Gender susceptibility for cigarette smoking-attributable lung cancer: a systematic review and meta-analysis

Ten reasons to screen women at risk of lung cancer

This opinion piece reviews major reasons for promoting lung cancer screening in at-risk women who are smokers or ex-smokers, from the age of 50. The epidemiology of lung cancer in European women is extremely worrying, with lung cancer mortality expected to surpass breast cancer mortality in most European countries. There are conflicting data as to whether women are at increased risk of developing lung cancer compared to men who have a similar tobacco exposure. The sharp increase in the incidence of lung cancer in women exceeds the increase in their smoking exposure which is in favor of greater susceptibility. Lung and breast cancer screening could be carried out simultaneously, as the screening ages largely coincide. In addition, lung cancer screening could be carried out every 2 years, as is the case for breast cancer screening, if the baseline CT scan is negative.As well as detecting early curable lung cancer, screening can also detect coronary heart disease and osteoporosis induced by smoking. This enables preventive measures to be taken in addition to smoking cessation assistance, to reduce morbidity and mortality in the female population. Key points • The epidemiology of lung cancer in European women is very worrying.• Lung cancer is becoming the leading cause of cancer mortality in European women.• Women benefit greatly from screening in terms of reduced risk of death from lung cancer.

Pre-clinical lung squamous cell carcinoma mouse models to identify novel biomarkers and therapeutic interventions

Primary lung carcinoma or lung cancer (LC) is classified into small-cell or non-small-cell (NSCLC) lung carcinoma. Lung squamous cell carcinoma (LSCC) is the second most common subtype of NSCLC responsible for 30% of all LCs, and its survival remains low with only 24% of patients living for five years or longer post-diagnosis primarily due to the advanced stage of tumors at the time of diagnosis. The pathogenesis of LSCC is still poorly understood and has hampered the development of effective diagnostics and therapies. This review highlights the known risk factors, genetic and epigenetic alterations, miRNA biomarkers linked to the development and diagnosis of LSCC and the lack of therapeutic strategies to target specifically LSCC. We will also discuss existing animal models of LSCC including carcinogen induced, transgenic and xenograft mouse models, and their advantages and limitations along with the chemopreventive studies and molecular studies conducted using them. The importance of developing new and improved mouse models will also be discussed that will provide further insights into the initiation and progression of LSCC, and enable the identification of new biomarkers and therapeutic targets.

The Weakness of the Strong Sex: Differences Between Men and Women Affected by Diabetic Foot Disease

We aimed to analyze sex-related differences in clinical outcomes among patients with diabetic foot disease (DFD) managed in a third-level referral center. We retrospectively analyzed data of admissions performed in our department between 2011 and 2015 for DFD. We collected demographic and clinical data, procedures performed during the admission, and short- and long-term outcomes in terms of healing rate and healing time, major amputation, and mortality rates during the follow-up. We focused on differences between genders and tried to figure out if sex could be considered a predictive factor. We collected data from 1237 admission performed in 842 patients (615 men [73%] and 227 women [27%]; age: 68.6 ± 27.9 years; diabetes duration: 16.4 ± 13.4 years; body mass index: 28.2 ± 6.4 kg/m²; hemoglobin A1c 7.9 ± 1.9%). Men showed a higher prevalence of comorbidities and previous ulcers or revascularization procedures. Men had a significantly higher healing rate compared with women (85.4% vs 63.2%, P < .001), but a longer healing time (124 ± 27 days vs 87 ± 14 days, P = .02). Major amputation did not differ between groups, while mortality rate was significantly higher in men (24.5% vs 16.1%, P = .02). In Cox's regression analysis, male sex was a positive predictive factor for healing and a negative one for time to heal and mortality. The difference in mortality was confirmed by a Kaplan-Meier analysis (log rank test: P = .03). DFD represents a severe disease and a strong marker of mortality affecting more severely on clinical outcomes and survival on men.

Depression Is Associated with an Increased Risk of Subsequent Cancer Diagnosis: A Retrospective Cohort Study with 235,404 Patients

Background: Depression and cancer share common risk factors and mechanisms of disease. The current literature has not explored the effect of depression on cancer risk. We assessed the difference in cancer risk in patients with and without depression in a large cohort in Germany. Methods: We compared cancer risk and incidence in patients with and without depression aged 18 or above diagnosed between 2015 and 2018 documented in the Disease Analyzer Database. Patients from a comparator group were matched 1:1 to patients with depression based on propensity scores. Patients with previous bipolar disorder (F31), mania (F30) or schizophrenia (F20-29) and cancer diagnosis 3 years prior to index date were excluded. Analyses were stratified by cancer type, age group, and gender. Results: A total of 117,702 patients with depression were included and matched 1:1, resulting in a cohort overall of 235,404. 4.9% of patients with depression compared to 4.1% without depression received at least one cancer diagnosis over 3.9 years median follow-up. The depression group showed an 18% increase in risk for a cancer diagnosis overall, with largest increased risk in lung cancer (HR: 1.39 [1.21-1.60], p < 0.0001), cancers of the gastro-intestinal-tract (HR: 1.30 [1.15-1.46], p < 0.0001), breast (HR: 1.23 [1.12-1.35], p < 0.0001) and urinary (HR: 1.23 [1.06-1.43], p < 0.01). Similarly, the incidence of cancer diagnosis overall increased by 22% for depressed patients. IRs showed no difference across cancer types. Conclusions: Depression increased the risk for cancer diagnosis consistently independent of the comparison method used. The potential mediating factors or shared mechanisms of the disease require further investigation.

