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Objective: to characterize the county variability of the impact of smoking elimination on rates of smoking-related cancers and explore whether common environmental indices predicted which metropolitan counties would experience high rates of smoking-related cancers even after smoking was eliminated., Methods: Surveillance, Epidemiology, and End Results Program (SEER) and Environmental Protection Agency (EPA) data were obtained. County level cancer rates for 257 metropolitan SEER counties, including the observed rates and those predicted after eliminating smoking, were derived via multilevel regression modeling and age standardized to the 2016 SEER population. Associations between the EPA's Environmental Quality Index (EQI) scores and "Low Benefit" counties (counties that remain above the top 20th percentile of post-smoking elimination incidence rates) were explored via logistic regression., Results: Reductions in smoking-related cancer incidence ranged from 58.4 to 3.2%. The overall EQI (OR = 1.96, 95% CI [1.34, 2.86]) and the air quality index (OR = 5.99, 95% CI [3.20, 11.22]) scores predicted higher odds of being a "Low Benefit" county., Conclusions: Substantial inequities in the post-smoking elimination cancer rates were observed; air pollution appears to be a primary explanation for this. Cancer prevention in metropolitan counties with high levels of air pollution should prioritize pollution control at least as much as tobacco control.

Background: Debates over the importance of "lifestyle" versus "environment" contributions to cancer have been going on for over 40 years. While it is clear that cigarette smoking is the most significant cancer risk factor, the contributions of occupational and environmental carcinogens in air, water and food remain controversial. In practice, most cancer prevention messaging focuses on reducing cigarette smoking and changing other personal behaviors with little mention of environmental chemicals, despite widespread exposure to many known carcinogens. To inform decision-making on cancer prevention priorities, we evaluated the potential impact of smoking cessation on cancer rates., Methods: Using cancer incidence data from 612 counties in the SEER database, and county-level smoking prevalences, we investigated the impact of smoking cessation on incidence for 12 smoking-related cancer types, 2006-2016. A multilevel mixed-effects regression model quantified the association between county-level smoking prevalence and cancer incidence, adjusting for age, gender and variability over time and among counties. We simulated complete smoking cessation and estimated the effects on county-level cancer rates., Results: Regression models showed the expected strong association between smoking prevalence and cancer incidence. Simulating complete smoking cessation, the incidence of the 12 smoking-related cancer types fell by 39.8% (54.9% for airways cancers; 28.9% for non-airways cancers). And, while the actual rates of smoking-related cancers from 2006 to 2016 declined (annual percent change (APC) = - 0.8, 95% CI = - 1.0 to - 0.5%), under the scenario of smoking elimination, the trend in cancer incidence at these sites was not declining (APC = - 0.1, 95% CI = - 0.4 to + 0.1%). Not all counties were predicted to benefit equally from smoking elimination, and cancer rates would fall less than 10% in some counties., Conclusions: Smoking prevention has produced dramatic reductions in cancer in the US for 12 major types. However, we estimate that eliminating smoking completely would not affect about 60% of cancer cases of the 12 smoking-related types, leaving no improvement in the incidence trend from 2006 to 2016. We conclude that cancer prevention strategies should focus not only on lifestyle changes but also the likely contributions of the full range of risk factors, including environmental/occupational carcinogens.

The Monographs produced by the International Agency for Research on Cancer (IARC) apply rigorous procedures for the scientific review and evaluation of carcinogenic hazards by independent experts. The Preamble to the IARC Monographs, which outlines these procedures, was updated in 2019, following recommendations of a 2018 expert advisory group. This article presents the key features of the updated Preamble, a major milestone that will enable IARC to take advantage of recent scientific and procedural advances made during the 12 years since the last Preamble amendments. The updated Preamble formalizes important developments already being pioneered in the Monographs program. These developments were taken forward in a clarified and strengthened process for identifying, reviewing, evaluating, and integrating evidence to identify causes of human cancer. The advancements adopted include the strengthening of systematic review methodologies; greater emphasis on mechanistic evidence, based on key characteristics of carcinogens; greater consideration of quality and informativeness in the critical evaluation of epidemiological studies, including their exposure assessment methods; improved harmonization of evaluation criteria for the different evidence streams; and a single-step process of integrating evidence on cancer in humans, cancer in experimental animals, and mechanisms for reaching overall evaluations. In all, the updated Preamble underpins a stronger and more transparent method for the identification of carcinogenic hazards, the essential first step in cancer prevention., (© The Author(s) 2019. Published by Oxford University Press.)

