Lung cancer incidence in never smokers

Reproductive and Hormonal Factors in Relation to Lung Cancer Among Nepali Women

Background: Of the 1.8 million global incident lung cancer cases estimated in 2012, approximately 60% occurred in less developed regions. Prior studies suggest sex differences in lung cancer risk and a potential role for reproductive and hormonal factors in lung cancer among women. However, the majority of these studies were conducted in developed regions. No prior study has assessed these relationships among Nepali women.

Methods: Using data from a hospital-based case-control study conducted in B. P. Koirala Memorial Cancer Hospital (Nepal, 2009–2012), relationships between reproductive and hormonal factors and lung cancer were examined among women aged 23–85 years. Lung cancer cases (n = 268) were frequency-matched to controls (n = 226) based on age (±5 years), ethnicity and residential area. The main exposures in this analysis included menopausal status, age at menarche, age at menopause, menstrual duration, gravidity, and age at first live-birth. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression.

Results: Among postmenopausal women, those with a younger age at menopause (<45 years; 45–49 years) had an increased odds of lung cancer compared to those with an older (≥50 years) age at menopause [OR (95%CI): 2.14 (1.09, 4.17); OR (95% CI): 1.93 (1.07, 3.51)], after adjusting for age and cumulative active smoking years. No statistically significant associations were observed with the other reproductive and hormonal factors examined.

Conclusion: These results suggest that Nepali women with prolonged exposure to endogenous ovarian hormones, via later age at menopause, may have a lower odds of lung cancer.

Spatial Analysis of Built Environment Risk for Respiratory Health and Its Implication for Urban Planning: A Case Study of Shanghai

Urban planning has been proven and is expected to promote public health by improving the built environment. With a focus on respiratory health, this paper explores the impact of the built environment on the incidence of lung cancer and its planning implications. While the occurrence of lung cancer is a complicated and cumulative process, it would be valuable to discover the potential risks of the built environment. Based on the data of 52,009 lung cancer cases in Shanghai, China from 2009 to 2013, this paper adopts spatial analytical methods to unravel the spatial distribution of lung cancer cases. With the assistance of geographic information system and Geo-Detector, this paper identifies certain built environments that are correlated with the distribution pattern of lung cancer cases in Shanghai, including the percentage of industrial land (which explains 28% of the cases), location factors (11%), and the percentages of cultivated land and green space (6% and 5%, respectively). Based on the quantitative study, this paper facilitates additional consideration and planning intervention measures for respiratory health such as green buffering. It is an ecological study to illustrate correlation that provides approaches for further study to unravel the causality of disease incidence and the built environment.

Tumor suppressor function of miR-129-5p in lung cancer

Lung cancer causes severe health problems worldwide and, in China, besides being the principal cause of mortality among urbanites, it is the second leading cause of mortality in the rural population, preceded by hepatocellular carcinoma. Between 80 and 85% of lung cancer is classified as non-small cell lung cancer (NSCLC). The high mobility group box 1 (HMGB1) protein serves an important function in the tumor microenvironment and antitumor response, and may be targeted by microRNA (miR). In the present study, miR-129-5p was identified to target HMGB1 and miR-129-5p exhibited low expression levels in NSCLC tissues. Overexpression of miR-129-5p inhibited cell proliferation and promoted cell apoptosis. In conclusion, the results of the present study suggested the inhibitory function of miR-129-5p and revealed a novel therapeutic target for further investigation.

Serum Metabolomics Study of Nonsmoking Female Patients with Non-Small Cell Lung Cancer Using Gas Chromatography-Mass Spectrometry

The incidence of nonsmoking female patients with non-small cell lung cancer (NSCLC) has increased in recent decades; however, the pathogenesis of patients is unclear, and early diagnosis biomarkers are in urgent need. In this study, 136 nonsmoking female subjects (65 patients with NSCLC, 6 patients with benign lung tumors, and 65 healthy controls) were enrolled, and their metabolic profiling was investigated by using pseudotargeted gas chromatography-mass spectrometry. A total of 56 annotated metabolites were found and verified to be significantly different in nonsmoking females with NSCLC compared with the control. The metabolic profiling was featured by disturbed energy metabolism, amino acid metabolism, oxidative stress, lipid metabolism, and so on. Cysteine, serine, and 1-monooleoylglycerol were defined as the biomarker panel for the diagnosis of NSCLC patients. 98.5 and 91.4% of subjects were correctly distinguished in the discovery and validation sets, respectively. The biomarker panel was also useful for the diagnosis of in situ malignancy patients, with an accuracy of 97.7 and 97.8% in the discovery and validation sets, respectively. The study provides a biomarker panel for the auxiliary diagnosis of nonsmoking females with NSCLC.

Report of the Korean Association of Lung Cancer Registry (KALC-R), 2014

Purpose

The aim of this study was to investigate epidemiology, clinical characteristics and sex differences of patients with lung cancer using nationwide registry in Korea.

Materials and Methods

The Korean Association for Lung Cancer developed a registry in cooperation with the Korean Central Cancer Registry, and surveyed about 10% of lung cancer cases. For this first survey of cases diagnosed in 2014, cases were selected through a systematic sampling method.

Results

Total 2,621 lung cancer patients were surveyed, and the median patient age was 70 years. During the study period, adenocarcinoma was the most frequent histologic type, the proportion of female patients was 28.4%, and women had a better prognosis (median survival, not reached vs. 13 months; p<0.001) than did men for non-small cell lung cancer. The proportion of never-smokers was 36.4%, and never-smoking was more prevalent in women than in men (87.5 vs. 16.0%, p<0.001). Epidermal growth factor receptor (EGFR) mutations were found in 36.8% of stage IV adenocarcinoma patients, and higher in female compared to male patients (51.2 vs. 26.6%, p<0.001). In addition, patients with EGFR mutation showed better survival (median survival, 18 vs. 8 months; p<0.001) than patients without EGFR mutation in these patients.

Conclusion

This is the first survey to gather unbiased nationwide lung cancer statistics in Korea. More than one-third of lung cancer patients had no smoking history. Female had a high proportion of non-smoker, more adenocarcinoma with EGFR mutation and generally better prognosis than male.

Cancer incidence in the Agricultural Health Study after 20 years of follow-up

PURPOSE

To evaluate cancer incidence in the Agricultural Health Study (AHS), a cohort of private pesticide applicators, their spouses, and commercial applicators, based on 12,420 cancers, adding 5,989 cancers, and 9 years of follow-up since last evaluation.

METHODS

We calculated age, year, sex, and race-adjusted standardized incidence ratios (SIR) and 95% confidence intervals (CI) for cancer sites in the AHS relative to the general population.