Burden of Cancer Due to Cigarette Smoking and Alcohol Consumption in Korea

This study aimed to estimate the burden of cancer in Koreans attributable to smoking and alcohol consumption using disability-adjusted life years and population attributable fractions. We estimated the burden of 12 cancers due to simultaneous and independent smoking and alcohol exposure in Koreans aged ≥40 years. In men, the cancer burden attributable to the combined risk factors, smoking alone, and alcohol consumption alone were 9.5, 14.8, and 6.1%, respectively; the corresponding values for women were 1.1, 2.5, and 2.7%, respectively. In men, tracheal, bronchial, and lung cancers were the most common cancer types. The disease burden may have been reduced by 16.8, 32.3, and 4.1% in the absence of the combined risk factors, smoking alone, and alcohol consumption alone, respectively. Our findings suggest that risk factor-based intervention may have the greatest preventative effect for lung cancer among all cancers in men. Our real-world data methodology could provide further evidence-based methods to explore and facilitate effective health promotion interventions for specific target groups and may lay the foundation for the establishment of healthcare services according to population subgroups or regional characteristics.

Fish Intake, Dietary Polyunsaturated Fatty Acids, and Lung Cancer: Systematic Review and Dose-Response Meta-Analysis of 1.7 Million Men and Women

To determine the association between fish intake and dietary polyunsaturated fatty acids (PUFA) and incidence of lung cancer. We systematically reviewed and meta-analyzed all available studies to quantify the associations of fish and PUFA consumption with risk of lung cancer. Relative risk (RR) with 95% confidence interval (CI) was calculated. 13 population-based prospective cohort studies involving 1,785,000 participants and two randomized control trials were included. Our study demonstrated that dietary PUFA significant reduced risk of lung cancer for men (RR 0.99, 95%CI 0.98 to 1.00) and the U.S. population (RR 0.99, 95%CI 0.98 to 1.00). Dose-response analysis indicated that a 5 g/day increment of dietary PUFA was associated with 5% lower risk of lung cancer (RR 0.95, 95%CI 0.91 to 0.99). In addition, PUFA supplementation is significant improved overall survival in patients with lung cancer (RR 1.98, 95%CI 1.09 to 3.59). Our study showed an inverse association between dietary PUFA and risk of lung cancer in males and among the U.S. population. Although smoking cessation is the single biggest factor associated with lung cancer risk reduction, this study adds to a growing body of evidence that diet may have a role in modestly reducing lung cancer risk.

The role of gender in non-small cell lung cancer: a narrative review

The role of gender in the development, treatment and prognosis of thoracic malignancies has been underappreciated and understudied. While most research has been grounded in tobacco-related malignancies, the incidence of non-smoking related lung cancer is on the rise and disproportionately affecting women. Recent research studies have unveiled critical differences between men and women with regard to risk factors, timeliness of diagnosis, incongruent screening practices, molecular and genetic mechanisms, as well as response to treatment and survival. These studies also highlight the increasingly recognized need for targeted therapies that account for variations in the response and complications as a function of gender. Similarly, screening recommendations continue to evolve as the role of gender is starting to be ellucidated. As women have been underrepresented in clinical trials until recently, the data regarding optimal care and outcomes is still lagging behind. Understanding the underlying similarities and differences between men and women is paramount to providing adequate care and prognostication to patients of either gender. This review provides an overview of the critical role that gender plays in the care of patients with non-small cell lung cancer and other thoracic malignancies, with an emphasis on the need for increased awareness and further research to continue elucidating these disparities.

Synchronous bone metastasis in lung cancer: retrospective study of a single center of 15,716 patients from Tianjin, China

Background

This study aimed to describe the incidence, clinical characteristics, and prognosis of lung cancer patients with synchronous bone metastasis (SBM) and to analyze the prognostic factors of the lung cancer patients with SBM.

Methods

A total of 15,716 lung cancer patients who were diagnosed between 2009 to 2018 in the Tianjin Medical University Cancer Institute and Hospital were retrospectively reviewed. Among them, patients with SBM were checked. Both the demographic and clinical characteristics were included as follows: age, gender, marital status, history of smoking, alcohol consumption, family history of tumor, Karnofsky score, lymph node metastasis, histological type. Besides, laboratory data such as alkaline phosphatase, lactate dehydrogenase, carcinoembryonic antigen, squamous cell carcinoma antigen, cytokeratin-19 fragment, and neuron specific enolase were also included. The log-rank test and multivariate Cox regression analysis were employed to reveal the potential prognostic predictors. A further analysis using the Kaplan–Meier was employed to demonstrate the difference on the prognosis of LC patients between adenocarcinoma and non-adenocarcinoma.

