Trends In Childhood Cancer Incidence Research Articles

Racial and ethnic and socioeconomic disparities in childhood cancer incidence trends in the United States, 2000-2019.

Population-based surveillance of pediatric cancer incidence trends is critical to determine high-risk populations, drive hypothesis generation, and uncover etiologic heterogeneity. We provide a comprehensive update to the current understanding of pediatric cancer incidence trends by sex, race and ethnicity, and socioeconomic status (SES). The Surveillance, Epidemiology, and End Results 22 data (2000-2019) was used to summarize age-adjusted incidence rates for children and adolescents aged 0-19 years at diagnosis. The annual percentage change (APC) and 95% confidence interval (CI) were estimated to evaluate incidence trends by sex, race and ethnicity, and SES overall and for cancer subtypes. Tests of statistical significance were 2-sided. Substantial variation was observed overall and for several histologic types in race and ethnicity- and SES-specific rates. Overall, we observed a statistically significant increase in incidence rates (APC = 0.8%, 95% CI = 0.6% to 1.1%). All race and ethnic groups saw an increase in incidence rates, with the largest occurring among non-Hispanic American Indian and Alaska Native children and adolescents (APC = 1.7%, 95% CI = 0.5% to 2.8%) and the smallest increase occurring among non-Hispanic White children and adolescents (APC = 0.7%, 95% CI = 0.5% to 1.0%). The lowest SES quintiles saw statistically significant increasing trends, while the highest quintile remained relatively stable (quintile 1 [Q1] APC = 1.6%, 95% CI = 0.6% to 2.6%; quintile 5 [Q5] APC = 0.3%, 95% CI = -0.1% to 0.7%). Childhood cancer incidence is increasing overall and among every race and ethnic group. Variation by race and ethnicity and SES may enable hypothesis generation on drivers of disparities observed.

Trends in childhood cancer incidence in sub-Saharan Africa: Results from 25 years of cancer registration in Harare (Zimbabwe) and Kyadondo (Uganda).

We examined trends in childhood cancer incidence in sub-Saharan Africa using data from two population-based cancer registries in Harare (Zimbabwe) and Kyadondo (Uganda) with cases classified according to the International Classification of Childhood Cancer and explored reasons for observed variations and changes. Over the whole 25-year period (1991-2015) studied, there were only small, and nonsignificant overall trends in incidence. Nevertheless, within the period, peaks in incidence occurred from 1996 to 2001 in Harare (Zimbabwe) and from 2003 to 2006 in Kyadondo (Uganda). Kaposi sarcoma and non-Hodgkin lymphoma accounted for the majority of the cases during these periods. These fluctuations in incidence rates in both registries can be linked to similar trends in the prevalence of HIV, and the availability of antiretroviral therapy. In addition, we noted that, in Harare, incidence rates dropped from 2003 to 2004 and 2007 to 2008, correlating with declines in national gross domestic product. The results indicate that the registration of childhood cancer cases in resource-poor settings is linked to the availability of diagnostic services mediated by economic developments. The findings highlight the need for specialised diagnostic and treatment programmes for childhood cancer patients as well as positive effects of HIV programmes on certain childhood cancers.

Incidence trends of childhood acute lymphoblastic leukemia in Saudi Arabia: Increasing incidence or competing risks?

