Risk of squamous cell carcinoma and adenocarcinoma of the lung in relation to lifetime filter cigarette smoking

Comparative study of lung cancer between smokers and nonsmokers: A real-world study based on the whole population from Tianjin City, China

INTRODUCTION

The purpose of this study was to examine the prevalence, clinical characteristics, and changing trends of non-smokers with lung cancer (LC) based on data from a population-wide cancer registry in northern China.

METHODS

The study used LC incidence and follow-up data from 2010 to 2019 from the Cancer Registry System of Tianjin city, which included 82769 cases. Trends in the incidence and proportion of non-smokers with LC were examined by joinpoint regression analysis. Life table and Cox survival analyses were used to calculate the survival rates and compare the death hazard ratios (HRs) in different groups, respectively.

RESULTS

Among the 82769 new diagnosis cases of LC during 2010 to 2019, there were 34589 (41.8%) current smokers, 14913 (18.0%) ex-smokers, 28123 (34.0%) non-smokers, and 5144 (6.2%) unknowns. The proportion of non-smokers changed slightly from 2010 (35.36%) to 2019 (36.87%) (annual percentage change, APC= -0.01%, p>0.05). This proportion declined in men (2010 vs 2019; 22.06% vs 20.66%) and increased in women (2010 vs 2019; 53.02% vs 62.35%), and in the 0-44 years age group it showed an upward trend from 2015 to 2019 (APC=4.82%, 95% CI: 1.8-7.9). Compared with smokers with LC, non-smokers with LC were predominantly females (64.15% vs 27.26%), had a predominantly adenocarcinoma histological subtypes (76.71% vs 42.22%), and had a 20% lower risk of death than smokers (HR=0.80; 95% CI: 0.78-0.81).

CONCLUSIONS

The proportion of non-smokers with LC was relatively high in northern China, with an increasing trend in the proportion of females and younger age groups. Non-smokers with LC had different epidemiological and clinical characteristics compared with smokers with LC.

Changing smoking habits and the occurrence of lung cancer in Sweden-a population analysis

BACKGROUND

The objective is to estimate the importance of the decrease of smoking habits in Sweden for the occurrence of lung cancer.

METHODS

The change in smoking habits in the general population was retrieved from surveys and on taxation of sale of cigarettes. We used data from the Swedish Cancer Register on incidence of lung cancer between 1970 and 2021, stratified for sex, age and cell type, and compared the occurrence overtime in ages between 40 and 84 years.

RESULTS

The sale of cigarettes peaked in 1980 to 1800 cigarettes per person and decreased to 600 per person in 2021. The change in incidence rates of squamous cell cancer and other cell types varied over time, sex, and age in a pattern that partly seems to be explained by change in the prevalence of daily smokers. The incidence of adenocarcinoma was similar in men and women 1970-2021 and increased, e.g. for women and men 75-79 years of age from around 20 cases in early 1970s to around 120 cases per 100 000 person-years in the 2020s.

CONCLUSIONS

Our data indicate that the risk of lung cancer several years after smoking cessation is less favourable than previously studies have indicated. There is a similar increase in the incidence of adenocarcinoma in men and women which is hard to explain only with changing smoking habits. The change from non-filter to filter cigarettes in the 1960s-1970s may be a contributing factor.

Three-dimensional analysis reveals a high incidence of lung adenocarcinoma in the upper region

PURPOSE

The lung is a unique organ with a ventilation-perfusion mismatch, which can cause inhomogeneous incidence rates of lung cancer depending on the location in the lung. We aimed to evaluate the incidence of lung adenocarcinoma in each lobe by analyzing the incidence per unit volume, to evaluate the incidence without being affected by differences in the size of each lobe or in the size of the lungs between individuals.

METHODS

The number of adenocarcinomas in each lobe was counted. Lung volumes were measured using a three-dimensional computer workstation. The tumor incidence per unit volume was analyzed based on the number of tumors in each lobe.

RESULTS

The number of tumors per unit volume was 0.467 in the right upper lobe (RUL), 0.182 in the right middle lobe, 0.209 in the right lower lobe, 0.306 in the left upper segment (LUS), 0.083 in the left lingular segment, and 0.169 in the left lower lobe. The tumor incidence rate of RUL + LUS was 2.269 times that of the other lobes, a value that was significantly higher when using the bootstrap method (p < 0.001).

CONCLUSIONS

The incidence of adenocarcinoma per unit volume in both upper lobes was higher than that in other lobes.

Protecting public health and the environment: towards a general ban on cellulose acetate cigarette filters in the European Union

After the establishment of a causal relationship between tobacco use and cancer in the 1950s, cellulose acetate filters were introduced with the claim to reduce the adverse health impact of unfiltered cigarettes. Often perceived to be more pleasant and healthy, filters encouraged smoking. However, filtered cigarettes are more deeply inhaled to obtain the same nicotine demand while altered combustion releases more tobacco-specific nitrosamines. The increasing use of cigarette filter ventilation is associated with a sharp rise in lung adenocarcinomas in recent decades. While not preventing adverse health effects, a global environmental problem has been created due to the non-biodegradable filter litter, causing ecotoxicological effects and the spread of microplastics. Recently, the Belgian Superior Health Council advised policymakers to ban cigarette filters as single-use plastics at both national and European levels. This article outlines the arguments used to justify this plea (human health and environment), the expected effects of a filter ban, as well as the public reception and reactions of the tobacco industry. The specific context of the European Union is discussed including the revision of the Single-Use Plastics Directive, affording a new opportunity to ban plastic filters. This perspective article aims to fuel the momentum and cooperation among member states for this purpose.

The Effectiveness of Bisphosphonate to Reduce Pain in Lung Cancer Patients with Bone Metastasis

Background: Bisphosphonates (BPs) are commonly used as supportive therapy to prevent skeletal-related events in lung cancer patients with bone metastasis, including severe bone pain, hypercalcemia, and pathological fractures. The purpose of this study was to assess the effectiveness of bisphosphonate therapy to reduce pain in non-small cell lung cancer (NSCLC) patients with bone metastasis.  Methods: This was a cross-sectional study carried on 38 patients diagnosed with lung cancer based on cytology or histopathology findings. Radiological examination such as thoracic CT scan, bone survey, and bone scan was performed to determine bone metastasis. Multimodality therapy is carried out for lung cancer palliative therapy including chemotherapy, radiotherapy, and bisphosphonate therapy (zoledronic acid and ibandronate) as supportive therapy to reducing cancer pain. Pain was assessed using the Visual Analog Scale (VAS) determined by patients themselves. Statistical tests were performed by paired T-test in which p< 0.05 was considered significant.  Results: As many as 38 patients enrolled in this study consisting of 29 men (76.3%) and 9 women (23.7%). The subtype of adenocarcinoma was mostly found in 31 cases (81.58%) and 7 cases (18.42%) was Squamous Cell Carcinoma. Cancer pain was found in all patients. Measurement of pain prior to treatment showed that most patients had VAS level of 7-10. After bisphosphonate therapy, the VAS level significantly decreased to 1-3 (p<0.01).  Conclusion: Bisphosphonate therapy was proven to effectively decrease the severity level of cancer pain in lung cancer patients with bone metastasis.