Results

Among the included patients, 2738 patients (17.42%) were diagnosed with SBM. A total of 938 patients (34.3%) with SBM were successfully followed and the median survival was 11.53 months (95%CI: 10.57–12.49 months), and the 1-, 2-, and 5-year overall survival rate was 51, 17, and 8%, respectively. Multivariable Cox regression results showed history of smoking and high level of NSE were associated with the poor prognosis, while adenocarcinoma histological type was associated with better survival.

Conclusion

The prevalence of SBM in lung cancer is relatively high with poor survival. The lung cancer patients with SBM showed diverse prognosis. Among all the pathological types, the division of adenocarcinoma suggested different prognosis of the lung cancer patients with SBM. The present study emphasized the importance of pathological diagnosis on prognostic determinants in lung cancer patients with SBM.

Sex and Survival After Surgery for Lung Cancer: A Swedish Nationwide Cohort

BACKGROUND

Prior reports on a possible female survival advantage in both surgical and nonsurgical cohorts of patients with lung cancer are conflicting. Previously reported differences in survival after lung cancer surgery could be the result of insufficient control for disparities in risk factor profiles in men and women.

RESEARCH QUESTION

Do women who undergo pulmonary resections for lung cancer have a better prognosis than men when taking a wide range of prognostic factors into account?

STUDY DESIGN AND METHODS

We performed a nationwide population-based observational cohort study analyzing sex-specific survival after pulmonary resections for lung cancer. We identified 6356 patients from the Swedish National Quality Register for General Thoracic Surgery and performed individual-level record linkage to other national health-data registers to acquire detailed information regarding comorbidity, socioeconomic status, and vital status. Inverse probability of treatment weighting was used to account for differences in baseline characteristics. The association between female sex and all-cause mortality was assessed with Cox regression models, and flexible parametric survival models were used to estimate the absolute survival differences with 95% CIs. We also estimated the difference in restricted mean survival time.

RESULTS

We observed a lower risk of death in women compared with men (hazard ratio, 0.73; 95% CI, 0.67-0.79). The absolute survival difference at 1, 5, and 10 years was 3.0% (95% CI, 2.2%-3.8%), 10% (95% CI, 7.0%-12%), and 12% (95% CI, 8.5%-15%), respectively. The restricted mean survival time difference at 10 years was 0.84 year (95% CI, 0.61-1.07 years). The findings were consistent across several subgroups.

INTERPRETATION

Women who underwent pulmonary resections for lung cancer had a significantly better prognosis than men. The survival advantage was evident regardless of age, common comorbidities, socioeconomic status, lifestyle factors, physical performance, type and extent of surgery, tumor characteristics, and stage of disease.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT03567538; URL: www.clinicaltrials.gov.

Increasing trends in the prevalence of prior cancer in newly diagnosed lung, stomach, colorectal, breast, cervical, and corpus uterine cancer patients: a population-based study

Background

Cancer survivors are frequently excluded from clinical research, resulting in their omission from the development of many cancer treatment strategies. Quantifying the prevalence of prior cancer in newly diagnosed cancer patients can inform research and clinical practice. This study aimed to describe the prevalence, characteristics, and trends of prior cancer in newly diagnosed cancer patients in Japan.

Methods

Using Osaka Cancer Registry data, we examined the prevalence, characteristics, and temporal trends of prior cancer in patients who received new diagnoses of lung, stomach, colorectal, female breast, cervical, and corpus uterine cancer between 2004 and 2015. Site-specific prior cancers were examined for a maximum of 15 years before the new cancer was diagnosed. Temporal trends were evaluated using the Cochran-Armitage trend test.

Results

Among 275,720 newly diagnosed cancer patients, 21,784 (7.9%) had prior cancer. The prevalence of prior cancer ranged from 3.3% (breast cancer) to 11.1% (lung cancer). In both sexes, the age-adjusted prevalence of prior cancer had increased in recent years (P values for trend < 0.001), especially in newly diagnosed lung cancer patients. The proportion of smoking-related prior cancers exceeded 50% in patients with newly diagnosed lung, stomach, colorectal, breast, and cervical cancer.

Conclusions

The prevalence of prior cancer in newly diagnosed cancer patients is relatively high, and has increased in recent years. Our findings suggest that a deeper understanding of the prevalence and characteristics of prior cancer in cancer patients is needed to promote more inclusive clinical research and support the expansion of treatment options.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08011-3.

The molecular basis of gender disparities in smoking lung cancer patients

AIMS

Gender disparities exist in smoking-related lung cancer epidemiology, but the molecular basis has not been explored so far. We aimed at identifying genes with gender-bias expression pattern in smoking lung cancer patients for understanding the molecular basis of gender bias in smokers using meta-analysis of microarray gene expression data.

