Tobacco smoking as a risk factor of bronchioloalveolar carcinoma of the lung: pooled analysis of seven case-control studies in the International Lung Cancer Consortium (ILCCO)

Health effects associated with smoking: a Burden of Proof study

As a leading behavioral risk factor for numerous health outcomes, smoking is a major ongoing public health challenge. Although evidence on the health effects of smoking has been widely reported, few attempts have evaluated the dose-response relationship between smoking and a diverse range of health outcomes systematically and comprehensively. In the present study, we re-estimated the dose-response relationships between current smoking and 36 health outcomes by conducting systematic reviews up to 31 May 2022, employing a meta-analytic method that incorporates between-study heterogeneity into estimates of uncertainty. Among the 36 selected outcomes, 8 had strong-to-very-strong evidence of an association with smoking, 21 had weak-to-moderate evidence of association and 7 had no evidence of association. By overcoming many of the limitations of traditional meta-analyses, our approach provides comprehensive, up-to-date and easy-to-use estimates of the evidence on the health effects of smoking. These estimates provide important information for tobacco control advocates, policy makers, researchers, physicians, smokers and the public.

Biodistribution of 99mTc-PLA/PVA/Atezolizumab Nanoparticles for Non-Small Cell Lung Cancer Diagnosis

Lung cancer (LC) is a common type of cancer, which is a leading cause of death around the world. There is an urgency for the development of new drugs that could diagnose the LC in the early stages and in a precise manner. In this direction, the development of nanoparticles radiolabeled with the diagnostic radioisotopes represent an important advance in the field of cancer imaging. In this study were developed PLA/PVA/Atezolizumab nanoparticles which were radiolabeled with ^99mTc (Technetium-99m). The radiolabeled nanoparticles were evaluated in both: in-vitro (L-929 and A-549) as in-vivo (mice). The results showed no cytotoxicity effect in the healthy cells (L-929) and cytotoxicity effect in the tumor cells (A-549). The biodistribution assay demonstrated that ^99mTc-PLA/PVA/Atezolizumab could reach the tumor site 14-folds higher than the nonparticulate atezolizumab. In conclusion, ^99mTc-PLA/PVA/Atezolizumab nanoparticles showed to be a new drug which is able to precisely image the lung tumor, and it must be considered for clinical trials.

Overdiagnosis in lung cancer screening: Estimates from the German Lung Cancer Screening Intervention Trial

Overdiagnosis is a major potential harm of lung cancer screening; knowing its potential magnitude helps to optimize screening eligibility criteria. The German Lung Screening Intervention Trial ("LUSI") is a randomized trial among 4052 long-term smokers (2622 men), 50.3 to 71.9 years of age from the general population around Heidelberg, Germany, comparing five annual rounds of low-dose computed tomography (n = 2029) with a control arm without intervention (n = 2023). After a median follow-up of 9.77 years postrandomization and 5.73 years since last screening, 74 participants were diagnosed with lung cancer in the control arm and 90 in the screening arm: 69 during the active screening period; of which 63 screen-detected and 6 interval cancers. The excess cumulative incidence in the screening arm (N = 16) represented 25.4% (95% confidence interval: -11.3, 64.3] of screen-detected cancer cases (N = 63). Analyzed by histologic subtype, excess incidence in the screening arm appeared largely driven by adenocarcinomas. Statistical modeling yielded an estimated mean preclinical sojourn time (MPST) of 5.38 (4.76, 5.88) years and a screen-test sensitivity of 81.6 (74.4%, 88.8%) for lung cancer overall, all histologic subtypes combined. Based on modeling, we further estimated that about 48% (47.5% [43.2%, 50.7%]) of screen-detected tumors have a lead time ≥4 years, whereas about 33% (32.8% [28.4%, 36.1%]) have a lead time ≥6 years, 23% (22.6% [18.6%, 25.7%]) ≥8 years, 16% (15.6% [12.2%, 18.3%]) ≥10 years and 11% (10.7% [8.0%, 13.0%]) ≥12 years. The high proportions of tumors with relatively long lead times suggest a major risk of overdiagnosis for individuals with comparatively short remaining life expectancies.

