Are incidence rates of adult leukemia in the United States significantly associated with birth cohort?

Trends in Oral Tongue Cancer Incidence in the US

Importance

Oral tongue cancer (OTC) incidence has increased rapidly among young (<50 years) non-Hispanic White individuals in the US during the past 2 decades; however, it is unknown if age-associated trajectories have persisted.

Objective

To examine US trends in OTC incidence and project future case burden.

Design, Setting, and Participants

This cross-sectional analysis of OTC incidence trends used the US Cancer Statistics Public Use Database, which covers approximately 98% of the US population, and included individuals with an OTC diagnosis reported to US cancer registries between January 1, 2001, and December 31, 2019.

Exposures

Sex, race and ethnicity, and age.

Main Outcomes and Measures

Estimated average annual percentage change in OTC incidence from 2001 to 2019. Given the substantial incidence rate increases among non-Hispanic White individuals compared with those of racial and ethnic minority groups, subsequent analyses were restricted to non-Hispanic White individuals. Forecasted OTC incidence trends and case burden among non-Hispanic White individuals to 2034.

Results

There were 58 661 new cases of OTC identified between 2001 and 2019. Male individuals (57.6%), non-Hispanic White individuals (83.7%), those aged 60 years or older (58.0%), and individuals with localized stage disease at diagnosis (62.7%) comprised most cases. OTC incidence increased across all age, sex, and racial and ethnic groups, with marked increases observed among non-Hispanic White individuals (2.9% per year; 95% CI, 2.2%-3.7%). Increases among female individuals aged 50 to 59 years were most notable and significantly outpaced increases among younger non-Hispanic White female individuals (4.8% per year [95% CI, 4.1%-5.4%] vs 3.3% per year [95% CI, 2.7%-3.8%]). While all non-Hispanic White birth cohorts from 1925 to 1980 saw sustained increases, rates stabilized among female individuals born after 1980. Should trends continue, the burden of new OTC cases among non-Hispanic White individuals in the US is projected to shift more toward older individuals (from 33.1% to 49.3% among individuals aged 70 years or older) and female individuals (86% case increase vs 62% among male individuals).

Conclusions and Relevance

The results of this cross-sectional study suggest that the period of rapidly increasing OTC incidence among younger non-Hispanic White female individuals in the US is tempering and giving way to greater increases among older female individuals, suggesting a birth cohort effect may have been associated with previously observed trends. Recent increases among non-Hispanic White individuals 50 years or older of both sexes have matched or outpaced younger age groups. Continuing increases among older individuals, particularly female individuals, may be associated with a shift in the OTC patient profile over time.

Secular trend in disease burden of leukemia and its subtypes in China from 1990 to 2019 and its projection in 25 years

Leukemia and its subtypes impose a major public health challenge in China. Identifying the secular trend of leukemia burden is critical to facilitate optimal healthcare planning and improve the management of leukemia. The incidence rates of leukemia from 1990 to 2019 were collected from the Global Burden of Disease Study 2019 database according to the following: subtype (acute lymphocytic leukemia [ALL], acute myeloid leukemia [AML], chronic lymphocytic leukemia [CLL], chronic myelogenous leukemia [CML], and other leukemia subtypes), sex, and age group. The average annual percentage changes and relative risks were calculated using joinpoint regression and the age-period-cohort model, respectively. The Bayesian age-period-cohort model was also applied to predict the future trend of the incidence of leukemia and its subtypes in the next 25 years. From 1990 to 2019, the age-standardized incidence rates (ASIRs) of leukemia slightly declined in males and females, which is similar to the trend of other leukemia subtypes. However, the four major leukemia subtypes, namely, ALL, AML, CLL, and CML, have been on the rise over the past three decades. The incidence rates of leukemia in children and the elderly were considerably higher than those in other age groups in males and females. Age effects were the most influential risk factor for leukemia incidence. Period effects showed that the risks of leukemia and its subtypes incidence increased with time. For cohort effects, the risks of leukemia and its subtypes were higher among the early-born cohorts compared with the late-born cohorts. The ASIRs of leukemia and its subtypes will continue to increase in the next 25 years. The burden of leukemia and its subtypes is expected to continue to increase in the next 25 years in males and females. A comprehensive understanding of the risk characteristics and disease pattern of leukemia and its subtypes is needed to formulate timely and effective intervention measures to reduce the leukemia burden in China.

