Incidence Rate Of Leukemia Research Articles

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.

Low Cloud Cover-Adjusted Ultraviolet B Irradiance Is Associated with High Incidence Rates of Leukemia: Study of 172 Countries.

There are 52,380 cases of leukemia and 24,090 deaths from it in the US annually. Its causes are unknown and no preventive strategies have been implemented. We hypothesized that leukemia is due mainly to vitamin D deficiency, which is due mainly to low solar ultraviolet B (UVB) irradiance. To test this hypothesis, we estimated age-standardized cloud-cover-adjusted winter UVB irradiance using cloud cover data from the International Satellite Cloud Climatology Project, latitudes of population centroids, and standard astronomical calculations. Incidence rates for 172 countries, available from the International Agency for Cancer Research, were plotted according to cloud-adjusted UVB irradiance. We used multiple regression to account for national differences in elevation and average life expectancy. Leukemia incidence rates were inversely associated with cloud-adjusted UVB irradiance in males (p ≤ 0.01) and females (p ≤ 0.01) in both hemispheres. There were few departures from the trend line, which was parabolic when plotted with the equator at the center of the display, northern hemisphere countries on the right side and southern hemisphere countries on the left. The bivariate association displayed by the polynomial trend line indicated that populations at higher latitudes had at least two times the risk of leukemia compared to equatorial populations. The association persisted in males (p ≤ 0.05) and females (p ≤ 0.01) after controlling for elevation and life expectancy. Incidence rates of leukemia were inversely associated with solar UVB irradiance. It is plausible that the association is due to vitamin D deficiency. This would be consistent with laboratory studies and a previous epidemiological study. Consideration should be given to prudent use of vitamin D for prevention of leukemia.

Incidence rates of chronic lymphocytic leukemia in US states are associated with residential radon levels.

Environmental risk factors for chronic lymphocytic leukemia (CLL) have not been consistently identified. An etiologic role for ionizing radiation in CLL is controversial. Because most of the ionizing radiation to which individuals are exposed comes from radon at home, we examined CLL incidence rates in relation to residential radon levels. We used population-based rates for CLL for US states from 2007 to 2011 and measurements of residential radon made by the US Environmental Protection Agency. Incidence rates for CLL were significantly correlated with residential radon levels among whites (both genders together and each gender separately; p < 0.005) and among blacks (p < 0.05). We speculate that radon increases CLL risk and that the mechanisms may be similar to those by which radon causes lung cancer.

INCIDENCE OF MALIGNANT NEOPLASMS OF CERTAIN ORGANS DEPENDING ON INDIVIDUALIZED ACCUMULATED IRRADIATION DOSES

The subject of the study is the population affected after the Chernobyl accident (1-7 groups of primary accounting). We studied cases of malignant neoplasms of lymphoid, hematopoietic or related tissues, cases of thyroid cancer, cancer of the testicles, ovary, kidney, corpus uteri, prostate and bladder over 1986-2014. We calculated and analyzed the parameters of the standardized incidence ratio depending on radiation doses. Women revealed a statistically significant dependence of the incidence rates of thyroid cancer and chronic lymphocytic leukemia on radiation dose, men revealed such a dependence in cancer of the testicles.

Geographical variation in the incidence of childhood leukaemia in Manitoba

Identification of geographical areas and ecological factors associated with higher incidence of childhood leukaemias can direct further study for preventable factors and location of health services to manage such individuals. The aim of this study was to describe the geographical variation and the socio-demographic factors associated with childhood leukaemia in Manitoba. Information on childhood leukaemia incidence between 1992 and 2008 was obtained from the Canadian Cancer Registry and the socio-demographic characteristics for the area of residence from the 2006 Canadian Census. Bayesian spatial Poisson mixed models were used to describe the geographical variation of childhood leukaemia and to determine the association between childhood leukaemia and socio-demographic factors. The south-eastern part of the province had a higher incidence of childhood leukaemia than other parts of the province. In the age and sex-adjusted Poisson regression models, areas with higher proportions of visible minorities and immigrant residents had higher childhood leukaemia incidence rate ratios. In the saturated Poisson regression model, the childhood leukaemia rates were higher in areas with higher proportions of immigrant residents. Unemployment rates were not a significant factor in leukaemia incidence. In Manitoba, areas with higher proportions of immigrants experience higher incidence rates of childhood leukaemia. We have identified geographical areas with higher incidence, which require further study and attention.