MATERIALS AND METHODS

Transcriptome of around 1100 samples from 13 studies were used in the meta-analysis to identify 'Lung Cancer genes specific to Female-Smokers' (LCFS) and 'Lung Cancer genes specific to Male-Smokers' (LCMS). The expression profiles of these genes were validated with an independent microarray report and TCGA-RNA-sequencing data. The molecular interactions, pathway, and other functional annotations were portrayed for the key genes identified.

KEY FINDINGS

We identified 1159 gender-biased genes in smoking lung cancer patients. Of these, 400 and 474 genes showed differential expression in cancerous compared to normal lung of women (LCFS) and men (LCMS), respectively. While many up-regulated LCFS were involved in 'immune responses' including T-cell activation, leukocyte cell-cell adhesion, the LCMS were mainly involved in 'positive regulation of gene expression', signaling pathways including RAS, VEGF, insulin-receptor signaling, and 'cell cycle'.

SIGNIFICANCE

The strategic-method identified genes, particularly, SNX20, GIMAP6, MTMR2, FAM171B, IDH1, MOBP, FBXO17, LPXN and WIPF1, which were consistently differentially expressed in at least 4 studies, and in agreement with RNA-Seq data. Exploring their functions could be beneficial to the gender-based diagnosis, prognosis, and treatment of lung cancer in smokers. The current meta-analysis supports existing knowledge of sexual-dimorphism of immune responses in cancer.

Sex-specific association between type 1 diabetes and the risk of end-stage renal disease: a systematic review and meta-analysis

PURPOSE

This meta-analysis was conducted given the inconsistent findings of studies regarding the sex discrepancy in the relationship between type 1 diabetes (T1D) and the risk of end-stage renal disease (ESRD).

METHODS

Articles published on PubMed between January 1, 1966 and March 31, 2019 were systematically retrieved without language restrictions. The included articles all presented sex-specific data of the incidence rate ratio, standardized incidence or mortality ratio, hazard ratio, relative risk, or odds ratio, or provided data to estimate the association between T1D and ESRD or kidney disease-related mortality. The gender-specific effect estimates and pooled ratio (female-to-male) for ESRD and for deaths from T1D-related renal disease were acquired via a random-effects meta-analysis with inverse variance weighting, regardless of heterogeneity evaluated based on the I² statistic.

RESULTS

Nineteen studies, including 122,842 individuals, were finally selected for this meta-analysis. Sex differences in effect estimates were found in ESRD (pooled ratio = 0.81 (95% confidence interval 0.69-0.94)) with considerable heterogeneity (I² = 66.9%), but not in mortality with T1D-associated renal disease.

CONCLUSION

Women with T1D have a lower risk of ESRD compared with that in men, but this finding may be biased by potential confounding factors and must be verified by other well-planned prospective studies.

Incidence and death in 29 cancer groups in 2017 and trend analysis from 1990 to 2017 from the Global Burden of Disease Study

Background and aims

Cancer has become the second most serious disease threatening human health, followed by cardiovascular diseases. This study aimed to quantitatively estimate the mortality, morbidity, and analyze the trends of 29 cancer groups in 195 countries/regions between 1990 and 2017.

Methods

Detailed information of 29 cancer groups were collected from the Global Burden of Disease (GBD) study in 2017 and age-standardized incidence rates (ASIR) and age-standardized death rates (ASDR) of 29 cancer groups were calculated based on gender, age, region, and country. Trend analyses were conducted for major cancer types.

Results

In 2017, the global death population caused by cancer reached 9 million, which was nearly twice the number in 1990. The ASDR and ASIR of cancer in males were about 1.5 times those of females. Breast cancer showed the highest mortality rate in females in 2017. Individuals aged over 50 are at high risk of developing cancer and the number of cases and deaths in this age group accounted for more than 80% of all cancers in all age groups. Asia has the heaviest cancer burden due to its large population density. Different cancers in varied countries globally have their own characteristics. The ASDR and ASIR of some major cancers demonstrated changes from 1990 to 2017.

Conclusions

Analyses of these data provided basis for future investigations to the common etiological factors, leading to the occurrence of different cancers, the development of prevention strategies based on local characteristics, socioeconomic and other conditions, and the formulation of more targeted interventions.

Electronic supplementary material

The online version of this article (10.1186/s13045-019-0783-9) contains supplementary material, which is available to authorized users.

ADA activity is decreased in lymphocytes from patients with advanced stage of lung cancer

Cigarette smoking is directly associated with lung cancer. Non-small cell lung carcinoma (NSCLC) represents approximately 80% from all types of lung cancer. This latter is hard to diagnose and to treat due to the lack of symptoms in early stages of the disease. The aim of this study was to evaluate ADA activity and the expression of P2X7, A1, and A2A receptors and in lymphocytes. In addition, the profile of pro-inflammatory and anti-inflammatory cytokines serum levels of patients with lung cancer in advanced stage was evaluated. Patients (n = 13) previously treated for lung cancer at stage IV (UICC) with chemotherapy had their blood collected. Cancer patients showed a decrease in ADA activity and an increase in A1 receptor expression in lymphocytes when compared to the control group. Moreover, patients exhibited an increase in IL-6 and TNF-α, while IL-17 and INF-ϒ serum levels were lower in patients with lung cancer. The decreased ADA activity and the increase in A1 receptor expression may contribute to adenosine pro-tumor effects by increasing IL-6 and TNF-α and decreasing IL-17 and INF-γ serum levels. Our data show an indirect evidence that purinergic signaling may have a role in promoting a profile of cytokines levels that favors tumor progression.

