Anna Sällfors Holmqvist

Childhood cancer survivor cohorts in Europe

Abstract With the advent of multimodality therapy, the overall five-year survival rate from childhood cancer has improved considerably now exceeding 80% in developed European countries. This growing cohort of survivors, with many years of life ahead of them, has raised the necessity for knowledge concerning the risks of adverse long-term sequelae of the life-saving treatments in order to provide optimal screening and care and to identify and provide adequate interventions. Childhood cancer survivor cohorts in Europe. Considerable advantages exist to study late effects in individuals treated for childhood cancer in a European context, including the complementary advantages of large population-based cancer registries and the unrivalled opportunities to study lifetime risks, together with rich and detailed hospital-based cohorts which fill many of the gaps left by the large-scale population-based studies, such as sparse treatment information. Several large national cohorts have been established within Europe to study late effects in individuals treated for childhood cancer including the Nordic Adult Life after Childhood Cancer in Scandinavia study (ALiCCS), the British Childhood Cancer Survivor Study (BCCSS), the Dutch Childhood Oncology Group (DCOG) LATER study, and the Swiss Childhood Cancer Survivor Study (SCCSS). Furthermore, there are other large cohorts, which may eventually become national in scope including the French Childhood Cancer Survivor Study (FCCSS), the French Childhood Cancer Survivor Study for Leukaemia (LEA), and the Italian Study on off-therapy Childhood Cancer Survivors (OTR). In recent years significant steps have been taken to extend these national studies into a larger pan-European context through the establishment of two large consortia – PanCareSurFup and PanCareLIFE. The purpose of this paper is to present an overview of the current large, national and pan-European studies of late effects after childhood cancer. This overview will highlight the strong cooperation across Europe, in particular the EU-funded collaborative research projects PanCareSurFup and PanCareLIFE. Overall goal. The overall goal of these large cohort studies is to provide every European childhood cancer survivor with better care and better long-term health so that they reach their full potential, and to the degree possible, enjoy the same quality of life and opportunities as their peers.

Young age at diagnosis is a risk factor for negative late socio-economic effects after acute lymphoblastic leukemia in childhood†

The increasing number of survivors after childhood cancer requires characterization of the late complications of these diseases and their treatment. We examined a large number of possible socio‐economic late effects following treatment for acute lymphoblastic leukemia (ALL) in order to identify factors leading to a poor outcome.

The Adult Life After Childhood Cancer in Scandinavia (ALiCCS) Study: Design and Characteristics

During the last five decades, survival of childhood cancer has increased from 25% to 80%. At the same time, however, it has become evident that survivors experience a broad range of therapy‐related late adverse health effects. The aim of the Adult Life after Childhood Cancer in Scandinavia (ALiCCS) study is to investigate long‐term health consequences of past and current therapies in order to improve follow‐up care of survivors and to reduce treatment‐related morbidity of future patients.

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.

Long-term risk of renal and urinary tract diseases in childhood cancer survivors: A population-based cohort study

BACKGROUND Childhood cancer has been associated with long-term risk of urinary tract diseases, but risk patterns remain to be comprehensively investigated. We analysed the lifetime risk of urinary tract diseases in survivors of childhood cancer in the Nordic countries. METHODS We identified 32,519 one-year survivors of childhood cancer diagnosed since the 1940s and 1950s in the five Nordic cancer registries and selected 211,156 population comparisons of a corresponding age, sex, and country of residence from the national population registries. To obtain information on all first-time hospitalizations for a urinary tract disease, we linked all study subjects to the national hospital registry of each country. Relative risks (RRs) and absolute excess risks (AERs) and associated 95% confidence intervals (CIs) for urinary tract diseases among cancer survivors were calculated with the appropriate morbidity rates among comparisons as reference. RESULTS We observed 1645 childhood cancer survivors ever hospitalized for urinary tract disease yielding an RR of 2.5 (95% CI 2.4-2.7) and an AER of 229 (95% CI 210-248) per 100,000 person-years. The cumulative risk at age 60 was 22% in cancer survivors and 10% in comparisons. Infections of the urinary system and chronic kidney disease showed the highest excess risks, whereas survivors of neuroblastoma, hepatic and renal tumours experienced the highest RRs. CONCLUSION Survivors of childhood cancer had an excess risk of urinary tract diseases and for most diseases the risk remained elevated throughout life. The highest risks occurred following therapy of childhood abdominal tumours.