Age-standardized Incidence Rates for Leukemia Associated with Consanguineous Marriages in 68 Countries, an Ecological Study.

Consanguineous marriage that defines as a union between biologically related persons has a variety of known deleterious correlations with factors that affect public health within human populations. To investigate the association between the mean of inbreeding coefficient (α) and incidence of leukemia, the present ecological study on 68 countries was carried out. Statistical analysis showed that the age-standardized incidence rate of leukemia positively correlated with log10GNI per capita (r=0.699, df=66, P<0.001) and negatively correlated with log10α (r=−0.609, df=66, P<0.001). Controlling log10GNI per capita, a significant negative correlation between log10α and the age-standardized incidence rate of leukemia was observed (r=−0.392, df=65, P=0.001). The countries were stratified according to their annual GNI per capita, low and high-income countries with GNI per capita less than and more than 10,000$, respectively. Statistical analysis showed that in high-income countries, after controlling for log10GNI per capita, the correlation between the age-standardized incidence rate of leukemia and log10α was still significant (r=−0.600, df=36, P<0.001). It should be noted that there was no significant association between the age-standardized mortality rate due to leukemia and log10α (P>0.05). The present finding indicates that the rate of leukemia, age-standardized for incidence, is lower in countries with a high prevalence of consanguineous marriages.

Abstract 271: Rising rates of acute lymphocytic leukemia in Hispanic children: A review of trends in childhood leukemia incidence from 1973-2010

Abstract Background: Childhood leukemia is the most common cancer in children under 20 years of age in the United States, and incidence rates have increased over the last few decades. The incidence rate for all childhood leukemia is higher among Hispanic children [2006-2010 age-adjusted incidence rate (AAIR)= 5.71; 95%CI: 5.47, 5.97] than among non-Hispanic White children (2006-2010 AAIR=3.95; 95%CI: 3.81, 4.09). This analysis aims to describe secular trends from 1992-2010 in the incidence of childhood leukemia, independently for Hispanic and non-Hispanic children. Methods: Surveillance, Epidemiology and End Results (SEER) data were used to evaluate trends in the incidence of childhood leukemia diagnosed in children less than 20 years of age between 1992-2010 by ethnicity. Trends among Hispanic and non-Hispanic children were examined overall and by age, gender, and histologic subtype. AAIRs, annual percent change (APC) estimates, and 95% confidence intervals (95%CIs) were calculated using SEER*stat v.8.0.4. Results: Hispanic children were more likely than non-Hispanic children to be diagnosed with leukemia (all subtypes combined), and with acute lymphocytic leukemia when examined by gender and by age (0-4, 5-9, 10-14, 15-19 years at diagnosis). A greater increase in AAIRs was observed for Hispanic children as compared to non-Hispanic children for all types of leukemia from 1992-2010 (APCHispanic=1.16; 95%CI: 0.55, 1.76; APCnon-Hispanic=0.52; 95%CI: 0.01, 1.03). When restricting to acute lymphocytic leukemias (ALL), statistically significant increases were observed for Hispanic children (APC=1.31; 95%CI:0.68, 1.94), but not for non-Hispanic children (APC=0.50; 95%CI: -0.19, 1.19). Among Hispanic children, the strongest increase was found among children diagnosed from 10-19 years of age. Incidence rates were higher for Hispanic males (AAIR=5.26; 95%CI: 4.93, 5.60;) than for Hispanic females (AAIR=4.07; 95%CI: 3.78, 4.39). Conclusion: Incidence rates of childhood leukemia rose from 1992-2010, with the greatest increase for ALL among older Hispanic children (aged 10-19 years). In future studies aimed at evaluating exposures responsible for increasing incidence rates of childhood ALL, researchers should consider risk factors that may explain the rising rates among Hispanic children. Citation Format: Jessica Barrington-Trimis, Myles Cockburn, Catherine Metayer, W. James Gauderman, Joseph Wiemels, Roberta McKean-Cowdin. Rising rates of acute lymphocytic leukemia in Hispanic children: A review of trends in childhood leukemia incidence from 1973-2010. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 271. doi:10.1158/1538-7445.AM2014-271

Epidemiological assessment of leukemia in Kazakhstan, 2003- 2012.