Introduction. The incidence of childhood acute lymphoblastic leukemia (cALL) varies between countries likely as a result of competing risks including infections, access-to-care, socioeconomic influences, and/or ethnicity. However, little is known about disease burden in high-income Arab countries offering free-of-charge healthcare. The hypothesis was that, due to population characteristics (young age, high fertility and parental consanguinity rate), the incidence of cALL in Saudi Arabia is equal or higher than that observed in high-income Western countries.Methods. Saudi databases were used to calculate the incidence of cALL from 2001 to 2014. Incidence trends over time of children with ALL, 14-years of age or younger, were analyzed and compared with those reported in USA.Results. The age-adjusted incidence over the years was lower in Saudi Arabia compared to USA. However, the incidence trend of cALL in Saudi Arabia was increasing at a rate higher than that observed in USA (p < 0.001). The overall incidence of cALL in Saudi Arabia increased from 1.58/100,000 in 2001 to 2.35/100,000 population in 2014. The median annual increase was 4.58 %. The incidence in males increased from 1.88 to 2.71/100,000, and from 1.21 to 1.86/100,000 population in females.Conclusions. The reported incidence of cALL in Saudi Arabia is rapidly increasing. The increasing trend may reflect evolving socioeconomic structure, improved access-to-cancer care, and improved diagnosis/ reporting capacity. This highlights the need for better understanding of cALL causes and the need for the formation of separate national pediatric cancer registries in different countries to monitor childhood cancer incidence trends.

Childhood cancer incidence and survival trends in Estonia (1970\u20132016): a nationwide population-based study

BackgroundChildhood cancers represent a small proportion of all cancers but are still a major public health problem. The study analysed long-term trends in childhood cancer incidence and survival in Estonia in relation to societal and health care transition.MethodsData on all malignant tumours, diagnosed in children aged 0–14 during 1970–2016, were derived from the Estonian Cancer Registry. Age-standardised (World standard) incidence rates were calculated by ICCC-3 site groups and joinpoint regression was used to estimate annual percentage change (APC) for incidence trends. Cohort and period approach were used to estimate 5-year survival. Internal age standardisation was applied.ResultsA total of 1628 incident cancer cases were diagnosed during the study period and overall incidence increased significantly at a rate of 0.5% per year. Significant increases were seen for neuroblastoma and germ cell tumours, for lymphoid leukemias and some CNS sub-sites. At the same time, decline in incidence was seen in almost all subgroups of unspecified neoplasms. The overall 5-year survival improved from 24% in 1970–1979 to 73% in 2010–2016, with the largest changes occurring in the 1990s and 2000s. For many sites, survival increase thereafter has been marginal.ConclusionIn this first comprehensive population-based study of childhood cancer incidence and survival in Estonia, long-term trends are shown in the context of societal and health care changes. Even though the increasing incidence of some sites may, at least partially, be explained by improved diagnostics reflected in the decreased incidence of unspecified neoplasms, the overall cancer incidence in children seems to be rising. Rapid progress in diagnosis and care have improved childhood cancer survival immensely, but deficit in Estonia persists compared to other European countries. Results of the study accentuate the need for a more in-depth analysis of clinical data, but also for the prioritization of childhood cancer in Estonia, to ensure access to standard care and innovative treatments.

Epidemiological Trends for Childhood and Adolescent Cancers in the Period 1994-2016 in the Czech Republic.

Our study aimed to evaluate incidence and mortality trends for childhood and adolescent cancers in the period 1994-2016 in the Czech Republic. Data on childhood cancers, which are recorded in the Czech National Cancer Registry, were validated using a clinical database of childhood cancer patients and combined with data from the National Register of Hospitalised Patients and with data from death certificates. These validated data were used to establish cancer incidence. Data from death certificates were used to evaluate long-term trends in mortality. Incidence and mortality trends were assessed by the average annual percentage change. The age-standardised incidence trend for childhood cancers (i.e. those diagnosed in patients aged 0-19 years) showed a statistically significant slight long-term increase in the number of new cases, +0.5% annually on average (p &lt; 0.01), more specifically an increase of +0.6% in girls and a statistically insignificant decrease of 0.1% in boys. In children aged 0-14 years, other malignant epithelial neoplasms and malignant melanomas showed the largest statistically significant average annual increase in incidence (+4.9%; p &lt; 0.01), followed by central nervous system neoplasms (+1.3%; p &lt; 0.05). Lymphomas, by contrast, showed a statistically significant average annual decrease in incidence in children aged 0-14 years (2.1%; p &lt; 0.01). In adolescents aged 15-19 years, other malignant epithelial neoplasms and malignant melanomas also showed a statistically significant average annual increase in incidence (+5.2%; p &lt; 0.01), followed by central nervous system neoplasms (+1.5%; p &lt; 0.05). Mortality trends showed a statistically significant long-term decrease: on average, 5.1% annually in children aged 0-14 years (p &lt; 0.01), and 3.7% annually in adolescents aged 15-19 years (p &lt; 0.01). Available data make it possible to analyse long-term trends in childhood cancer incidence and mortality.

