SummaryBackgroundCancer is a major cause of death in children worldwide, and the recorded incidence tends to increase with time. Internationally comparable data on childhood cancer incidence in the past two decades are scarce. This study aimed to provide internationally comparable local data on the incidence of childhood cancer to promote research of causes and implementation of childhood cancer control.MethodsThis population-based registry study, devised by the International Agency for Research on Cancer in collaboration with the International Association of Cancer Registries, collected data on all malignancies and non-malignant neoplasms of the CNS diagnosed before age 20 years in populations covered by high-quality cancer registries with complete data for 2001–10. Incidence rates per million person-years for the 0–14 years and 0–19 years age groups were age-adjusted using the world standard population to provide age-standardised incidence rates (WSRs), using the age-specific incidence rates (ASR) for individual age groups (0–4 years, 5–9 years, 10–14 years, and 15–19 years). All rates were reported for 19 geographical areas or ethnicities by sex, age group, and cancer type. The regional WSRs for children aged 0–14 years were compared with comparable data obtained in the 1980s.FindingsOf 532 invited cancer registries, 153 registries from 62 countries, departments, and territories met quality standards, and contributed data for the entire decade of 2001–10. 385 509 incident cases in children aged 0–19 years occurring in 2·64 billion person-years were included. The overall WSR was 140·6 per million person-years in children aged 0–14 years (based on 284 649 cases), and the most common cancers were leukaemia (WSR 46·4), followed by CNS tumours (WSR 28·2), and lymphomas (WSR 15·2). In children aged 15–19 years (based on 100 860 cases), the ASR was 185·3 per million person-years, the most common being lymphomas (ASR 41·8) and the group of epithelial tumours and melanoma (ASR 39·5). Incidence varied considerably between and within the described regions, and by cancer type, sex, age, and racial and ethnic group. Since the 1980s, the global WSR of registered cancers in children aged 0–14 years has increased from 124·0 (95% CI 123·3–124·7) to 140·6 (140·1–141·1) per million person-years.InterpretationThis unique global source of childhood cancer incidence will be used for aetiological research and to inform public health policy, potentially contributing towards attaining several targets of the Sustainable Development Goals. The observed geographical, racial and ethnic, age, sex, and temporal variations require constant monitoring and research.FundingInternational Agency for Research on Cancer and the Union for International Cancer Control.

Aspects of radiation-induced lung cancer were evaluated in an international study of Hodgkin's disease. The study population consisted of 227 patients with lung cancer and 455 matched controls. Unique features included dose determinations to the specific location in the lung where each cancer developed and quantitative data on both chemotherapy and tobacco use obtained from medical records. The estimated excess relative risk (ERR) per Gy was 0.15 (95% CI: 0.06-0.39), and there was little evidence of departure from linearity even though lung doses for the majority of Hodgkin's disease patients treated with radiotherapy exceeded 30 Gy. The interaction of radiation and chemotherapy that included alkylating agents was almost exactly additive, and a multiplicative relationship could be rejected (P = 0.017). Conversely, the interaction of radiation and smoking was consistent with a multiplicative relationship, but not with an additive relationship (P < 0.001). The ERR/Gy for males was about four times that for females, although the difference was not statistically significant. There was little evidence of modification of the ERR/Gy by time since exposure (after a 5-year minimum latent period), age at exposure, or attained age. Because of the very high radiation doses received by Hodgkin's disease patients and the immunodeficiency inherent to this lymphoma and that associated with chemotherapy, generalizing these findings to other populations receiving considerably lower doses of radiation should be done cautiously.