Epidemiological Study of Lung Cancer Incidence in Lebanon

Background and Objectives: Lung cancer (LC) is the most common cancer in the world. Developing countries in the Middle East and North Africa (MENA) region, including Lebanon, have witnessed a great increase in the incidence rates of this disease. The aim of our study is to investigate the incidence rates of lung cancer in Lebanon from 2005 to 2015 and to compare these rates to other countries from the MENA region and other regions of the world. Material and Methods: Lung cancer data for the years 2005-2015 were collected from the National Cancer Registry of Lebanon and stratified by gender and age group. Age-specific and age-standardized incidence rates were calculated and analyzed using joinpoint regression. Age-standardized incidence rates to the world population (ASR(w)) for other countries were obtained from two online databases. Results: Lung cancer ranked as the second most common cancer in Lebanon and accounted for 9.2% of all newly diagnosed cancers. Lung cancer ASR(w) showed a significantly increasing trend over the period studied for males and females. Lung cancer ASR(w) among males in Lebanon came second after Malta when compared to other MENA countries, but it was among the lowest when compared to non-MENA countries. For females, Lebanon ranked first when compared to other MENA countries but was among the lowest when compared to countries in other regions of the world. The lung cancer incidence rate increased with age in both sexes and 89.2% of patients were 50 years of age or older. Conclusion: Lebanon has the highest incidence of LC in females and the second highest for males in the MENA region. The lung cancer incidence rate is on the rise and older age groups are much more burdened by this disease than the young ones. Several risk factors, particularly smoking, play a role in increased LC incidence among the Lebanese population.

Dysregulation of lipid metabolism induced by airway exposure to polycyclic aromatic hydrocarbons in C57BL/6 mice

Polycyclic aromatic hydrocarbons (PAHs), originated from cigarette smoke and fine particle matter (PM2.5), are important inducers of lung cancer. Lipid metabolic disorder is an important biological feature in the progression of lung cancer. However, the dysregulation of lipid metabolism induced by airway exposure to PAHs remains unknown. In this study, an untargeted lipidomics approach was performed to characterize the effects of airway exposure to benzo[a]pyrene (BaP) on lipid metabolism of C57BL/6 mice. Lipidome of serum samples were analyzed with an ultra-performance liquid chromatography coupled with quadrupole-orbitrap mass spectrometer. Lipid profiling and multivariate statistical analysis results demonstrated that airway exposure to BaP mainly disturbed glycerophospholipid metabolism of mice. Moreover, sex-dependent and time-dependent effects of BaP exposure on lipids profile of mice were observed. Several phosphatidylcholines (PCs), Lysophosphatidylcholines (LysoPCs), phosphatidylethanolamines (PEs), Lysophosphatidylethanolamines (LysoPEs) and phosphatidylinositols (PIs) were significantly down-regulated in mice serum after BaP exposure. Meanwhile, these altered lipids showed different susceptibility and change trends in male and female mice. Our results are corresponding with the lipid metabolic alterations induced by cigarette smoke and PM2.5 in animals or human. Compared with the dysregulation of lipid metabolism in patients with lung cancer, these results indicated that the lipid metabolism response to PAHs airway exposure may contribute to the lung cancer progression.

The Relevance of Gender in Tumor-Influencing Epigenetic Traits

Tumorigenesis as well as the molecular orchestration of cancer progression are very complex mechanisms that comprise numerous elements of influence and regulation. Today, many of the major concepts are well described and a basic understanding of a tumor's fine-tuning is given. Throughout the last decade epigenetics has been featured in cancer research and it is now clear that the underlying mechanisms, especially DNA and histone modifications, are important regulators of carcinogenesis and tumor progression. Another key regulator, which is well known but has been neglected in scientific approaches as well as molecular diagnostics and, consequently, treatment conceptualization for a long time, is the subtle influence patient gender has on molecular processes. Naturally, this is greatly based on hormonal differences, but from an epigenetic point of view, the diverse susceptibility to stress and environmental influences is of prime interest. In this review we present the current view on which and how epigenetic modifications, emphasizing DNA methylation, regulate various tumor diseases. It is our aim to elucidate gender and epigenetics and their interconnectedness, which will contribute to understanding of the prospect molecular orchestration of cancer in individual tumors.

Risk of lung cancer in relation to various metrics of smoking history: a case-control study in Montreal

Background

Few epidemiologic findings are as well established as the association between smoking and lung cancer. It is therefore somewhat surprising that there is not yet a clear consensus about the exposure-response relationships between various metrics of smoking and lung cancer risk. In part this is due to heterogeneity of how exposure-response results have been presented and the relative paucity of published results using any particular metric of exposure. The purposes of this study are: to provide new data on smoking-lung cancer associations and to explore the relative impact of different dimensions of smoking history on lung cancer risk.