Childhood cancer incidence in Canada: demographic and geographic variation of temporal trends (1992-2010).

Surveillance of childhood cancer incidence trends can inform etiologic research, policy and programs. This study presents the first population-based report on demographic and geographic variations in incidence trends of detailed pediatric diagnostic groups in Canada. The Canadian Cancer Registry data were used to calculate annual age-standardized incidence rates (ASIRs) from 1992 to 2010 among children less than 15 years of age by sex, age and region for the 12 main diagnostic groups and selected subgroups of the International Classification of Childhood Cancer (ICCC), 3rd edition. Temporal trends were examined by annual percent changes (APCs) using Joinpoint regression. The ASIRs of childhood cancer among males increased by 0.5% (95% confidence interval (CI) = 0.2-0.9) annually from 1992 to 2010, whereas incidence among females increased by 3.2% (CI = 0.4-6.2) annually since 2004 after an initial stabilization. The largest overall increase was observed in children aged 1-4 years (APC = 0.9%, CI = 0.4-1.3). By region, the overall rates increased the most in Ontario from 2006 to 2010 (APC = 5.9%, CI = 1.9-10.1), and increased non-significantly in the other regions from 1992 to 2010. Average annual ASIRs for all cancers combined from 2006 to 2010 were lower in the Prairies (149.4 per million) and higher in Ontario (170.1 per million). The ASIRs increased for leukemias, melanoma, carcinoma, thyroid cancer, ependymomas and hepatoblastoma for all ages, and neuroblastoma in 1-4 year olds. Astrocytoma decreased in 10-14 year olds (APC = -2.1%, CI = -3.7 to -0.5), and among males (APC = -2.4%, CI = -4.6 to -0.2) and females (APC = -3.7%, CI = -5.8 to -1.6) in Ontario over the study period. Increasing incidence trends for all cancers and selected malignancies are consistent with those reported in other developed countries, and may reflect the changes in demographics and etiological exposures, and artefacts of changes in cancer coding, diagnosis and reporting. Significant decreasing trend for astrocytoma in late childhood was observed for the first time.

Epidemiological analysis of childhood cancer in Japan based on population-based cancer registries, 1993-2009.

There are few recent data on trends in childhood cancer incidence using population-based cancer registries in Japan. This study comprised 6110 reported cases of patients aged 0-14 years who were diagnosed as having primary cancer between 1993 and 2009. We chose cancer registries of seven prefectures, according to the international cancer registry standard of fewer than 10% death certificate only cases among cancer registries in Japan. We analyzed population-based cancer registration data in the seven prefectures between 1993 and 2009. We calculated childhood cancer incidence, age-specific incidence, crude incidence rate, age-adjusted incidence rate, confidence intervals and annual change for each prefecture and classified the data into 12 diagnostic groups, according to the International Classification of Childhood Cancer (ICCC). According to sex-specific incidence, males accounted for slightly more cases than females. Children 0-3 years old accounted for 41.1% of patients. Leukemia accounted for 36.0% of cancers, followed by central nervous system tumors with 15.0%, according to the ICCC. The crude incidence rate did not change substantially, remaining at an average 8-11 per 100 000 population. In addition, the age-adjusted incidence rate remained constant with an average 2 per 100 000 population. Using population-based cancer registry data, age-specific incidence and 12 diagnostic groups according to the ICCC showed characteristics of childhood cancers. The incidence rate of childhood cancers has been nearly stable in Japan over the past 15 years.