RESULTS

Overall AHS cancer incidence was lower than the general population (SIR_private = 0.91, CI 0.89-0.93; SIR_spouse = 0.89, CI 0.86-0.92; SIR_commercial = 0.83, CI 0.76-0.92), with notable deficits across applicators and spouses for oral cavity, pancreas, and lung cancers. Cancer excesses included prostate cancer, lip cancer, certain B-cell lymphomas (e.g., multiple myeloma), acute myeloid leukemia (AML), thyroid cancer, testicular cancer, and peritoneal cancer. The lung cancer deficit was strongest among applicators reporting potential exposure to endotoxin at study enrollment (tasks such as raising animals and handling stored grain).

CONCLUSIONS

Although an overall deficit in cancer was observed, there were notable exceptions, including newly observed excesses for AML, thyroid, testicular, and peritoneal cancers. Furthermore, endotoxin exposure may, in part, account for observed lung cancer incidence deficits. Cancer incidence patterns in the AHS suggest farm exposures' relevance to cancer etiology.

Pan-Asian adapted Clinical Practice Guidelines for the management of patients with metastatic non-small-cell lung cancer: a CSCO-ESMO initiative endorsed by JSMO, KSMO, MOS, SSO and TOS

The most recent version of the European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of metastatic non-small-cell lung cancer (NSCLC) was published in 2016. At the ESMO Asia Meeting in November 2017 it was decided by both ESMO and the Chinese Society of Clinical Oncology (CSCO) to convene a special guidelines meeting immediately after the Chinese Thoracic Oncology Group Annual Meeting 2018, in Guangzhou, China. The aim was to adapt the ESMO 2016 guidelines to take into account the ethnic differences associated with the treatment of metastatic NSCLC cancer in Asian patients. These guidelines represent the consensus opinions reached by experts in the treatment of patients with metastatic NSCLC representing the oncological societies of China (CSCO), Japan (JSMO), Korea (KSMO), Malaysia (MOS), Singapore (SSO) and Taiwan (TOS). The voting was based on scientific evidence, and was independent of both the current treatment practices and the drug availability and reimbursement situations in the six participating Asian countries. During the review process, the updated ESMO 2018 Clinical Practice Guidelines for metastatic NSCLC were released and were also considered, during the final stages of the development of the Pan-Asian adapted Clinical Practice Guidelines.

Lymph/angiogenesis contributes to sex differences in lung cancer through oestrogen receptor alpha signalling

Oestrogen signalling pathways are emerging targets for lung cancer therapy. Unravelling the contribution of oestrogens in lung cancer development is a pre-requisite to support the development of sex-based treatments and identify patients who could potentially benefit from anti-oestrogen treatments. In this study, we highlight the contribution of lymphatic and blood endothelia in the sex-dependent modulation of lung cancer. The orthotopic graft of syngeneic lung cancer cells into immunocompetent mice showed that lung tumours grow faster in female mice than in males. Moreover, oestradiol (E2) promoted tumour development, increased lymph/angiogenesis and VEGFA and bFGF levels in lung tumours of females through an oestrogen receptor (ER) alpha-dependent pathway. Furthermore, while treatment with ERb antagonist was inefficient, ERa antagonist (MPP) and tamoxifen decreased lung tumour volumes, altered blood and lymphatic vasculature and reduced VEGFA and bFGF levels in females, but not in males. Finally, the quantification of lymphatic and blood vasculature of lung adenocarcinoma biopsies from patients aged between 35 and 55 years revealed more extensive lymphangiogenesis and angiogenesis in tumour samples issued from women than from men. In conclusion, our findings highlight an E2/ERa-dependent modulation of lymphatic and blood vascular components of lung tumour microenvironment. Our study has potential clinical implication in a personalised medicine perspective by pointing to the importance of oestrogen status or supplementation on lung cancer development that should be considered to adapt therapeutic strategies.

Global Epidemiology of Lung Cancer

While lung cancer has been the leading cause of cancer-related deaths for many years in the United States, incidence and mortality statistics - among other measures - vary widely worldwide. The aim of this study was to review the evidence on lung cancer epidemiology, including data of international scope with comparisons of economically, socially, and biologically different patient groups. In industrialized nations, evolving social and cultural smoking patterns have led to rising or plateauing rates of lung cancer in women, lagging the long-declining smoking and cancer incidence rates in men. In contrast, emerging economies vary widely in smoking practices and cancer incidence but commonly also harbor risks from environmental exposures, particularly widespread air pollution. Recent research has also revealed clinical, radiologic, and pathologic correlates, leading to greater knowledge in molecular profiling and targeted therapeutics, as well as an emphasis on the rising incidence of adenocarcinoma histology. Furthermore, emergent evidence about the benefits of lung cancer screening has led to efforts to identify high-risk smokers and development of prediction tools. This review also includes a discussion on the epidemiologic characteristics of special groups including women and nonsmokers. Varying trends in smoking largely dictate international patterns in lung cancer incidence and mortality. With declining smoking rates in developed countries and knowledge gains made through molecular profiling of tumors, the emergence of new risk factors and disease features will lead to changes in the landscape of lung cancer epidemiology.

Molecular heterogeneity in lung cancer: from mechanisms of origin to clinical implications

Molecular heterogeneity is a frequent event in cancer responsible of several critical issues in diagnosis and treatment of oncologic patients. Lung tumours are characterized by high degree of molecular heterogeneity associated to different mechanisms of origin including genetic, epigenetic and non-genetic source. In this review, we provide an overview of recognized mechanisms underlying molecular heterogeneity in lung cancer, including epigenetic mechanisms, mutant allele specific imbalance, genomic instability, chromosomal aberrations, tumor mutational burden, somatic mutations. We focus on the role of spatial and temporal molecular heterogeneity involved in therapeutic implications in lung cancer patients.

Regulation of sex hormone receptors in sexual dimorphism of human cancers

Gender differences in the incidences of cancers have been found in almost all human cancers. However, the mechanisms that underlie gender disparities in most human cancer types have been under-investigated. Here, we provide a comprehensive overview of potential mechanisms underlying sexual dimorphism of each cancer regarding sex hormone signaling. Fully addressing the mechanisms of sexual dimorphism in human cancers will greatly benefit current development of precision medicine. Our discussions of potential mechanisms underlying sexual dimorphism in each cancer will be instructive for future cancer research on gender disparities.

High Receipt of Statins Reduces the Risk of Lung Cancer in Current Smokers With Hypercholesterolemia: The National Health Insurance Service-Health Screening Cohort

BACKGROUND

The incidence and mortality of lung cancer have risen steadily with the increasing popularity of tobacco smoking. Observational studies suggest that statins, which are widely used to lower cholesterol, may prevent lung cancer; however, other studies have produced conflicting results. We investigated the effect of statin receipt on lung cancer risk in Korean men according to smoking status.