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.

Late mortality after allogeneic blood or marrow transplantation in childhood for leukemia: a report from the Blood or Marrow Transplant Survivor Study-2

Allogeneic blood or marrow transplantation (BMT) is often used with curative intent to treat subgroups of childhood leukemia identified to be at a high risk of relapse [1–3]. However, there is limited information regarding overall and cause-specific late mortality experienced by children undergoing allogeneic BMT for leukemia [4–6]. We address this gap by conducting a detailed evaluation of late mortality, relapse-related mortality (RRM) and non-relapserelated mortality (NRM) among 2-year survivors after allogeneic BMT in childhood for acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML)/ myelodysplastic syndrome (MDS) and chronic myelogenous leukemia (CML). The Blood or Marrow Transplant Survivor Study-2 (BMTSS-2) is a collaborative effort between City of Hope (COH), University of Minnesota (UMN), and University of Alabama at Birmingham (UAB), examining long-term outcome after BMT. To be included in the present study, patients had to have received allogeneic BMT for ALL, AML, MDS or CML between 1974 and 2010 at COH or UMN, at age ≤ 21 years, and survived ≥ 2 years after transplantation. Information on type of leukemia, conditioning regimen, type of donor stem cells (related or unrelated), stem cell source, disease status at transplantation, graft vs. host disease (GvHD) prophylaxis, and demographic characteristics, was obtained from institutional transplant databases. National Death Index (NDI) Plus [7] and/or medical records provided information regarding the date and cause of death through 31 December 2015. Information from medical records and Accurint databases [8] was used to extend the vital status information through 31 December 2016. All patients were assigned a primary and, if present, a secondary cause of death. Human Subjects Committee at participating institutions approved the BMTSS-2 protocol. Informed consent was obtained in accordance with the Declaration of Helsinki. Kaplan–Meier techniques were used to describe overall survival, conditional on surviving ≥ 2 years from BMT. Standardized mortality ratio (SMR), a ratio of observed to expected number of deaths, was used to compare the mortality in this cohort to age(5-year interval), sex-, and calendar-specific mortality of the US general population [9]. Absolute excess risk (AER) was defined as the difference between the observed and expected number of deaths, per 1000 person-years of follow-up. Cumulative incidence rates * Smita Bhatia sbhatia@peds.uab.edu

Late mortality after autologous blood or marrow transplantation in childhood: a Blood or Marrow Transplant Survivor Study-2 report

Autologous blood or marrow transplantation (BMT) is a curative option for several types of childhood cancer. However, there is little information regarding the risk of late mortality. We examined all-cause mortality, relapse-related mortality (RRM), and nonrelapse-related mortality (NRM) in 2-year survivors of autologous BMT performed before age 22 between 1980 and 2010 at 1 of 2 US transplant centers. Vital status information was collected using medical records, National Death Index, and Accurint databases. Overall survival was calculated using Kaplan-Meier techniques. Cumulative incidence of mortality used competing risk methods. Standardized mortality ratio (SMR) was calculated using age-, sex-, and calendar-specific mortality rates from Centers for Disease Control and Prevention. Cox regression analysis was used to determine predictors of all-cause late mortality. Among the 345 2-year survivors, 103 deaths were observed, yielding an overall survival of 70.3% 15 years post-BMT. The leading causes of death included primary disease (50.0%), subsequent neoplasm (21.4%), and infection (18.2%). Overall, the cohort was at a 22-fold increased risk of late mortality (SMR, 21.8; 95% CI, 17.9-26.3), compared with the general population. Mortality rates remained elevated among the 10-year survivors (SMR, 20.6; 95% CI, 9.9-37.2) but approached those of the general population ≥15 years post-BMT. The 10-year cumulative incidence of RRM (14.3%) exceeded that of NRM (10.4%). The 10-year cumulative mortality rate declined over time (<1990, 35.1%; 1990-1999, 25.6%; 2000-2010, 21.8%; P = .05). In conclusion, childhood autologous BMT recipients have an increased risk of late mortality, compared with the general population. The late mortality rates have declined over the past 3 decades.

