Childhood leukaemias in New Zealand: time trends and ethnic differences

A review on fetal dose in Radiotherapy: A historical to contemporary perspective

This paper aims to review on fetal dose in radiotherapy and extends and updates on a previous work¹ to include proton therapy. Out-of-field doses, which are the doses received by regions outside of the treatment field, are unavoidable regardless of the treatment modalities used during radiotherapy. In the case of pregnant patients, fetal dose is a major concern as it has long been recognized that fetuses exposed to radiation have a higher probability of suffering from adverse effects such as anatomical malformations and even fetal death, especially when the 0.1Gy threshold is exceeded. In spite of the low occurrence of cancer during pregnancy, the radiotherapy team should be equipped with the necessary knowledge to deal with fetal dose. This is crucial so as to ensure that the fetus is adequately protected while not compromising the patient treatment outcomes. In this review paper, various aspects of fetal dose will be discussed ranging from biological, clinical to the physics aspects. Other than fetal dose resulting from conventional photon therapy, this paper will also extend the discussion to modern treatment modalities and techniques, namely proton therapy and image-guided radiotherapy, all of which have seen a significant increase in use in current radiotherapy. This review is expected to provide readers with a comprehensive understanding of fetal dose in radiotherapy, and to be fully aware of the steps to be taken in providing radiotherapy for pregnant patients.

Cannabinoid exposure as a major driver of pediatric acute lymphoid Leukaemia rates across the USA: combined geospatial, multiple imputation and causal inference study

BACKGROUND

Acute lymphoid leukaemia (ALL) is the commonest childhood cancer whose incidence is rising in many nations. In the USA, between 1975 and 2016, ALL rates (ALLRs) rose 93.51% from 1.91 to 3.70/100,000 <  20 years. ALL is more common in Caucasian-Americans than amongst minorities. The cause of both the rise and the ethnic differential is unclear, however, prenatal cannabis exposure was previously linked with elevated childhood leukaemia rates. We investigated epidemiologically if cannabis use impacted nationally on ALLRs, its ethnic effects, and if the relationship was causal.

METHODS

State data on overall, and ethnic ALLR from the Surveillance Epidemiology and End Results databank of the Centre for Disease Control (CDC) and National Cancer Institute (NCI) were combined with drug (cigarettes, alcoholism, cannabis, analgesics, cocaine) use data from the National Survey of Drug Use and Health; 74.1% response rate. Income and ethnicity data was from the US Census bureau. Cannabinoid concentration was from the Drug Enforcement Agency Data. Data was analyzed in R by robust and spatiotemporal regression.

RESULTS

In bivariate analyses a dose-response relationship was demonstrated between ALLR and Alcohol Use Disorder (AUD), cocaine and cannabis exposure, with the effect of cannabis being strongest (β-estimate = 3.33(95%C.I. 1.97, 4.68), P = 1.92 × 10^- 6). A strong effect of cannabis use quintile on ALLR was noted (Chi.Sq. = 613.79, P = 3.04 × 10^- 70). In inverse probability weighted robust regression adjusted for other substances, income and ethnicity, cannabis was independently significant (β-estimate = 4.75(0.48, 9.02), P = 0.0389). In a spatiotemporal model adjusted for all drugs, income, and ethnicity, cannabigerol exposure was significant (β-estimate = 0.26(0.01, 0.52), P = 0.0444), an effect increased by spatial lagging (THC: β-estimate = 0.47(0.12, 0.82), P = 0.0083). After missing data imputation ethnic cannabis exposure was significant (β-estimate = 0.64(0.55, 0.72), P = 3.1 × 10^- 40). 33/35 minimum e-Values ranged from 1.25 to 3.94 × 10³⁶ indicative of a causal relationship. Relaxation of cannabis legal paradigms had higher ALLR (Chi.Squ.Trend = 775.12, P = 2.14 × 10^- 112). Cannabis legal states had higher ALLR (2.395 ± 0.039 v. 2.127 ± 0.008 / 100,000, P = 5.05 × 10^- 10).

CONCLUSIONS

Data show that ALLR is associated with cannabis consumption across space-time, is associated with the cannabinoids, THC, cannabigerol, cannabinol, cannabichromene, and cannabidiol, contributes to ethnic differentials, demonstrates prominent quintile effects, satisfies criteria for causality and is exacerbated by cannabis legalization.