PATIENTS AND METHODS

We collected data from the 2002-2015 National Health Insurance Service-National Health Screening Cohort (NHIS-HEALS). We included a total of 16,588 men in the final analysis. We classified the participants as having high or low statin receipt or as not receiving statins. We used Cox proportional hazards regression models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for lung cancer risk by statin receipt after adjusting for potential confounders.

RESULTS

We identified 363 patients with a new diagnosis of lung cancer from 2005 to 2015. Compared to participants who did not receive statins, high statin receipt resulted in a reduced lung cancer risk (HR = 0.64; 95% CI, 0.47, 0.85) after adjustment for confounders. Among current smokers, the fully adjusted HR for high statin receipt compared to those who did not receive statin therapy was 0.50 (95% CI, 0.32, 0.79).

CONCLUSION

High statin receipt was associated with lower risk of lung cancer in Korean men with hypercholesterolemia, especially current smokers.

Role of Low-Dose Computerized Tomography in Lung Cancer Screening among Never-Smokers

INTRODUCTION

The incidence of lung cancer among never-smokers has been increasing rapidly. The U. S. National Lung Screening Trial and the NELSON trial showed that screening using low-dose computerized tomography (LDCT) effectively reduced lung cancer mortality among heavy smokers. However, its effectiveness in never-smokers has not been well investigated. This study investigated the role of LDCT in lung cancer screening among never-smokers.

METHODS

The study was designed as a single-center, retrospective cohort study. We analyzed the data on patients who underwent LDCT screening between May 2003 and June 2016. Nodules detected by computerized tomography were classified according to the Lung Imaging Reporting and Data System criteria. The detection rate and lung cancer outcomes (type of cancer, staging of lung cancer, and mortality) according to smoking history were determined.

RESULTS

Of the 28,807 enrolled patients, 12,176 were never-smokers; of these patients, 7744 (63.6%) were women and 1218 (10.0%) were found to have lung nodules. Overall, lung cancer was diagnosed in 55 never-smokers (0.45%). In contrast, lung cancer was diagnosed in 143 (0.86%) of the 16,631 ever-smokers. Of the never-smokers with lung cancer, 51 (92.7%) presented with stage I disease, and all patients had adenocarcinomas.

CONCLUSIONS

In the never-smoker population, LDCT screening helped to detect a significant number of lung cancers. Most of these lung cancers were detected at a very early stage. The positive results of the National Lung Screening Trial in the United States and the NELSON trial may have established the value of LDCT screening for heavy smokers, but future research should consider the value of using LDCT screening in the never-smoker population.

Potential Mechanisms of Age Acceleration Caused by Estrogen Deprivation: Do Endocrine Therapies Carry the Same Risks?

Longer duration of endocrine therapy decreases breast cancer recurrence and mortality, but these benefits need to be weighed against potential risks to overall health. Notable side effects of endocrine therapy include cataracts, uterine cancer, thromboembolic events, osteoporosis and fracture risk, chronic musculoskeletal complaints, as well as vaginal dryness and discharge, and vasomotor symptoms. Estrogen deprivation in healthy women younger than 50 years undergoing bilateral oophorectomy has been shown to accelerate the development of diseases related to aging, including coronary artery disease, cardiac arrhythmias, stroke, dementia, and osteoporosis, raising concern that even less dramatic modulation of estrogen homeostasis may adversely affect health outcomes. Diminished available estrogen at the cellular and molecular level may facilitate mechanisms that underlie the aging process, often termed the hallmarks of aging. In this review, we describe estrogen's role in normal physiology across tissues, review the effects of estrogen deprivation on health outcomes in the setting of both surgical and natural menopause, and examine the hallmarks of aging with attention to the effects of estrogen and estrogen blockade on each molecular mechanism underlying the aging process.

Survival difference according to mutation status in a prospective cohort study of Australian patients with metastatic non-small-cell lung carcinoma

BACKGROUND

Non-small-cell lung cancer (NSCLC) is a heterogeneous disease comprising not only different histological subtypes but also different molecular subtypes.

AIM

To describe the frequency of oncogenic drivers in patients with metastatic NSCLC, the proportion of patients tested and survival difference according to mutation status in a single-institution study.

METHODS

Metastatic NSCLC patients enrolled in a prospective Thoracic Malignancies Cohort Study between July 2012 and August 2016 were selected. Patients underwent molecular testing for epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK) gene rearrangements, Kirsten rat sarcoma (KRAS), B-Raf proto-oncogene (BRAF) mutations and ROS1 gene rearrangements. Survival was calculated using the Kaplan-Meier method for groups of interest, and comparisons were made using the log-rank test.

RESULTS

A total of 392 patients were included, 43% of whom were female with median age of 64 years (28-92). Of 296 patients tested, 172 patients (58%) were positive for an oncogenic driver: 81 patients (27%) were EGFR positive, 25 patients (9%) were ALK positive, 57 patients (19%) had KRAS mutation and 9 patients (3%) were ROS1 or BRAF positive. Patients with an actionable mutation (EGFR/ALK) had a survival advantage when compared with patients who were mutation negative (hazard ratio (HR) 0.49; 95% confidence interval (CI) 0.33-0.71; P < 0.01). Survival difference between mutation negative and mutation status unknown was not statistically significant when adjusted for confounding factors in a multivariate analysis (HR 1.29; 95% CI 0.97-1.78, P = 0.08).

CONCLUSION

In this prospective cohort, the presence of an actionable mutation was the strongest predictor of overall survival. These results confirm the importance of molecular testing and suggest likely survival benefit of identification and treatment of actionable oncogenes.

Common cancer-driver mutations and their association with abnormally methylated genes in lung adenocarcinoma from never-smokers

OBJECTIVES

Lung adenocarcinoma in never-smokers accounts for 15-20% of all lung cancer. Although targetable mutations are more prevalent in these tumors, the biological and clinical importance of coexisting and/or mutually exclusive abnormalities is just emerging. This study evaluates the relationships between common genetic and epigenetic aberrations in these tumors.

MATERIALS AND METHODS

Next-generation sequencing was employed to screen 20 commonly mutated cancer-driver genes in 112 lung adenocarcinomas from never-smokers. The relationship of these mutations with cancer-related methylation of 59 genes, and geographical/ethnic differences in the prevalence for mutations compared to multiple East Asian never-smoker lung adenocarcinoma cohorts was studied.

RESULTS

The most common driver mutation detected in 40% (45/112) of the tumors was EGFR, followed by TP53 (18%), SETD2 (11%), and SMARCA4 (11%). Over 72% (81/112) of the cases have mutation of at least one driver gene. While 30% (34/112) of the tumors have co-mutations of two or more genes, 42% (47/112) have only one driver gene mutation. Differences in the prevalence for some of these mutations were seen between adenocarcinomas in East Asian versus US (mainly Caucasian) never-smokers including a significantly lower rate of EGFR mutation among the US patients. Interestingly, aberrant methylation of multiple cancer-related genes was significantly associated with EGFR wildtype tumors. Among 15 differentially methylated genes by EGFR mutation, 14 were more commonly methylated in EGFR wildtype compared to mutant tumors. These findings were independently validated using publicly available data.