Exposure to outdoor air pollution at different periods and the risk of leukemia: a meta-analysis

The causes of leukemia remain largely unknown; our aims were to examine the association between the exposure to outdoor air pollution and leukemia risk and to explore the effect of this exposure during different periods of pregnancy and early life. We searched for all case-control and cohort studies published before February 20, 2021, which measured the risk of leukemia in relation to exposure to the air pollutants: particulate matter, benzene, nitrogen dioxide (NO₂), and nitrogen oxides (NO_x). We then carried out a meta-analysis and calculated the summary relative risks (RRs) of leukemia by using a random-effects model. The potential dose-response relationship was further explored. The results showed that the highest exposure to benzene (RR: 1.20, 95%CI: 1.06-1.35) and NO₂ (RR: 1.04, 95%CI; 1.02-1.08) were positively correlated with leukemia risk when compared to the lowest exposure categories for each air pollutant. During pregnancy, exposure to benzene in the third trimester, as well as exposure to NO₂ in the second trimester and entire pregnancy, could also increase the risk of leukemia. In the dose-response analysis, benzene exposure and NO₂ exposure were linearly associated with the risk of leukemia. Other air pollutants did not have a statistical correlation with leukemia risk. There was a certain degree of publication bias in studies on benzene. Overall, our results support a link between outdoor air pollution and leukemia risk, particularly due to benzene and NO₂. Prospero Registration Number: PROSPERO CRD42020207025.

Mortality and cancer incidence among underground uranium miners in the Czech Republic 1977-1992

OBJECTIVES

Uranium miners in Příbram, Czech Republic were exposed to low and moderate levels of radon gas and other hazards. It is unknown whether these hazards increase the risk of mortality or cancer incidence when compared with the general Czech population.

METHODS

A cohort of 16 434 male underground miners employed underground for at least 1 year between 1946 and 1976, and alive and residing in the Czech Republic in 1977, were followed for mortality and cancer incidence through 1992. We compared observed deaths and cancer incidence to expectation based on Czech rates. Standardised mortality ratios (SMRs), standardised incidence ratios (SIRs) and causal mortality ratios were calculated.

RESULTS

Underground workers in the Příbram mines had higher rates of death than expected due to all causes (SMR=1.23, 95% CI 1.20 to 1.27), all cancers (SMR=1.52, 95% CI 1.44 to 1.60), lung cancer (SMR=2.12, 95% CI 1.96 to 2.28) and extrathoracic cancer (SMR=1.41, 95% CI 1.15 to 1.77). Similar excess was observed in cancer incidence analyses, with the addition of stomach cancer (SIR=1.37, 95% CI 1.11 to 1.63), liver cancer (SIR=1.70, 95% CI 1.16 to 2.25) and rectal cancer (SIR=1.41, 95% CI 1.16 to 1.66). The SIR was elevated for all leukaemias (SIR=1.51, 95% CI 1.08 to 2.07) and for lymphatic and haematopoietic cancers combined (SIR=1.31, 95% CI 1.05 to 1.61), but results for specific subtypes were imprecise. Deaths due to hazardous mining conditions resulted in 0.33 person-years of life lost per miner.

CONCLUSIONS

Occupational exposure to the Příbram mines resulted in excess cancers at several sites, including sites previously linked to radon and uranium exposure. Incidence analyses showed relative excess of several additional cancer subtypes.

Use of age-period-cohort analysis in cancer epidemiology research

PURPOSE OF REVIEW

Age-period-cohort (APC) models simultaneously estimate the effects of age - biological process of aging; time period - secular trends that occur in all ages simultaneously; and birth cohort - variation among those born around the same year or from one generation to the next. APC models inform understanding of cancer etiology, natural history, and disparities. We reviewed findings from recent studies (published 2008-2018) examining age, period, and cohort effects and summarized trends in age-standardized rates and age-specific rates by birth cohort. We also described prevalence of cancer risk factors by time period and birth cohort, including obesity, current smoking, human papilloma virus (HPV), and hepatitis C virus (HCV).

RECENT FINDINGS

Studies (n=29) used a variety of descriptive analyses and statistical models to document age, period, and cohort trends in cancer-related outcomes. Cohort effects predominated, particularly in breast, bladder, and colorectal cancers, whereas period effects were more variable. No effect of time period was observed in studies of breast, bladder, and oral cavity cancers. Age-specific prevalence of obesity, current smoking, HPV, and HCV also varied by birth cohort, which generally paralleled cancer incidence and mortality rates.

SUMMARY

We observed strong cohort effects across multiple cancer types and less consistent evidence supporting the effect of time period. Birth cohort effects point to exposures early in life - or accumulated across the life course - that increase risk of cancer. Birth cohort effects also illustrate the importance of reconsidering the timing and duration of well-established risk factors to identify periods of exposure conferring the greatest risk.

