Association Between Lung Cancer Incidence and Family History of Lung Cancer

Lung cancer in nonsmokers- A risk factor analysis

INSTITUTIONS

STONY BROOK MEDICAL CENTERRATIONALE: Lung Cancer screening for the high-risk smoking population has been proven to save lives. However, in 2022, 20% of newly diagnosed lung cancers (47,300) were in nonsmokers. These patients were found to be diagnosed at later stages. This may be at least partly due to not meeting criteria for and participating in current lung cancer screening. This study aims to describe characteristics of a never smoker patient population to help identify common risk factors which might merit inclusion in lung cancer screening and thus improve patient outcomes.

METHODS

This retrospective single center study included never-smoker patients diagnosed with lung nodules and never-smoker patients diagnosed with lung cancer from 2016 to 2022. Data was obtained from the Stony Brook Medical Center electronic medical record. 16,056 patients were identified as never-smokers who were asked by the medical assistant if they ever smoked in their lifetime. Patients were eliminated if they had any smoking history up to first diagnosis date. Demographics, radiology, histology, diagnosis dates, comorbidities, smoking status, and exposures collected through ICD10 codes and not self-reported, were investigated.

RESULTS

Of 16,056 never-smoking patients, 9315 (58.02%) were females diagnosed with lung nodules and 6741 (41.98%) were males diagnosed with lung nodules. The univariate analysis showed significant differences between gender, age at nodule diagnosis, and patients with and without comorbidities including chronic obstructive pulmonary disease (COPD), hypertension (HTN), and family history (FHX) of lung cancer. The percentage of lung cancer patients among females was significantly higher than among males. Patients having lung cancer were older. The percentages of lung cancer patients with these comorbidities were significantly higher than those without. However, there was no significant difference found between patients with and without diabetes mellitus (DM). The multivariable logistic regression suggested that age at nodule diagnosis and comorbidities including COPD (which included asthma, emphysema and chronic bronchitis) and family history of lung cancer were significantly associated with lung cancer. Older patients and patients with those comorbidities had a higher risk of developing cancer than those who were younger or without those comorbidities. The study excluded HTN and included age at nodule diagnosis in the logistic regression model as HTN was found to be protective against lung cancer due to age at lung nodule diagnosis. Please refer to the appendix for further details.

CONCLUSION

Never-smoker patients who were older and with COPD and Family History of lung cancer had higher risk of developing lung cancer than younger patients without these comorbidities. In this study, gender had no impact on outcome.

Correlation analysis of lung mucosa-colonizing bacteria with clinical features reveals metastasis-associated bacterial community structure in non-small cell lung cancer patients

BACKGROUND

Microbes colonizing lower airways can regulate the host immune profile and consequently participate in lung disease. Increasing evidence indicate that individual microbes promote lung cancer progression and are involved in metastasis incidence. To date, however, no study has revealed the community structure of lung bacteria in metastatic non-small cell lung cancer (NSCLC) patients.

METHODS

We prospectively enrolled 50 healthy subjects and 57 NSCLC patients. All healthy subjects and NSCLC patients underwent bronchoscope procedures for brush specimen collection. The 16 S ribosomal RNA gene was sequenced to characterize the community structure of lung mucosa-colonizing bacteria. The peripheral blood of NSCLC patients was also measured for leukocytes and cancer markers.

RESULTS

The lung bacteria of healthy subjects and NSCLC patients were divided into four communities. All community 2 members showed increased abundance in NSCLC patients compared with healthy subjects, and most community 2 members showed increased abundance in the metastatic NSCLC patients compared with the non-metastatic group. These bacteria were significantly and positively correlated with eosinophils, neutrophils and monocytes in the metastatic NSCLC group. In addition, the correlation between lung bacteria and cancer markers differed between the metastatic and non-metastatic NSCLC patients. Furthermore, bronchoalveolar lavage fluid from lung adenocarcinoma patients directly promoted NSCLC cell migration.

CONCLUSIONS

The community structure of lung mucosa-colonizing bacteria was relatively stable, but changed from the healthy population to NSCLC patients, especially the metastatic group. This distinct community structure and specific correlation with immune cells and cancer markers could help to distinguish NSCLC patients with or without metastasis.

Isoflavone and soy food intake and risk of lung cancer in never smokers: report from prospective studies in Japan and China

PURPOSE

Evidence from several cohorts has suggested that a higher intake of isoflavone is associated with lower risk of lung cancer in never smokers, but the association has not been investigated by histologic type of lung cancer. Adenocarcinoma is a common histologic type found in never smokers. We hypothesized that a higher intake of isoflavone is associated with a lower risk of lung adenocarcinoma among never smokers. Here, we examined the associations of isoflavone and soy food intake with lung cancer and its histologic types in never smokers.