Cancer is a major health problem facing the entire world, and Kazakhstan is not the exception. The aim of this study was to present an epidemiological assessment of leukemia in the population of Kazakhstan during 2003-2012. This descriptive and retrospective study was based on data obtained from all oncological organizations of the whole country. Age standardized incidence rates per 100,000 population for leukemia were calculated. Totally, 6,741 new cases of leukemia were registered in Kazakhstan during the 10 year period. The mean age of patients with leukemia was 48.5. The ASRs for leukemia among men and women were 5.3 and 3.6, respectively (p<0.001). In conclusion, our results showed a high incidence rate of leukemia in Kazakhstan, especially in the north of the country. The incidence of leukemia was significantly higher in males and increased with age. Determining and controlling important risk factors of leukemia may lead to decrease in its burden.

Association between leukaemia and X‐ray in children: A nationwide study

The frequency of employing radiography is increasing. Long-term risks of performing X-ray procedures on children and adolescents for medical diagnosis have raised significant concerns. In this study, we adopt the case-control methodology to evaluate the relationship between the incidence rate of acute leukaemia and exposure to radiation during diagnostic X-ray examinations for children. Based on 1998-2010 data obtained from the Taiwan Bureau of National Health Insurance database, we selected 58 children with leukaemia and randomly selected an additional 232 children as the control group. The mean age of children with leukaemia is 8.92 ± 5.24 years. The risk of leukaemia in children who underwent X-ray examinations increased 2.14-fold (95% CI, 1.18-3.87). In this study, we identified that, when undergoing X-ray examinations, the risk of leukaemia in children increased for both sex and age groups. Specifically, the relationship between leukaemia and X-ray in boys (OR = 3.28, 95%CI, 1.33-8.07) and in ages of 6 to 11 years (OR = 2.58, 95%CI, 1.09-6.10) was significant. Overall, the risk of leukaemia in children who underwent X-ray examinations progressively increased from a ratio of 1.65 to 3.14. Moreover, an identical trend was observed for boys (1.85 to 6.42). Exposure to X-ray increased the risk of leukaemia in children.

The risk of leukaemia in young children from exposure to tritium and carbon-14 in the discharges of German nuclear power stations and in the fallout from atmospheric nuclear weapons testing

Towards the end of 2007, the results were published from a case-control study (the "KiKK Study") of cancer in young children, diagnosed <5 years of age during 1980-2003 while resident near nuclear power stations in western Germany. The study found a tendency for cases of leukaemia to live closer to the nearest nuclear power station than their matched controls, producing an odds ratio that was raised to a statistically significant extent for residence within 5 km of a nuclear power station. The findings of the study received much publicity, but a detailed radiological risk assessment demonstrated that the radiation doses received by young children from discharges of radioactive material from the nuclear reactors were much lower than those received from natural background radiation and far too small to be responsible for the statistical association reported in the KiKK Study. This has led to speculation that conventional radiological risk assessments have grossly underestimated the risk of leukaemia in young children posed by exposure to man-made radionuclides, and particular attention has been drawn to the possible role of tritium and carbon-14 discharges in this supposedly severe underestimation of risk. Both (3)H and (14)C are generated naturally in the upper atmosphere, and substantial increases in these radionuclides in the environment occurred as a result of their production by atmospheric testing of nuclear weapons during the late 1950s and early 1960s. If the leukaemogenic effect of these radionuclides has been seriously underestimated to the degree necessary to explain the KiKK Study findings, then a pronounced increase in the worldwide incidence of leukaemia among young children should have followed the notably elevated exposure to (3)H and (14)C from nuclear weapons testing fallout. To investigate this hypothesis, the time series of incidence rates of leukaemia among young children <5 years of age at diagnosis has been examined from ten cancer registries from three continents and both hemispheres, which include registration data from the early 1960s or before. No evidence of a markedly increased risk of leukaemia in young children following the peak of above-ground nuclear weapons testing, or that incidence rates are related to level of exposure to fallout, is apparent from these registration rates, providing strong grounds for discounting the idea that the risk of leukaemia in young children from (3)H or (14)C (or any other radionuclide present in both nuclear weapons testing fallout and discharges from nuclear installations) has been grossly underestimated and that such exposure can account for the findings of the KiKK Study.