Associations of smoking behavior with lifestyle and mental health among Japanese dental students

BACKGROUND

Smoking is a major risk factor for cancer and cardiovascular disease. However, mental stress leads to smoking in dental students. We believe that dentists, as health professionals, should set an example for the public. Therefore, this study determined the prevalence of and factors associated with regular smoking among Japanese dental students. We also surveyed their attitudes regarding smoking cessation and how to counsel smokers about quitting.

METHODS

We collected demographic and behavioral data from 453 students at Kyushu Dental University, and evaluated their mental health with the 12-item General Health Questionnaire (GHQ 12). We also asked them nine questions related to their intentions to counsel smokers about quitting. A multivariate binary logistic regression analysis was used to identify factors associated with smoking.

RESULTS

Fifty-two (11.5%) of the dental students smoked. Univariate analyses indicated that male gender, higher academic year, greater number of times eating out per day, alcohol consumption, prevalence of skipping breakfast, poor health, and poor sleep habits were significantly associated with regular smoking. Regular smokers were less likely to have GHQ 12 scores ≥4. On multivariate analysis, male gender (OR = 5.449, 95% CI = 1.851-16.040), sixth year students (OR = 21.971, 95% CI = 1.686-286.290), eating out two or more times a day (OR = 2.492, 95% CI = 1.165-5.331), drinking alcohol three or more times per week (OR = 9.484, 95% CI = 3.335-26.970), and GHQ 12 score ≥ 4 (OR = 0.339, 95% CI = 0.136-0.845) were significantly associated with regular smoking. Overall, 50.1% of the non-smokers and 71.2% of the regular smokers responded that patients' chances of quitting smoking are not increased when a dentist advises them to quit.

CONCLUSIONS

Regular smoking was strongly associated with male gender, higher academic year, alcohol consumption, and higher frequency of eating out per day. Mental health status among regular smokers was better than that among non-current smokers. Furthermore, we found that more than half of dental students have inadequate attitudes to advise their patients to quit smoking. It is necessary to develop educational programs regarding smoking for dental students.

Lung epithelial response to cigarette smoke and modulation by the nicotinic alpha 7 receptor

Cigarette smoking (CS) is a principal contributor to a spectrum of devastating lung diseases whose occurrence and severity may vary between individuals and not appear for decades after prolonged use. One explanation for the variability and delay in disease onset is that nicotine, the addictive component of CS, acts through the ionotropic nicotinic acetylcholine receptor (nAChR) alpha7 (α7) to modulate anti-inflammatory protection. In this study we measured the impact α7 signaling has on the mouse distal lung response to side-stream CS exposure for mice of the control genotype (α7G) and those in which the α7-receptor signaling mechanisms are restricted by point mutation (α7E260A:G). Flow cytometry results show that after CS there is an increase in a subset of CD11c (CD11chi) alveolar macrophages (AMs) and histology reveals an increase in these cells within the alveolar space in both genotypes although the α7E260A:G AMs tend to accumulate into large aggregates rather than more widely distributed solitary cells common to the α7G lung after CS. Changes to lung morphology with CS in both genotypes included increased tissue cavitation due to alveolar expansion and bronchial epithelium dysplasia in part associated with altered club cell morphology. RNA-Seq analysis revealed changes in epithelium gene expression after CS are largely independent of the α7-genotype. However, the α7E260A:G genotype did reveal some unique variations to transcript expression of gene sets associated with immune responsiveness and macrophage recruitment, hypoxia, genes encoding mitochondrial respiration complex I and extracellular fibrillary matrix proteins (including alterations to fibrotic deposits in the α7G proximal airway bronchioles after CS). These results suggest α7 has a central role in modulating the response to chronic CS that could include altering susceptibility to associated lung diseases including fibrosis and cancer.

TControl: A mobile app to follow up tobacco-quitting patients

BACKGROUND AND OBJECTIVE

Tobacco smoking is a major risk factor for a wide range of respiratory and circulatory diseases in active and passive smokers. Well-designed campaigns are raising awareness to the problem and an increasing number of smokers seeks medical assistance to quit their habit. In this context, there is the need to develop mHealth Apps that assist and manage large smoke quitting programs in efficient and economic ways.