METHODS

We performed a pooled analysis using data from the Japan Public Health Center-based Prospective Study, Shanghai Women's Health Study and Shanghai Men's Study with 147,296 never smokers aged 40-74 years with no history of cancer. During 1,990,040 person-years of follow-up, 1247 lung cancer cases were documented. Dietary isoflavone and soy food intake were assessed using a food-frequency questionnaire. Multivariable Cox proportional hazards models assessed the associations between isoflavone and soy intake with incidence of lung cancer by histologic type.

RESULTS

A higher intake of dietary isoflavone and soy food were associated with reduced risk of lung adenocarcinoma. The multivariable hazard ratios (HRs) (95% CI) of risk of lung adenocarcinoma for the highest versus lowest intakes of isoflavone and soy food were 0.74 (0.60-0.92) and 0.78 (0.63-0.96), respectively. The multivariable HRs of risk of lung adenocarcinoma associated with each 10 mg/day increase in isoflavone and each 50 g/day increase in soy food intake were 0.81 (0.70-0.94) and 0.84 (0.73-0.96), respectively.

CONCLUSION

Higher intake of isoflavone and soy food was associated with lower risk of lung adenocarcinoma in never smokers.

Risk factors for the development of lung cancer among never smokers: A systematic review

This review aimed to summarize the up-to-date evidence on non-genetic factors for the development of never smoking lung cancer (NSLC) and to explore reasons behind the conflicting results. Relevant literature was searched in three electronic databases (PubMed, Embase and Web of Science) from 1 January 2000-31 July 2022. Cohort studies that investigated non-genetic risk factors for primary lung cancer in never smokers were included. The effect of non-genetic factors about NSLC were summarized with pooled relative risk (RR) and 95 % confidence intervals (CIs) through meta-analysis or narrative description when unexplained statistical heterogeneity was observed. The Newcastle-Ottawa Scale was used to appraise the methodological quality of included studies. Sixty cohort studies were included, covering population from Asia, Europe and America. Most included studies (42, 70.0 %) were of high methodological quality. Over 50 years old (RR = 5.26), environmental tobacco smoke (Pooled RR = 1.30), Chronic obstructive pulmonary disease (COPD) (RR = 2.67), family history of lung cancer (Pooled RR = 1.83) and higher level of neutrophil-lymphocyte ratio (RR = 1.73) increased the risk of NSLC. Dairy foods consumption (RR = 0.79), isoflavone intake (Pooled RR = 0.65), and riboflavin intake (RR = 0.62) decreased the risk among female population. Inconsistency or unclear definition for never smokers and risk factors could be observed in included studies. Most life behavior factors associated with NSLC can be modified through lifestyle changes. Future cohort studies are suggested to adopt a clearer definition on never smokers and exposure, conducting subgroup analysis when evidence indicating there is heterogeneity between genders, and explore dose-response relationship between the identified factors and NSLC.

Mechanistic studies of MALAT1 in respiratory diseases

Background: The incidence of respiratory diseases and the respiratory disease mortality rate have increased in recent years. Recent studies have shown that long non-coding RNA (lncRNA) MALAT1 is involved in various respiratory diseases. In vascular endothelial and cancer cells, MALAT1 expression triggers various changes such as proinflammatory cytokine expression, cancer cell proliferation and metastasis, and increased endothelial cell permeability. Methods: In this review, we performed a relative concentration index (RCI) analysis of the lncRNA database to assess differences in MALAT1 expression in different cell lines and at different locations in the same cell, and summarize the molecular mechanisms of MALAT1 in the pathophysiology of respiratory diseases and its potential therapeutic application in these conditions. Results: MALAT1 plays an important regulatory role in lncRNA with a wide range of effects in respiratory diseases. The available evidence shows that MALAT1 plays an important role in the regulation of multiple respiratory diseases. Conclusion: MALAT1 is an important regulatory biomarker for respiratory disease. Targeting the regulation MALAT1 could have important applications for the future treatment of respiratory diseases.