Epidemiology of Leukemia and Multiple Myeloma in Golestan, Iran

The aim of this paper was to present the incidence rates of leukemia and multiple myeloma (MM) in Golestan province located in northeastern Iran during 2004-2009. This was a descriptive cross-sectional study. Data on newly diagnosed (incident) leukemia and MM cases were obtained from collected from Golestan population-based cancer registry. Data was entered into CanReg-4 software. Age standardized incidence rates (ASR) (per 100000 person-years) for leukemia and MM were calculated. Data on Golestan population was obtained from the data of Iranian national census in 2006. Totally, 11036 new cancer cases were registered in GPRC from 2004-2009. Leukemia and MM accounted for 693 and 124 of cases, respectively. The mean age in patients with leukemia and MM was 43.8 and 62.4 years, respectively. The ASRs for leukemia among men and women were 10.4 and 7.8, respectively (p<0.001). The ASRs for MM were 2.1 and 2 in men and women, respectively (p=0.93). The rate of leukemia was significantly higher in rural areas (p=0.02) whereas the incidence of MM was higher in urban areas (p<0.001). Our results showed a high incidence rate of leukemia in Golestan province of Iran. The incidence of leukemia was significantly higher in males and residents of rural areas. High exposure to pesticides and other agricultural related products may be a possible explanation for epidemiological pattern of leukemia in this area. Determining and controlling important risk factors, especially environmental factors, of leukemia may lead to decrease in its burden in Golestan province of Iran.

Childhood leukemia and lymphoma: time trends and factors affecting survival in five Southern and Eastern European Cancer Registries

Within Europe, incidence and mortality rates of childhood leukemia and lymphoma are rather heterogeneous. The present study comprising data from five Southern and Eastern European Cancer Registries aims to compare time trends and examine whether sociodemographic variables, clinical parameters, and proxies of efficient care affect survival. Data spanning 1996-2010 were obtained for a total of 3,041 newly diagnosed childhood leukemia and 1,183 lymphoma cases reported by the Greek Nationwide Registry for Childhood Hematological Malignancies, Bulgarian National Cancer Registry, Moscow Region and Turkey (Antalya and Izmir) Cancer Registries. Poisson modeling for the evaluation of time trends and multivariate Cox regression analysis for the assessment of prognostic factors were performed. The incidence of leukemia was increasing in all cases, with Bulgaria and Greece presenting statistically significant annual changes (+3.5, and +1.7 %, respectively), followed by marginally increasing trends in Izmir and Moscow; by contrast, there was a remarkable, statistically significant, decreasing mortality trend for leukemia. Rates for lymphoma remained flat. Greece experienced almost twofold better survival rates for both leukemia and lymphoma, probably due to its higher socioeconomic status during the study period. Overall, patients with leukemia living in rural areas had a 28 % lower prognosis (RR: 1.28, 95 % CI 1.03-1.59), pointing to effects of remoteness, when the most privileged country (Greece) was excluded from the analysis. The favorable mortality trends highlight the progress in Southern-Eastern European countries along their trajectory to converge with Northern-Western EU counterpart states. Socioeconomic status may act as a multipotent factor underlying the study findings.

Are Incidence Rates of Adult Leukemia in the United States Significantly Associated with Birth Cohort?