Childhood Cancer Incidence Trends in Association With US Folic Acid Fortification (1986–2008)

Epidemiologic evidence indicates that prenatal vitamin supplementation reduces risk for some childhood cancers; however, a systematic evaluation of population-based childhood cancer incidence trends after fortification of enriched grain products with folic acid in the United States in 1996-1998 has not been previously reported. Here we describe temporal trends in childhood cancer incidence in association with US folic acid fortification. Using Surveillance, Epidemiology, and End Results program data (1986-2008), we calculated incidence rate ratios and 95% confidence intervals to compare pre- and postfortification cancer incidence rates in children aged 0 to 4 years. Incidence trends were also evaluated by using joinpoint and loess regression models. From 1986 through 2008, 8829 children aged 0 to 4 years were diagnosed with malignancies, including 3790 and 3299 in utero during the pre- and postfortification periods, respectively. Pre- and postfortification incidence rates were similar for all cancers combined and for most specific cancer types. Rates of Wilms tumor (WT), primitive neuroectodermal tumors (PNETs), and ependymomas were significantly lower postfortification. Joinpoint regression models detected increasing WT incidence from 1986 through 1997 followed by a sizable decline from 1997 through 2008, and increasing PNET incidence from 1986 through 1993 followed by a sharp decrease from 1993 through 2008. Loess curves indicated similar patterns. These results provide support for a decrease in WT and possibly PNET incidence, but not other childhood cancers, after US folic acid fortification.

Childhood Cancer Incidence Trends in Association With US Folic Acid Fortification (1986-2008)

Childhood Cancer Incidence Trends in Association With US Folic Acid Fortification (1986-2008)

Abstract 629: Childhood cancer incidence trends in association with folic acid fortification in the United States (1986-2008)

Abstract Folic acid plays a critical role in embryonic development and sufficient maternal prenatal folic acid consumption significantly reduces the incidence of congenital abnormalities in offspring. Epidemiological evidence supports the hypothesis that maternal prenatal folic acid supplementation lowers the risk of childhood cancer in offspring; however a systematic evaluation of population-based childhood cancer incidence trends following fortification of enriched grain products with folic acid in the U.S. in 1996-1998 has not been previously reported. Here we describe temporal trends in childhood cancer incidence in association with U.S. folic acid fortification. Using Surveillance, Epidemiology, and End Results program data (1986-2008) we calculated incidence rate ratios (IRRs) and 95% confidence intervals (CIs) to compare pre- and post-fortification incidence rates in children aged 0-4 years. Using joinpoint and loess regression models, we looked for inflection points during this period where the incidence trend changed in magnitude and/or direction. From 1986-2008, 8,829 children aged 0-4 years were diagnosed with malignancies, including 3,790 and 3,299 in utero during the pre- and post-fortification periods, respectively. Pre- and post-fortification incidence rates were similar for all cancers combined (IRR=1.01, 95% CI: 0.96-1.06) and for most specific cancer types examined. Rates of ependymomas (IRR=0.70, 95% CI: 0.51-0.97), primitive neuroectodermal tumors (PNETs) (IRR=0.56, 95% CI: 0.37-0.84) and Wilms tumor (WT) (IRR=0.80, 95% CI: 0.68-0.95) were significantly lower post-fortification. Notably, a greater reduction in post-fortification incidence was observed for the latter two subtypes upon restricting the analysis to infants, in whom any true effect of folic acid is expected to be greater. Joinpoint regression models detected increasing PNET incidence from 1986-1993 (annual percent change, APC=11.5, 95% CI: -5.0-31.0) followed by a sharp decrease from 1993-2008 (APC=−7.4%, 95% CI: -12.1- -2.4), and increasing WT incidence from 1986-1997 (APC=2.2, 95% CI: -1.2-5.8) followed by a sizable decline from 1997-2008 (APC=−4.0%, 95% CI: -7.3- -0.6). Loess curves indicated similar patterns. These results provide support for decreases in PNET and WT incidence, but not other childhood cancers, following U.S. folic acid fortification. Ten years of data are now available post-fortification and any substantial changes in childhood cancer rates attributable to fortification should be evident. Drawing firm conclusions regarding the isolated effects of folic acid is difficult, however, as other temporal trends occurred during the time period examined. Alternative study designs are required to rule out other explanations and confirm causal relationships. Supported by NIH Grants T32 CA099936 and K05 CA157439, and Children's Cancer Research Fund, Minneapolis, MN. A.M. Linabery and K.J. Johnson contributed equally to this work. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 629. doi:1538-7445.AM2012-629