Ethnic differences in acute promyelocytic leukaemia between New Zealand Polynesian and European patients

Ethnic differences in haematologic malignancies remain poorly elucidated, hence research in this area is important. This was a retrospective study into potential ethnic disparity in the presentation and outcomes of acute promyelocytic leukaemia (APL) between New Zealand (NZ) Polynesian and European patients. Data were analysed for patients treated at Auckland City Hospital (ACH; n = 55) and recorded in the New Zealand Cancer Registry (NZCR; n = 173), both for the period 2000-2017. We found that Polynesian patients treated at ACH presented at a younger age than European (P = 0.005), showed higher blast counts (P = 0.033), and a marginally higher prothrombin ratio (P = 0.02). Treatment with all-trans retinoic acid (ATRA) was started faster in Polynesian patients than European (P = 0.021), suggesting Polynesians were sicker at presentation but were managed accordingly. There were no differences in bleeding events, transfusion requirements and early deaths during the first month of treatment. Long-term survival was also similar. Data extracted from the NZCR confirmed NZ Polynesian patients with APL were younger than European (P < 0.001), but long-term survival was similar (P = 0.920). In summary, this study indicates a discrepancy in the presentation and severity of APL between NZ Polynesian and European patients but treatment initiation was rapid with no difference in outcomes. The distinctive features of APL in NZ Polynesians raise the possibility of a predisposing genetic factor or a different risk factor profile, elucidation of which is important for all patients with APL.

Ionising radiation and childhood leukaemia revisited

Increased incidences of childhood acute leukaemia were noted among survivors of the atomic bombings of Hiroshima and Nagasaki. In Western societies, Childhood Acute Lymphoblastic Leukaemia has a distinct epidemiology peaking at 3 years old. Exposure to ionising radiation is an established hazard but it is difficult to gauge the precise risk of less than 100 mSv. Since 1983 significant leukaemia incidences have been reported among families residing near nuclear installations. The target cells (naïve neonatal lymphocytes) get exposed to multiple xenobiotic challenges and undergo extraordinary proliferation and physiological somatic genetic change. Population movements and ionising radiation are considered taking account of updated understanding of radiation biology, cancer cytogenetics and immunological diversity. Double Strand Breaks in DNA arise through metabolic generation of Reactive Oxygen Species, and nearly always are repaired; but mis-repairs can be oncogenic. Recombinant Activating Gene enzymes in rapidly dividing perinatal pre-B lymphocytes being primed for antibody diversity are targeted to Signal Sequences in the Immunoglobulin genes. off target pseudo-sequences may allow RAG enzymes to create autosomal DSBs which, when mis-repaired, become translocated oncogenes. Immunogens acting by chance at crucial stages may facilitate this. In such circumstances, oncogenic DSBs from ionising radiation are less likely to be significant.

International long-term trends and recent patterns in the incidence of leukemias and lymphomas among children and adolescents ages 0-19 years

To enhance understanding of etiology, we examined international population-based cancer incidence data for lymphoid leukemia, non-Hodgkin lymphoma, Hodgkin lymphoma and myeloid leukemia among children aged 0-19. Based on temporal trends during 1978-2007 in 24 populations, lymphoid leukemia and myeloid leukemia incidence rates generally have not changed greatly and differences in rates for non-Hodgkin and for Hodgkin lymphoma have diminished in some regions. Lymphoid leukemia rates during 2003-2007 in 54 populations varied about 10-fold, with rates highest in US white Hispanics (50.2 per million person-years) and Ecuador (48.3) and lowest in US blacks (20.4), Tunisia (17.7) and Uganda (6.9). Non-Hodgkin lymphoma rates varied 30-fold, with very high rates in sub-Saharan Africa (146.0 in Malawi and 54.3 in Uganda) and low rates (≤ 10) in some Asian populations (China, Japan, India, the Philippines and Thailand) and U.S. Asian-Pacific Islanders, eastern and northern European populations and Puerto Rico. Hodgkin lymphoma rates varied 15-fold, with rates highest in Italy (21.3) and lowest in China (1.7). Myeloid leukemia rates varied only about fivefold, with rates highest in the Philippines and Korea (exceeding 14.0) and lowest in Eastern Europe (5.9 in Serbia and 5.3 in the Czech Republic) and Uganda (2.7). The boy/girl average incidence rate ratios were 2.00 or lower. Age-specific patterns differed among the four hematopoietic malignancies, but were generally consistent within major categories world-wide, except for non-Hodgkin lymphoma. A systematic world-wide approach comparing postulated etiologic factors in low- versus high-risk populations may help clarify the etiology of these childhood malignancies.