Early Diagnosis of Lung Cancer in the United Arab Emirates: Challenges and Strategic Recommendations

In the United Arab Emirates (UAE), lung cancer (LC) was the third leading cause of deaths due to cancer in 2017. Around 80% of the patients in the UAE are diagnosed at a late stage, rendering the treatment less effective in improving survival outcomes. Lack of awareness of disease symptomatology, deficient screening initiatives, misdiagnosis, and delayed referral to the specialist are contributing factors for delayed diagnosis. Effective screening at a primary care setting can be crucial for early diagnosis, referral to specialists, and enhancing patient outcomes. It is important to establish screening and referral guidelines through which each suspected case can be identified and provided timely intervention. Although the international screening and referral pathway framework are comprehensive, several regional barriers need to be addressed before they can be adapted at the national level. A group of LC experts from the UAE deliberated on issues like delayed diagnosis of LC and strategic recommendations for overcoming the challenges. The discussion was based on the review of the published evidence, international and regional guidelines for screening and early diagnosis of LC. Herein, we present a guideline, endorsed by the esteemed panel of experts, for aiding early diagnosis and optimizing the management of LC in the UAE.

Individual 5-Year Lung Cancer Risk Prediction Model in Korea Using a Nationwide Representative Database

Early detection of lung cancer by screening has contributed to reduce lung cancer mortality. Identifying high risk subjects for lung cancer is necessary to maximize the benefits and minimize the harms followed by lung cancer screening. In the present study, individual lung cancer risk in Korea was presented using a risk prediction model. Participants who completed health examinations in 2009 based on the Korean National Health Insurance (KNHI) database (DB) were eligible for the present study. Risk scores were assigned based on the adjusted hazard ratio (HR), and the standardized points for each risk factor were calculated to be proportional to the b coefficients. Model discrimination was assessed using the concordance statistic (c-statistic), and calibration ability assessed by plotting the mean predicted probability against the mean observed probability of lung cancer. Among candidate predictors, age, sex, smoking intensity, body mass index (BMI), presence of chronic obstructive pulmonary disease (COPD), pulmonary tuberculosis (TB), and type 2 diabetes mellitus (DM) were finally included. Our risk prediction model showed good discrimination (c-statistic, 0.810; 95% CI: 0.801-0.819). The relationship between model-predicted and actual lung cancer development correlated well in the calibration plot. When using easily accessible and modifiable risk factors, this model can help individuals make decisions regarding lung cancer screening or lifestyle modification, including smoking cessation.

Chronic obstructive pulmonary disease (COPD) and lung cancer: common pathways for pathogenesis

Chronic obstructive pulmonary disease (COPD) and lung cancer comprise the leading causes of lung disease-related mortality worldwide. Exposure to tobacco smoke is a mutual aetiology underlying the two diseases, accounting for almost 90% of cases. There is accumulating evidence supporting the role of immune dysfunction, the lung microbiome, extracellular vesicles and underlying genetic susceptibility in the development of COPD and lung cancer. Further, epigenetic factors, involving DNA methylation and microRNA expression, have been implicated in both diseases. Chronic inflammation is a key feature of COPD and could be a potential driver of lung cancer development. Using next generation technologies, further studies investigating the genomics, epigenetics and gene-environment interaction in key molecular pathways will continue to elucidate the pathogenic mechanisms underlying the development of COPD and lung cancer, and contribute to the development of novel diagnostic and prognostic tools for early intervention and personalised therapeutic strategies.

Population-Based Relative Risks for Lung Cancer Based on Complete Family History of Lung Cancer

INTRODUCTION

Published risk estimates for diagnosis of lung cancer based on family history are typically focused on close relatives, rather than a more diverse or complete family history. This study provides estimates of relative risk (RR) for lung cancer based on comprehensive family history data obtained from a statewide cancer registry linked to a high-quality genealogy data resource that is extensive and deep. The risk estimates presented avoid common recall, recruitment, ascertainment biases, and are based on an individual's (proband's) lung cancer family history constellation (pattern of lung cancer affected relatives); numerous constellations are explored.

METHODS

We used a population-based genealogic resource linked to a statewide electronic Surveillance Epidemiology and End Results program cancer registry to estimate RR for lung cancer for an individual based on their lung cancer family history. The family history data available for a proband included degree of relationship (first- to third-degree), paternal or maternal family lung cancer history, number of lung cancer-affected relatives, and age at diagnosis of affected relatives. More than 1.3 million probands with specific constellations of lung cancer were analyzed. To estimate RRs for lung cancer, the observed number of lung cancer cases among probands with a specific family history constellation was compared to the expected number using internal cohort-specific rates.