Trends in childhood cancer incidence and mortality in urban Shanghai, 1973–2005

To describe trends in cancer incidence and mortality among children less than 15 years of age in urban Shanghai between 1973 and 2005. Annual rates of cancer incidence were calculated per 1,000,000 children for 3-year intervals between 1973 and 2005. Linear regression models were used to analyze the annual percent change (APC) in incidence and mortality across these distinct intervals. For all cancers combined, the incidence rate during the observed time period did not substantially change in urban Shanghai. Rates for the incidence of individual cancer did exhibit variations. Leukemia incidence remained relatively stable but the incidence of myeloid leukemia decreased sharply in both males (APC -8.6%) and females (APC -9.5%). The rate of NHL varied little among males with APC 2.1% and modestly increased among females with APC 9.3%. Anatomic sites that only occasionally demonstrate malignancy, bone and joints in males and endocrines in females, showed upward trends in incidence. A significant reduction in liver cancer incidence in males was observed. Examining mortality rates, all cancer mortality decreased by -6.0% annually in males and by -3.9% in females. This trend was mainly due to the reduction in mortality for leukemia, particularly the myeloid subtype, which decreased in males (APC -7.2%) and females (APC -7.3%). Childhood cancer incidence rates showed no substantial changes but mortality demonstrated a dramatic reduction during the observed time period, suggesting an improvement in both childhood cancer diagnosis and treatment.

Trends in childhood cancer incidence in the U.S. (1992–2004)

The etiology of most pediatric neoplasms remains elusive. Examination of population-based incidence data provides insight regarding etiology among various demographic groups and may result in new hypotheses. The objective of the current study was to present updated information regarding childhood cancer incidence and trends in the U.S. overall and among demographic subgroups, including Asian/Pacific Islanders and Hispanics, for whom to the authors' knowledge trends have not been previously examined. Data obtained by 13 registries of the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program were evaluated to assess incidence and trends of common primary cancers diagnosed between 1992 and 2004 among children aged birth to 19 years. Frequencies, age-adjusted incidence rates, and joinpoint regression results, including annual percent change (APC) in incidence rates (and 95% confidence intervals [95% CI]), were calculated. Between 1992 and 2004, a modest, nonsignificant increase in the average annual incidence rate (APC, 0.4%; 95% CI, -0.1%-0.8%) was observed for all pediatric cancer diagnoses combined. There was a suggestion of an increase in leukemia (APC, 0.7%; 95% CI, -0.1%-1.5%), and acute lymphoblastic leukemia in particular (APC, 0.8%; 95% CI, -0.4%-1.9%), whereas rates for central nervous system tumors overall were stable (APC, -0.1%; 95% CI, -1.1%-1.0%); 2 joinpoints were observed for astrocytoma. Rate increases were noted for hepatoblastoma (APC, 4.3%; 95% CI, 0.2%-8.7%) and melanoma (APC, 2.8%; 95% CI, 0.5%-5.1%). Differences by demographic group (sex, age, and race/ethnicity) are also described. The observed trends reinforce an ongoing need for population-based surveillance and further etiologic studies.