OBJECTIVES

Our main objective is to develop an efficient and free mHealth app that facilitates the management of, and assistance to, people who want to quit smoking. As secondary objectives, our research also aims at estimating the economic effect of deploying that App in the public health system.

METHODS

Using JAVA and XML we develop and deploy a new free mHealth App for Android, called TControl (Tobacco-quitting Control). We deploy the App at the Tobacco Unit of the Santa Maria Hospital in Lleida and determine its stability by following the crashes of the App. We also use a survey to test usability of the app and differences in aptitude for using the App in a sample of 31 patients. Finally, we use mathematical models to estimate the economic effect of deploying TControl in the Catalan public health system.

RESULTS

TControl keeps track of the smoke-quitting users, tracking their status, interpreting it, and offering advice and psychological support messages. The App also provides a bidirectional communication channel between patients and clinicians via mobile text messages. Additionally, registered patients have the option to interchange experiences with each other by chat. The App was found to be stable and to have high performances during startup and message sending. Our results suggest that age and gender have no statistically significant effect on patient aptitude for using TControl. Finally, we estimate that TControl could reduce costs for the Catalan public health system (CPHS) by up to € 400M in 10 years.

CONCLUSIONS

TControl is a stable and well behaved App, typically operating near optimal performance. It can be used independent of age and gender, and its wide implementation could decrease costs for the public health system.

Secondhand Tobacco Smoke Exposure and Lung Adenocarcinoma In Situ/Minimally Invasive Adenocarcinoma (AIS/MIA)

The aim of this study was to estimate the effect of exposure to secondhand tobacco smoke on the incidence of lung adenocarcinoma in situ/minimally invasive adenocarcinoma (AIS/MIA). Data from seven case-control studies participating in the International Lung Cancer Consortium (ILCCO) were pooled, resulting in 625 cases of AIS/MIA and 7,403 controls, of whom 170 cases and 3,035 controls were never smokers. Unconditional logistic regression was used to estimate adjusted ORs (ORadj) and 95% confidence intervals (CI), controlling for age, sex, race, smoking status (ever/never), and pack-years of smoking. Study center was included in the models as a random-effects intercept term. Ever versus never exposure to secondhand tobacco smoke was positively associated with AIS/MIA incidence in all subjects (ORadj = 1.48; 95% CI, 1.14-1.93) and in never smokers (ORadj = 1.45; 95% CI, 1.00-2.12). There was, however, appreciable heterogeneity of ORadj across studies (P = 0.01), and the pooled estimates were largely influenced by one large study (40% of all cases and 30% of all controls). These findings provide weak evidence for an effect of secondhand tobacco smoke exposure on AIS/MIA incidence. Further studies are needed to assess the impact of secondhand tobacco smoke exposure using the newly recommended classification of subtypes of lung adenocarcinoma.

Race, insurance type, and stage of presentation among lung cancer patients

The purpose of this study was to determine whether African-American lung cancer patients are diagnosed at a later stage than white patients, regardless of insurance type. The relationship between race and stage at diagnosis by insurance type was assessed using a Poisson regression model, with relative risk as the measure of association. The setting of the study was a large tertiary care cancer center located in the southeastern United States. Patients who were diagnosed with lung cancer between 2001 and 2010 were included in the study. A total of 717 (31%) African-American and 1,634 (69%) white lung cancer patients were treated at our facility during the study period. Adjusting for age, sex, and smoking-related histology, African-American patients were diagnosed at a statistically significant later stage (III/IV versus I/II) than whites for all insurance types, with the exception of Medicaid. Our results suggest that equivalent insurance coverage may not ensure equal presentation of stage between African-American and white lung cancer patients. Future research is needed to determine whether other factors such as treatment delays, suboptimal preventive care, inappropriate specialist referral, community segregation, and a lack of patient trust in health care providers may explain the continuing racial disparities observed in the current study.