CONCLUSION

Most lung adenocarcinomas from never-smokers harbor targetable mutation/co-mutations. In the absence of EGFR mutation that drives 40% of these tumors, EGFR wildtype tumors appear to develop by acquiring aberrant promoter methylation that silences tumor-suppressor genes.

Autochthonous murine models for the study of smoker and never-smoker associated lung cancers

Lung cancer accounts for the greatest number of cancer deaths in the world. Tobacco smoke-associated cancers constitute the majority of lung cancer cases but never-smoker cancers comprise a significant and increasing fraction of cases. Recent genomic and transcriptomic sequencing efforts of lung cancers have revealed distinct sets of genetic aberrations of smoker and never-smoker lung cancers that implicate disparate biology and therapeutic strategies. Autochthonous mouse models have contributed greatly to our understanding of lung cancer biology and identified novel therapeutic targets and strategies in the era of targeted therapy. With the emergence of immuno-oncology, mouse models may continue to serve as valuable platforms for novel biological insights and therapeutic strategies. Here, we will review the variety of available autochthonous mouse models of lung cancer, their relation to human smoker and never-smoker lung cancers, and their application to immuno-oncology and immune checkpoint blockade that is revolutionizing lung cancer therapy.

The epidemiology of lung cancer

The incidence and mortality from lung cancer is decreasing in the US due to decades of public education and tobacco control policies, but are increasing elsewhere in the world related to the commencement of the tobacco epidemic in various countries and populations in the developing world. Individual cigarette smoking is by far the most common risk factor for lung carcinoma; other risks include passive smoke inhalation, residential radon, occupational exposures, infection and genetic susceptibility. The predominant disease burden currently falls on minority populations and socioeconomically disadvantaged people. In the US, the recent legalization of marijuana for recreational use in many states and the rapid growth of commercially available electronic nicotine delivery systems (ENDS) present challenges to public health for which little short term and no long term safety data is available.

Higher Lung Cancer Incidence in Young Women Than Young Men in the United States

BACKGROUND

Previous studies showed a higher incidence of lung cancer among young women than among young men in the United States. Whether this pattern has continued in contemporary birth cohorts and, if so, whether it can be fully explained by sex differences in smoking behaviors are unknown.

METHODS

We examined the nationwide population-based incidence of lung cancer according to sex, race or ethnic group, age group (30 to 34, 35 to 39, 40 to 44, 45 to 49, and 50 to 54 years), year of birth (1945 to 1980), and calendar period of diagnosis (1995-1999, 2000-2004, 2005-2009, and 2010-2014), and we calculated female-to-male incidence rate ratios. We also examined the prevalence of cigarette smoking, using data from the National Health Interview Survey from 1970 to 2016.

RESULTS

Over the past two decades, the age-specific incidence of lung cancer has generally decreased among both men and women 30 to 54 years of age in all races and ethnic groups, but the declines among men have been steeper. Consequently, among non-Hispanic whites, the female-to-male incidence rate ratios increased, exceeding 1.0 in the age groups of 30 to 34, 35 to 39, 40 to 44, and 45 to 49 years. For example, the female-to-male incidence rate ratio among whites 40 to 44 years of age increased from 0.88 (95% confidence interval [CI], 0.84 to 0.92) during the 1995-1999 period to 1.17 (95% CI, 1.11 to 1.23) during the 2010-2014 period. The crossover in sex-specific rates occurred among non-Hispanic whites born since 1965. Sex-specific incidence rates converged among non-Hispanic blacks, Hispanics, and non-Hispanic Asians and Pacific Islanders but crossed over from a higher incidence among men to a higher incidence among women only among Hispanics. The prevalence of cigarette smoking among women born since 1965 has approached, but generally not exceeded, the prevalence among men.

CONCLUSIONS

The patterns of historically higher incidence rates of lung cancer among men than among women have reversed among non-Hispanic whites and Hispanics born since the mid-1960s, and they are not fully explained by sex differences in smoking behaviors. Future studies are needed to identify reasons for the higher incidence of lung cancer among young women. (Funded by the American Cancer Society.).

A comprehensive approach of the gender bias in occupational cancer epidemiology: A systematic review of lung cancer studies (2003-2014)

BACKGROUND

In occupational epidemiology, a male-centered perspective often predominates. We aimed to describe current research practices in terms of gender consideration at different stages of epidemiological studies.

METHODS

A systematic review of occupational lung cancer publications indexed in PubMed was conducted over the period 2003-2014. Articles were described according to the sex composition of their study sample.

RESULTS

In 243 studies, 7 (3%) were women-only, 101 (41%) were mixed, with a disproportionate men-to-women ratio (P50 = 3.5; P75 = 12.4). A shift was observed from mixed and unspecified source populations to men-only final samples. Our results also suggest implicit generalization of results from men-only studies, a lack of tests of interaction and often unjustified sex-adjustment for mixed studies.

CONCLUSIONS

The lower proportion of women in studies cannot be fully explained by their under-representation in the target populations, since there were large numbers of women among both potentially exposed workers and patients diagnosed with lung cancer.

Lung cancer in never smokers from the Princess Margaret Cancer Centre

Introduction

Lung cancer in never smokers represents a distinct epidemiological, clinical, and molecular entity.

Results

Most 712 never smoking lung cancer patients were female (72%) with a median age at diagnosis of 62.2 years (18–94). Caucasians (46%), East Asians (42%), adenocarcinoma histology (87%) and presentation with metastatic disease at diagnosis (59%) were common. Of 515 patients with available archival tissue, the most common identified single mutations were EGFR (52.2%), followed by ALK (7.5%), KRAS (2.3%), TP53 (1.3%), ERBB2 (1%), BRAF (0.4%), PIK3CA (0.4%), SMAD4 (0.4%), CTNNB1 (0.2%), AKT1 (0.2%), and NRAS (0.2%); 8% tumors had multiple mutations, while 25.8% had none identified. Median overall survival (mOS) was 42.2 months (mo) for the entire cohort. Patients with mutations in their tumors had significantly better mOS (69.5 mo) when compared to those without (31.0 mo) (HR = 0.59; 95% CI: 0.44–0.79; p < 0.001). Earlier stage (p < 0.001), adenocarcinoma histology (p = 0.012), good performance status (p < 0.001) and use of targeted therapy (p < 0.001) were each independently associated with longer survival. Patients with ALK-translocation-positive tumours have significantly longer OS compared to those without any mutations (p = 0.0029) and to those with other and null mutations (p = 0.022).