Bayesian methods for early detection of changes in childhood cancer incidence: Trends for acute lymphoblastic leukaemia are consistent with an infectious aetiology

Published data on time trends in the incidence of childhood leukaemia show inconsistent patterns, with some studies showing increases and others showing relatively stable incidence rates. Data on time trends in childhood cancer incidence from the Childhood Cancer Registry of Piedmont, Italy were analysed using two different approaches: standard Poisson regression and a Bayesian regression approach including an autoregressive component. Our focus was on acute lymphoblastic leukaemia (ALL), since this is hypothesised to have an infectious aetiology, but for purposes of comparison we also conducted similar analyses for selected other childhood cancer sites (acute non-lymphoblastic leukaemia (AnLL), central nervous system (CNS) tumours and neuroblastoma (NB)). The two models fitted the data equally well, but led to different interpretations of the time trends. The first produced ever-increasing rates, while the latter produced non-monotonic patterns, particularly for ALL, which showed evidence of a cyclical pattern. The Bayesian analysis produced findings that are consistent with the hypothesis of an infectious aetiology for ALL, but not for AnLL or for solid tumours (CNS and NB). Although sudden changes in time trends should be interpreted with caution, the results of the Bayesian approach are consistent with current knowledge of the natural history of childhood ALL, including a short latency time and the postulated infectious aetiology of the disease.

Epidemiological application of a Bayesian nonparametric smoother based on a GLMM with an autoregressive error component

Temporal variations in the incidence of rare diseases are a subject of great interest to epidemiologists, who look for recognizable patterns and associations with putative causal factors in order to gain aetiological clues. These data are typically characterised by overdispersion and correlated errors, nevertheless the standard method of analysis in this field has so far been the Poisson regression. The aim of this preliminary study was to suggest the novel employment of a Bayesian nonparametric model (based on a GLMM), a validated statistical approach, to the context of the estimation of childhood cancer incidence trends. The model includes fixed effect terms (age and year of diagnosis) and a random effect vector, intended to represent smooth variation over time, specified in the forward direction as a second order Gaussian autoregressive component. The best use for the model proposed is as "early warning" to epidemiologists for the identification of changes in trends. This and similarly flexible models are in fact characterised by high sensitivity to changes of behaviour; the price we must pay for such high a sensitivity being low specificity.

Assessment of trends in childhood cancer incidence

Assessment of trends in childhood cancer incidence

Trends in childhood cancer incidence and mortality in Catalonia, Spain, 1975-1998.

Childhood cancer mortality has sharply declined in most economically developed countries over the last years, whereas no substantial changes in the incidence have been observed. In Catalonia (Spain), childhood cancer mortality showed a considerable decline until 1992, but incidence trends have not been analysed in this population. To assess both recent incidence and mortality trends in this population, we analysed childhood (0-14 years) cancer data from the population-based Tarragona Cancer Registry and from the Mortality Registry of Catalonia (Spain) from 1980 to 1998. All cancer mortality decreased by -2.6% annually in boys (95% confidence interval, 95% CI -3.7, -1.6) and -3.7% in girls (95% CI -4.9, -2.5). Mortality due to leukaemia decreased annually -3.0% in boys (95% CI -4.7, -1.4) and -4.4% in girls (95% CI -6.3, -2.4). Mortality for brain tumours showed a reduction of -3.2% in boys (95% CI -5.5, -0.9) and of -4.4% in girls (95% CI -6.3, -2.4). No significant trend in incidence rates, either in boys or in girls, was observed (annual per cent of change for all cancers -0.5%, 95% CI -3.5, 2.7, in boys and 1.7%, 95% CI -1.9, 5.5, in girls). These results suggest an improvement in both childhood cancer diagnosis and treatment, which may explain current higher childhood cancer survival rates.

Cancer surveillance series: recent trends in childhood cancer incidence and mortality in the United States.