Risk of lung cancer among women in relation to lifetime history of tobacco smoking: a population-based case-control study in France (the WELCA study)

Background

This study aims to provide new insights on the role of smoking patterns and cigarette dependence in female lung cancer, and to examine differences by histological subtype.

Methods

We conducted a population-based case-control study in the great Paris area among women including 716 incident cases diagnosed between 2014 and 2017 and 757 age-matched controls. Detailed data on smoking history was collected during in-person interviews to assess intensity and duration of tobacco smoking, time since cessation, smoking habits (depth of smoke inhalation, use of filter, type of tobacco, and type of cigarettes) and Fagerström test for cigarette dependence. The comprehensive smoking index (CSI), a score modelling the combined effects of intensity, duration and time since quitting smoking was determined for each subject. Multivariable logistic regression models were fitted to calculate odds ratios (ORs) and their confidence intervals (95%CI) of lung cancer associated with smoking variables.

Results

Lung cancer risk increased linearly with intensity and duration of tobacco smoking while it decreased with time since cessation, to reach the risk in never-smokers after 20 years of abstinence. The combined effect of intensity and duration of tobacco smoking was more than multiplicative (p-interaction 0.012). The OR in the highest vs the lowest quartile of CSI was 12.64 (95%CI 8.50; 18.80) (p-trend < 0.001). The risk of small cell or squamous cell carcinomas increased with the CSI more sharply than the risk of adenocarcinomas. Deep smoke inhalation, dark vs blond tobacco, conventional vs light cigarettes, and unfiltered vs filtered cigarettes, as well as having mixed smoking habits, were found to be independent risk factors. Having high cigarette addiction behaviours also increased the risk after adjusting for CSI.

Conclusion

This study provides additional insights on the effects of tobacco smoking patterns on lung cancer risk among women.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08433-z.

Smokers' awareness of filter ventilation, and how they believe it affects them: findings from the ITC Four Country Survey

BACKGROUND

Filter ventilation creates sensations of 'lightness' or 'smoothness' and is also highly effective for controlling machine-tested yields of tar, nicotine and carbon monoxide. Nearly all factory-made cigarettes (FMC) now have filter ventilation in countries such as Australia, Canada, the UK and the USA. Research conducted before 'light' and 'mild' labelling was banned found low smoker awareness of filter ventilation and its effects. This study explores current levels of awareness of filter ventilation and current understanding of its effects in these four countries.

METHODS

We used data from the 2018 wave of the ITC Four Country Smoking and Vaping Survey with samples from USA, England, Canada and Australia. Analyses were conducted initially on a weighted sample of 11 844, and subsequently on 7541 daily FMC smokers.

FINDINGS

Only 40.3% of all respondents reported being aware of filter ventilation. Among daily FMC smokers, only 9.4% believed their cigarettes had filter ventilation. Believing that their usual cigarettes are smoother was positively associated with believing they are also less harmful. Both these beliefs independently predict believing their cigarettes are ventilated (smoother OR=1.97 (95% CI 1.50 to 2.59) and less harmful OR=2.41 (95% CI 1.66 to 3.49) in relation to those believing each characteristic is average.

INTERPRETATION

Awareness of filter ventilation is currently low, despite decades of public 'education efforts around the misleading nature of 'light' and 'mild" descriptors. Few smokers realise that their cigarettes almost certainly are vented. Smokers who believed their cigarettes have filter ventilation were more likely to believe they were both smoother and less harmful. Awareness of the technology appears to be insufficient to prevent smokers being deceived by it. Filter ventilation is inherently misleading to smokers and it is time to ban it.

Characteristics and health effects of potentially pathogenic bacterial aerosols from a municipal solid waste landfill site in Hamadan, Iran

The aim of this study was to evaluate the potential pathogenic bacterial aerosols produced from the municipal solid waste landfill site and its health risk assessment in the Hamadan city at west of Iran. In this study, air samples were collected every month during spring and summer at six locations including the active zone, leachate collection pond, infectious waste landfill, upwind, closure landfill, and downwind using the Andersen impactor. Spatial and seasonal variations of the potential pathogenic bacterial aerosols were detected. Also, Health risk associated were estimated based on the average daily dose rates (ADD) of exposure by inhalation. The mean concentration of potentially pathogenic bacterial aerosols were 468.7 ± 140 CFU m^- 3 1108.5 ± 136.9 CFU m^- 3 detected in the active zone in spring and summer, respectively. Also, there was a significant relationship between meteorological parameters and bacterial concentration (p < 0.05). The predominant potential pathogenic bacterial identified in the spring were Proteus mirabilis, Streptococcus sp., and Pseudomonas sp., while in summer were Pseudomonas sp., Staphylococcus aureus, and Escherichia coli. The hazard quotient (HQ) in both seasons were less of 1. Bacteria were spread throughout the landfill space, but their maximum density was observed around the active zone and leachate collection pond. This study highlights the importance of exposure to potential pathogenic bacterial aerosols in the summer and its adverse effects, especially in the MSW landfill site active zone. Finally, controlled exposure can reduce the health hazard caused by the potential pathogenic bacterial aerosols.

Epidemiology of stage III lung cancer: frequency, diagnostic characteristics, and survival

Stage III non-small cell lung cancer (NSCLC) includes a highly heterogeneous group of patients with differences in the extent and localization of disease. Many aspects of stage III disease are controversial. The data supporting treatment approaches are often subject to a number of limitations, due to the heterogeneous patient populations involved in the trials. Furthermore, the definition of stage III disease has changed over time, and early studies were frequently inadequately powered to detect small differences in therapeutic outcome, were not randomized, or had a limited follow-up times. Major improvements in therapy, including the use of more active chemotherapy agents and refinements in radiation and surgical techniques, also limit the interpretation of earlier clinical trials. Lastly, improvements in pretreatment staging have led to reclassification of patients with relatively minimal metastatic disease as stage IV rather than stage III, leading to an apparent increase in the overall survival of both stage III and IV patients. Median overall stage III NSCLC survival ranges from 9 to 34 months. Higher survival rates are observed in younger Caucasian women with good performance status, adenocarcinoma, mutations, stage IIIA, and in patients with multidisciplinary-team-based diagnoses.