RESULTS

A total of 5048 lung cancer cases were identified. Significantly elevated RR was observed for any number of lung cancer-affected relatives among first-, second-, or third-degree relatives. RRs for lung cancer were significantly elevated for each additional lung cancer first-degree relative (FDR) ranging from RR = 2.57 (confidence interval [CI] 95%: 2.39, 2.76) for 1 or more FDR to RR = 4.24 (CI 95%: 1.56, 9.23) for 3 or more FDRs affected. In an absence of FDR family history, increased risk for lung cancer was significant for increasing numbers of affected second-degree relatives (SDRs) ranging from 1.41 (CI 95%: 1.30, 1.52) for 1 or more SDRs to 4.76 (CI 95%: 1.55, 11.11) for 4 or more SDRs. In the absence of affected FDRs and SDRs, there were significantly increased risks based on lung cancer-affected third-degree relatives (TDRs) ranging from 1.18 (CI 95%: 1.11, 1.24) for 1 or more affected TDRs to 1.55 (CI 95%: 1.03, 2.24) for 4 or more affected TDRs. RRs were significantly increased with earlier age at diagnosis of a FDR, and equivalent risks for maternal compared to paternal history were observed.

CONCLUSIONS

This study provides population-based estimates of lung cancer risk based on a proband's complete family history (lung cancer constellation). Many individuals at two to five or more times increased risk for lung cancer are identified. Estimates of RR for lung cancer based on family history are arguably relevant clinically. The constellation RR estimates presented could serve in individual decision-making to direct resource use for lung cancer screening, and could be pivotal in decision-making for screening, treatment, and post-treatment surveillance.

Association between Family History of Cancer and Lung Cancer Risk among Japanese Men and Women

Although cigarette smoking is a major risk factor for lung cancer, genetic susceptibility may also affect lung cancer risk. To explore the role of genetic risk, this case-control study investigated the association between family history of cancer at several sites and lung cancer risk. A total of 1,733 lung cancer cases and 6,643 controls were selected from patients aged 30 years and over admitted to a single hospital in Japan between 1997 and 2009. Information on family history of cancer was collected using a self-administered questionnaire and odds ratios (ORs) were estimated by unconditional logistic regression. Family history of lung cancer in first-degree relatives was associated with an increased risk of lung cancer among both sexes. According to histology and type of relatives, a parental history of lung cancer was significantly associated with an increased risk of female adenocarcinoma (OR = 1.72). Stratification by smoking status revealed that this significant positive association in women was limited to ever-smokers (OR = 4.13). In men, a history of lung cancer in siblings was significantly associated with an increased risk of small cell carcinoma (OR = 2.28) and adenocarcinoma (OR = 2.25). Otherwise, positive associations between history of breast (OR = 1.99) and total (OR = 1.71) cancers in siblings and the risk of male adenocarcinoma were observed. These results suggest that inherited genetic susceptibility may contribute to the development of lung cancer. In men, shared exposure to environmental factors among siblings may also be responsible for the increase in lung cancer risk.

Lung nodules: A comprehensive review on current approach and management

In daily clinical practice, radiologists and pulmonologists are faced with incidental radiographic findings of pulmonary nodules. Deciding how to manage these findings is very important as many of them may be benign and require no further action, but others may represent early disease and importantly early-stage lung cancer and require prompt diagnosis and definitive treatment. As the diagnosis of pulmonary nodules includes invasive procedures which can be relatively minimal, such as bronchoscopy or transthoracic aspiration or biopsy, but also more invasive procedures such as thoracic surgical biopsies, and as these procedures are linked to anxiety and to cost, it is important to have clearly defined algorithms for the description, management, and follow-up of these nodules. Clear algorithms for the imaging protocols and the management of positive findings should also exist in lung cancer screening programs, which are already established in the USA and which will hopefully be established worldwide. This article reviews current knowledge on nodule definition, diagnostic evaluation, and management based on literature data and mainly recent guidelines.

Smoking and Lung Cancer Mortality in the United States From 2015 to 2065: A Comparative Modeling Approach

BACKGROUND

Tobacco control efforts implemented in the United States since the 1960s have led to considerable reductions in smoking and smoking-related diseases, including lung cancer.

OBJECTIVE

To project reductions in tobacco use and lung cancer mortality from 2015 to 2065 due to existing tobacco control efforts.

DESIGN

Comparative modeling approach using 4 simulation models of the natural history of lung cancer that explicitly relate temporal smoking patterns to lung cancer rates.

SETTING

U.S. population, 1964 to 2065.

PARTICIPANTS

Adults aged 30 to 84 years.

MEASUREMENTS

Models were developed using U.S. data on smoking (1964 to 2015) and lung cancer mortality (1969 to 2010). Each model projected lung cancer mortality by smoking status under the assumption that current decreases in smoking would continue into the future (status quo trends). Sensitivity analyses examined optimistic and pessimistic scenarios.