Leukemia is a common cancer among U.S. adults but there are few established risk factors. If leukemia risks are substantially influenced by exposures that vary in prevalence across generations, then population incidence rates should vary significantly by birth cohort. However, prior studies have not examined leukemia birth cohort effects using contemporary data and methods. We used incidence data from the National Cancer Institute's Surveillance, Epidemiology and End Results Program from 1992 through 2009 for adults 25-84 years old and age period cohort models to estimate incidence rate ratios according to birth cohort for acute myeloid leukemia (AML), acute lymphoid leukemia (ALL), chronic myeloid leukemia (CML), and chronic lymphoid leukemia (CLL). Leukemia incidence varied significantly between birth cohorts for each major leukemia type in men and women except female AMLs; changes on the order of 1% per birth year or 20% per generation were observed. The most significant birth cohort signatures were observed for CLLs and AMLs in men, which were decreasing and increasing, respectively, in cohorts born since 1946. Our results support the hypothesis that adult leukemia risks are significantly modulated by environmental and lifestyle exposures. A number of well-established (smoking, certain chemicals, radiation) and newly recognized (obesity) leukemia risk factors are modifiable; ultimately, efforts to promote healthy lifestyles might also help reduce incidence rates of adult leukemia.

Highlights of This Issue

Worldwide, squamous cell carcinoma (SSC) represents the dominant type for cancers of the upper aero-digestive tract (UADT). Although high intake of red and processed meat is a well-established risk factor for colorectal cancer, its association to UADT SCC is not clear. Steffen and colleagues investigated this association and report that, among smokers, the intake of processed meat was positively associated with risk of UADT SCC. These results suggest that smokers could be increasing their risk for UADT SCC if they also consume large amounts of processed meat.Bladder cancer is among the five most common malignancies worldwide. In this study, Urquidi and colleagues report a urothelial cell transcriptomic signature associated with bladder cancer. Gene expression profiling was applied to urine samples from patients with known bladder disease status. The analysis resulted in a 14-gene diagnostic signature that predicts the presence of bladder cancer with high accuracy. An accurate, noninvasive bladder cancer detection assay could lead to better detection, monitoring and control.Although leukemia is common in the United States, there are few established risk factors. If risk factors vary across birth cohorts, leukemia incidence should reflect these changes. To examine the incidence rates of leukemia across to birth cohorts, Rosenberg and colleagues used data from the NCI's SEER program and report that adult leukemia incidence varied significantly across birth cohorts for most leukemia types. These results support the hypothesis that adult leukemia risks are significantly modulated by environmental and lifestyle exposures and that identifying these risk factors could help reduce incidence rates of adult leukemia.Because both mammographic breast density and endogenous sex-hormone levels are strong risk factors for breast cancer, Varghese and colleagues investigated whether these risk factors share a genetic basis. This study found no significant associations between estradiol, testosterone, or sex-hormone binding globulin levels and three different breast density measures. Thus, breast density and sex hormones can be considered independent sets of traits and used as intermediate phenotypes in the search for breast cancer susceptibility loci.

Crude and Age-Adjusted Ph+/Bcr-Abl+ Chronic Myeloid Leukemia Incidence Rate in St. Petersburg and Leningrad Region Between 2006–2011