Spatial and Temporal Analysis of Lung Cancer in Shenzhen, 2008-2018

Lung cancer is the most commonly diagnosed cancer in China. The incidence trend and geographical distribution of lung cancer in southern China have not been reported. The present study explored the temporal trend and spatial distribution of lung cancer incidence in Shenzhen from 2008 to 2018. The lung cancer incidence data were obtained from the registered population in the Shenzhen Cancer Registry System between 2008 and 2018. The standardized incidence rates of lung cancer were analyzed by using the joinpoint regression model. The Moran's I method was used for spatial autocorrelation analysis and to further draw a spatial cluster map in Shenzhen. From 2008 to 2018, the average crude incidence rate of lung cancer was 27.1 (1/100,000), with an annual percentage change of 2.7% (p < 0.05). The largest average proportion of histological type of lung cancer was determined as adenocarcinoma (69.1%), and an increasing trend was observed in females, with an average annual percentage change of 14.7%. The spatial autocorrelation analysis indicated some sites in Shenzhen as a high incidence rate spatial clustering area. Understanding the incidence patterns of lung cancer is useful for monitoring and prevention.

Impact of Filter on the Estimation of Quantitative Mixture Risk Caused by Some Chemical Constituents Generated from Popular Cigarette Brands in Iran

Background

This study was conducted to evaluate the impact of filter on the eventual carcinogenic and non-carcinogenic risks caused by the main toxic constituents of popular cigarette brands in Iran.

Methods

At this laboratory study, the concentration of benzene, formaldehyde, arsenic, and cadmium in the mainstream smoke of 11 popular cigarette brands in Iran, on the without and with-filter modes was determined based on an established method. The hazard quotient (HQ), incremental lifetime cancer risk (ILCR), and mixture quantitative risk assessments (QRAs) were performed based on the QRA method recommended by United States Environmental Protection Agency (USEPA).

Findings

The mean of HQ due to benzene, formaldehyde, arsenic, and cadmium in without-filter cigarette smoke was from 3.96 to 3505. The findings indicated that the HQs related to benzene, formaldehyde, arsenic, and cadmium in cigarette smoke were decreased with filter by 48.3%, 25.3%, 37.6%, and 49.1%, respectively. The filter of cigarette decreased ILCR of benzene, formaldehyde, arsenic, and cadmium in cigarette smoke by 53.02%, 25.31%, 37.70%, and 61.01%, respectively. The mixture of non-carcinogenic and carcinogenic estimated risks due to inhalation of studied cigarettes smoke was very high and unacceptable.

Conclusion

The cigarette filter plays an essential role in reducing inhalation exposure to hazardous compounds in mainstream cigarette smoke; nevertheless, the average of overall mixture HQs and ILCRs estimated caused by studied compounds was higher than the acceptable value. It is recommended that future empirical studies investigate the impact of the type of fiber used in cigarette filter on reducing carcinogenic and non-carcinogenic risks caused by cigarette smoke.

How long is cessation of preoperative smoking required to improve postoperative survival of patients with pathological stage I non-small cell lung cancer?

Background

Smoking can cause non-small cell lung cancer (NSCLC). However, the effects of preoperative smoking on tumor progression are not well-known. In addition, the duration of smoking cessation that can provide NSCLC patients with smoking history similar postoperative prognosis as that of nonsmokers remains unknown. This study aimed to investigate the period of smoking cessation that may “compensate” for past smoking history regarding postoperative survival in cases of resected pathological stage I NSCLC by examining the relationship between clinicopathological factors and preoperative smoking.

Methods

We retrospectively examined clinicopathological factors including preoperative smoking status and postoperative survival in 453 patients with pathologically proven stage I NSCLC at our Institute. Smoking status was evaluated using the following four parameters: cigarettes per day, number of years of smoking, pack-years, and number of years since smoking cessation.

Results

Pathological factors that reflect tumor invasiveness including vascular invasion (VI) and pleural invasion (PL) were associated with the degree of preoperative smoking in adenocarcinomas, particularly invasive diameters of 2–3 cm. Such a relationship was not identified for non-adenocarcinomas. Heavy smoking status was significantly related to PL in lepidic or papillary predominant adenocarcinomas and to VI in acinar or solid predominant adenocarcinomas. Former smokers who quit smoking for ≥10 years had similar postoperative survival as non-smokers for adenocarcinoma ≤3 cm.

Conclusions

Accumulative smoking habit correlated with VI and PL, particularly in 2–3 cm adenocarcinoma, whereas larger adenocarcinomas and non-adenocarcinomas of any size appear to grow and become invasive independent of preoperative smoking status. Longer smoking cessation ≥10 years can result in postoperative survival similar to that of non-smokers with adenocarcinomas ≤3 cm. Current smokers should quit smoking immediately to ensure longer survival even though they suffer from small-sized lung adenocarcinomas in the future.

Influence of Estrogen on the NSCLC Microenvironment: A Comprehensive Picture and Clinical Implications

Lung cancer mortality represents the leading cause of cancer related deaths in the United States and worldwide. Almost half of these deaths occur in female patients, making lung cancer the most common cause of cancer mortality in women with a higher annual mortality rate than breast, uterine, and ovarian cancers combined. The distinct epidemiological, histological and biological presentation of non-small cell lung cancer (NSCLC) in women combined with extensive preclinical data have demonstrated that the female sex hormone β-estradiol (E2) plays an important role in NSCLC tumorigenesis, prognosis, and treatment response. Estrogen receptors are widely expressed on stromal and immune cells, and estrogen-linked signaling pathways are known to be involved in regulating the response of both the innate and adaptive immune system. Immune evasion has been recognized as a “hallmark” of cancer and immunotherapy has re-defined standard of care treatment for NSCLC. Despite these advancements, the low response rates observed in patients treated with immune checkpoint inhibitors has led to a search for mediators of immunosuppression and ways to augment the action of these agents. We focus on emerging data describing sex differences that modulate immunotherapy efficacy in NSCLC, immunosuppressive properties of E2 that lead to a pro-tumor microenvironment (TME), and the translational potential of altering the immune microenvironment by targeting the estrogen signaling pathway. E2-induced modulation affects multiple cell types within the TME, including cancer-associated fibroblasts, tumor infiltrating myeloid cells, and tumor infiltrating lymphocytes, all of which interplay with lung tumor cells via E2 and estrogen receptor engagement, ultimately shaping the TME that may, in part, be responsible for the sex-based disparities observed in NSCLC. An improved understanding of the role of the estrogen pathway in NSCLC anti-cancer immunity may lead to novel therapeutic approaches for altering the TME to improve the efficacy of immunotherapy agents.

Lung Cancer in Women: A Modern Epidemic

Lung cancer in women is a modern epidemic and a major health crisis. Cigarette smoking remains the most important risk factor for lung cancer, and unfortunately smoking rates are either stabilized or continue to increase among women. Women may not be more susceptible to the carcinogenic effects of tobacco, but the biology of lung cancer differs between the sexes. This paper summarizes the biological sex differences in lung cancer, including molecular abnormalities, growth factor receptors, hormonal influences, DNA repair capacity, as well as differences in the histology and treatment outcomes of lung cancer in women.