Gli-1/PI3K/AKT/NF-kB pathway mediates resistance to radiation and is a target for reversion of responses in refractory acute myeloid leukemia cells

Total body irradiation combined with chemotherapy is currently the most effective procedure as a preparative myeloablative regimen. However, resistance to radiotherapy and chemotherapy in refractory acute myeloid leukemia is associated with short-time recurrence after allogeneic hematopoietic stem cell transplantation. To address this issue, we used three cell lines, HL60, HL60/ADR (adriamycin-resistant cells), and HL60/RX (a radiation-resistant cell line established from HL60 cells), as cellular models to investigate the mechanism of the Hedgehog (Hh) signaling pathway resulting in radioresistance, and the efficacy of LDE225 (an inhibitor of the Hh pathway) to enhance radiation sensitivity. Our results indicated that HL60/RX and HL60/ADR cells showed an increased in radioresistance and elevated activity of Hh pathway proteins compared with HL60 cells (P<0.001). In addition, LDE225 significantly reduced clonogenic survival with a sensitivity enhancement ratio (SER) of 1.283 for HL60/ADR and 1.245 for HL60/RX cells. The combination of LDE225 with irradiation significantly increased radiation-induced apoptosis and expression of γ-H2AX and BAK compared with single-treatment groups in both HL60/RX and HL60/ADR cells (P<0.001). In vivo, the combination of LDE225 with irradiation exerted a significant antitumor effect compared with the control and single agents in HL60/RX- and HL60/ADR-xenografted mouse models (P<0.001). Furthermore, our data obtained from western blot and IHC analyses showed that the activation of pAKT and NF-kB was reduced by LDE225 treatment in both HL60/ADR and HL60/RX cells. This demonstrates that the Gli-1/PI3K/AKT/NF-kB pathway plays a key role in resistance to radiation, and that inhibition of the Hh pathway sensitizes cells to radiation by overcoming radioresistance.

A web tool for age-period-cohort analysis of cancer incidence and mortality rates

BACKGROUND

Age-period-cohort (APC) analysis can inform registry-based studies of cancer incidence and mortality, but concerns about statistical identifiability and interpretability, as well as the learning curves of statistical software packages, have limited its uptake.

METHODS

We implemented a panel of easy-to-interpret estimable APC functions and corresponding Wald tests in R code that can be accessed through a user-friendly Web tool.

RESULTS

Input data for the Web tool consist of age-specific numbers of events and person-years over time, in the form of a rate matrix of paired columns. Output functions include model-based estimators of cross-sectional and longitudinal age-specific rates, period and cohort rate ratios that incorporate the overall annual percentage change (net drift), and estimators of the age-specific annual percentage change (local drifts). The Web tool includes built-in examples for teaching and demonstration. User data can be input from a Microsoft Excel worksheet or by uploading a comma-separated-value file. Model outputs can be saved in a variety of formats, including R and Excel.

CONCLUSIONS

APC methodology can now be carried out through a freely available user-friendly Web tool. The tool can be accessed at http://analysistools.nci.nih.gov/apc/.

IMPACT

The Web tool can help cancer surveillance researchers make important discoveries about emerging cancer trends and patterns.

Pancreatic cancer death rates by race among US men and women, 1970-2009

BACKGROUND

Few studies have examined trends in pancreatic cancer death rates in the United States, and there have been no studies examining recent trends using age-period-cohort analysis.

METHODS

Annual percentage change in pancreatic cancer death rates was calculated for 1970 to 2009 by sex and race among adults aged 35 to 84 years using US mortality data provided by the National Center for Health Statistics and Joinpoint Regression. Age-period-cohort modeling was performed to evaluate the changes in cohort and period effects. All statistical tests were two-sided.

RESULTS

In white men, pancreatic cancer death rates decreased by 0.7% per year from 1970 to 1995 and then increased by 0.4% per year through 2009. Among white women, rates increased slightly from 1970 to 1984, stabilized until the late 1990s, then increased by 0.5% per year through 2009. In contrast, the rates among blacks increased between 1970 and the late 1980s (women) or early 1990s (men) and then decreased thereafter. Age-period-cohort analysis showed that pancreatic cancer death risk was highest for the 1900 to 1910 birth cohort in men and the 1920 to 1930 birth cohort in women and there was a statistically significant increase in period effects since the late 1990s in both white men and white women (two-sided Wald test, P < .001).

CONCLUSIONS

In the United States, whites and blacks experienced opposite trends in pancreatic cancer death rates between 1970 and 2009 that are largely unexplainable by known risk factors. This study underscores the needs for urgent action to curb the increasing trends of pancreatic cancer in whites and for better understanding of the etiology of this disease.