Methods

Based on a large lung cancer case-control study (1203 cases and 1513 controls) conducted in Montreal in 1996–2000, we estimated the lifetime prevalence of smoking and odds ratios in relation to several smoking metrics, both categorical and continuous based on multivariable unconditional logistic regression.

Results

Odds ratios (ORs) for ever vs never smoking were 7.82 among males and 11.76 among females. ORs increased sharply with every metric of smoking examined, more so for duration than for daily intensity. In models using continuous smoking variables, all metrics had strong effects on OR and mutual adjustment among smoking metrics did not noticeably attenuate the OR estimates, indicating that each metric carries some independent risk-related information. Among all the models tested, the one based on a smoking index that integrates several smoking dimensions, provided the best fitting model. Similar patterns were observed for the different histologic types of lung cancer.

Conclusions

This study provides many estimates of exposure-response relationships between smoking and lung cancer; these can be used in future meta-analyses. Irrespective of the histologic type of lung cancer and the smoking metric examined, high levels of smoking led to high levels of risk, for both men and women.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5144-5) contains supplementary material, which is available to authorized users.

Smoking as a risk factor for lung cancer in women and men: a systematic review and meta-analysis

OBJECTIVES

To investigate the sex-specific association between smoking and lung cancer.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

We searched PubMed and EMBASE from 1 January 1999 to 15 April 2016 for cohort studies. Cohort studies before 1 January 1999 were retrieved from a previous meta-analysis. Individual participant data from three sources were also available to supplement analyses of published literature.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Cohort studies reporting the sex-specific relative risk (RR) of lung cancer associated with smoking.

RESULTS

Data from 29 studies representing 99 cohort studies, 7 million individuals and >50 000 incident lung cancer cases were included. The sex-specific RRs and their ratio comparing women with men were pooled using random-effects meta-analysis with inverse-variance weighting. The pooled multiple-adjusted lung cancer RR was 6.99 (95% Confidence Interval (CI) 5.09 to 9.59) in women and 7.33 (95% CI 4.90 to 10.96) in men. The pooled ratio of the RRs was 0.92 (95% CI 0.72 to 1.16; I2=89%; p<0.001), with no evidence of publication bias or differences across major pre-defined participant and study subtypes. The women-to-men ratio of RRs was 0.99 (95% CI 0.65 to 1.52), 1.11 (95% CI 0.75 to 1.64) and 0.94 (95% CI 0.69 to 1.30), for light, moderate and heavy smoking, respectively.

CONCLUSIONS

Smoking yields similar risks of lung cancer in women compared with men. However, these data may underestimate the true risks of lung cancer among women, as the smoking epidemic has not yet reached full maturity in women. Continued efforts to measure the sex-specific association of smoking and lung cancer are required.

Cigarette smoking as a risk factor for type 2 diabetes in women compared with men: a systematic review and meta-analysis of prospective cohort studies

Background

Few studies have investigated the effect of smoking on type 2 diabetes in women compared with men, even though several epidemiological studies provided a clear picture of the risk among the entire population.

Methods

We systematically searched PubMed and Embase up to August 2017 for prospective studies that were stratified by sex with measures of the relative risk (RR) for type 2 diabetes and current smoking compared with non-smoking. The sex-specific RRs and their ratios (RRRs), comparing women with man, were pooled using random-effects models.

Results

Seventeen articles were identified including 20 prospective cohorts with 5 077 289 participants and 223 084 incident cases of type 2 diabetes. The pooled RRR suggested a similar risk of type 2 diabetes associated with smoking in women compared with men (RRR: 0.98, 95% confidence interval [CI]: 0.96–1.01). Furthermore, no significant sex difference in the RR was found between former smokers and those who had never smoked (RRR: 0.98, 95% CI: 0.92–1.04).

Conclusions

The findings of this meta-analysis indicate that female smokers had similar risk of type 2 diabetes with male smokers.

Prognostic score for life expectancy evaluation of lung cancer patients after bone metastasis

BACKGROUND

This study identifies the overall survival status of lung cancer patients with bone metastasis and metastasis patterns. Poor prognostic factors were identified to develop a scoring system for estimating survival period after bone metastasis.

METHODS

A retrospective cohort analysis was performed at Chiang Mai University for the period January 1, 2006 and December 31, 2013. Time-to-event analysis was performed to estimate survival rate. The primary end point was death related to lung cancer. Univariate and multivariate analysis of the prognostic variables was done using the Cox's regression model. The score was derived from the corresponding estimated regression coefficients of significantly poor prognostic factors.

RESULTS

A total of 505 lung cancer with bone metastasis patients were analyzed. Four hundred two cases (79.6%) were concurrent diagnosis and 103 (20.4%) were subsequent diagnosis. The median survival time of lung cancer after bone metastasis 148 days. Male gender and ECOG 3-4 were significant poor prognostic factors for lung cancer after bone metastasis, with hazard ratios of 1.42 (95% CI 1.17-1.73), and 1.30 (95% CI 1.06-1.60), respectively. Prognosis score was determined using the binary term present/not-present for those factors. The curve from prognostic score summations of 2, 1 and 0 presented a good discrimination of survival expectancy, showing an expected median survival time of approximately 109, 146, and 225 days, respectively.