Temporal Trends and Geographic Patterns of Lung Cancer Incidence by Histology in Thailand, 1990 to 2014

Purpose

Lung cancer is one of the most common cancers worldwide and in Thailand. We characterize and forecast region-specific patterns of lung cancer incidence by histology and sex.

Methods

We analyzed lung cancer incidence trends in Thailand by histology (adenocarcinoma [AdC]; squamous cell carcinoma [SCC]; and large-cell, small-cell, and other carcinomas) from 1990 to 2014 in four cancer registries in three regions (north, Chiang Mai Province and Lampang Province; northeast: Khon Kaen Province; south: Songkhla Province). Annual percent change (APC) was calculated to quantify the incidence rate trends using joinpoint regression. Age-period-cohort models were used to examine the temporal trends of AdC and SCC by age, calendar year, and birth cohort. We projected the incidence of AdC and SCC up to 2030 using three independent approaches: joinpoint, age-period-cohort, and Nordpred models.

Results

AdC incidence significantly increased from 1990 to 2012 in Chiang Mai males (APC, 1.3%), Songkhla males from 2004 to 2014 (APC, 2.5%), Songkhla females from 1990 to 2014 (APC, 5.9%), and Khon Kaen females from 2005 to 2014 (APC, 3.1%). Conversely, SCC incidence significantly decreased from 1990 to 2012 in Chiang Mai males and females (APC, −1.2% and −4.8%, respectively), Lampang males and females from 1993 to 2014 (APC, −5.4% and −5.2%, respectively), and Songkhla females from 1990 to 2014 (APC, −2.1%). In general, trends of AdC and SCC correlated more with birth cohort than with calendar year. Three projection models suggested that incidence rates of AdC in Songkhla may continue to increase until 2030.

Conclusion

Temporal trends of lung cancer by histology varied among regions in Thailand. Reduction of lung cancer incidence in Thailand likely will require prevention strategies tailored to each specific region.

Lung cancer in Spain: information from the Thoracic Tumors Registry (TTR study)

Background

Lung cancer remains a leading cause of cancer incidence and mortality worldwide. Although Spain contributes to global statistics related to cancer, it is difficult to discern aspects linked to clinical presentation of the disease or molecular testing. The Thoracic Tumor Registry (TTR) was created with the aim of filling this gap.

Methods

Observational cohort multicenter study performed in Spain, including patients with lung cancer or other types of thoracic tumors undergoing active treatment or palliative care only. Enrollment took place between August 2016 and December 2018. The evaluation included a review of demographic, epidemiological, clinical and molecular data.

Results

A total of 6,600 patients diagnosed with non-small cell lung cancer (NSCLC) were recruited at 56 Spanish hospitals. The mean age at diagnosis was 64 years. The majority of patients (80%) presented with advanced disease, being adenocarcinoma the most frequent histological type. Up to 86% of patients were current- or ex-smokers, with men starting to smoke earlier than women (average age 17.9 vs. 19.2 years). Sixty-seven percent of patients underwent some type of molecular testing. Mutations in EGFR and KRAS genes were found in 18% and 28% of patients, respectively.

Conclusions

Our findings suggest that the TTR study accurately describes the clinical reality of lung cancer in Spain, including useful information on smoking status as well as molecular profiling and tumor histology, and can therefore be used to drive improvements in health care. Social and political pressure to reduce tobacco consumption among the population should be reinforced, particularly among youth.

The estrogen pathway as a modulator of response to immunotherapy

Lung cancer is the leading cause of cancer deaths worldwide, with a 5-year survival rate of about 18%. Thus, there is a great need for novel therapeutic approaches to treat non-small-cell lung cancer (NSCLC). Immune checkpoint inhibitors (ICIs) have improved outcomes for a subset of patients, especially those with high programmed death-ligand 1 expression and/or high tumor mutational burden, but have failed in the majority of patients. Increasing evidence suggests that the estrogen signaling pathway may be a therapeutic target in metastatic NSCLC and that the estrogen pathway may play a role in sex-based responses to ICIs. This report will review the epidemiologic, preclinical and clinical data on the estrogen pathway in NSCLC, its implications in sex-based responses to ICIs and the potential use of antiestrogen therapy in combination with ICIs.

Genetic Polymorphism of CYP2A6 and Its Relationship with Nicotine Metabolism in Male Bataknese Smokers Suffered from Lung Cancer in Indonesia

BACKGROUND

Cytochrome P450 2A6 (CYP2A6) is known as an enzyme which is responsible for the metabolism of chemical compounds.

AIM

This study aimed to analyse the relationship between CYP2A6 gene polymorphism with nicotine metabolism rates and lung cancer incidence among smokers of Batak ethnic group in Indonesia.

METHODS

This study was a case-control study involving 140 research subjects through a purposive sampling technique from three hospitals in Medan, Indonesia. An examination of nicotine metabolism rates was conducted for all subjects using the 3HC/cotinine ratio parameter with LC-MS/MS technique. The examination of the CYP2A6 gene was performed with PCR-RFLP. Data were analysed with Conditional Logistic Regression test using Epi Info 7.0 software.

RESULTS

The allele frequencies of CYP2A6*1A, CYP2A6*1B, and CYP2A6*4A found were 44.3%, 48.9%, and 6.8%, respectively. The *1B allele showed the highest metabolism rate. It is found that slow metabolizer individuals were 5.49 times more likely to develop lung cancer (P = 0.01, 95%CI 1.2-24.8).

CONCLUSION

Among the Bataknese smokers studied, the CYP2A6*1B allele was found to be the most common allele and showed the highest rate of nicotine metabolism. However, the results show the insignificant relationship among CYP2A6 genetic polymorphism, nicotine metabolism, and lung cancer incidence.

Epidemiology of Lung Cancer

Lung cancer has been transformed from a rare disease into a global problem and public health issue. The etiologic factors of lung cancer become more complex along with industrialization, urbanization, and environmental pollution around the world. Currently, the control of lung cancer has attracted worldwide attention. Studies on the epidemiologic characteristics of lung cancer and its relative risk factors have played an important role in the tertiary prevention of lung cancer and in exploring new ways of diagnosis and treatment. This article reviews the current evolution of the epidemiology of lung cancer.