AbstractAbstract 4432 Background:The incidence of chronic myeloid leukemia (CML), reported from some population based registries, varies significantly. CML is known as age-dependent disease, so population age structure may strongly influent on the data. For international comparisons several systems for age-standardization are using in epidemiological studies. We conducted our retrospective study to reveal differences in CML incidence rates on the basis of calculation – crude or age-adjusted according to different population standards in St. Petersburg and Leningrad region. Methods:In 2005 the database of Ph- and/or bcr-abl- positive CML patients (pts) was conducted in St. Petersburg and Leningrad region. Since then the data from all newly diagnosed CML patients were included prospectively on population basis. The database was updated at least bi-annually. The data were obtained from hematologists, as general practitioners and private physicians are not licensed to treat oncohematological disorders. The data were double checked from the list of Imatinib distribution (the only drug reimbursed for first line treatment). To calculate crude CML incidence rate we use the data of the general census of the population in Russia in 2010 (the whole population of our region is 6596434 with population in age 15 and above 5821133). For age-adjusted CML incidence rate we use three of currently existing standards: The Segi (“World”), The Scandinavian (“European”) and the WHO standard (based on world average population between 2000–2025). Results:There are 258 (242 in chronic, 9 in accelerated and 7 in blastic phases) CML adult (15 years and above) pts, registered during 2006–2011. The median age is 53 years (48,5 and 55,5 years for men and women respectively). Sokal score was evaluable in 209 pts. It is low in 37%, intermediate in 35% and high in 28% pts. The crude CML incidence rate is slightly higher in men than in women with ratio 1,2:1. Mean annual crude CML incidence rate was 0,65 per 100 000 whole population of Saint Petersburg and Leningrad region, but it was 0,74 in adult population (15 years old and above). Mean annual CML incidence rates in the same age groups were slightly higher in all three standardized systems: 0,94 in Segi, 0,84 in Scandinavian and 0,88 in WHO standard populations. CML incidence rates in all age groups are presented in the table 1. CML incidence rate was lowest in young pts. It was unexpectedly very low in senior pts.CML incidence rates nearly for all age groups were slightly higher in St. Petersburg than in the Leningrad region. The majority of pts (98%) were treated with Imatinib (93% first or second line) or other tyrosine kinase inhibitors (5% first line-in international clinical trials, 18% after Imatinib failure or intolerance). Stem cell transplantation was performed only in 8/258 (3%) pts. Only 25235 (7,5%) evaluable pts progressed from chronic to advanced phases. Only 29/258 (11%) pts dead mostly due to CML (21 CML related deaths were reported). Estimated 5 years overall survival is 91,5%. Mean annual overall CML pts death rate was 1,9% (mean annual death rate between 2006–2010 in whole population of our region was 1,6%). Mean pts accumulated very fast - annual CML prevalence increasing rate between 2005–2011 was more than 14% (Picture 1). Conclusions:CML incidence both crude and age-adjusted in our population based registry is nearly the same in young and middle age, but much lower in senior (65 years and above) pts groups in comparison with published data from other registries which probably represents peculiarities of health system rather than real incidence. In the tyrosine kinase inhibitors era CML patients death rate is very low (nearly the same as in whole population) and CML pts is accumulated very fast in our region.Tab. 1Mean annual crude and age adjusted CML incidence rate in St. Petersburg and Leningrad region between 2006–2011.Age groups (years)CML incidence rateCrudeBy Segi (“World”)By Scandinavian (“European”)By WHO world standard15–190,250,140,180,1520–240,290,320,360,3125–290,380,410,470,4130–340,700,930,790,7335–390,450,550,470,4640–440,921,010,870,9245–490,730,930,790,9250–541,021,671,191,5555–591,102,021,351,7860–641,302,081,672,2465–691,171,180,881,2070–740,962,401,602,1775–790,792,271,141,5080–840,773,541,771,9485+0,401,010,510,80 [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Reply: ‘Childhood leukaemia and socioeconomic status’

Sir, We thank you for giving us the opportunity to respond to Dr Franceschi's (2012) letter. We reported consistently higher childhood leukaemia incidence rates in more affluent communities within England and Wales in each of the three decades up to 2005, and discussed several possible explanations (Kroll et al, 2011). Dr Franceschi queries our interest in the possibility of uneven diagnosis, and suggests that it would be of interest if the effects of adjustment by maternal parity and/or maternal age could be reported. It is true that the relationship of childhood leukaemia to the socioeconomic measure used in our study (quintiles of the Carstairs deprivation index) might have been attenuated if the analysis had been adjusted by maternal parity and/or maternal age (or any other factor related to socioeconomic status). We were unable to make such adjustments because this was a study of incidence in the whole childhood population, not a case–control study, and birth records were not available for all registered cases. However, we note that, strictly, these factors are not ‘known to influence childhood leukaemia risk', as Dr Franceschi implies, but are known to be associated with it; the explanation is unknown. The study mentioned by Dr Franceschi (Dockerty et al, 2001) was included in the systematic review that we cited (Poole et al, 2006), and was therefore not discussed individually in our paper. This study differed from ours in several respects. It was a case–control study for the diagnosis period 1968–1986, restricted to children for whom birth records were available, and using a deprivation score derived from address at birth, rather than address at diagnosis. Nevertheless, with increasing deprivation there was a statistically significant decreasing trend in risk of acute lymphoblastic leukaemia, the major subtype in children (Table 5, Dockerty et al, 2001). We certainly did not mean to suggest that British paediatricians discriminate in any way in the care they provide. Rather, we suggest that recognition of leukaemia as a potential underlying cause of non-specific symptoms might be uneven: for example, in poorer communities, provision of primary care may be less generous, and parents may be younger and less well-educated. Thus, for example, under-diagnosis might contribute to the associations with maternal parity and maternal age that Dr Franceschi mentions. A further study (Kroll et al, 2012) uses clinical data to examine this possibility in detail.