CONCLUSIONS

Prognostic score is a clinically simple and easy method for estimating life expectancy and for guiding interventions in bone metastasis of lung cancer.

Gendermetrics of cancer research: results from a global analysis on lung cancer

BACKGROUND

Cancer research is critically dependent on a continuous recruitment of junior research staff that devotes its academic life not only to clinical duties but also to basic and translational research. The present study aims to elucidate the success concerning gender equality in cancer research in the last decade (from 2008 to 2016) with lung cancer as the target parameter.

MATERIALS AND METHODS

On the basis of the Gendermetrics Platform, a total of 19,724 articles related to lung cancer research were analyzed. The key method was the combined analysis of the proportion of female authorships and the female-to-male odds ratio for first, co- and last authorships. The distribution of prestigious authorships was measured by the Prestige Index.

RESULTS

31.3% of all authorships and 35.2% of the first, 32.2% of the co- and 22.1% of the last authorships were held by women. The corresponding female-to-male odds ratio is 1.22 (CI: 1.18-1.27) for first, 1.19 (CI: 1.16-1.23) for co- and 0.59 (CI: 0.57-0.61) for last authorships. Women are underrepresented at prestigious authorships compared to men (Prestige Index = -0.22). The female underrepresentation accentuates in articles with many authors that attract the highest citation rates.

CONCLUSIONS

While the current system promotes early career promotion of women, men still outnumber women in leadership positions. However, this male-female career dichotomy has been narrowed in the last decade and will likely be further reduced in the next decade.

Trends in lung cancer incidence in Lebanon by gender and histological type over the period 2005-2008

Introduction: Lung cancer incidence rates, overall and by histologic subtypes, vary substantially by gender and smoking. This study’s aim was to review data regarding trends in the number of cases of different lung-cancer histologies and relate these to smoking habits by gender in Lebanon.

Materials and methods: Lung cancer data using ICD-O, 3rd edition, from the Lebanese National Cancer Registry from 2005 to 2008 were stratified by gender for histology type for patients aged over 18 years.

Results: Lung cancer cases among males were 2.5 times higher than those in females. The most common lung cancer histology type for males and females was adenocarcinoma for all observed years. The proportion of squamous cell carcinoma in incident cases was significantly higher in males than in females for the total period from 2005 to 2008, P = 0.032, but not in individual years. The ratio of adenocarcinoma to squamous cell carcinoma in incident cases between 2005 and 2008 was 2:45 for males and 3:15 for females.

Conclusion: Lung cancer histology in Lebanon is following a pattern similar to that found in most countries of North America and in Europe, where adenocarcinoma is the most prevalent subtype among both males and females.

Women Epidemiology Lung Cancer (WELCA) study: reproductive, hormonal, occupational risk factors and biobank

Background

Lung cancer aetiology and clinical aspects have been mainly studied in men, although specific risk factors probably exist in women. Here we present the rationale, design and organization of the WELCA study (Women Epidemiology Lung CAncer) that has been launched to investigate lung cancer in women, focusing particularly on hormonal and occupational factors.

Methods/Design

WELCA is a population based case-control study and planned to recruit 1000 cases and 1000 controls in three years, based on study power calculation. Eligible cases are female patients newly diagnosed with lung cancer, living in Paris and the Ile de France area and aged up to 75 years. Almost all Parisian pneumology and oncology clinical departments are involved. The control group is a random sample of the population living in the same area, frequency-matched on age and additionally stratified on the distribution of socio-professional categories of women residing there. After acquisition of written consent, research nurses administer standardized computer assisted questionnaires to all the subjects in face-to-face interviews and acquire anthropometric measures. Besides usual socio-demographic characteristics, information is gathered about menstrual and reproductive factors, hormonal treatments, lifestyle and leisure characteristics, occupational history, personal and familial medical history. Biological samples are also collected, in order to establish a biobank for molecular epidemiology studies. Molecular characteristics of the tumours will be obtained and patients will be followed up for five years.

Discussion

The WELCA study aims to answer key questions in lung cancer aetiology and clinical characteristics specifically in women. The role of hormonal impregnation is investigated, and the interactions with cigarette smoking or body mass index (BMI) will be analyzed in detail. The occupational history of the subjects is carefully reconstructed, focusing in particular on the service sector. The creation of a biobank for collection of serum, plasma, DNA and tumour tissue will allow the genetic and biochemical characterization of both the subjets and the tumours. The follow-up of the patients will help in disentangling the role of hormonal factors and tumour molecular characteristics in survival.