SummaryBackgroundGlobal inequalities in access to health care are reflected in differences in cancer survival. The CONCORD programme was designed to assess worldwide differences and trends in population-based cancer survival. In this population-based study, we aimed to estimate survival inequalities globally for several subtypes of childhood leukaemia.MethodsCancer registries participating in CONCORD were asked to submit tumour registrations for all children aged 0–14 years who were diagnosed with leukaemia between Jan 1, 1995, and Dec 31, 2009, and followed up until Dec 31, 2009. Haematological malignancies were defined by morphology codes in the International Classification of Diseases for Oncology, third revision. We excluded data from registries from which the data were judged to be less reliable, or included only lymphomas, and data from countries in which data for fewer than ten children were available for analysis. We also excluded records because of a missing date of birth, diagnosis, or last known vital status. We estimated 5-year net survival (ie, the probability of surviving at least 5 years after diagnosis, after controlling for deaths from other causes [background mortality]) for children by calendar period of diagnosis (1995–99, 2000–04, and 2005–09), sex, and age at diagnosis (<1, 1–4, 5–9, and 10–14 years, inclusive) using appropriate life tables. We estimated age-standardised net survival for international comparison of survival trends for precursor-cell acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML).FindingsWe analysed data from 89 828 children from 198 registries in 53 countries. During 1995–99, 5-year age-standardised net survival for all lymphoid leukaemias combined ranged from 10·6% (95% CI 3·1–18·2) in the Chinese registries to 86·8% (81·6–92·0) in Austria. International differences in 5-year survival for childhood leukaemia were still large as recently as 2005–09, when age-standardised survival for lymphoid leukaemias ranged from 52·4% (95% CI 42·8–61·9) in Cali, Colombia, to 91·6% (89·5–93·6) in the German registries, and for AML ranged from 33·3% (18·9–47·7) in Bulgaria to 78·2% (72·0–84·3) in German registries. Survival from precursor-cell ALL was very close to that of all lymphoid leukaemias combined, with similar variation. In most countries, survival from AML improved more than survival from ALL between 2000–04 and 2005–09. Survival for each type of leukaemia varied markedly with age: survival was highest for children aged 1–4 and 5–9 years, and lowest for infants (younger than 1 year). There was no systematic difference in survival between boys and girls.InterpretationGlobal inequalities in survival from childhood leukaemia have narrowed with time but remain very wide for both ALL and AML. These results provide useful information for health policy makers on the effectiveness of health-care systems and for cancer policy makers to reduce inequalities in childhood cancer survival.FundingCanadian Partnership Against Cancer, Cancer Focus Northern Ireland, Cancer In...

To attempt to confirm associations found in a companion study in Atlanta, Georgia between Down's syndrome and acute leukemia and between pyloric stenosis and childhood cancer, the authors used the State Health Registry of Iowa to link the records of infants and children with cancer for 1983 to 1989 with the records of infants with birth defects for 1983 to 1988. During the study period, birth defects were diagnosed in 10,891 infants younger than 1 year of age, and cancer was diagnosed in 396 children younger than 8 years of age. The authors compared the observed number of children with a defect who developed cancer with the number expected on the basis of the cancer registry rates. Of the 10,891 children with birth defects, 16 developed cancer (standardized incidence ratio (SIR) = 2.0, 95% confidence interval (CI) 1.2-3.3). Of 251 children with Down's syndrome (trisomy 21), two developed leukemia (SIR = 32.1, 95% CI 3.9-116.0). None of the infants with cancer had pyloric stenosis (SIR = 0.0, 95% CI 0.0-6.7). The results of this study supported the association found in the Atlanta study between Down's syndrome and leukemia, but did not support the association found there between pyloric stenosis and childhood cancer. This study, however, had a shorter follow-up period and a smaller number of subjects than the Atlanta study.

PURPOSE: Information on agricultural practices has been obtained by questionnaire in several epidemiologic investigations. This project evaluated the reliability of self-reported information on pesticide use and various demographic and lifestyle factors among a group of farmers from Iowa.METHODS: 2,921 Iowa farmers participating in the Agricultural Health Study completed enrollment questionnaires approximately one year apart. Responses on the two questionnaires were compared for percent agreement and by Kappa statistics to evaluate reliability.RESULTS: Percent agreement for ever/never use of specific pesticides and application practices was quite high and generally ranged from 70% to over 90% and did not vary by age or educational level. Kappas were typically in the 0.50 to 0.60 range. Agreement was lower (typically 50% to 60%) for duration or frequency of use of specific pesticides. Agreement on lifestyle and non-agricultural factors was comparable to that reported in other studies.CONCLUSIONS: Level of agreement regarding pesticide use in this population is similar to that found for diet, physical activity, and medical conditions, which have been successfully evaluated in many epidemiologic studies. Information on agricultural practices from self-completed questionnaires has sufficient reliability for use in epidemiologic investigations.