Chronic myeloid leukemia incidence trends among Caucasians in the United States.

e17005 Background: Information on trend of Chronic Myeloid Leukemia (CML) incidence rate is scant. This study was conducted to evaluate the time trends of CML incidence rates among Caucasians in the U.S. Methods: We used the Surveillance, Epidemiology, and End Results (SEER) Program to extract annual age-adjusted incidence rates of CML from 1973-2008 for &lt;60yr and &gt;60yr age groups classified by gender. Trends of incidence rates were evaluated using the National Cancer Institute’s Joinpoint Regression Program (v 3.5.2). The maximum number of joinpoints used was 4. The annual percentage change (APC %) for the final selected joinpoint model for each cohort is shown in the table. Results: The annual age-adjusted CML incidence rates for 1973 vs. 2008 were 0.72/0.67, 5.67/4.47, 0.93/0.67, and 10.5/8.5 per 100,000 population for the 4 cohorts: women (&lt;60yr, &gt;60yr) and men (&lt;60yr, &gt;60yr), respectively. Among Caucasian women (&gt;60yr), the incidence rate decreased significantly from 5.58/100,000 in 2001 to 4.47/100,000 in 2008 (APC= -3.08, CI -5.8 to -0.3, p = 0.004). The incidence trend from 1973-2001 was stable for this cohort (APC=0.1, CI -0.3 to 0.5). The incidence trends among women &lt;60yr, men &lt;60yr, and men &gt;60yr were stable from 1973-2008. Conclusions: The annual age-adjusted incidence rates of chronic myeloid leukemia among older (&gt;60 year) Caucasian women has declined sharply from 2001-2008. The rate change is unexplained. It may help generate hypotheses regarding risk factors for CML. [Table: see text]

Outcomes in older adults with acute lymphoblastic leukaemia (ALL): results from the international MRC UKALL XII/ECOG2993 trial

Although the incidence rate of acute lymphoblastic leukaemia (ALL) is slightly higher in older than in younger adults, response rates to induction chemotherapy and survival rates are poorer. The contribution of disease-related versus treatment-related factors remains unclear. We analysed 100 older patients (aged 55-65years) treated on the UKALLXII/ECOG2993 trial compared with 1814 younger patients (aged 14-54years). Baseline characteristics, induction chemotherapy course, infections, drug reductions and survival outcomes were compared. There were more Philadelphia-positive (Ph+) patients in the older group (28% vs. 17%, P=0·02), and a trend towards higher combined cytogenetic risk score (46% vs. 35%, P=0·07). The complete remission rate in older patients was worse (73% vs. 93%, P<0·0001) as was 5-year overall survival (21% vs. 41%, P<0·0001) and event-free survival (EFS) (19% vs. 37%, P<0·0001). Older patients had more infections during induction (81% vs. 70%, P=0·05), and drug reductions (46% vs. 28%, P=0·0009). Among older patients, Ph+ and cytogenetic risk category as well as infection during induction predicted for worse EFS. Poorer outcomes in these patients are partly due to cytogenetic risk, but there is significant morbidity and mortality during induction chemotherapy with frequent delays and drug reductions. New approaches, including better risk stratification and use of targeted therapies, could improve treatment for these patients.