Association of 12 polymorphic variants conferring genetic risk to lung cancer in Indian population: An extensive meta-analysis

Candidate gene as well as genome-wide association studies identified several polymorphic variants to be associated with lung cancer worldwide including in India. However, contradictory results have failed to estimate the overall effect of the polymorphic variants on the disease. Textmining was conducted on PubMed following specific search strings to gather all the publications related to genetic association with lung cancer in India. Out of 211 PubMed hits only 30 studies were selected for meta-analysis following specific inclusion criteria. Heterogeneity between studies was calculated by Cochran's Q-test (P < 0.05) and heterogeneity index (I² ). Publication bias was visualized by funnel plots and Egger's regression test. For each variant, following a fixed-effect model, summary odds ratio (OR) along with 95% confidence interval (CI) was estimated. The meta-analysis revealed three polymorphic variants viz. 'deletion polymorphism (del1) (OR = 1.39, 95% CI = 1.03-1.87, P = 0.027) in GSTT1', 'deletion polymorphism (del2) (OR = 1.30, 95% CI = 1.01-1.67, P = 0.038) in GSTM1' and 'rs1048943 (OR = 1.98, 95% CI = 1.27-3.10, P = 0.002) in CYP1A1' to be associated with lung cancer. However, after multiple testing correction, only rs1048943 was found to be significantly associated (P value = 0.0321) with lung cancer. None of the polymorphic variants showed any evidence of heterogeneity between studies or of publication bias. Our meta-analysis revealed strong association of rs1048943 in CYP1A1, but a suggestive association of deletion polymorphisms in GSTT1 and GSTM1 with lung cancer, which provides a comprehensive insight on the overall effect of the polymorphic variants, reported in various case-control studies on Indian population, on the risk of lung cancer development. Environ. Mol. Mutagen. 58:688-700, 2017. © 2017 Wiley Periodicals, Inc.

The increasing challenge of never smokers with adenocarcinoma lung: Need to look beyond tobacco exposure

BACKGROUND

Lung cancer continues to remain as one of the leading causes of morbidity and mortality worldwide, despite the decreasing trends in smoking prevalence worldwide. An earlier study from the authors' institute reported the increasing trends of "Nonsmoking associated lung cancers."

MATERIALS AND METHODS

All consecutive histologically confirmed patients with lung cancer who presented to the outpatient department over a year (November 2014-October 2015) were included in this current prospective study.

RESULTS

Seven hundred and thirteen patients presented with clinicoradiologically suspicious findings of lung cancer in the said period. A pathological confirmation of lung cancer could be ascertained in 495 patients, and this cohort was further analyzed. The mean age of presentation was 57.76 years; the male to female ratio was approximately 2.5:1. Interestingly, 55.35% of the patients were nonsmokers. Adenocarcinoma (63%) was the predominant histology. Never smokers, both among men (P = 0.02) and women (P = 0.001), presented more frequently with adenocarcinoma histology. Further, 84.9% (45/53) of rural and 76.1% (19/25) of urban women who were never smokers reported exposure to indoor air pollution (secondhand smoke/fuel used for cooking purposes) which was significantly associated with adenocarcinoma histology.

CONCLUSION

Our study confirmed our initial observation of the changing epidemiology of lung cancer in the Indian subcontinent, paralleling the global trends of rise in adenocarcinoma. Lung cancer in never smokers outnumbering that among smokers was another interesting observation. The take-home message for both the clinicians as well as the policymakers is to study factors beyond tobacco exposure to understand the direction of the current lung cancer epidemic.

Pollutional haze as a potential cause of lung cancer

Along with fast economic growth over the past few decades, the world is faced with cumulatively serious environmental pollution and now is paying increased attention to pollutional haze. In the last few years, multiple epidemiological studies and animal models have provided compelling evidences that inhalation of pollutional haze could be linked to several adverse health effects. Since the respiratory tract is the crucial passageway of entry of pollutional haze, the lung is the main affected organ. Therefore, here, we reviewed some of the important information around long-term exposure to pollutional haze and lung cancer, as well as highlight important roles of pollutional haze in human lung carcinogenesis, providing evidence for pollutional haze acting as another risk factor for lung cancer.

Lower lung cancer rates in Jewish smokers in Israel and the USA

Lung cancer rates in Israeli Jews have remained stable over the last five decades and are much lower than in most developed countries despite high historical smoking rates. We compared lung cancer risk in Jews and non-Jews in Israel and in the United States. Data were derived from a population-based, case-control study in Israel (638 cases, 496 controls) to estimate lung cancer risk associated with smoking. Data were also acquired from a case-control study in the United States with information on religious affiliation (5,093 cases, 4,735 controls). Smoking was associated with lung cancer risk in all religion/gender groups in both studies. However, major differences in risk magnitude were noted between Jews and non-Jews; ever smoking was associated with a moderately elevated risk of lung cancer in Jewish men and women in Israel (OR = 4.61, 2.90-7.31 and OR = 2.10, 1.36-3.24, respectively), and in Jewish men and women in the United States (OR = 7.63, 5.34-10.90 and OR = 8.50, 5.94-12.17) but were significantly higher in Israeli non-Jewish men (OR = 12.96, 4.83-34.76) and US non-Jewish men and women (OR = 11.33, 9.09-14.12 and OR = 12.78, 10.45-15.63). A significant interaction between smoking and religion was evident in light, moderate and heavy male and female smokers. The differences in risk level between Israeli Jews and non-Jews could not be explained by lung cancer genetic risk variants which were identified in GWAS (genes in the CHRNA5, TERT and CLPTM1L regions). Data from the two studies support the notion of a reduced risk of lung cancer in Jewish compared to non-Jewish smokers in different areas of the world.

Lung cancer molecular epidemiology in China: recent trends

Lung cancer is both the most common diagnosed cancer and the leading cause of cancer related deaths in China. During the past three decades, the incidence and mortality of lung cancer in China are increasing rapidly. According to data from National Central Cancer Registry (NCCR) in 2010, the crude incidence of lung cancer in China was 46.08 per 100,000 population (61.86 per 100,000 men and 29.54 per 100,000 women), with an estimated over 600,000 new diagnosed lung cancer patients (416,333 males and 189,613 females). Meanwhile, the crude mortality of lung cancer in China was 37.00 per 100,000 population (50.04 per 100,000 men and 23.33 per 100,000 women). Consistent with the change in developed countries, adenocarcinoma has become the most predominant histological subtype of lung cancer in China. For the majority advanced non-small-cell lung cancer (NSCLC) patients, especially patients with adenocarcinoma, targeted therapy became increasing important in the treatment. Chinese researcher have done a lot work in terms of lung cancer molecular epidemiology, therefore, in this review, we further summarized the epidemiology of driver genes in NSCLC, hoping to help clinicians to better screen certain driver genes in China for treatment decisions.

Patterns in lung cancer incidence rates and trends by histologic type in the United States, 2004-2009

OBJECTIVE

The examination of lung cancer by histology type is important for monitoring population trends that have implications for etiology and prevention, screening and clinical diagnosis, prognosis and treatment. We provide a comprehensive description of recent histologic lung cancer incidence rates and trends in the USA using combined population-based registry data for the entire nation.