S-PC: an e-treatment application for management of smoke-quitting patients

The main objective of this paper is to present a new program that facilitates the management of people who want to quit smoking, implemented through an e-treatment software called S-PC (Smoker Patient Control). S-PC is a web-based application that manages groups of patients, provides a bidirectional communication through mobile text messages and e-mails between patients and clinicians and offers advice and control to keep track of the patients and their status. A total of 229 patients were enrolled in the study, randomly divided into two groups, although some variables were tested to ensure that there were no significant differences between the groups that could have an impact on the outcome of the treatment. There were no significant differences between the two groups regarding the ratio/number of males/females, tobacco dependence, co-oximetry, average cigarette consumption, current age and age when smoking started. The first group was made up of 104 patients (45.4% of the total) and followed a treatment that incorporated the S-PC tool, while the second one had 125 patients without the S-PC tool. S-PC was evaluated for its effectiveness at assisting the patients to give up smoking, and its effect on clinician time management. 74% of the S-PC group completed the treatment without relapses and remained abstinent three months after the completion of the treatment, understanding abstinence as being continuous (with no relapses allowed and co-oximetry below 1 ppm) from the day of stopping. In contrast only 45.6% of the No S-PC group completed the treatment without relapses and remained abstinent three months after completion of the treatment. The rate of admittance to the program has doubled in one year and patients went from having to wait for 3 months to be immediately admitted into the program. This therapeutic e-health program aims at maximizing the number of patients that a professional can effectively help to quit smoking. In addition, the system also detects patients who are not progressing appropriately, allowing the professional to improve their treatment parameters dynamically.

Modeling the natural history and detection of lung cancer based on smoking behavior

In this study, we developed a method for modeling the progression and detection of lung cancer based on the smoking behavior at an individual level. The model allows obtaining the characteristics of lung cancer in a population at the time of diagnosis. Lung cancer data from Surveillance, Epidemiology and End Results (SEER) database collected between 2004 and 2008 were used to fit the lung cancer progression and detection model. The fitted model combined with a smoking based carcinogenesis model was used to predict the distribution of age, gender, tumor size, disease stage and smoking status at diagnosis and the results were validated against independent data from the SEER database collected from 1988 to 1999. The model accurately predicted the gender distribution and median age of LC patients of diagnosis, and reasonably predicted the joint tumor size and disease stage distribution.

Predictors of lung cancer: noteworthy cell type differences

OBJECTIVE

To study risk factors for cell types of lung cancer.

METHODS

Cohort study of 126,293 persons with 1852 subjects with incident cancer. We performed Cox proportional hazards models (8 covariates) to estimate risk of the 4 most numerous specific cell types: adenocarcinoma, squamous cell carcinoma, small cell carcinoma, and bronchioloalveolar carcinoma.

RESULTS

Smoking 1 or more cigarette packs per day was a powerful predictor (p < 0.0001) of all cell types, with hazard ratios ranging from 5.8 for bronchioloalveolar to 62.7 for squamous cell carcinoma. Other hazard ratio ranges included male/female from 0.6 (bronchioloalveolar, p < 0.05) to 2.0 (squamous, p < 0.001); black/white from 0.8 (small cell, p < 0.05) to 1.7 (squamous, p < 0.001); Asian/white from 0.8 (small cell) to 1.9 (bronchioloalveolar); and alcohol intake of 3 or more drinks per day from 1.0 (squamous) to 1.5 (adenocarcinoma, p < 0.01). College graduation and increasing body mass index were inversely related to risk of several cell types. Noteworthy sex-specific associations included increased risk of Asian vs white women for adenocarcinoma, squamous cell carcinoma and bronchioloalveolar carcinoma and substantially increased risk of adenocarcinoma in women with alcohol intake of 3 or more drinks per day.

CONCLUSIONS

These risk factor disparities for lung cancer cell types presumably reflect biologic differences. Future investigation may contribute to increased understanding of tumorigenesis and optimal treatment.