International variations in childhood cancer in indigenous populations: a systematic review

Although the cancer burden in indigenous children has been reported in some countries, up to now, no international comparison has been made. We therefore aimed to assess the available evidence of the burden of childhood cancer in indigenous populations. We did a systematic review of reports on cancer incidence, mortality, and survival in indigenous children worldwide. Our findings highlight the paucity of accessible information and advocate the pressing need for data by indigenous status in countries where population-based cancer registries are established. The true extent of disparities between the burden in the indigenous community needs to be measured so that targeted programmes for cancer control can be planned and implemented.

Temporal trends in childhood leukaemia incidence following exposure to radioactive fallout from atmospheric nuclear weapons testing

Notably raised rates of childhood leukaemia incidence have been found near some nuclear installations, in particular Sellafield and Dounreay in the United Kingdom, but risk assessments have concluded that the radiation doses estimated to have been received by children or in utero as a result of operations at these installations are much too small to account for the reported increases in incidence. This has led to speculation that the risk of childhood leukaemia arising from internal exposure to radiation following the intake of radioactive material released from nuclear facilities has been substantially underestimated. The radionuclides discharged from many nuclear installations are similar to those released into the global environment by atmospheric nuclear weapons testing, which was at its height in the late-1950s and early-1960s. Measurements of anthropogenic radionuclides in members of the general public resident in the vicinity of Sellafield and Dounreay have found levels that do not differ greatly from those in persons living remote from nuclear installations that are due to ubiquitous exposure to the radioactive debris of nuclear weapons testing. Therefore, if the leukaemia risk to children resulting from deposition within the body of radioactive material discharged from nuclear facilities has been grossly underestimated, then a pronounced excess of childhood leukaemia would have been expected as a consequence of the short period of intense atmospheric weapons testing. We have examined childhood leukaemia incidence in 11 large-scale cancer registries in three continents for which data were available at least as early as 1962. We found no evidence of a wave of excess cases corresponding to the peak of radioactive fallout from atmospheric weapons testing. The absence of a discernible increase in the incidence of childhood leukaemia following the period of maximum exposure to the radioactive debris of this testing weighs heavily against the suggestion that conventional methods are seriously in error when assessing the risk of childhood leukaemia from exposure to man-made radionuclides released from nuclear installations.

Epidemiology of childhood leukemia in New Zealand: studies of infectious hypotheses

The etiology of childhood leukemia remains an enigma despite decades of research. Hypotheses of an infectious etiology have been around for a long time, and in the last 20 years there have been two main theoretical contenders. One of these involves the possibility of a specific infectious agent having a causative role, and animal leukemia viruses would be analogous to this. Another theory relates to the possible involvement of unusual patterns of infections in infancy and how they might relate to aberrant immune responses. The first of these is easier to test. In New Zealand, since the early 1990s we have embarked on a program of research on the epidemiology of childhood leukemia. One of the goals has been to test hypotheses about the role of infection in causation. A variety of study designs have been employed, including descriptive, clustering, case-control and contributions to pooled international analyses. Some of the more interesting findings include: there has been a marked increase in the incidence of acute lymphoblastic leukemia among young children in New Zealand since the mid 1960s, poorer families are at greater risk, and there is no clear support for hypotheses of an infectious cause from the New Zealand data. However because of our small total population (4 million people) we cannot produce clear results on our own. Hence our current international collaborations, for example in CLIC (the Childhood Leukemia International Consortium) represent an important step forward. As countries work together across international boundaries we have a renewed hope that the causes of the childhood leukemias will be unlocked in the foreseeable future.

Incidence, time trends and regional variation of childhood leukaemia in Germany and Europe

This paper presents data on the German and Europe-wide incidence, time trends and regional variations of childhood leukaemia. Data were provided by the German Childhood Cancer Registry (GCCR), a population-based cancer registry recording all cases of malignant diseases in children under 15 y of age residing in Germany and by the Automated Childhood Cancer Information System (ACCIS) co-ordinated at International Agency for Research on Cancer, Lyon, that combines and evaluates data from several European population-based cancer registries. The incidence of leukaemia (44.0 per million) has increased in Europe as well as in Germany in the last decades (0.6% annually on average). Germany shows no systematic aggregation of regions with low or high cancer incidence in terms of regional clustering. Incidence rates differ between European regions with the highest rates in Northern Europe (48.0 per million) and the lowest rates in Eastern Europe (39.1). Altogether, the results from ACCIS and the GCCR show good agreement.

