributable to status as a childhood cancer survivor and standardised hospitalisation rate ratios (SHRRs). FINDINGS: Of the childhood cancer survivors, 3292 had contact with a hospital for an endocrine disorder, yielding a SHRR of 4·8 (95% CI 4·6-5·0); the highest risks were in survivors of leukaemia (SHRR 7·3 [95% CI 6·7-7·9]), CNS tumours (6·6 [6·2-7·0]), and Hodgkin's lymphoma (6·2 [5·6-7·0]). The absolute excess risk for endocrine disorders was roughly 1000 per 100,000 person-years before 20 years of age, and 400 per 100,000 person-years during the remaining lifetime. For children with cancer diagnosed at 5-9 years of age, the cumulative risk for endocrine disorders was highest, and reached 43% at the age of 60 years. Diagnoses of pituitary hypofunction (SHRR 88·0), hypothyroidism (9·9), and testicular and ovarian dysfunction (42·5 and 4·7, respectively) together constituted 61% (655 of 1078) of all excess disease-induced and treatment-induced endocrine disorders in survivors of childhood cancer. INTERPRETATION: A cumulative risk for endocrine disorders at 60 years of age of above 40% in survivors of childhood cancer emphasises the importance of minimisation of damaging treatment, intensification of secondary prevention, and targeting of survivor follow-up throughout life. Since most long-term childhood cancer survivors are not followed in a specialised late-effect clinic, they are a growing challenge for the primary care physician and medical specialists working outside the late-effect area. FUNDING: The Danish Council for Strategic Research.