Benzene and childhood acute leukemia in Oklahoma

BACKGROUND

Although childhood cancer is a leading cause of childhood mortality in the US, evidence regarding the etiology is lacking. The goal of this study was to evaluate the association between benzene, a known carcinogen, and childhood acute leukemia.

METHODS

We conducted a case-control study including cases diagnosed with acute leukemia between 1997 and 2012 (n = 307) from the Oklahoma Central Cancer Registry and controls matched on week of birth from birth certificates (n = 1013). We used conditional logistic regression to evaluate the association between benzene, measured with the 2005 National-Scale Air Toxics Assessment (NATA) at census tract of the birth residence, and childhood acute leukemia.

RESULTS

We observed no differences in benzene exposure overall between cases and controls. However, when stratified by year of birth, cases born from 2005 to 2010 had a three-fold increased unadjusted odds of elevated exposure compared to controls born in this same time period (4th Quartile OR: 3.53, 95% CI: 1.35, 9.27). Furthermore, the estimates for children with acute myeloid leukemia (AML) were stronger than those with acute lymphoid leukemia, though not statistically significant.

CONCLUSIONS

While we did not observe an association between benzene and childhood leukemia overall, our results suggest that acute leukemia is associated with increased benzene exposure among more recent births, and children with AML may have increased benzene exposure at birth. Using the NATA estimates allowed us to assess a specific pollutant at the census tract level, providing an advantage over monitor or point source data. Our study, however, cannot rule out the possibility that benzene may be a marker of other traffic-related exposures and temporal misclassification may explain the lack of an association among earlier births.

The injured heart: early cardiac effects of hematopoietic stem cell transplantation in children and young adults

We hypothesized that subclinical cardiac injury in the peri-transplant period is more frequent than currently appreciated in children and young adults. We performed echocardiographic screening on 227 consecutive patients prior to hematopoietic stem cell transplantation (HSCT), and 7, 30 and 100 days after transplant. We measured cardiac biomarkers cardiac troponin-I (cTn-I), and soluble suppressor of tumorigenicity 2 (sST2) prior to transplant, during conditioning, and days +7, +14, +28 and +49 in 26 patients. We subsequently analyzed levels of cTn-I every 48-72 h in 15 consecutive children during conditioning. Thirty-two percent (73/227) of patients had a new abnormality on echocardiogram. New left ventricular systolic dysfunction (LVSD) occurred in 6.2% of subjects and new pericardial effusion in 27.3%. Eight of 227 (3.5%) patients underwent pericardial drain placement, and 5 (2.2%) received medical therapy for clinically occult LVSD. cTn-I was elevated in 53.0% of all samples and sST2 in 38.2%. At least one sample had a detectable cTn-I in 84.6% of patients and an elevated sST2 in 76.9%. Thirteen of fifteen patients monitored frequently during condition had elevation of cTn-I. Echocardiographic and biochemical abnormalities are frequent in the peri-HSCT period. Echocardiogram does not detect all subclinical cardiac injuries that may become clinically relevant over longer periods.

Pancreatic Cancer: A Survival Analysis Study in Oklahoma

BACKGROUND

Pancreatic cancer is among the most deadly cancers. Risk factors associated with the disease include age, race, sex, smoking status, and diabetes status.

METHOD

We conducted a prospective analysis of risk factors and length of survival among pancreatic cancer patients living in Oklahoma between 1997 and 2012 (n=6,291). Kaplan-Meier survival curves were created followed by the log-rank test to compare difference in the survival time. Cox proportional hazard regression models were used to examine the strength of association through the estimated hazard ratios.

RESULTS

The median survival time of the cohort was three months. Significant risk factors for reduced survival times included age, stage at diagnosis, and year of diagnosis.

CONCLUSION

Results are in agreement with previous research findings. There have been small but noteworthy improvements in survival times for pancreatic cancer patients in Oklahoma. Length of survival during the study period was significantly associated with known risk factors such as age and stage of diagnosis.