Neurologic disorders in 4858 survivors of central nervous system tumors in childhood—an Adult Life after Childhood Cancer in Scandinavia (ALiCCS) study

Background A comprehensive overview of neurologic complications among survivors of central nervous system (CNS) tumors in childhood is lacking. We aimed to investigate the risk for these disorders in a large, population-based study with outcome measures from nationwide hospital registries. Methods We identified 4858 five-year survivors with diagnoses of CNS tumor in childhood in Denmark, Iceland, Finland, and Sweden in 1943-2007, and 166658 matched population comparison subjects. Inpatient discharge diagnoses of neurologic disorders were used to calculate relative risks (RRs) and absolute excess risks (AERs). Results A neurologic disorder was verified in 1309 survivors, while 92.4 were expected, yielding an overall RR of 14.2 (95% confidence interval [CI]: 13.3-15.1) and an AER of 20 hospitalizations per 1000 persons per year. The risks remained increased more than 20 years after diagnosis (RR: 6.3, 95% CI: 5.6-7.2; AER: 11, 9-12). The most frequent diagnoses were epilepsy (affecting 14.1% of all survivors) followed by hydrocephalus (9.5%) and paralytic syndromes (4.2%), with RRs of 28.7 (95% CI: 26.0-31.6), 243 (95% CI: 190-311), and 40.3 (95% CI: 33.1-49.2), respectively. Of these outcomes, 30%-40% were diagnosed prior to or synchronously with the CNS tumor. The survivors had highly increased RRs for infectious diseases of the CNS, disorders of cranial nerves, and degenerative diseases of the nervous system. Conclusions Survivors of childhood CNS tumors are at markedly increased risk for neurologic disorders throughout their lives. Health care professionals must be aware of survivors who might benefit from preventive interventions and intensive follow-up.

Assessment of Late Mortality Risk After Allogeneic Blood or Marrow Transplantation Performed in Childhood

Importance Allogeneic blood or marrow transplantation (BMT) is a curative option for malignant and nonmalignant diseases of childhood. However, little is known about trends in cause-specific late mortality in this population during the past 3 decades. Objectives To examine cause-specific late mortality among individuals who have lived 2 years or more after allogeneic BMT performed in childhood and whether rates of late mortality have changed over time. Design, Setting, and Participants A retrospective cohort study was conducted of individuals who lived 2 years or more after undergoing allogeneic BMT performed in childhood between January 1, 1974, and December 31, 2010. The end of follow-up was December 31, 2016. Exposure Allogeneic BMT performed in childhood. Main Outcomes and Measures All-cause mortality, relapse-related mortality, and non–relapse-related mortality. Data on vital status and causes of death were collected using medical records, the National Death Index Plus Program, and Accurint databases. Results Among 1388 individuals (559 females and 829 males) who lived 2 years or more after allogeneic BMT performed in childhood, the median age at transplantation was 14.6 years (range, 0-21 years). In this cohort, there was a total of 295 deaths, yielding an overall survival rate of 79.3% at 20 years after BMT. The leading causes of death were infection and/or chronic graft-vs-host disease (121 of 244 [49.6%]), primary disease (60 of 244 [24.6%]), and subsequent malignant neoplasms (45 of 244 [18.4%]). Overall, the cohort had a 14.4-fold increased risk for death (95% CI, 12.8-16.1) compared with the general population (292 deaths observed; 20.3 deaths expected). Relative mortality remained elevated at 25 years or more after BMT (standardized mortality ratio, 2.9; 95% CI, 2.0-4.1). The absolute excess risk for death from any cause was 12.0 per 1000 person-years (95% CI, 10.5-13.5). The cumulative incidence of non–relapse-related mortality exceeded that of relapse-related mortality throughout follow-up. The 10-year cumulative incidence of late mortality decreased over time (before 1990, 18.9%; 1990-1999, 12.8%; 2000-2010, 10.9%; P = .002); this decrease remained statistically significant after adjusting for demographic and clinical factors (referent group: <1990; 1990-1999: hazard ratio, 0.64; 95% CI, 0.47-0.89; P = .007; 2000-2010: hazard ratio, 0.49; 95% CI, 0.31-0.76; P = .002; P < .001 for trend). Conclusions and Relevance Late mortality among children undergoing allogeneic BMT has decreased during the past 3 decades. However, these patients remain at an elevated risk of late mortality even 25 years or more after transplantation when compared with the general population, necessitating lifelong follow-up.