Incidence rates of leukemia in French Polynesia

It was importantto report the abnormally high incidence of this rare disease.The Hoˆtel-Dieu hospital in Paris has an agreement with theFrench Polynesian government to organize clinical, epidemio-logical and scientific support for patients suffering from hem-atological conditions. Our collaboration started in May 1985and is still continuing. The large number of leukemias led usto work with F. De Vathaire

Hiatus in Infant Acute Leukemia Incidence rates in Belarus: Adaptation-to-Low-Dose-Radiation Phenomenon?

Abstract 507The question of whether child acute leukemia (ChAL) incidence has changed as a result of Chernobyl is of great scientific and public interest. Our initial report (Nature, 1993) showed no increase in the incidence rates (IR) of ChAL in Belarus in the whole group of children (0–14 y.o.) 5 years (1986 – 1991) after accident. This data were confirmed in several European countries. As concerns infant’s AL (0–1 y.o.), Petridou et al. reported 2.6 times increase of AL in Greek infants, exposed in utero to Chernobyl radiation. No significant difference in IR was found among children aged 1 – 4 y.o. or older. All epidemiological data concerning separate analysis of infant (0–1 y.o.) ChL was concentrated on the first decade after Chernobyl and no any systematic data is available after 1996. Since 1979 the occurrence of leukemia has been documented accurately through the Registry of Blood diseases. The patients had to be inhabitants of Belarus and were grouped by age at diagnosis. AL diagnostic accuracy was confirmed by the international experts. Rates were standardized directly to the standard world population. We present the age-cohort-period analyses of IR trends of ChAL from 1979 to 2006 in Belarus. It comprised 1077 ChAL cases (0–4 y.o.). Number of cases and equivalent doses of whole body radiation exposure was tabulated by age at diagnosis and period of observation (seven pre-accident years, 1979–1985) and post-accident 7-year periods: 1986–1992, 1993–1999 and 2000–2006.During first 7 years after the accident (1986–1992) the IR of infant AL (0–1 y.o.) increased significantly – from 49 (IR=4.33) before Chernobyl to 67 cases (IR=6.36) in 1986–1992 (RR=1.47; p=0.04). Older age group (1–4 y.o.) did not show any increase in ChAL rates. Following 7-years period (1993–1999) revealed the statistically significant decrease of incidence of infant leukemia: from 49 (IR=4.33) before Chernobyl to 16 cases (IR=2.29) in 1993–1999 years (RR=0.53; p=0.024). Surprisingly, during the next 7 years (2000–2006) we found a further decrease of the incidence of infant leukemia with only 3 cases (IR=0.47) in 7 years. It is highly significant when compared with 49 cases (IR=4.33) before Chernobyl (p= 0.0000053, RR=0.11) and 67 cases (IR=6.36) appeared during first 7 years following Chernobyl accident (p < 0.0000001, RR=0.04). As concerns the older group (1–4 y.o.) we did not find any decrease of IR into the second (1993–1999) and third (2000–2006) 7-year periods.Actually we are working on the next time period (2007–2010) and new upgraded data will be presented.Long-term analysis of incidence of post-Chernobyl childhood acute leukemia permitted to discover the biphasic dynamics of infant's AL incidence rate. Significant increase into the first 7-year period followed by dramatic decrease between year +8 and year + 21. From radiological point of view it is relatively simpler to explain the increase into the first 7 years, because ionizing radiation is one of the few exposures for which the casual relationship with childhood leukemia has been established. Much more difficult to explain following after decrease in incidence rate of infant leukemia in Belarus. Can we speculate about the “adaptation-to-radiation” mechanisms? Over the past decades the growing body of data from cell cultures, experimental animals and humans suggests that low-dose ionizing radiation may have some beneficial (hormetic or adoptive) effect. Several epidemiological studies (India, China, Japan, USA) of a long-term low dose environmental irradiation are in favor of the hypothesis of radiation hormesis or adaptation. The carcinogenic effects of low dose radiation exposure may be restricted to children exposed in utero or in early infancy (0-12 months) during the first years after explosion. Following after dramatic decrease of IRs of infant leukemia might be explained by the developing of adaptive response to chronic low dose ionizing radiation exposure. The presented data may be one of the first clinical evidence concerning human ability of adaptation to long-term low dose radiation. Disclosures:No relevant conflicts of interest to declare.