Racial, Ethnic, and Age Differences in the Incidence and Survival of Childhood Cancer in Oklahoma, 1997-2012

While cancer is relatively rare in children under 20, it is the leading cause of disease-related death among children aged 5 to 14 years. We aimed to describe the incidence and survival of childhood cancer in Oklahoma from 1997-2012. We calculated age-adjusted incidence rates and five-year observed survival by cancer type using Oklahoma Central Cancer Registry and Surveillance, Epidemiology, and End Results program data among children diagnosed with cancer under the age of 20 from 1997-2012. The average annual age-adjusted incidence rate of childhood cancer was 168.9 per million for the US and 171.7 per million for Oklahoma. Overall, Oklahoma had lower survival from childhood cancer compared to the US (77.0% v. 80.6%). In recent years, research has been conducted on the epidemiology of childhood cancer. Little research has been done, however, on the incidence or survival of childhood cancer at state levels and none focused exclusively on Oklahoma.

Five-Year Cancer Survival Rates in Oklahoma from 1997 to 2008

INTRODUCTION

This study evaluated the five-year observed survival rates of American Indians/Alaskan Native, African American, and white cancer patients among various demographic characteristics in Oklahoma focusing on lung and bronchus, colon and rectum, female breast, and prostate for the cancer patients diagnosed between 1997 and 2008.

METHODS

The five-year observed survival rates were calculated for overall cancer and specific cancer sites, using Kaplan-Meier method with data from the Oklahoma Central Cancer Registry.

RESULTS

Overall, 51.5% patients diagnosed with cancer survived for five years. For specific sites we found: 79.2% for female breast cancer survived; 77.5% for prostate cancer; 12.9% for lung and bronchus cancer; and 49.9% for colorectal cancer.

CONCLUSIONS

The five-year observed survival rates in Oklahoma were consistent with national trends. Overall, cancer survival seems to be improving over time, but there remains disparity with the AA and AI/AN populations in contrast to whites in Oklahoma.

Traffic-related air pollution and childhood acute leukemia in Oklahoma

BACKGROUND

While many studies have evaluated the association between acute childhood leukemia and environmental factors, knowledge is limited. Ambient air pollution has been classified as a Group 1 carcinogen, but studies have not established whether traffic-related air pollution is associated with leukemia. The goal of our study was to determine if children with acute leukemia had higher odds of exposure to traffic-related air pollution at birth compared to controls.

METHODS

We conducted a case-control study using the Oklahoma Central Cancer Registry to identify cases of acute leukemia in children diagnosed before 20 years of age between 1997 and 2012 (n=307). Controls were selected from birth certificates and matched to cases on week of birth (n=1013). Using a novel satellite-based land-use regression model of nitrogen dioxide (NO2) and estimating road density based on the 2010 US Census, we evaluated the association between traffic-related air pollution and childhood leukemia using conditional logistic regression.

RESULTS

The odds of exposure to the fourth quartile of NO2 (11.19-19.89ppb) were similar in cases compared to controls after adjustment for maternal education (OR: 1.08, 95% CI: 0.75, 1.55). These estimates were stronger among children with acute myeloid leukemia (AML) than acute lymphoid leukemia, with a positive association observed among urban children with AML (4th quartile odds ratio: 5.25, 95% confidence interval: 1.09, 25.26). While we observed no significant association with road density, male cases had an elevated odds of exposure to roads at 500m from the birth residence compared to controls (OR: 1.39, 95% CI: 0.93, 2.10), which was slightly attenuated at 750m.

CONCLUSIONS

Although we observed no association overall between NO2 or road density, this was the first study to observe an elevated odds of exposure to NO2 among children with AML compared to controls suggesting further exploration of traffic-related air pollution and AML is warranted.