Aetiology of childhood acute leukaemias: current status of knowledge

Acute leukaemia is a consequence of malignant transformation of a haematopoetic progenitor cell. Molecular studies have revealed a prenatal origin of many childhood leukaemias. According to current models, a preleukaemic stem cell clone is generated by a first mutation in utero which, in a minority of children, progresses to leukaemia after receiving further postnatal genetic hits. The nature of pre- and postnatal events involved in leukaemogenesis in children is not well understood. Although genetic predisposition and specific environmental exposures may account for individual cases, the bulk of childhood leukaemia cannot be explained by any of these factors. The higher incidence of the most common leukaemia subtype in affluent societies, as well as the age peak between 2-5 y, suggest a contributory role of socioeconomic factors. An abnormal immune response during delayed exposure to common infections provides a plausible mechanism for malignant progression of preleukaemic clones in a subgroup of children. As highlighted in this review, a common cause for all types and subtypes of childhood leukaemia is highly unlikely. Deeper insights into the pathogenesis of childhood leukaemia will rely on large-scale and combined epidemiological and biomolecular studies.

Trends in childhood acute lymphoblastic leukemia in Western Australia, 1960-2006

Increases in the incidence of childhood acute lymphoblastic leukemia (ALL) have been reported in some countries, while other reports from similar geographical regions have indicated stable rates. The reasons for the discrepancies have been debated in the literature, with the focus on whether the observed increases are "real" or an artifact resulting from improvements in diagnosis, case ascertainment and population coverage over time. We used population-based data from Western Australia to investigate trends in the incidence of childhood ALL between 1960 and 2006. Age-standardized incidence rates (ASRs) and rate ratios (indicating annual percent change) were estimated using Poisson regression. Between 1960 and 2006, the ASR was 3.7 per 100,000 person-years, with an annual percent increase of 0.40% (95% CI: -0.20, 1.00). Between 1982 and 2006, the ASR was 3.8, with an annual percent increase of 0.80% (95% CI = -0.70 to 2.30). This increased to 1.42% (95% CI: -0.30, 3.0) when a sensitivity analysis was undertaken to assess the effect of excluding the final 2 years of data. Annual increases of 3.7% (95% CI: -0.50, 8.00) among children aged 5-14 years, and of 3.10% (95% CI: 0.50, 5.70) in girls, were observed for this latter period. These results were supported by national Australian incidence data available for 1982-2003. There may have been a small increase in the incidence of ALL since 1982 among girls and older children, but an overall increase appears unlikely. No impact of folate supplementation or fortification is apparent.

Vitamin and mineral supplements in pregnancy and the risk of childhood acute lymphoblastic leukaemia: a case-control study

Background

An earlier case-control study from Western Australia reported a protective effect of maternal folic acid supplementation during pregnancy on the risk of childhood acute lymphoblastic leukaemia (ALL). The present study tested that association.

Methods

A national case-control study was conducted in New Zealand. The mothers of 97 children with ALL and of 303 controls were asked about vitamin and mineral supplements taken during pregnancy.

Results

There was no association between reported folate intake during pregnancy and childhood ALL (adjusted odds ratio (OR) 1.1, 95% confidence interval (CI) 0.5–2.7). Combining our results with the study from Western Australia and another study from Québec in a meta-analysis gave a summary OR of 0.9 (95% CI 0.8–1.1).

Conclusion

Our own study, of similar size to the Australian study, does not support the hypothesis of a protective effect of folate on childhood ALL. Neither do the findings of the meta-analysis.

Time trends of cancer incidence in European children (1978-1997): report from the Automated Childhood Cancer Information System project

Within the framework of the Automated Childhood Cancer Information System (ACCIS), time trend analyses for childhood cancer were performed using data from 33 population-based cancer registries in 15 European countries for the period 1978-1997. The overall incidence rate based on 77,111 cases has increased significantly (P<0.0001), with an average annual percentage change (AAPC) of 1.1%. The rising trend was observed in all five geographical regions and in the majority of the disease groups (in order of AAPC): soft tissue sarcomas (1.8%), brain tumours, tumours of the sympathetic nervous system, germ-cell tumours, carcinomas, lymphomas, renal tumours, and leukaemias (0.6%). No change was seen in incidence of bone tumours, hepatic tumours and retinoblastoma. The increased incidence can only partly be explained by changes in diagnostic methods and by registration artefacts. The patterns and magnitude of these increases suggest that other factors, e.g. changes in lifestyle and in exposure to a variety of agents, have contributed to the increase in childhood cancer in the recent decades.