Conclusions

Lung cancer in never smokers represents a distinct clinical and molecular entity characterized by a high incidence of targetable mutations and long survival.

Methods

We analyzed retrospectively the data from electronic patient records of never smokers diagnosed with lung cancer treated at the Princess Margaret Cancer Centre (Toronto) between 1988–2015 to characterize demographic and clinical features, pathology, molecular profile (using hotspot or targeted sequencing panels), treatment and survival.

Assessment of the cancer risk factors of solitary pulmonary nodules

There are no large samples or exact prediction models for assessing the cancer risk factors of solitary pulmonary nodules (SPNs) in the Chinese population. We retrospectively analyzed the clinical and imaging data of patients with SPNs who underwent computer tomography guided needle biopsy in our hospital from Jan 1st of 2011 to March 30th of 2016. These patients were divided into a development data set and a validation data set. These groups included 1078 and 344 patients, respectively. A prediction model was developed from the development data set and was validated with the validation data set using logistic regression. The predictors of cancer in our model included female gender, age, pack-years of smoking, a previous history of malignancy, nodule size, lobulated and spiculated edges, lobulation alone and spiculation alone. The Area Under the Curves, sensitivity and specificity of our model in the development and validation data sets were significantly higher than those of the Mayo model and VA model (p < 0.001). We established the largest sampling risk prediction model of SPNs in a Chinese cohort. This model is particularly applicable to SPNs > 8 mm in size. SPNs in female patients, as well as SPNs featuring a combination of lobulated and spiculated edges or lobulated edges alone, should be evaluated carefully due to the probability that they are malignant.

The association of polymorphisms in miRNAs with nonsmall cell lung cancer in a Han Chinese population

Background

MicroRNAs (miRNAs) have been demonstrated to play important roles in cancer progression. Recently, studies have revealed that polymorphisms in miRNAs might be associated with cancer susceptibility.

Materials and methods

In the current study, we investigated the associations of single nucleotide polymorphisms (SNPs) in miRNAs (rs11134527 in pri-miR-218-2, rs74693964 in pri-miR-145, rs6062251 in pri-miR-133a-2, and rs4705343 in pri-miR-143) with nonsmall cell lung cancer (NSCLC) in a Han population from Yunnan Province, Southwest China using a binary logistic regression analysis. A total of 452 patients with NSCLC and 452 healthy individuals were recruited for polymorphism genotyping using the TaqMan assay.

Results

Our results showed that the allelic frequencies of rs11134527 and rs4705343 were significantly different between the NSCLC and control groups (P=0.025 and 0.029). Additionally, the genotypic frequencies of rs11134527 were significantly different between the NSCLC and control groups (P=0.045). The mode of inheritance analysis showed that genotypes A/G+G/G of rs11134527 were associated with a lower risk of NSCLC under the dominant model (OR=0.69; 95% CI: 0.51–0.94). In addition, genotypes 2C/C+C/T of rs4705343 were associated with an increased risk of NSCLC under the log-additive model (OR=1.25; 95% CI: 1.01–1.53). However, there was no significant difference in the other SNPs between the NSCLC and control groups (P>0.05). Moreover, the association analysis of these SNPs between adenocarcinoma and squamous cell carcinoma (SCC) showed that allele A of rs11134527 was associated with SCC (OR=0.65; 95% CI: 0.48–0.88).

Conclusion

Our results indicated that the A allele of rs11134527 might be a risk factor (OR=1.24; 95% CI: 1.03–1.50) and that the T allele of rs4705343 might be a protective factor (OR=0.80; 95% CI: 0.66–0.98) for NSCLC in a Han Chinese population.

Spotlight on dabrafenib/trametinib in the treatment of non-small-cell lung cancer: place in therapy

Advanced non-small-cell lung cancer (NSCLC) remains a challenging disease. The limited utility of chemotherapy indicates the need for additional therapeutic options. Targeted therapy continues to be an important tool in the treatment of NSCLC. Mutations within the RAS–RAF–MEK–MAPK pathway, specifically the BRAF V600E mutation, have become an important target for the subset of NSCLC patients with this mutation. This paper summarizes the clinical evidence that lead to the recent approval of the combination of dabrafenib and trametinib to treat patients with advanced NSCLC who harbor a BRAF V600E mutation.

Lung squamous cell carcinoma associated with hypoparathyroidism with sensorineural deafness and renal dysplasia syndrome: a case report

Hypoparathyroidism with sensorineural deafness and renal dysplasia (HDR) syndrome is an autosomal dominant condition caused by mutations of the gene encoding the dual zinc-finger transcription factor, GATA3. A previous study identified some patients with GATA3 gene variants and breast cancer, suggesting that GATA3 variants may contribute to tumorigenesis in estrogen receptor 1-positive breast tumors; however, these patients did not have HDR syndrome. A 32-year-old nonsmoking Japanese woman was histologically diagnosed with lung squamous cell carcinoma associated with HDR syndrome and a c.C952T>C (p.C318R) germline mutation in GATA3. This is the first report describing cancer in a patient with HDR syndrome. Our data indicates that GATA3 mutations may be a potential therapeutic target for lung cancer.

A Decade of Never-smokers Among Lung Cancer Patients-Increasing Trend and Improved Survival

BACKGROUND

It is not known whether clinicopathologic characteristics, treatment, and survival of never-smokers among lung cancer incident cases have changed over time. We assessed the trend and overall survival (OS) of these patients within our institution during a 10-year period.

PATIENTS AND METHODS

We reviewed 2 cohorts of non-small-cell lung cancer patients with a diagnosis from 1999 to 2002 and from 2008 to 2011. The patient characteristics and OS were compared by smoking status within each cohort and between the 2 cohorts over time.

RESULTS

Of the 992 patients in the 1999-2002 cohort and the 1318 patients in the 2008-2011 cohort, 902 and 1272 had a known smoking status, respectively. The proportion of never-smokers increased from 31% in 1999-2002 to 48% in 2008-2011 (P < .001). Within both cohorts, the differences in characteristics among never-, former-, and current-smokers have remained largely constant over time. A greater proportion of never-smokers had Eastern Cooperative Oncology Group performance status 0 to 1 and adenocarcinoma. The median OS increased from 15.5 months in 1999-2002 to 24.9 months in 2008-2011 (P = .001) for never-smokers, 12.3 to 15.9 months (P = .150) for former-smokers, and 10.5 to 13.9 months (P = .011) for current-smokers. The larger survival improvement among never-smokers was likely accounted for by the larger increase in never-smokers who were treated with tyrosine kinase inhibitors and pemetrexed over time.

CONCLUSION

We found an increasing trend of never-smokers among incident lung cancer cases and improved survival for these patients during a 10-year period. The documentation of smoking status in any national cancer registry is vital to estimate the true incidence of lung cancer among never-smokers over time.