MATERIALS AND METHODS

Histologic lung cancer incidence data was analyzed from CDC's National Program of Cancer Registries (NPCR) and the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) Program. Standardized rates and trends were calculated for men and women by age, race/ethnicity, and U.S. Census region. Rate ratios were examined for differences in rates between men and women, and annual percent change was calculated to quantify changes in incidence rates over time.

RESULTS

Trend analysis demonstrate that overall rates have decreased, but incidence has remained stable for women aged 50 or older. Adenocarcinoma and squamous cell carcinoma were the two most common histologic subtypes. Adenocarcinoma rates continued to increase in men and women, and squamous cell rates increased in women only. All histologic subtype rates for white women exceeded rates for black women. Histologic rates for black men exceeded those for white men, except for small cell carcinoma. The incidence rate for Hispanics was nearly half the rate for blacks and whites.

CONCLUSION

The continuing rise in incidence of lung adenocarcinoma, the rise of squamous cell cancer in women, and differences by age, race, ethnicity and region points to the need to better understand factors acting in addition to, or in synergy with, cigarette smoking that may be contributing to observed differences in lung cancer histology.

Genetic Instability in Peripheral Lymphocytes as Biological Marker for Non-Small Cell Lung Cancer Patients in the South Indian State of Andhra Pradesh

Objectives

This study aims, first, at evaluating the DNA and chromosomal damage in non-small cell lung cancer (NSCLC) patients from the South Indian state of Andhra Pradesh, and then at correlating these results with possible confounding factors that might potentially play a role in causing genetic damage.

Methods

The study included 246 NSCLC patients (177 men and 69 women) and 250 healthy controls (180 men and 70 women) for the analysis of DNA and chromosomal damage using the comet assay and micronucleus test.

Results

Both DNA and chromosomal damage were found to be increased in NSCLC patients compared to healthy controls, and the extent of the damage was higher in males than female patients. The smoking status had a profound effect on the extent of DNA and chromosomal damage in NSCLC patients. The degree of genetic damage correlated with the stage of the disease. However, the histological status had no effect on the extent of DNA and chromosomal damage among NSCLC patients.

Conclusions

We here report, for the first time, that the NSCLC patients selected form the Andhra Pradesh population had increased DNA damage and higher mean micronucleus frequencies in peripheral lymphocytes, indicating a strong background level of genetic instability.

Epidemiology of lung cancer

Incidence and mortality attributed to lung cancer has risen steadily since the 1930s. Efforts to improve outcomes have not only led to a greater understanding of the etiology of lung cancer, but also the histologic and molecular characteristics of individual lung tumors. This article describes this evolution by discussing the extent of the current lung cancer epidemic including contemporary incidence and mortality trends, the risk factors for development of lung cancer, and details of promising molecular targets for treatment.

Systematic review with meta-analysis of the epidemiological evidence in the 1900s relating smoking to lung cancer

BACKGROUND

Smoking is a known lung cancer cause, but no detailed quantitative systematic review exists. We summarize evidence for various indices.

METHODS

Papers published before 2000 describing epidemiological studies involving 100+ lung cancer cases were obtained from Medline and other sources. Studies were classified as principal, or subsidiary where cases overlapped with principal studies. Data were extracted on design, exposures, histological types and confounder adjustment. RRs/ORs and 95% CIs were extracted for ever, current and ex smoking of cigarettes, pipes and cigars and indices of cigarette type and dose-response. Meta-analyses and meta-regressions investigated how relationships varied by study and RR characteristics, mainly for outcomes exactly or closely equivalent to all lung cancer, squamous cell carcinoma ("squamous") and adenocarcinoma ("adeno").

RESULTS

287 studies (20 subsidiary) were identified. Although RR estimates were markedly heterogeneous, the meta-analyses demonstrated a relationship of smoking with lung cancer risk, clearly seen for ever smoking (random-effects RR 5.50, CI 5.07-5.96) current smoking (8.43, 7.63-9.31), ex smoking (4.30, 3.93-4.71) and pipe/cigar only smoking (2.92, 2.38-3.57). It was stronger for squamous (current smoking RR 16.91, 13.14-21.76) than adeno (4.21, 3.32-5.34), and evident in both sexes (RRs somewhat higher in males), all continents (RRs highest for North America and lowest for Asia, particularly China), and both study types (RRs higher for prospective studies). Relationships were somewhat stronger in later starting and larger studies. RR estimates were similar in cigarette only and mixed smokers, and similar in smokers of pipes/cigars only, pipes only and cigars only. Exceptionally no increase in adeno risk was seen for pipe/cigar only smokers (0.93, 0.62-1.40). RRs were unrelated to mentholation, and higher for non-filter and handrolled cigarettes. RRs increased with amount smoked, duration, earlier starting age, tar level and fraction smoked and decreased with time quit. Relationships were strongest for small and squamous cell, intermediate for large cell and weakest for adenocarcinoma. Covariate-adjustment little affected RR estimates.

CONCLUSIONS

The association of lung cancer with smoking is strong, evident for all lung cancer types, dose-related and insensitive to covariate-adjustment. This emphasises the causal nature of the relationship. Our results quantify the relationships more precisely than previously.

Impact of histopathological diagnosis with ancillary immunohistochemical studies on lung cancer subtypes incidence and survival: a population-based study

PURPOSE

The aim of this study was to assess the impact of immunohistochemical- (IHC-) studies on incidence and survival of lung cancer histotypes.

PATIENTS AND METHODS

Lung cancers occurred in southern Switzerland between 1996 and 2010 were selected by the Ticino Cancer Registry and categorised into adenocarcinoma (AC), squamous-cell-carcinoma (SqCC), small-cell-carcinoma (SmCC), and large-cell carcinoma/non-small-cell lung cancer (LCC/NSCLC). Incidence rates, annual-percentage-change (APC), and two-year overall survival (OS) (follow-up: 31.12.2010) were performed.

RESULTS

2467 cases were selected: 997 (40.4%) AC; 522 (21.2%) LCC/NSCLC, 378 (15.3%) SmCC, and 570 (23.1%) SqCC. Trend-analysis showed significant increase in AC (APC: 4.6; 95% CI: 3.1; 6.0) and decrease of LCC/NSCLC, with significant joinpoint in 2003 (APC: -14.7; 95% CI: -21.6; -7.1). Improved OS and decreased OS were detected in SqCC and LCC/NSCLC, respectively.

CONCLUSIONS

This study highlights that diagnosis with ancillary immunohistochemical studies will change incidence and survival of precisely defined lung cancer subtypes. It calls attention to the need for cautious interpretation of studies and clinical trials, where the diagnosis was based on histology unaccompanied by IHC studies, and to the need of standardised diagnostic procedures.