RESULTS

Under the assumption of continued decreases in smoking, age-adjusted lung cancer mortality was projected to decrease by 79% between 2015 and 2065. Concomitantly, and despite the expected growth, aging, and longer life expectancy of the U.S. population, the annual number of lung cancer deaths was projected to decrease from 135 000 to 50 000 (63% reduction). However, 4.4 million deaths from lung cancer are still projected to occur in the United States from 2015 to 2065, with about 20 million adults aged 30 to 84 years continuing to smoke in 2065.

LIMITATION

Projections assumed no changes to tobacco control efforts in the future and did not explicitly consider the potential effect of lung cancer screening.

CONCLUSION

Tobacco control efforts implemented since the 1960s will continue to reduce lung cancer rates well into the next half-century. Additional prevention and cessation efforts will be required to sustain and expand these gains to further reduce the lung cancer burden in the United States.

PRIMARY FUNDING SOURCE

National Cancer Institute.

Genetic Contribution to Nonsquamous, Non-Small Cell Lung Cancer in Nonsmokers

INTRODUCTION

Lung carcinogenesis is strongly influenced by environmental and heritable factors. The genetic contribution to the different histologic subtypes is unknown.

METHODS

A population-based computerized genealogy resource linked to a statewide cancer registry of lung cancer cases (N = 5408) was analyzed to evaluate the heritable contribution to lung cancer histologic subtype in smokers (n = 1751) and nonsmokers (n = 818). Statistical methods were used to test for significant excess relatedness of lung cancer cases.

RESULTS

Significant excess distant relatedness was observed for all lung cancer histologic subgroups analyzed except for the SCLC subset (p = 0.213). When histologic subsets of smokers and nonsmokers with lung cancer were considered, excess relatedness was observed only in nonsmokers with NSCLC (n = 653 [p = 0.026]) and, in particular, in those nonsmokers with the nonsquamous histologic subtype (n = 561 [p = 0.036]). A total of 61 pedigrees demonstrating a significant excess risk of nonsquamous lung cancer in nonsmokers were identified, and an excess of cases in females was observed among the individuals with these high-risk pedigrees.

CONCLUSIONS

This analysis supports a genetic predisposition to lung cancer carcinogenesis in nonsmokers with nonsquamous NSCLC.

Higher frequency but random distribution of EGFR mutation subtypes in familial lung cancer patients

Despite the advancement of epidermal growth factor receptor (EGFR) inhibitors in lung cancer therapy, it remains unclear whether EGFR mutation status in familial lung cancers is different from that of sporadic cases. In this multicenter retrospective study, we compared both the EGFR mutation frequency and patterns between familial and sporadic cases. The results explored that family history of lung cancer is an independent predictor for higher EGFR mutation rate in 1713 lung adenocarcinoma patients (Odd ratio 1.68, 95% CI 1.06–2.67, P = 0.028). However, the distribution of EGFR mutation subtypes was similar to that of sporadic cases. Part of our study involved 40 lung cancer families with at least 2 tumor tissues available within each single family (n = 88) and there was no familial aggregation pattern in EGFR mutation subtypes. There were two families harboring the YAP1 R331W germline risk allele and EGFR mutation statuses among YAP1 family members also varied. These phenomena may hint at the direction of future research into lung carcinogenesis and EGFR mutagenesis.

Characteristics, survival, and risk factors of Chinese young lung cancer patients: the experience from two institutions

Limited data is available regarding lung cancer in Chinese young adults. This study was aimed to determine the characteristics, survival, and prognostic factors of young lung cancer patients in China. We reviewed demographic and clinical data, and survival information of 420 young patients (20-45 years old) diagnosed with lung cancer in two Chinese hospitals between 2000 and 2013. The results showed that lung cancer occurred more frequently (70%) and affected more males than females (43.8% vs 26.7%) in patients older than 36; whereas, more females were affected under age 35 (16.7% vs 12.8%). Most patients had adenocarcinoma (67.6%) and stage IV disease (72.4%) at presentation. The median survival of all young patients with lung cancer was 44 months (95% CI: 39-49), of which patients with stage I-IIIA disease had a longer survival than those with stage IIIB/IV disease (101 vs 22 months, p < 0.001). No significant difference in survival was found in patients having different histological subtypes or genders. Multivariate analysis revealed that high exposure risk occupations, smoking, family history of lung cancer were risk factors of young lung cancer patients. This study provides an overview of the clinical characteristics, patterns and prognostic factors of young patients with lung cancer in China.