MiR-146a polymorphism correlates with lung cancer risk in Chinese nonsmoking females

This study provides evidence that the common rs2910164 polymorphism in miR-146a strongly correlates with lung cancer risk in nonsmoking females in northeast China. The genotypes of miR-146a rs2910164 were determined in 1131 patients with lung cancer and 1003 healthy control subjects. Tissue samples were used to evaluate the association between miRNA expression and lung cancer risk as well as the correlation between rs2910164 genotypes and miR-146a expression. The secondary structures of the wild-type and variant miR-146a sequences were predicted, and luciferase-based target assays were used to test whether miR-146a bound to tumor necrosis factor receptor associated factor 6 (TRAF6) mRNA. Individuals carrying heterozygous CG genotype of miR-146a rs2910164 had less risk of lung cancer than those carrying homozygous wild CC genotype (OR = 0.76, 95% CI = 0.60-0.98, P = 0.032). We found no significant association between miR-146a expression and lung cancer risk. MiR-146a expression differed in those carrying the CC genotype as compared with the CG or the GG genotype (P = 0.032 and 0.001), and the secondary structure of the C allele differed slightly from the G allele. Significantly lower levels of luciferase activity were observed when the TRAF6 3′UTR was cotransfected with miR-146a-3p carrying the rs2910164 C allele (P = 0.001). Thus, miR-146a rs2910164 polymorphism may influence susceptibility to lung cancer in Chinese nonsmoking females through targeting TRAF6.

A cross-sectional study examining the expression of splice variants K-RAS4A and K-RAS4B in advanced non-small-cell lung cancer patients

OBJECTIVES

Mammalian cells differently express 4 RAS isoforms: H-RAS, N-RAS, K-RAS4A and K-RAS4B, which are important in promoting oncogenic processes when mutated. In lung cancer, the K-RAS isoform is the most frequently altered RAS protein, being also a difficult therapeutic target. Interestingly, there are two K-RAS splice variants (K-RAS4A and K-RAS4B) and little is known about the role of K-RAS4A. Most studies targeting K-RAS, or analysing it as a prognostic factor, have not taken into account the two isoforms. Consequently, the in-depth investigation of them is needed.

METHODS

The present study analysed 98 specimens from advanced non-small cell lung cancer (NSCLC) adenocarcinoma patients originated from Brazil. The alterations present in K-RAS at the DNA level (Sanger sequencing) as well as the expression of the splicing isoforms at the RNA (qRT-PCR) and protein levels (immunohistochemistry analysis), were evaluated. Possible associations between clinicopathological features and the molecular findings were also investigated.

RESULTS

Our results showed that in the non-smoking population, the cancer incidence was higher among women. In contrast, in smokers and former smokers, the incidence was higher among men. Regarding sequencing results, 10.5% of valid samples presented mutations in exon 2, being all wild-type for exon 3, and the most frequently occurring base change was the transversion G → T. Our qRT-PCR and immunohistochemical analysis showed that both, K-RAS4A and K-RAS4B, were differently expressed in NSCLC tumour samples. For example, tumour specimens showed higher K-RAS4A mRNA expression in relation to commercial normal lung control than did K-RAS4B. In addition, K-RAS4B protein expression was frequently stronger than K-RAS4A in the patients analysed.

CONCLUSION

Our results highlight the differential expression of K-RAS4A and K-RAS4B in advanced adenocarcinoma NSCLC patients and underline the need to further clarify the enigma behind their biological significance in various cancer types, including NSCLC.

The relationship of lung cancer with menstrual and reproductive factors may be influenced by passive smoking, cooking oil fumes, and tea intake: A case-control study in Chinese women

The aim of this study was to investigate the association of menstrual and reproductive factors with risk of lung cancer in women. Potential etiological clues related to lung cancer in women are identified to inform preventive strategies.Case-control study of 477 newly diagnosed women with lung cancer and 479 age-matched (±2 years) controls. Data on menstrual and reproductive factors and history of oral contraceptive use were obtained on personal interviews using a structured questionnaire. Risk factors were analyzed by unconditional logistic regression analysis.Maternal age ≥25 years at first birth appeared to protect against female lung cancer [odds ratios (ORs): 0.511, 95% confidence interval (CI), 0.376-0.693]. Age at menopause > 50 years and use of contraceptives was associated with an increased risk of lung cancer in women (OR: 1.471, 95% CI, 1.021-2.119 and OR: 1.844, 95% CI: 1.111-3.061, respectively). Age ≥13 years at menarche was associated with a decreased risk of lung adenocarcinoma (OR: 0.563, 95% CI, 0.317-0.997). There was significant heterogeneity in the levels of cooking oil fume (COF) exposure (Pheterogeneity = .015). Higher levels of exposure to passive smoking, COF, and lack of tea intake were associated with an increased risk of lung cancer.Menstrual and reproductive factors are considered to play a role in the development of lung cancer in women. Exposure to passive smoking, COF, and lack of tea intake appeared to significantly modify the relationship.

The 150 most important questions in cancer research and clinical oncology series: questions 57-66 : Edited by Chinese Journal of Cancer

Since the beginning of 2017, Chinese Journal of Cancer has published a series of important questions in cancer research and clinical oncology, which sparkle diverse thoughts, interesting communications, and potential collaborations among researchers all over the world. In this article, 10 more questions are presented as followed. Question 57. What are the major stresses that drive the formation, progression, and metastasis of a cancer? Question 58. What is the mechanism responsible for altering an acidic intracellular pH and a basic extracellular pH in normal tissue cells to a basic intracellular pH and an acidic extracellular pH in cancer cells, a fundamental and yet largely ignored phenomenon? Question 59. Where are the tumor-associated plasma microRNAs from in cancer patients? Question 60. Can we identify mechanisms employed by tumor subpopulations to evade standard therapies and seed relapse/metastatic tumors before treatment? Question 61. Why are mutation rates in epidermal growth factor receptor (EGFR) and erb-b2 receptor tyrosine kinase 2 (ERBB2) higher in lung cancer from never smokers than that from smokers? Question 62. Does tumor vasculogenic mimicry contribute to the resistance against antiangiogenic therapy in renal cancer? Question 63. What molecular targeted drugs would be effective for non-clear cell renal cell carcinoma (RCC), especially metastatic papillary RCC and chromophobe RCC? Question 64. Can it be more effective by targeting both the vascular endothelial growth factor receptor (VEGFR) and MET signaling pathways in sporadic metastatic papillary renal cell carcinoma (RCC)? Question 65. What are the predictive biomarkers that may be used to identify the renal cell carcinoma (RCC) patients who can benefit from immune checkpoint inhibitor treatment? Question 66. How do we identify predictive molecular biomarkers to stratify clear cell renal cell carcinoma patients for targeted therapies?