Trends in incidence of small cell lung cancer and all lung cancer

BACKGROUND

The incidence of small cell lung cancer (SCLC) is often quoted as 'around 20%' of all lung cancers but is reportedly decreasing over time. We analysed the trends in incidence of SCLC and compared these with the trends in lung cancer overall among males and females in South East England.

METHODS

We identified 237,792 patients diagnosed with lung cancer (ICD-10 C33-C34) between 1970 and 2007. We used a Poisson regression age-cohort model to estimate the age-specific rates in the 1890-1960 birth cohorts. We computed age-standardised incidence rates using the European standard population. In addition, we analysed the trends of lung cancer subtypes according to morphology.

RESULTS

In the most recent time period, SCLC accounted for 10% and 11% of cases of all lung cancer among males and females, respectively. Among the morphologically specified lung cancers, SCLC accounted for 15% and 17% among males and females, respectively. There was a decrease of SCLC incidence over time and by birth cohort in both sexes. The decrease in SCLC was more marked than that in all lung cancers.

CONCLUSION

The decrease in SCLC incidence rates may reflect decreases in the prevalence of cigarette smoking, and changes in the type of cigarettes smoked.

Lung cancer in women: the differences in epidemiology, biology and treatment outcomes

Although the prevalence of lung cancer in men has been decreasing, it has been increasing in women. Without a doubt, lung cancer is a major health problem for women in the USA, not only owing to its high incidence rate but, more alarming, the high mortality rate. Lung cancer kills more women each year than breast, ovarian and uterine cancers combined. One of the most important risk factors for the development of lung cancer in both men and women is cigarette smoking. Unfortunately, the prevalence of smoking among women has increased significantly since 1980, which is a major concern as epidemiologic data suggest that women may be more susceptible to developing lung cancer than men. Many will argue, however, that after adjusting for tobacco exposure, some studies have failed to show that women are at a higher risk for developing lung cancer. Indeed, the increased risk of lung cancer in women remains controversial. There is, however, little controversy to the fact that the biology of lung cancer differs between the sexes. This paper summarizes the explanations for the sex differences in lung cancer, including differences in molecular abnormalities, growth factor receptors, hormonal influences, differences in cytochrome P-450 enzymes and DNA repair capacity, as well as variations in treatment outcomes.

Nicotine dependence phenotype and lung cancer risk

BACKGROUND

A behavioral phenotype that characterizes nicotine dependence, the time to first cigarette after waking, is hypothesized to increase the risk of lung cancer.

METHODS

A case-control study of histologically confirmed lung cancer was conducted. The current analysis included 4775 lung cancer cases and 2835 controls who were regular cigarette smokers.

RESULTS

Compared with subjects who smoked their first cigarette > 60 minutes after waking, the pack-years-adjusted odds ratio was 1.31 (95% confidence interval [95% CI], 1.11-1.54) for subjects who smoked 31 minutes to 60 minutes after waking and 1.79 (95% CI, 1.56-2.07) for subjects who smoked within 30 minutes of waking. The risk estimates were similar when smoking was modeled as total years, smoking status (current vs former), number of cigarettes smoked per day, years since quitting, and excess odds ratio. The findings were consistent for all histologic types of lung cancer.

CONCLUSIONS

The findings of the current study indicate that a specific nicotine dependence phenotype that is associated with the amount of smoke uptake per cigarette is independently associated with lung cancer risk. These findings may help to identify high-risk individuals who would benefit from targeted interventions.

Polonium and lung cancer

The alpha-radioactive polonium 210 (Po-210) is one of the most powerful carcinogenic agents of tobacco smoke and is responsible for the histotype shift of lung cancer from squamous cell type to adenocarcinoma. According to several studies, the principal source of Po-210 is the fertilizers used in tobacco plants, which are rich in polyphosphates containing radio (Ra-226) and its decay products, lead 210 (Pb-210) and Po-210. Tobacco leaves accumulate Pb-210 and Po-210 through their trichomes, and Pb-210 decays into Po-210 over time. With the combustion of the cigarette smoke becomes radioactive and Pb-210 and Po-210 reach the bronchopulmonary apparatus, especially in bifurcations of segmental bronchi. In this place, combined with other agents, it will manifest its carcinogenic activity, especially in patients with compromised mucous-ciliary clearance. Various studies have confirmed that the radiological risk from Po-210 in a smoker of 20 cigarettes per day for a year is equivalent to the one deriving from 300 chest X-rays, with an autonomous oncogenic capability of 4 lung cancers per 10000 smokers. Po-210 can also be found in passive smoke, since part of Po-210 spreads in the surrounding environment during tobacco combustion. Tobacco manufacturers have been aware of the alpha-radioactivity presence in tobacco smoke since the sixties.

Molecular epidemiology of female lung cancer

Lung cancer is still a leading cause of cancer mortality in the world. The incidence of lung cancer in developed countries started to decrease mainly due to global anti-smoking campaigns. However, the incidence of lung cancer in women has been increasing in recent decades for various reasons. Furthermore, since the screening of lung cancer is not as yet very effective, clinically applicable molecular markers for early diagnosis are much required. Lung cancer in women appears to have differences compared with that in men, in terms of histologic types and susceptibility to environmental risk factors. This suggests that female lung cancer can be derived by carcinogenic mechanisms different from those involved in male lung cancer. Among female lung cancer patients, many are non-smokers, which could be studied to identify alternative carcinogenic mechanisms independent from smoking-related ones. In this paper, we reviewed molecular susceptibility markers and genetic changes in lung cancer tissues observed in female lung cancer patients, which have been validated by various studies and will be helpful to understand the tumorigenesis of lung cancer.

Small cell lung cancer: are we making progress?

Although the incidence of small cell lung cancer (SCLC) has declined during the past 30 years, it remains a significant cause of cancer mortality in the United States and across the world. With appropriate treatment, about 20% of patients who present with limited stage SCLC can be cured of their disease. Unfortunately, the outcome for the remainder of patients is extremely poor. The only significant advance in extensive stage SCLC in the past 2 decades is the recent discovery that prophylactic cranial irradiation improves survival in those patients whose disease has responded to initial chemotherapy. Numerous attempts to enhance the antitumor effects of traditional chemotherapy for SCLC have not been successful. As the understanding of the biology of SCLC increased, a number of rational molecular targets for therapy have been identified. Although initial attempts at "targeted therapy" in SCLC have been unsuccessful, several newly identified targets hold promise and give hope that significant improvements in therapy for this challenging disease are not far away.

Unchanging clinico-epidemiological profile of lung cancer in north India over three decades

OBJECTIVE

In the recent past, adenocarcinoma has become the commonest histological type of lung cancer (LC) in the developed countries. The present study was conducted to assess the change in epidemiology of LC, if any, in North India.

METHODS

Prospectively collected data on 250 newly diagnosed LC patients presenting to a tertiary care institute was analyzed. Results were compared with the previously published data from this center.