Birth characteristics and the risk of childhood leukaemias and lymphomas in New Zealand: a case-control study

Background

Some studies have found that lower parity and higher or lower social class (depending on the study) are associated with increased risks of childhood acute lymphoblastic leukaemia (ALL). Such findings have led to suggestions that infection could play a role in the causation of this disease. An earlier New Zealand study found a protective effect of parental marriage on the risk of childhood ALL, and studies elsewhere have reported increased risks in relation to older parental ages. This study aimed to assess whether lower parity, lower social class, unmarried status and older parental ages increase the risk of childhood ALL (primarily). These variables were also assessed in relation to the risks of childhood acute non-lymphoblastic leukaemia, non-Hodgkin's lymphomas and Hodgkin's disease.

Methods

A case control study was conducted. The cases were 585 children diagnosed with leukaemias or lymphomas throughout New Zealand over a 12 year period. The 585 age and sex matched controls were selected at random from birth records. Birth records from cases (via cancer registration record linkage) and from controls provided accurate data on maternal parity, social class derived from paternal occupation, maternal marital status, ages of both parents, and urban status based on the address on the birth certificate. Analysis was by conditional logistic regression.

Results

There were no statistically significant associations overall between childhood ALL and parity of the mother, social class, unmarried maternal status, increasing parental ages (continuous analysis), or urban status. We also found no statistically significant associations between the risks of childhood acute non-lymphoblastic leukaemia, non-Hodgkin lymphomas, or Hodgkin's disease and the variables studied.

Conclusion

This study showed no positive results though of reasonable size, and its record linkage design minimised bias. Descriptive studies (eg of time trends of ALL) show that environmental factors must be important for some diagnoses. Work has been done on the risk of ALL in relation to chemicals (eg pesticides) and drugs, dietary factors (eg vitamins), electromagnetic fields and infectious hypotheses (to name some); but whether these or other unknown factors are truly important remains to be seen.

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.

Childhood malignancies in French Polynesia during the 1985-1995 period

We report an estimation of the incidence of childhood cancer among natives of French Polynesia (FP) during the 1985-1995 period. Our data were acquired from the Cancer Registry of FP and through an extensive investigation of other potential sources of information. The mean population of children between 1985 and 1995 was estimated to be 63 401 inhabitants, 32 487 of whom were boys and 30 914 girls, born and residing in FP. During the 1985-1995 period, 87 incident cases of childhood cancer were recorded among inhabitants born in FP or of an unknown place of birth (n = 2). Childhood cancer incidence had attained 125 cases/million child years and was very similar among girls (126 x 10(-6)) and boys (123 x 10(-6)), this incidence being slightly lower than among other populations of similar ethnic origin: Standardized Incidence Ratio (SIR) = 0.8 (95% CI: 0.7-1.0) when compared with New Zealand Maoris and SIR = 0.8 (95% CI: 0.6-1.0) when compared with natives from Hawaii. For both sexes considered together, the most frequent cancer type was leukaemia, followed by central nervous system (CNS) malignancies, neuroblastoma, and non-Hodgkin's lymphoma (NHL). Only one case of gonadal and germ cell tumours and one case of carcinoma were reported. Childhood cancer incidence was predominant among children living in the Windward, Leeward and Marquesas Islands and the Tuamotu-Gambier archipelago, but lower in the Austral Islands. The incidence of acute non-lymphocytic leukaemia (ANLL) decreased from 3.3 x 10(-5) between 1985 and 1989, an unexpectedly high incidence, to 0.8 x 10(-5) between 1990 and 1995.