Lung Cancer Risk Prediction Model Incorporating Lung Function: Development and Validation in the UK Biobank Prospective Cohort Study

Purpose Several lung cancer risk prediction models have been developed, but none to date have assessed the predictive ability of lung function in a population-based cohort. We sought to develop and internally validate a model incorporating lung function using data from the UK Biobank prospective cohort study. Methods This analysis included 502,321 participants without a previous diagnosis of lung cancer, predominantly between 40 and 70 years of age. We used flexible parametric survival models to estimate the 2-year probability of lung cancer, accounting for the competing risk of death. Models included predictors previously shown to be associated with lung cancer risk, including sex, variables related to smoking history and nicotine addiction, medical history, family history of lung cancer, and lung function (forced expiratory volume in 1 second [FEV1]). Results During accumulated follow-up of 1,469,518 person-years, there were 738 lung cancer diagnoses. A model incorporating all predictors had excellent discrimination (concordance (c)-statistic [95% CI] = 0.85 [0.82 to 0.87]). Internal validation suggested that the model will discriminate well when applied to new data (optimism-corrected c-statistic = 0.84). The full model, including FEV1, also had modestly superior discriminatory power than one that was designed solely on the basis of questionnaire variables (c-statistic = 0.84 [0.82 to 0.86]; optimism-corrected c-statistic = 0.83; pFEV1 = 3.4 × 10-13). The full model had better discrimination than standard lung cancer screening eligibility criteria (c-statistic = 0.66 [0.64 to 0.69]). Conclusion A risk prediction model that includes lung function has strong predictive ability, which could improve eligibility criteria for lung cancer screening programs.

Familial risk for lung cancer

Lung cancer, which has a low survival rate, is a leading cause of cancer-associated mortality worldwide. Smoking and air pollution are the major causes of lung cancer; however, numerous studies have demonstrated that genetic factors also contribute to the development of lung cancer. A family history of lung cancer increases the risk for the disease in both smokers and never-smokers. This review focuses on familial lung cancer, in particular on the familial aggregation of lung cancer. The development of familial lung cancer involves shared environmental and genetic factors among family members. Familial lung cancer represents a good model for investigating the association between environmental and genetic factors, as well as for identifying susceptibility genes for lung cancer. In addition, studies on familial lung cancer may help to elucidate the etiology and mechanism of lung cancer, and may identify novel biomarkers for early detection and diagnosis, targeted therapy and improved prevention strategies. This review presents the aetiology and molecular biology of lung cancer and then systematically introduces and discusses several aspects of familial lung cancer, including the characteristics of familial lung cancer, population-based studies on familial lung cancer and the genetics of familial lung cancer.

Lung Cancer in Never Smokers

Lung cancer is predominantly associated with cigarette smoking; however, a substantial minority of patients with the disease have never smoked. In the US it is estimated there are 17,000-26,000 annual deaths from lung cancer in never smokers, which as a separate entity would be the seventh leading cause of cancer mortality. Controversy surrounds the question of whether or not the incidence of lung cancer in never-smokers is increasing, with more data to support this observation in Asia. There are several factors associated with an increased risk of developing lung cancer in never smokers including second hand smoke, indoor air pollution, occupational exposures, and genetic susceptibility among others. Adenocarcinoma is the most common histology of lung cancer in never smokers and in comparison to lung cancer in smokers appears less complex with a higher likelihood to have targetable driver mutations.

Evidence for a genetical contribution to non-smoking-related lung cancer

BACKGROUND

The majority of lung cancers are smoking-related, with environmental and genetical factors contributing. The interplay between environmental and genetical contributions in non-smoking-related lung cancers is less clear.

METHODS

We analysed a population-based computerised genealogy resource linked to a state-wide cancer registry of lung cancer cases (n=5544) for evidence of a genetical contribution to lung cancer predisposition in smoking (n=1747) and non-smoking cases (n=784). Statistical methods were used to test for significant excess relatedness of cases and estimate relative risk (RR) in close and distant relatives of lung cancer cases.

RESULTS

Significant excess relatedness was observed for all lung cancer cases (p<0.001) and for the subsets of smoking-related (p<0.001) and non-smoking-related (p<0.001) cases when all pairwise relationships were considered. Only the non-smoking-related subset of cases showed significant excess relatedness when close relationships were ignored (p=0.020). First-degree, second-degree, and fourth-degree relatives of non-smoking-related lung cancer cases had significantly elevated RR. An even higher elevated RR was observed for first-degree, second-degree, third-degree and fourth-degree relatives of smoking-related lung cancer cases.