Inhibition of cholinergic signaling causes apoptosis in human bronchioalveolar carcinoma

Recent case-controlled clinical studies show that bronchioalveolar carcinomas (BAC) are correlated with smoking. Nicotine, the addictive component of cigarettes, accelerates cell proliferation through nicotinic acetylcholine receptors (nAChR). In this study, we show that human BACs produce acetylcholine (ACh) and contain several cholinergic factors including acetylcholinesterase (AChE), choline acetyltransferase (ChAT), choline transporter 1 (CHT1, SLC5A7), vesicular acetylcholine transporter (VAChT, SLC18A3), and nACh receptors (AChRs, CHRNAs). Nicotine increased the production of ACh in human BACs, and ACh acts as a growth factor for these cells. Nicotine-induced ACh production was mediated by α7-, α3β2-, and β3-nAChRs, ChAT and VAChT pathways. We observed that nicotine upregulated ChAT and VAChT. Therefore, we conjectured that VAChT antagonists, such as vesamicol, may suppress the growth of human BACs. Vesamicol induced potent apoptosis of human BACs in cell culture and nude mice models. Vesamicol did not have any effect on EGF or insulin-like growth factor-II-induced growth of human BACs. siRNA-mediated attenuation of VAChT reversed the apoptotic activity of vesamicol. We also observed that vesamicol inhibited Akt phosphorylation during cell death and that overexpression of constitutively active Akt reversed the apoptotic activity of vesamicol. Taken together, our results suggested that disruption of nicotine-induced cholinergic signaling by agents such as vesamicol may have applications in BAC therapy.

Cigarette smoking associated with lung adenocarcinoma in situ in a large case-control study (SFBALCS)

INTRODUCTION

Adenocarcinoma in situ (AIS), formerly bronchioloalveolar carcinoma, is an uncommon subtype of lung adenocarcinoma and accounts for approximately 3% to 4% of lung cancers. Compared with other lung cancer histologies, AIS patients are less likely to be smokers, yet associations with other lung cancer risk factors and differences by sex have not been determined.

METHODS

A total of 338 AIS patients and frequency-matched controls from the parent study (cases = 6039, controls = 2073) were included in these analyses. Odds ratios and 95% confidence intervals as estimates of the relative risk were obtained from multivariable unconditional logistic regression analyses.

RESULTS

Risk of AIS was associated with ever smoking (OR = 2.7, 95% confidence intervals: 2.1, 3.6), increased 20% to 30% for each 10-year increase in pack-years of smoking and decreased with increased years since quitting (p for trend <0.0001). There was no evidence that risk differed by sex but there was some suggestion that risk may differ by exposure to asbestos and by second-hand tobacco smoke exposure in whites.

CONCLUSION

There is an association between AIS and smoking, which is smaller in magnitude than the association between other subtypes of non-small-cell lung cancer and smoking. Our findings suggesting that effects may differ by exposure to asbestos and second-hand tobacco smoke should be interpreted conservatively and warrant validation and further evaluation in larger studies of AIS.

miRNAs expression profiling to distinguish lung squamous-cell carcinoma from adenocarcinoma subtypes

PURPOSE

We investigated whether miRNA expression profiles can distinguish and predict outcome of non-small-cell lung carcinoma (NSCLC) patients with different histological subtypes.

METHODS

High-throughput microarray was used to measure miRNA expression levels in six NSCLC samples. Subsequently, quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to verify findings in an independent set of 54 squamous-cell lung carcinomas (SCC), 51 lung adenocarcinomas (AD), and paired adjacent non-neoplastic lung tissue.

RESULTS

We showed that, compared to adjacent non-neoplastic lung tissues, the expressions of miR-125a-5p and let-7e were decreased in AD and SCC samples, while increased expressions of miR-93, miR-205, and miR-221 were observed in SCC samples. In addition, miR-205 expression was significantly higher in SCC patients with lymph node metastasis. Lower let-7e expression was associated with lymph node metastasis, >3 cm tumor size, and differentiation of the NSCLC AD subtype. High levels of miR-100 expression also correlated with the AD subtype in current smokers. Moreover, induction of miR-93 and miR-205 expressions and reduction of let-7e were strongly associated with shorter overall survival in SCC patients, whereas AD patient survival was only associated with reduced let-7e.

CONCLUSIONS

We identified differential expression profiles of miRNAs in AD and SCC. More importantly, in addition to morphology and immunocytochemistry approaches, we report that miR-93, miR-205, miR-221, and let-7e may represent novel biomarkers for differential diagnosis and prognosis of certain NSCLC subtypes or be new targets of histology-specific treatments. Furthermore, our results suggest a strong correlation between high expression of miR-100 and AD patients with history of heavy smoking.

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.