Incidence of childhood leukaemia and non-Hodgkinʼs lymphoma in France: National Registry of Childhood Leukaemia and Lymphoma, 1990–1999

The French National Registry of Childhood Leukaemia and Lymphoma (NRCL) covers the whole French mainland population aged less than 15 years (approximately 11 million children) for all childhood haematopoietic tumours since 1 January 1990, except Hodgkin's disease, which has been registered since 1 January 1999. During the period from 1990 to 1999, 5757 cases of leukaemia, lymphoma and myelodysplastic syndrome were registered in the NRCL, with an average of 2.5 sources per case. The age-standardized incidence rates per million per year were 43.1 for leukaemia (34.3 for acute lymphoblastic leukaemia, 7.1 for acute myeloblastic leukaemia, 0.6 for chronic myeloid leukaemia and 0.5 for chronic myelomonocytic leukaemia), 8.9 for non-Hodgkin's lymphomas and 6.7 for Hodgkin's disease. Down's syndrome was present in 110 cases of acute leukaemia (2.5%) and three cases of non-Hodgkin's lymphoma (0.3%). The incidence of acute lymphoblastic leukaemia showed a typical peak at age 2 years for girls and 3 years for boys. The incidence rates of leukaemia and non-Hodgkin's lymphoma did not show any temporal trends over the 10 year period.

Age- and Sex-Specific Incidence of Childhood Leukemia by Immunophenotype in the Nordic Countries

BACKGROUND

Studies from various countries have found an increasing incidence of childhood leukemia in recent decades. To characterize time trends in the age- and sex-specific incidence of childhood acute leukemia during the last 20 years in the Nordic countries, we analyzed a large set of population-based data from the Nordic Society of Paediatric Haematology and Oncology (NOPHO) in their acute leukemia database covering a population of approximately 5 million children aged 0-14 years.

METHODS

Temporal trends in acute myeloid leukemia and acute lymphoblastic leukemia incidence rates overall and for acute lymphoblastic leukemia immunophenotypes and for specific age groups were analyzed by Poisson regression adjusting for age, sex, and country. All statistical tests were two-sided.

RESULTS

We identified 1595 girls and 1859 boys diagnosed with acute lymphoblastic leukemia between January 1, 1982, and December 31, 2001, and 260 girls and 224 boys diagnosed with de novo acute myeloid leukemia between January 1, 1985, and December 31, 2001. No statistically significant change was seen in the overall incidence rate for acute lymphoblastic leukemia during the 20-year study (annual change = 0.22%, 95% confidence interval [CI] = -0.36% to 0.80%). The incidence rate of B-precursor acute lymphoblastic leukemia remained unchanged (annual change = 0.30%, 95% CI = -0.57% to 1.18%) from January 1, 1986, through December 31, 2001. A somewhat lower incidence in the first years of the study period indicated an early increasing incidence of B-precursor acute lymphoblastic leukemia that corresponded to a simultaneous decreasing incidence of unclassified acute lymphoblastic leukemia. Incidences of T-cell acute lymphoblastic leukemia (annual change = 1.55%, 95% CI = -1.14% to 4.31%) and acute myeloid leukemia (annual change = 0.58%, 95% CI = -1.24% to 2.44%) were stable during the study period.

CONCLUSION

Incidences of acute myeloid leukemia overall, acute lymphoblastic leukemia overall, and specific acute lymphoblastic leukemia immunophenotypes have been stable in the Nordic countries over the past two decades.

Increasing incidence of childhood leukemia in Northwest Italy, 1975-98

Although some childhood cancer registries reported increasing incidence, the evidence and magnitude of time trends in the incidence of childhood leukemia are debated and the scientific evidence is conflicting. Only limited data have so far been supplied from Southern European countries. We present an analysis of the incidence trend of childhood leukemia in Piedmont (NW Italy) in 1975-98, based on data from the population-based childhood cancer registry. The Childhood Cancer Registry of Piedmont has been recording cases of childhood neoplasms since 1967. Procedures have been uniform and are based on an active search for cases and relevant information. Only cases with confirmed residence in Piedmont at diagnosis are included. Eight hundred cases of leukemia (622 acute lymphoblastic [ALL], 133 acute nonlymphoblastic [AnLL], 45 other and unspecified) were recorded in the period 1975-98 considered in our study. Incidence trends were analyzed using piecewise regression and Poisson regression, based on annual incidence rates. As results from the 2 analyses were similar, only the former were reported. In the age group 1-4 years, a statistically significant annual 2.6% increase in incidence rate of ALL (adjusted by age and gender; 95% confidence interval [CI] 1.13-4.13) was estimated. There was no evidence of increase in other age groups. During 1980-98, a statistically significant 4.4% annual increase (95% CI 1.86-6.90) was seen for pre-B-All in the age group 1-4 years. An increase was also seen for T-ALL that was not statistically significant. Sensitivity analyses were conducted, with no relevant differences from the main results. Our data suggest an increasing trend in ALL incidence for children between the ages of 1 and 4 years. These results are unlikely to be explained by changes in quality of data or exhaustiveness in reporting in the study period. The results were not changed in the sensitivity analyses we conducted. Possible causes to be investigated include environmental factors, changes in family size and parental age, socioeconomic conditions and geographical distribution of cases.