Public concern about possible increases in childhood cancer incidence in the United States led us to examine recent incidence and mortality patterns. Cancers diagnosed in 14540 children under age 15 years from 1975 through 1995 and reported to nine population-based registries in the National Cancer Institute's Surveillance, Epidemiology, and End Results Program were investigated. Age-adjusted incidence was analyzed according to anatomic site and histologic categories of the International Classification of Childhood Cancer. Age-adjusted U.S. mortality rates were calculated. Trends in rates were evaluated by use of standard regression methods. A modest rise in the incidence of leukemia, the most common childhood cancer, was largely due to an abrupt increase from 1983 to 1984; rates have decreased slightly since 1989. For brain and other central nervous system (CNS) cancers, incidence rose modestly, although statistically significantly (two-sided P = .020), largely from 1983 through 1986. A few rare childhood cancers demonstrated upward trends (e.g., the 40% of skin cancers designated as dermatofibrosarcomas, adrenal neuroblastomas, and retinoblastomas, the latter two in infants only). In contrast, incidence decreased modestly but statistically significantly for Hodgkin's disease (two-sided P = .037). Mortality rates declined steadily for all major childhood cancer categories, although less rapidly for brain/CNS cancers. There was no substantial change in incidence for the major pediatric cancers, and rates have remained relatively stable since the mid-1980s. The modest increases that were observed for brain/CNS cancers, leukemia, and infant neuroblastoma were confined to the mid-1980s. The patterns suggest that the increases likely reflected diagnostic improvements or reporting changes. Dramatic declines in childhood cancer mortality represent treatment-related improvements in survival.

Childhood cancer incidence in Zaragoza and Navarre (Spain): 1973-1987.

Patterns and trends in childhood cancer incidence for Navarre and Zaragoza registries were studied over the 15-year period, 1973-1987. Overall cancer rates and rates for 10 specific types of cancer were analysed using a log-linear Poisson model or, alternatively, a gamma-Poisson model whenever overdispersion was present, with age, sex, registry and period being used as predictor variables. Childhood cancer was 30% more frequent in boys than in girls, and, except for lymphomas and bone tumours, incidence decreased remarkably with age. Adjusted rates were high in comparison with other European countries, particularly in the case of non-Hodgkin's lymphomas. Cancer rates proved somewhat higher in Navarre, but this difference attained statistical significance solely in the case of central nervous system tumours (rate ratio = 1.75; 95% confidence interval 1.21-2.54). A significant rise in overall incidence was observed (11% 5-yearly increase) due mainly to the upward trend in central nervous system tumours. While the rise in these tumours coincides with the period which witnessed the spread of computerised tomography in Spain, the trend nevertheless held steady over the last 5-year period, when access to this diagnostic technique had already become generalised nationwide.

Trends in cancer incidence among children in the U.S.

This report provides results of an analysis of temporal trends in childhood cancer incidence in the U.S. stratfied by age, sex, and to a lessor extent, race, within common histologic subtypes. Population-based data from nine registries of the Surveillance, Epidemiology, and End Results Program of the National Cancer Institute were analyzed. The analysis was limited to children age < or = 14 years. Cancer cases were restricted to those patients with a malignant neoplasm diagnosed between 1974 and 1991; more than 12,000 children were included. Average annual percentage change in incidence rates and corresponding 95% confidence intervals were estimated from the maximum likelihood method of Poisson regression. Among children age < or = 14 years there was a 1% average yearly increase (95% CI 0.6, 1.3) in the incidence rates of all malignant neoplasms combined. The average annual percentage change was similar for males and females, and slightly higher for black children compared with white children. Rates increased an average of 2% or more per year for astroglial tumors, rhabdomyosarcomas, germ cell tumors, and osteosarcomas. The average annual percentage change for acute lymphoid leukemia was 1.6% and trends were somewhat stronger for blacks than whites. Cancer trends, in general, were strongest in young children. In particular, increases in astroglial tumors and rhabdomyosarcomas were most apparent among children age < 3 years, and for retinoblastoma and neuroblastoma among children in their first year of life. The average annual percentage change for acute lymphoid leukemia did not vary dramatically with age, however children age < 2 years had stronger trends compared with older children. We found little evidence for increasing trends in Wilms' tumor, primitive neuroectodermal tumors, or hematopoietic neoplasms other than acute lymphoid leukemia. These results suggest that cancer occurrence among children within specific histologies increased modestly in the U.S. between 1974 and 1991, and that the increases were most apparent among young children.