CONCLUSIONS

Non-smoking-related lung cancer cases show significant excess relatedness for close and distant relationships, providing strong evidence for a genetical contribution as well as an environmental contribution. Significant excess relatedness for only close family relationships in all lung cancer cases and in only smoking-related lung cancer cases implies environmental contribution. Additionally, the highest RR for lung cancer was observed in the relatives of smoking-related lung cancer, suggesting predisposition gene carriers who smoke are at highest risk for lung cancer. Screening and gene identification should focus on high-risk pedigrees.

Correlation between familial cancer history and epidermal growth factor receptor mutations in Taiwanese never smokers with non-small cell lung cancer: a case-control study

BACKGROUND

Lung cancer is a leading cause of cancer deaths in the world. Cigarette smoking remains a prominent risk factor, but lung cancer incidence has been increasing in never smokers. Genetic abnormalities including epidermal growth factor receptor (EGFR) mutations predominate in never smoking lung cancer patients. Furthermore, familial aggregations of patients with these mutations reflect heritable susceptibility to lung cancer. The correlation between familial cancer history and EGFR mutations in never smokers with lung cancer requires investigation.

METHODS

This was a retrospective case-control study that evaluated the prevalence of EGFR mutations in lung cancer patients with familial cancer history. Never smokers with lung cancer treated at a hospital in Taiwan between April 2012 and May 2014 were evaluated. Inclusion criteria were never smokers with non-small cell lung cancer (NSCLC). Exclusion criteria involved patients without records of familial cancer history or tumor genotype.

RESULTS

This study included 246 never smokers with lung cancer. The study population mainly involved never smoking women with a mean age of 60 years, and the predominant tumor histology was adenocarcinoma. Lung cancer patients with familial cancer history had an increased prevalence of EGFR mutations compared to patients without family history [odds ratio (OR): 5.9; 95% confidence interval (CI): 3.3-10.6; P<0.001]. Specifically, 57 out of 85 cancer patients (67%) with familial cancer history had these mutations, while 41 out of 161 patients (25%) without family history harbored mutations. Subgroup analysis also revealed that patients with familial lung cancer history had stronger association with EGFR mutations (OR: 7.5; 95% CI: 3.4-16.3; P<0.001) compared to patients with family history of non-pulmonary cancers (OR: 5.0; 95% CI: 2.5-10.0; P<0.001).

CONCLUSIONS

The study demonstrated an increased prevalence of EGFR mutations in Taiwanese never smoking lung cancer patients with familial cancer history. Moreover, a sizable proportion of never smoking cancer patients harbored these mutations. These observations have implications for the treatment of lung cancer in never smokers.

Family history of lung cancer in never smokers with non-small-cell lung cancer and its association with tumors harboring EGFR mutations

INTRODUCTION

Inherited susceptibility to lung cancer is understudied. Never smokers are an important subgroup of patients enriched for tumors harboring oncogene aberrations in the EGFR and ALK genes. We aimed to better characterize the incidence of family history of lung cancer among never smokers with NSCLC.

METHODS

Clinicopathologic data, tumor genotype, family history of cancer, and specifically family history of lung cancer from 230 consecutive never smokers was retrospectively compiled and analyzed.

RESULTS

In our cohort, the median age was 56 years, 67% were women, 75% were white, 59% had advanced NSCLC and 87% had adenocarcinoma histology. In these tumors, 98/230 (42%) had an EGFR mutation, 17/155 (11%) had KRAS mutations and 27/127 (21%) had an ALK translocation. Family history of any cancer was common (57%) and specific family history of lung cancer was present in 42/230 cases (18%). The percentage of cases with family history of lung cancer was higher in the EGFR mutated versus EGFR wild-type NSCLCs. Out of the cases with a family history of any cancer, 22/53 (41.5%) EGFR mutated, 1/5 (20%) KRAS mutated and 3/19 (15.5%) ALK translocated cohorts had a family history of lung cancer. The ratio of family history of lung cancer to family history of cancer was significantly higher in the EGFR mutated cohort when compared to the ALK translocated plus KRAS mutated cohorts (p=0.039).

CONCLUSIONS

Family history of lung cancer is common in never smokers with NSCLC, and there seems to be a particular link in families in which the proband has an EGFR mutated tumor when compared to ALK translocated or KRAS mutated tumors. Further study of families with EGFR-mutated NSCLC may yield insights into the pathogenesis of this tumor type.