Propensity score analysis of lung cancer risk in a population with high prevalence of non-smoking related lung cancer

Background

Lung cancer has been the leading cause of cancer-related mortality worldwide among both men and women in recent years. There is an increase in the incidence of nonsmoking-related lung cancer in recent years. The purpose of the present study was to investigate multiple potential risk factors for nonsmoking-related lung cancer among Asian Ethnic Groups.

Methods

We used a propensity score-mated cohort analysis for this study. We retrospectively review the medical record of 1975 asymptomatic healthy subjects (40 ~ 80 years old) who voluntarily underwent low-dose chest CT from August 2013 to October 2014. Clinical information and nodule characteristics were recorded.

Results

A propensity score-mated cohort analysis was applied to adjust for potential bias and to create two comparable groups according to family history of lung cancer. For our primary analysis, we matched 392 pairs of subjects with family history of lung cancer and subjects without history. Logistic regression showed that female gender and a family history of lung cancer were the two most important predictor of lung cancer in the endemic area with high prevalence of nonsmoking-related lung cancer (OR = 11.199, 95% CI = 1.444–86.862; OR = 2.831, 95% CI = 1.000136–8.015). In addition, the number of nodules was higher in subjects with family history of lung cancer in comparison with subjects without family history of lung cancer (OR = 1.309, 95% CI = 1.066–1.607).

Conclusions

In conclusion, risk-based prediction model based on the family history of lung cancer and female gender can potentially improve efficiency of lung cancer screening programs in Taiwan.

Smoking and Lung Cancer: A Geo-Regional Perspective

Lung cancer is the leading cause of cancer-related deaths worldwide. Non-small cell lung cancer (NSCLC) represents the most frequently diagnosed subtype of this morbid malignancy. NSCLC is causally linked to tobacco consumption with more than 500 million smokers worldwide at high risk for this fatal malignancy. We are currently lagging in our knowledge of the early molecular (e.g., genomic) effects of smoking in NSCLC pathogenesis that would constitute ideal markers for early detection. This limitation is further amplified when considering the variable etiologic factors in NSCLC pathogenesis among different regions around the globe. In this review, we present our current knowledge of genomic alterations arising during early stages of smoking-induced lung cancer initiation and progression, including discussing the premalignant airway field of injury induced by smoking. The review also underscores the wider spectra and higher age-adjusted rates of tobacco (e.g., water-pipe smoke) consumption, along with elevated environmental carcinogenic exposures and relatively poorer socioeconomic status, in low-middle income countries (LMICs), with Lebanon as an exemplar. This “cocktail” of carcinogenic exposures warrants the pressing need to understand the complex etiology of lung malignancies developing in LMICs such as Lebanon.

Calcium plus vitamin D supplementation and lung cancer incidence among postmenopausal women in the Women's Health Initiative

BACKGROUND

Magnesium and calcium are antagonistic in many physiologic processes. However, few studies have investigated the associations of supplemental calcium with lung cancer risk taking this antagonism into account. We evaluated the effect of calcium and vitamin D supplementation on lung cancer incidence and explored whether the ratio of baseline calcium to magnesium (Ca:Mg) intake modifies the association in the Women's Health Initiative (WHI) calcium plus vitamin D supplementation (CaD) trial.

METHODS

The intervention phase of the WHI CaD was a double-blinded, randomized, placebo-controlled trial in 36,382 postmenopausal women aged 50-79 years, recruited at 40U.S. centers. Post-intervention follow-up continued among 29,862 (86%) of the surviving participants. Risk of lung cancer in association with CaD supplementation was evaluated using proportional hazard regression models.

RESULTS

After 11 years' cumulative follow-up, there were 207 lung cancers (incidence 0.11% per year) in the supplement arm and 241 (0.12%) in the placebo arm (hazard ratio (HR) for the intervention, 0.91; 95% confidence interval (CI), 0.71-1.17). Subgroup analyses suggested that the HR for lung cancer varied by baseline Ca:Mg intake ratio among women who were current smokers at enrollment (p=0.04 for interaction).

CONCLUSIONS

Over the entire follow-up period, calcium and vitamin D supplementation did not reduce lung cancer incidence among postmenopausal women. In exploratory analyses, an interaction was found for the baseline Ca:Mg intake ratio on lung cancer among current smokers at the trial entry. This findings need to be further studied for the role of calcium with magnesium in lung carcinogenesis in current smokers.

Lung Cancer Screening with Low-Dose CT in Female Never Smokers: Retrospective Cohort Study with Long-term National Data Follow-up

Purpose

Because of growing concerns about lung cancer in female never smokers, chest low-dose computed tomography (LDCT) screening is often performed although it has never shown clinical benefits. We examinewhether or not female never smokers really need annual LDCT screening when the initial LDCT showed negative findings.

Materials and Methods

This retrospective cohort study included 4,365 female never smokers aged 40 to 79 years who performed initial LDCT from Aug 2002 to Dec 2007. Lung cancer diagnosis was identified from the Korea Central Cancer Registry Database registered until December 31, 2013. We calculated the incidence, cumulative probability, and standardized incidence ratio (SIR) of lung cancer by Lung Imaging Reporting and Data System (Lung-RADS) categories showed on initial LDCT.

Results

After median follow-up of 9.69 years, 22 (0.5%) had lung cancer. Lung cancer incidence for Lung-RADS category 4 was 1,848.4 (95% confidence interval [CI], 1,132.4 to 3,017.2) per 100,000 person-years and 16.4 (95% CI, 7.4 to 36.4) for categories 1, 2, and 3 combined. The cumulative probability of lung cancer for category 4 was 10.6% at 5 years and 14.8% at 10 years while they were 0.07% and 0.17% when categories 1, 2, and 3 were combined. The SIR for subjects with category 4 was 43.80 (95% CI, 25.03 to 71.14), which was much higher than 0.47 (95% CI, 0.17 to 1.02) for categories 1, 2, and 3 combined.

Conclusion

Considering the low risk of lung cancer development in female never smokers, it seems unnecessary to repeat annual LDCT screening for at least 5 years or even longer unless the initial LDCT showed Lung-RADS category 4 findings.

Lung cancer in never-smokers - what are the differences?

INTRODUCTION

Characteristics of never-smokers with lung cancer are still not fully clarified. The aim of this study was to compare never-smokers and ever-smokers with non-small cell lung cancer (NSCLC) regarding patient and tumor characteristics.

METHODS

All consecutive newly NSCLC patients with known smoking status diagnosed between 2011 and 2015 were included in this retrospective cohort study. Clinical, histological, and molecular characteristics were compared between ever-smokers and never-smokers.