Standard versus intensified chemotherapy with granulocyte colony-stimulating factor support in small-cell lung cancer: a prospective European Organization for Research and Treatment of Cancer-Lung Cancer Group Phase III Trial-08923

PURPOSE

To assess the impact on survival of increasing dose-intensity (DI) of cyclophosphamide, doxorubicin, and etoposide (CDE) in small-cell lung cancer (SCLC).

PATIENTS AND METHODS

Previously untreated SCLC patients were randomized to standard CDE (cyclophosphamide 1,000 mg/m(2) and doxorubicin 45 mg/m(2) on day 1, and etoposide 100 mg/m(2) on days 1 to 3 every 3 weeks, for five cycles) or intensified CDE (cyclophosphamide 1,250 mg/m(2) and doxorubicin 55 mg/m(2) on day 1, and etoposide 125 mg/m(2) on days 1 to 3 with granulocyte colony-stimulating factor [G-CSF] 5 micro g/kg/d on days 4 to 13 every 2 weeks, for four cycles). Projected cumulative dose was almost identical on the two arms, whereas projected DI was nearly 90% higher on the intensified arm. Two hundred forty-four patients were enrolled. The first 163 patients were also randomized (2 x 2 factorial design) to prophylactic antibiotics or placebo to assess their impact on preventing febrile leukopenia (FL). This report focuses on chemotherapy DI results.

RESULTS

With a median follow-up of 54 months, 216 deaths have occurred. Actually delivered DI on the intensified arm was 70% higher than on the standard arm. Intensified CDE was associated with more grade 4 leukopenia (79% v 50%), grade 4 thrombocytopenia (44% v 11%), anorexia, nausea, and mucositis. FL and number of toxic deaths were similar on the two arms. The objective response rate was 79% for the standard arm and 84% for the intensified arm (P =.315). Median survival was 54 weeks and 52 weeks, and the 2-year survival rates were 15% and 18%, respectively (P =.885).

CONCLUSION

A 70% increase of CDE actual DI does not translate into an improved outcome in SCLC patients.

Acute lymphoblastic leukemia incidence during socioeconomic transition: selective increase in children from 1 to 4 years

Pre-school acute lymphoblastic leukemia (ALL) peak is consistent in developed but not in developing countries and its magnitude apparently correlates with the socioeconomic status. A population-based study describing ALL incidence during socioeconomic transition has been lacking. Central European post-communist countries (with very low foreign migration and centralized statistics) offer reliable data for the period before and during major socioeconomic changes. Population-based data on Czech ALL patients younger than 18 years were taken from two independent Czech national registries partially overlapping in time (1980-1998, n = 1236 and 1991-1999, n = 570). During the 1980s and 1990s, ALL incidence among children 1-4 years increased 1.5 times (P = 0.01). This increase was more prominent in females than in males (slopes 0.13 and 0.09, P values 0.03 and >0.05, respectively). No significant change was observed in other age groups (0, 5-9, 10-14, 15-17 years or all others combined). We discuss possible underlying socioeconomic factors including infant care and breast-feeding, hygiene, birth order, industry and pollution. Moreover, we try to pinpoint the immunophenotypic/molecular-genetic subsets of ALL that might be socioeconomically affected. Selective increase of ALL in children 1-4 years old provides epidemiological evidence that etiology and/or trigger mechanisms are different for a considerable proportion of these children and that these mechanisms are exogenous.

Lymphoma and lymphoid leukemia incidence in Florida children: ethnic and racial distribution

BACKGROUND

Incidence reports for pediatric lymphoma and lymphoid leukemia in Hispanic subpopulations in the United States are rare. The authors hypothesized that Florida's Hispanic children would have higher risks of lymphoma and lymphoid leukemia compared with non-Hispanic white children.