Blood-based omic profiling supports female susceptibility to tobacco smoke-induced cardiovascular diseases

We recently reported that differential gene expression and DNA methylation profiles in blood leukocytes of apparently healthy smokers predicts with remarkable efficiency diseases and conditions known to be causally associated with smoking, suggesting that blood-based omic profiling of human populations may be useful for linking environmental exposures to potential health effects. Here we report on the sex-specific effects of tobacco smoking on transcriptomic and epigenetic features derived from genome-wide profiling in white blood cells, identifying 26 expression probes and 92 CpG sites, almost all of which are affected only in female smokers. Strikingly, these features relate to numerous genes with a key role in the pathogenesis of cardiovascular disease, especially thrombin signaling, including the thrombin receptors on platelets F2R (coagulation factor II (thrombin) receptor; PAR1) and GP5 (glycoprotein 5), as well as HMOX1 (haem oxygenase 1) and BCL2L1 (BCL2-like 1) which are involved in protection against oxidative stress and apoptosis, respectively. These results are in concordance with epidemiological evidence of higher female susceptibility to tobacco-induced cardiovascular disease and underline the potential of blood-based omic profiling in hazard and risk assessment.

Carboxamide analog ITR-284 evokes apoptosis and inhibits migration ability in human lung adenocarcinoma A549 cells

Lung adenocarcinoma is the most common type of lung cancer and found in both smokers and non-smokers, but the treatment of lung cancer is limited. ITR-284 has been shown to be a potent carboxamide-derived anticancer agent and to induce apoptosis in leukemia and colon cancer cells. However, little is known whether ITR-284 has anticancer activity in human lung adenocarcinoma cells through induction of apoptosis and suppression of migration in vitro. We showed that ITR-284 inhibited human lung cancer A549 cells using the thiazolyl blue tetrazolium bromide (MTT) assay and evoked apoptosis via the cell cycle distribution at S phase arrest. After treatment with 20 nM ITR-284 for 24 h, apoptotic cells were induced and detected by Annexin V-FITC/PI staining. The production of reactive oxygen species (ROS) was dose-dependently increased in A549 cells caused by ITR-284. The results from immunoblotting analysis showed an elevation of protein levels of p53 and phosphorylation of p53 in A549 cells prior to ITR-284 exposure. Additionally, apoptosis-associated proteins such as Bax, cleaved caspase-3 and cleaved PARP were upregulated after ITR-284 treatment. By wound healing assay, low concentrations (1-5 nM) of ITR-284 exerted a greater effect on inhibition of A549 cell migration. The protein levels of E-cadherin and vimentin, which are the epithelial-mesenchymal transition (EMT) markers, were modulated in ITR-284-treated cells assessed by western blot analysis. Taken together, our data suggest that ITR-284 may be an effective anticancer agent for treating lung adenocarcinoma.

The regulation of cancer cell migration by lung cancer cell-derived exosomes through TGF-β and IL-10

Tumorigenesis has been considered to be as a result of abnormal cell-cell communication. It has been proposed that exosomes act as communicators between tumors and their microenvironment and have been demonstrated to be involved in tumorigenesis and subsequent metastasis. However, the mechanisms underlying the role of exosomes in these processes remains elusive. The present study sought to determine the underlying mechanisms. Using two lung cancer cell lines, it was demonstrated that exosomes derived from metastatic small cell lung cancer cells (NCI-H1688) have greater effects on cancer cell migration, compared with exosomes derived from primary non-small cell lung cancer cells (NCI-H2228). Further characterization of the contents of the exosomes demonstrated that there were increased levels of TGF-β and IL-10 in exosomes from NCI-H1688 cells compared with exosomes derived from NCI-H2228 cells, in particular under hypoxia. Blockade of TGF-β and IL-10 with antibodies confirmed that these cytokines were essential for the regulation of cancer cell migration. Taken together, the results of the present study indicated that exosomes derived from cancer cells regulated the cellular migration of tumor cells through TGF-β and IL-10, which may provide a novel approach for developing therapeutic methods against cancer.

Screening for lung cancer using low-dose computed tomography: concerns about the application in low-risk individuals

Low-dose computed tomography (LDCT) has been increasingly accepted as an efficient screening method for high-risk individuals to reduce lung cancer mortality. However, there remains a gap of knowledge in the practical implementation of screening on a larger scale, especially for low-risk individuals. The aim of this study is to initiate discussion through an evidence-based analysis and provide valuable suggestions on LDCT screening for lung cancer in clinical practice. Among previously published randomized controlled trials (RCTs), the National Lung Screening Trial (NLST) is the only one demonstrating positive results in a high-risk population of old age and heavy smokers. It is also shown that the potential harms include false-positive findings, radiation exposure etc., but its magnitude is uncertain. In the meantime, the current risk stratification system is inadequate, and is difficult to define selection criteria. Thus, the efficacy of LDCT in lung cancer screening needs to be confirmed in future trials, and the procedure should not be proposed to individuals without comparable risk to those in the NLST. Furthermore, there is a lack of evidence to support the expansion of LDCT screening to low-risk individuals. Therefore, recommendation of LDCT screening for these patients could be premature in clinical practice although some of them might be missed based on current definition of risk factors. Further studies and advances in risk assessment tools are urgently needed to address the concerns about lung cancer screening in order to improve the outcomes of lung cancer.