Purpose: We conducted external comparisons for the prevalence of asthma, hypertension, diabetes, and cancer among World Trade Center (WTC) general responders using the National Health Interview Survey (NHIS) as the reference, along with internal comparisons for the incidence of asthma., Methods: Standardized Morbidity Ratios (SMRs) were calculated for the prevalence of the health conditions, and risk ratios (RRs) for asthma incidence., Results: Relative to the NHIS, asthma prevalence was in excess in responders over the study years (age-adjusted SMRs = 1.3-2.8). Hypertension prevalence began to exceed expected from 2006 while diabetes was lower than expected. An upward trend towards excess cancer prevalence was observed. Internal comparisons showed elevated asthma incidence among protective service and utility workers compared to construction workers; while those who arrived at the WTC site in the morning of 9/11 had a lower asthma risk than those who arrived in the afternoon., Conclusions: The use of NHIS data as a reference population demonstrates and reconfirms several important patterns of excess risk in WTC responders. External comparisons are an alternative for disaster cohorts without an established comparison group., (© 2018 Wiley Periodicals, Inc.)

Cancer incidence is rising among adolescents ("teens"). The causes of the increase are unknown but studying incidence patterns and trends may produce insights into etiology. Using data from the US National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program we described trends of cancer incidence among teens (15-19 year olds). We reviewed and summarized incidence patterns for histologic cancer groups and the most frequently diagnosed sites of cancer among teens during 2008-2012 reported by the SEER Cancer Statistics Review. We calculated annual incidence rates for the years 1975-2012 and used linear regression analysis to evaluate trends and calculate rates of change. Incidence for all sites combined increased annually by 0.67% for males and 0.62% for females during the period 1975 through 2012 -resulting in more than a 25% increase over 38 years. The biggest annual incidence increases occurred in non-Hodgkin lymphoma (NHL) (2.16% females; 1.38% males), thyroid cancer (2.12% females; 1.59% males), acute myeloid leukemia (AML) (1.73% females) and testicular cancer (1.55% males). Incidence rates for most histologic groups and sites showed steady long term increases over the 38 years of data. Despite improvements in survival, rising incidence trends mean growing numbers of young adults are undergoing painful and costly cancer treatments. A concerted research program is vital to investigate causes of steadily rising teen cancer rates.

This article summarizes the evidence for environmental toxic exposures contributing to cancers in early life, focusing on the most common cancer sites in this age group. It provides examples of widespread avoidable exposures to human carcinogens through air, water, and food and then describes recent examples of successful initiatives to reduce exposure to chemicals linked to these cancer sites, through government policy, industry initiatives, and consumer activism. State government initiatives to reduce toxic chemical exposures have made important gains; the Toxics Use Reduction Act of Massachusetts is now 25 years old and has been a major success story. There are a growing number of corporate initiatives to eliminate toxics, especially carcinogens, from the products they manufacture and sell. Another important opportunity for cancer prevention is provided by online databases that list chemicals, their toxicity, and lower-toxicity alternatives; these can be used by businesses, health care institutions, consumers, and workers to reduce exposures to chemicals of concern. The article concludes by inviting pediatricians and public health professionals to include elimination of carcinogen exposures in their work to promote primary prevention of cancer in early life., (Copyright © 2016 by the American Academy of Pediatrics.)