METHODS

All cases of lymphoid leukemia, Hodgkin, non-Hodgkin, and Burkitt lymphoma (SEER International Classification of Diseases for Oncology codes) in children (< 15 years) in the Florida Cancer Data System (FCDS) from 1985 to 1997 were studied. Cases were classified as: 1) white, 2) Hispanic, or 3) black, and stratified by age. Age-adjusted rates for the three race-ethnic groups were calculated. Rates for Hispanics and blacks were compared with whites as standardized rate ratios (SRR) with 95% confidence intervals.

RESULTS

Seven hundred thirty-one incident cases of pediatric lymphoma and 1231 cases of lymphoid leukemia were identified during the study period. For children with lymphoma, the SRR for Hispanics was 1.32 (95% CI, 1.20-1.44), and for blacks, the SRR was 0.68 (95% CI, 0.63-0.72. For lymphoid leukemia, the SRR for Hispanics was 1.29 (95% CI, 1.28-1.30), and for blacks, the SRR was 0.55 (95% CI, 0.54-0.56). Similar rates were found for the Hodgkin and non-Hodgkin subgroups.

CONCLUSIONS

Incidences of Hodgkin and non-Hodgkin lymphoma were significantly higher in Florida's Hispanic children, with 30% increased relative risks, compared with whites. Black children had significantly decreased incidences and risk. Results for lymphoid leukemia were similar. Incidence of lymphoma in Florida's Hispanic children (primarily Cuban and Central American origin) differed from similar reports from Texas and California, where Hispanics are primarily of Mexican origin.

An assessment of spatial clustering of leukaemias and lymphomas among young people in New Zealand

STUDY OBJECTIVE

To assess spatial clustering of childhood leukaemias and lymphomas in New Zealand, using a national dataset from a country with no nuclear installations.

DESIGN

New Zealand Map Grid coordinates, derived from the birth addresses of cases and controls were used in clustering analyses that applied Cuzick and Edwards' method.

SETTING

The whole of New Zealand.

PARTICIPANTS

The cases were ascertained from the New Zealand Cancer Registry. They were diagnosed with leukaemia or lymphoma at ages 0-14 years during the period 1976 to 1987. For Hodgkin's disease, the age range was extended to include those aged from 0-24 years. The cancer registrations were linked with national birth records, to obtain the birth addresses of the cases. The controls were selected at random from birth records, with matching to cases (1:1) on age and sex. The analyses included 600 cases and 600 controls.

MAIN RESULTS

There was no statistically significant spatial clustering for any tumour group overall, including acute lymphoblastic leukaemia, acute nonlymphoblastic leukaemia, other leukaemias, non-Hodgkin's lymphomas, Hodgkin's disease, and all these combined. Significant clustering was found in a sub-analysis for one of three age specific subgroups of acute lymphoblastic leukaemia (ages 10-14 years, p = 0.003).

CONCLUSION

The subgroup finding may have been real or a chance association, as several comparisons were made. This study found little evidence for spatial clustering of leukaemias or lymphomas in a population with no nuclear installations.

Infant cancer in the U.S.: histology-specific incidence and trends, 1973 to 1992

BACKGROUND

Many cancers in infants demonstrate unique epidemiologic, clinical, and genetic characteristics compared with cancers in older children. Few epidemiologic reports, however, have focused on this important age group.

METHODS

Population-based data from the Surveillance, Epidemiology, and End Results (SEER) program were used to estimate relative frequency, incidence rates, and average annual percentage change of rates among children in their first year of life (infants) who were diagnosed with a malignant neoplasm from 1973 to 1992 (N = 1461).

RESULTS

The greatest proportion of cases (12%) was diagnosed during the first month of life, with extracranial neuroblastoma accounting for 35% of this total. Overall, the average annual incidence rate was 223/1,000,000 infants. Extracranial neuroblastoma was the most common infant malignancy (58/1,000,000 infants per year), followed by leukemias (37/1,000,000), brain and central nervous system (CNS) tumors (34/1,000,000), and retinoblastoma (27/1,000,000). White infants had a 32% higher incidence rate than black infants. The average annual percentage increase in rates for all cancer from 1973 to 1992 was 2.9% (95% CI: 1.9%, 3.8%). For neoplasms with at least 100 cases, increasing trends were greatest for retinoblastoma (4.6%), CNS (4.1%), and extracranial neuroblastoma (3.4%).

CONCLUSIONS

Incidence rates increased notably over the study period. Future studies should consider the unique presentation of infants with cancer when developing new hypotheses related to cancer etiology and gene-environment interactions.