RESULTS

Of the 558 included patients, 125 (22.4%) were never-smokers. These patients were more likely to be female (74% vs. 7%, p < .001), older (67 vs. 66 years-old, p = .019), and have adenocarcinoma (93% vs. 65%, p < .001). Never-smokers took longer to seek medical care after the symptoms onset (3 vs. 2 months, p < .001), regardless of the symptoms, histological type, or gender (OR: 1.2 [1.4-2.0]). The metastatic pattern was different in never-smokers: pleural metastases were more frequent (OR: 2.1 [1.1-4.0]), regardless of the histological type and gender. Never-smokers had a higher prevalence of ALK translocations (26% vs. 4%, p < .001) and EGFR mutations (36% vs. 8%, p < .001). The type of EGFR mutation was also significantly different between groups.

CONCLUSIONS

Never-smokers with NSCLC present distinct demographic and clinical characteristics. The characteristics of tumor also differ between never-smokers and ever-smokers, which may suggest different carcinogenic pathways.

Evaluation of Merkel cell polyomavirus in non-small cell lung cancer and adjacent normal cells

Several risk factors have been linked to lung cancer (LC). Nevertheless, a viral etiology has been mentioned for a subset of patients developing LC. The aim of this study was to evaluate the effect of Merkel cell polyomavirus (MCPyV) on developing non-small cell lung cancer (NSCLCs). In total, 96 paraffin-embedded NSCLC biopsies and 96 adjacent non-LC normal specimens were analyzed by quantitative real-time polymerase chain reaction (PCR) for the existence of the MCPyV DNA and the expressions of RNA transcripts. Among the 96 enrolled participants, 42 patients were adenocarcinomas (ADs) and 54 patients were squamous cell carcinoma (SCC). Of the 42 ADs, MCPyV DNA was determined in 15 (35.7%) samples and of the 54 SCC, MCPyV DNA was detected in 22 (40.7%) samples. Only one non-cancerous sample in SCC subjects was positive for MCPyV LT-Ag DNA load (0.216 × 10^-3). In MCPyV-positive subjects, the median MCPyV copy number was higher in the patients with ADs (0.016 × 10^-3 copies/cell) compared to SCCs (0.005 × 10^-3 copies/cell); but this difference was not statistically significant (P = 0.913). In the seven stages of LC, the MCPyV LT-Ag was quantified in stage IV (0.204 × 10^-3 copies/cell) more than in other stages. There was statistically significant difference between stages of cancer and MCPyV LT-Ag DNA load (P = 0.002). These results revealed for the first time the presence of MCPyV in a subset of patients with NSCLCs in Iran. Further studies should be carried out to clarify the role of MCPyV in lung carcinogenesis.

Antiestrogen use in breast cancer patients reduces the risk of subsequent lung cancer: A population-based study

BACKGROUND

There is accumulating epidemiological and preclinical evidence that estrogen might be a driver of lung cancer. Breast cancer survivors can offer a unique patient cohort to examine the effect of antiestrogen therapy on lung cancer carcinogenesis because many of these women would have received long-term selective estrogen receptor modulators (SERMs) and/or aromatase inhibitors (AIs) as adjuvant treatment. Our hypothesis is that estrogens play a role in lung cancer development, and that antiestrogen therapy would affect the incidence of subsequent lung cancer among breast cancer survivors.

METHODS

Using the Taiwan National Health Insurance (NHI) database, the study included 40,900 survivors of non-metastatic breast cancer after primary surgery, and most antiestrogen users complied well with the medication regimen. We evaluate the effect of antiestrogen therapy on the incidence of subsequent lung cancers.

RESULTS

This population-based study revealed that antiestrogen use in breast cancer patients was associated with a reduced risk of subsequent lung cancer in older patients (≥50 years) (HR 0.73, 95%CI 0.54-0.99) when compared with breast cancer survivors who did not use antiestrogens.

CONCLUSION

The study supports the hypothesis that antiestrogen therapy modifies lung cancer carcinogenesis in older women. Further well-designed clinical trials to explore the potential of antiestrogens in lung cancer prevention and treatment would be worthwhile.

Proportion and clinical features of never-smokers with non-small cell lung cancer

BACKGROUND

The proportion of never-smokers with non-small cell lung cancer (NSCLC) is increasing, but that in Korea has not been well addressed in a large population. We aimed to evaluate the proportion and clinical features of never-smokers with NSCLC in a large single institution.

METHODS

We analyzed clinical data of 1860 consecutive patients who were newly diagnosed with NSCLC between June 2011 and December 2014.

RESULTS

Of the 1860 NSCLC patients, 707 (38.0%) were never-smokers. The proportions of women (83.7% vs. 5.6%) and adenocarcinoma (89.8% vs. 44.9%) were higher among never-smokers than among ever-smokers. Significantly more never-smokers were diagnosed at a younger median age (65 vs. 68 years, P < 0.001) and earlier stage (stage I-II, 44.5% vs. 38.9%, P = 0.015) compared with ever-smokers. Epidermal growth factor receptor mutations (57.8% vs. 24.4%, P < 0.001) and anaplastic lymphoma kinase rearrangements (7.8% vs. 2.8%, P < 0.001) were more common in never-smokers, whereas Kirsten rat sarcoma viral oncogene homolog mutations (5.8% vs. 9.6%, P = 0.021) were less frequently encountered in never-smokers than in ever-smokers. Never-smokers showed longer survival after adjusting for the favorable effects of younger age, female sex, adenocarcinoma histology, better performance status, early stage disease, being asymptomatic at diagnosis, received antitumor treatment, and the presence of driver mutations (hazard ratio, 0.624; 95% confidence interval, 0.460-0.848; P = 0.003).

CONCLUSIONS

More than one-third of the Korean patients with NSCLC were never-smokers. NSCLC in never-smokers had different clinical characteristics and major driver mutations and resulted in longer overall survival compared with NSCLC in ever-smokers.

Hormone therapy and lung cancer mortality in women: Systematic review and meta-analysis

The mortality of lung cancer presents a significant difference between the sexes. A role of hormone therapy (HT) in lung cancer mortality has been suggested, but the evidence is inconclusive. We sought to elucidate this issue with a meta-analysis. We conducted a systematic literature search in both Pubmed and Embase. Studies that reported the association of HT and mortality of lung cancer cases were included. Pooled hazard ratio (HR) was computed as the effect size to reflect the association between HT and lung cancer mortality. In total, 11 studies were included in the meta-analysis. The pooled HR of HT in relation to lung cancer mortality was 0.97 (95% CI 0.83-1.12, I²=59.2%, p=0.006) in all studies disregarding study design, and it was 0.80 (95% CI: 0.69-0.92, I²=21.4%, p=0.278) in prospective cohort studies. Results of this meta-analysis were robust, and there was no indication of significant differences in association in small and large studies. We observed a protective role of HT use in lung cancer mortality in pooled prospective cohorts, but not in pooled retrospective cohorts and post hoc analyses of randomized controlled trials. Future studies that address smoking, type and time of HT, menopausal status, and histology are warranted.