Background: Firefighters are known to be exposed to recognized or probable carcinogens. Previous studies have found elevated risks of several types of cancers in firefighters., Methods: Standardized morbidity odds ratio (SMORs) were used to evaluate the cancer risk in white, male firefighters compared to police and all other occupations in the Massachusetts Cancer Registry from 1986 to 2003. Firefighters and police were identified by text search of the usual occupation field. All other occupations included cases with identifiable usual occupations not police or firefighter. Control cancers were those not associated with firefighters in previous studies., Results: Risks were moderately elevated among firefighters for colon cancer (SMOR = 1.36, 95% CI: 1.04-1.79), and brain cancer (SMOR = 1.90, 95% CI: 1.10-3.26). Weaker evidence of increased risk was observed for bladder cancer (SMOR = 1.22, 95% CI: 0.89-1.69), kidney cancer (SMOR = 1.34, 95% CI: 0.90-2.01), and Hodgkin's lymphoma (SMOR = 1.81, 95% CI: 0.72-4.53)., Conclusions: These findings are compatible with previous reports, adding to the evidence that firefighters are at increased risk of a number of types of cancer., ((c) 2008 Wiley-Liss, Inc.)

Background: Uncontrolled confounding by personal exposures like smoking can limit the inferential power of occupational cohort studies. We developed and demonstrate a refinement of an existing type of sensitivity analysis, indirect adjustment, for evaluating the potential magnitude of confounding by alcohol and tobacco. Results of a large retrospective cohort study of laryngeal cancer and exposure to metalworking fluids (MWF) are used to illustrate the methods., Methods: Data on smoking and drinking habits representative of the study cohort were obtained from a sample of US manufacturing workers from the 1977 National Health Interview Survey (NHIS). Two different mechanisms were assumed to affect the distribution of confounding factors between MWF exposure groups: socially determined and chance differences. Chance variation was investigated with Monte Carlo sampling from the NHIS survey distribution of smoking and drinking. An upper bound on systematic differences in smoking and drinking was set by assuming that differences between exposure groups within the same unionized blue collar workforce were very unlikely to be larger than differences between blue and white collar manufacturing workers in the NHIS data., Results: Under plausibly large differences in smoking and drinking habits among MWF exposure groups occurring by either mechanism, the exposure-risk association was unlikely to have been over- or under-estimated by as much as 20%., Conclusions: When comparing exposure groups within the same working population, it is unlikely that either systematic or chance differences in smoking and drinking habits will cause as much as a 20% change in the relative risk in large studies. While this study focused on an occupational exposure and laryngeal cancer, there are many situations in which epidemiologists are concerned that unmeasured 'lifestyle factors' may differ among exposure groups, and it would appear that the likely confounding effect of such differences will often be modest.

BackgroundRecently, the International Agency for Research on Cancer (IARC) Programme for the Evaluation of Carcinogenic Risks to Humans has been criticized for several of its evaluations, and also for the approach used to perform these evaluations. Some critics have claimed that failures of IARC Working Groups to recognize study weaknesses and biases of Working Group members have led to inappropriate classification of a number of agents as carcinogenic to humans.ObjectivesThe authors of this Commentary are scientists from various disciplines relevant to the identification and hazard evaluation of human carcinogens. We examined criticisms of the IARC classification process to determine the validity of these concerns. Here, we present the results of that examination, review the history of IARC evaluations, and describe how the IARC evaluations are performed.DiscussionWe concluded that these recent criticisms are unconvincing. The procedures employed by IARC to assemble Working Groups of scientists from the various disciplines and the techniques followed to review the literature and perform hazard assessment of various agents provide a balanced evaluation and an appropriate indication of the weight of the evidence. Some disagreement by individual scientists to some evaluations is not evidence of process failure. The review process has been modified over time and will undoubtedly be altered in the future to improve the process. Any process can in theory be improved, and we would support continued review and improvement of the IARC processes. This does not mean, however, that the current procedures are flawed.ConclusionsThe IARC Monographs have made, and continue to make, major contributions to the scientific underpinning for societal actions to improve the public's health.