RESULTS

No significant differences were observed in the demographical, histological or smoking profiles of LC patients compared to those seen three decades earlier. The mean [standard deviation] age was 57.9 [+/-11.3] years (previously 54.3 years). Male to female ratio was 4.43:1 (previously 4.48:1; p=0.952) while the smoker to non-smoker ratio was 2.67:1 (previously 2.68:1; p=0.980). The commonest histological types were squamous cell (34.8%), adenocarcinoma (26.0%) and small cell (18.4%) while previously these were 34.3%, 25.9% and 20.3%, respectively; p=0.916. However, in the present study, significant differences were observed between smokers and non-smokers in relation to distribution of gender, histology and disease stage.

CONCLUSIONS

There has been no significant change in the epidemiology of LC in North India over the past three decades. An absence of change in the smoking pattern of the population could be a possible reason.

Population-based trends in lung cancer incidence in women

Lung cancer is the leading cause of cancer mortality in women worldwide. Although the rise and growing epidemic status of lung cancer are overwhelmingly attributed to tobacco use, its rank in nonsmokers as the seventh most common cause of cancer worldwide suggests that other factors contribute to this disease. The majority of lung cancers among nonsmokers occur in women. Aside from geographic, cultural, and genetic differences, hormonal and possibly infectious factors also may play etiologic roles. This review aims to discuss the epidemiology of lung cancer in women, as well as the incidence of second primaries, and presents current opinions on the myriad of causes.

A case-control study of smoking and bladder cancer risk: emergent patterns over time

BACKGROUND

Cigarette smoking is a well-established risk factor for bladder cancer. The effects of smoking duration, intensity (cigarettes per day), and total exposure (pack-years); smoking cessation; exposure to environmental tobacco smoke; and changes in the composition of tobacco and cigarette design over time on risk of bladder cancer are unclear.

METHODS

We examined bladder cancer risk in relation to smoking practices based on interview data from a large, population-based case-control study conducted in Maine, New Hampshire, and Vermont from 2001 to 2004 (N = 1170 urothelial carcinoma case patients and 1413 control subjects). We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using unconditional logistic regression. To examine changes in smoking-induced bladder cancer risk over time, we compared odds ratios from New Hampshire residents in this study (305 case patients and 335 control subjects) with those from two case-control studies conducted in New Hampshire in 1994-1998 and in 1998-2001 (843 case patients and 1183 control subjects).

RESULTS

Regular and current cigarette smokers had higher risks of bladder cancer than never-smokers (for regular smokers, OR = 3.0, 95% CI = 2.4 to 3.6; for current smokers, OR = 5.2, 95% CI = 4.0 to 6.6). In New Hampshire, there was a statistically significant increasing trend in smoking-related bladder cancer risk over three consecutive periods (1994-1998, 1998-2001, and 2002-2004) among former smokers (OR = 1.4, 95% CI = 1.0 to 2.0; OR = 2.0, 95% CI = 1.4 to 2.9; and OR = 2.6, 95% CI = 1.7 to 4.0, respectively) and current smokers (OR = 2.9, 95% CI = 2.0 to 4.2; OR = 4.2, 95% CI = 2.8 to 6.3; OR = 5.5, 95% CI = 3.5 to 8.9, respectively) (P for homogeneity of trends over time periods = .04). We also observed that within categories of intensity, odds ratios increased approximately linearly with increasing pack-years smoked, but the slope of the increasing trend declined with increasing intensity.

CONCLUSIONS

Smoking-related risks of bladder cancer appear to have increased in New Hampshire since the mid-1990s. Based on our modeling of pack-years and intensity, smoking fewer cigarettes over a long time appears more harmful than smoking more cigarettes over a shorter time, for equal total pack-years of cigarettes smoked.

Relationships between lung adenocarcinoma and gender, age, smoking and occupational risk factors: A case-case study

BACKGROUND

The hypothesis that some risk factors for lung cancer may have more specific associations with particular histologic types remains controversial. The aim of this study was to investigate possible associations between adenocarcinoma and gender, age, smoking characteristics and selected occupational carcinogens in relation to other histologic types.

METHODS

This study included all histologically confirmed lung cancer cases diagnosed consecutively in two French University hospitals from 1997 to 2006. All medical data were obtained by face-to-face patient interviews. Occupational carcinogen exposures of each patient were assessed by an industrial hygienist. Relationships between risk factors and adenocarcinoma were analyzed by case-case comparisons using unconditional logistic regressions (ULRs).

RESULTS

A total of 1493 subjects were enrolled in this study, comprising 1303 men (87.3%), 67 nonsmokers (4.5%) and 489 adenocarcinomas (32.7%). Using ULR, no associations were observed between adenocarcinoma and age, gender or smoking characteristics except for a negative relationship with smoking duration (p<0.0001). Significant associations were observed between ADC and exposure to welding fumes and silica in the whole population and with polycyclic aromatic hydrocarbons in ever smokers.

CONCLUSION

This study demonstrated that some risk factors, such as duration of smoking and certain occupational exposures but not gender or age, have a more important influence on the incidence of lung ADC than on other histologic types. As the distribution of histologic types may reflect underlying biological mechanisms, these findings also suggest that lung carcinogenesis pathways should be studied in relation to smoking duration and other lung cancer risk factors.

Post-puff respiration measures on smokers of different tar yield cigarettes

The purpose of this study was to determine the effect of different tar yield cigarette brands on the post-puff inhalation/exhalation depth and duration for established smokers of the brands. The study was conducted with 74 established smokers of 1-17 mg Federal Trade Commission (FTC) tar products. The subjects were participating in a five-day inpatient clinical biomarker study during which time they were allowed to smoke their own brand of cigarette whenever they wished. On two separate days, the subjects' breathing pattern was measured using respiratory inductive plethysmography while they smoked one cigarette. This enabled the measurement of the post-puff inhalation volume, exhalation volume, inhalation duration, and exhalation duration for each subject after each puff on two of their own brand of cigarettes. The subjects were grouped according to the FTC tar yield of their product: 1-3 mg; 4-6 mg; 7-13 mg; 14 + mg. The post-puff inhalation volume for the 4-6 mg group was significantly lower than both the 7-13 mg and 14+ mg groups, and the 4-6 mg group exhalation volume was significantly lower than the 14+ mg group (p < 0.05). No other differences were found at the 95% confidence level. When volumes were normalized to resting tidal volume (tidal ratio), there were no differences between the groups for any of the respiratory measures. No significant slope was found for correlations with FTC tar yield for inhalation volume (p = 0.11, mean = 833 mL, R = 0.19), inhalation tidal ratio (p = 0.93, mean = 1.73, R = -0.01) or lung exposure time (p = 0.92, mean = 4.1 s, R = -0.01).