Patterns of Care for Localized Breast Cancer in Oklahoma, 2003-2006

Despite well-established clinical guidelines for breast cancer treatment, Standard of Care (SOC) is not universal in the U.S. The purpose of this study was to describe the extent to which patients receive guideline-based, stage-specific treatments for localized female breast cancer in Oklahoma. Data were obtained from the Oklahoma Central Cancer Registry for the period 2003-2006. We included localized, invasive female breast cancers and analyzed both treatment and demographic factors. We used the National Comprehensive Cancer Network (NCCN) treatment guidelines to determine SOC. Among women who received breast conserving surgery (BCS), we used logistic regression to evaluate factors related to SOC. In Oklahoma, 92 percent of the 4,177 localized breast cancer patients were treated with recognized SOC. In women aged ≥65 years with BCS, those ≥75 years had a lower adjusted odds of meeting SOC than did those without insurance, with comorbid conditions, or whose comorbid status was unknown. Among women aged <65 years, those with Medicare/Medicaid, Medicare only, or without insurance, along with comorbid conditions, had a lower adjusted odds of meeting SOC. Overall, 92 percent of women met SOC. Factors such as age, insurance type, and comorbid conditions were associated with meeting SOC.

Lung cancer deaths among American Indians and Alaska Natives, 1990-2009

OBJECTIVES

We examined regional differences in lung cancer among American Indians/Alaska Natives (AI/ANs) using linked data sets to minimize racial misclassification.

METHODS

On the basis of federal lung cancer incidence data for 1999 to 2009 and deaths for 1990 to 2009 linked with Indian Health Service (IHS) registration records, we calculated age-adjusted incidence and death rates for non-Hispanic AI/AN and White persons by IHS region, focusing on Contract Health Service Delivery Area (CHSDA) counties. We correlated death rates with cigarette smoking prevalence and calculated mortality-to-incidence ratios.

RESULTS

Lung cancer death rates among AI/AN persons in CHSDA counties varied across IHS regions, from 94.0 per 100,000 in the Northern Plains to 15.2 in the Southwest, reflecting the strong correlation between smoking and lung cancer. For every 100 lung cancers diagnosed, there were 6 more deaths among AI/AN persons than among White persons. Lung cancer death rates began to decline in 1997 among AI/AN men and are still increasing among AI/AN women.

CONCLUSIONS

Comparison of regional lung cancer death rates between AI/AN and White populations indicates disparities in tobacco control and prevention interventions. Efforts should be made to ensure that AI/AN persons receive equal benefit from current and emerging lung cancer prevention and control interventions.

Effects of perinatal thyroid hormone deprivation on the growth and behaviour of newborn mice

Experiments were designed to distinguish between neonatal effects due to maternal thyroxine (T4) deprivation and those due to autonomous (fetus/pup) T4 deprivation, employing mice heterozygous for the bTG-tk transgene TG66,19 which specifically directs high-level expression of herpes virus type I thymidine kinase to the thyrocytes. Heterozygous TG66.19 females were either untreated or Ganciclovir was administered to destroy their thyrocytes and so render them T4-deficient. When mated to normal males these heterozygous females are expected to produce on average 50% normal and 50% heterozygous transgenic conceptuses. Ganciclovir was administered to the dams (both untreated and Ganciclovir-pretreated) during days 14-18 of gestation. At optimum levels of in utero Ganciclovir administration the non-transgenic pups showed no discernible effect while the transgenic pups were rendered athyrocytic and completely T4-deficient. The dams pretreated with Ganciclovir are hypothyroid throughout gestation, while the dams to which Ganciclovir was administered for the first time during gestation are not expected to become hypothyroid until about the time of parturition. In this way four sets of pups were generated for purposes of comparison: hypothyroid (transgenic) and euthyroid (non-transgenic) pups born to euthyroid dams and hypothyroid and euthyroid pups born to hypothyroid (Ganciclovir-pretreated) dams. Normal growth during days 1-10 after birth was dominated by the T4 status of the dam during gestation. Growth during days 11-21 and the correct timing of eye opening and ear elevation were dominated by the autonomous T4 status of the fetus/pup. The timely development of the surface-righting reflex (relative to weight gain) was shown to require both maternal and fetus/pup T4. The development of the cliff-avoidance reflex was independent of the T4 status of both pup and dam and of pup weight. The size of the pups at birth depended primarily on a normal T4 status in the dam but surprisingly T4 deficiency in fetuses/pups partly compensated for maternal T4 deficiency. The results presented here clearly demonstrate the utility of the HSV-tk-transgene-Ganciclovir-administration protocol in studying the interplay of maternal and fetal T4 deprivation in rodents.