Increased risk of lung cancer in individuals with a family history of the disease: a pooled analysis from the International Lung Cancer Consortium

BACKGROUND AND METHODS

Familial aggregation of lung cancer exists after accounting for cigarette smoking. However, the extent to which family history affects risk by smoking status, histology, relative type and ethnicity is not well described. This pooled analysis included 24 case-control studies in the International Lung Cancer Consortium. Each study collected age of onset/interview, gender, race/ethnicity, cigarette smoking, histology and first-degree family history of lung cancer. Data from 24,380 lung cancer cases and 23,305 healthy controls were analysed. Unconditional logistic regression models and generalised estimating equations were used to estimate odds ratios and 95% confidence intervals.

RESULTS

Individuals with a first-degree relative with lung cancer had a 1.51-fold increase in the risk of lung cancer, after adjustment for smoking and other potential confounders (95% CI: 1.39, 1.63). The association was strongest for those with a family history in a sibling, after adjustment (odds ratios (OR) = 1.82, 95% CI: 1.62, 2.05). No modifying effect by histologic type was found. Never smokers showed a lower association with positive familial history of lung cancer (OR = 1.25, 95% CI: 1.03, 1.52), slightly stronger for those with an affected sibling (OR = 1.44, 95% CI: 1.07, 1.93), after adjustment.

CONCLUSIONS

The occurrence of lung cancer among never smokers and similar magnitudes of the effect of family history on lung cancer risk across histological types suggests familial aggregation of lung cancer is independent of those risks associated with cigarette smoking. While the role of genetic variation in the aetiology of lung cancer remains to be fully characterised, family history assessment is immediately available and those with a positive history represent a higher risk group.

Lung cancer in never smokers

Lung cancer in never smokers (LCINS) is the seventh leading cause of death among solid tumors. The main risk factor for lung cancer is smoking; however, approximately 15% of lung cancer patients have never smoked. LCINS is more frequent in women, irrespective of geographical location, nevertheless, the highest incidence has been found in South-East Asia. The histological incidence of adenocarcinoma is higher in the group of never smokers than squamous cell carcinoma. There is a familial clustering of lung cancer that is more pronounced in never smokers, where the family history was associated with an increased risk. Genome-wide association studies identified certain chromosomal aberrations in LCINS. Furthermore, the oncogenic mutation pattern is distinct in nonsmoking patients: activating mutations of EGFR or anaplastic lymphoma kinase are more frequent. The etiology of LCINS includes several environmental factors as well, such as environmental tobacco smoke, viral and hormonal factors, a variety of pulmonary diseases and certain occupational exposures. It is now established that EGFR-tyrosine kinase inhibitor treatment (erlotinib and geftinib) in lung cancer is more effective in LCINS, owing to the higher incidence of EGFR mutation in nonsmokers. Despite the growing body of information on LCINS in recent years there is a need to further investigate the pathogenesis of this particular lung cancer. Future studies on LCINS should try to tackle the issues of prevention, early diagnosis and the exploration of novel therapeutic targets to combat lung cancer disease.

Clinicopathological characteristics and prognosis of non-small cell lung cancer patients associated with a family history of lung cancer

INTRODUCTION

Clinicopathological characteristics and prognosis of non-small cell lung cancer (NSCLC) patients with a family history of lung cancer (FHLC) have not been well established.

METHODS

Clinical records of patients with NSCLC treated at our institute from 1982 to 2010 were reviewed with special reference to family history of lung cancer and clinicopathological factors including patient's outcome. Univariate analyses of the factors between the groups of FHLC and non-FHLC were performed using unpaired two-tailed t tests or the chi-square test. The Cox proportional hazards model was used to evaluate the hazard ratio of death.

RESULTS

Of the 1013 NSCLC patients, 124 (12.2%) had a FHLC of whom 119 (96%) were the first-degree relatives. The frequency of early stages of lung cancer was high in both groups of FHLC and non-FHLC patients. Patients with FHLC had a significantly higher frequency of early pathological stages and a prepomderance of adenocarcinoma, and a hazard ratio of death of 0.870 (95% confidence interval: 0.599-1.263, p value: 0.465) compared with the non-FHLC patients.

CONCLUSIONS

NSCLC patients with FHLC could be characterized by early pathological stages and preponderance of adenocarcinoma, however they were not at a decreased hazard ratio of death. These findings emphasize the importance of early detection of lung cancer and employment of less invasive therapeutic interventions.

[Forecasting model of risk of cancer in lung cancer pedigree in a case-control study]

背景与目的

对人群每年进行低剂量胸部CT筛查可提高早期肺癌诊断率，但其假阳性率较高，常导致不必要的手术。本研究拟建立肺癌家系风险度预测模型，从中细分高危人群，从而提高筛选效能。

方法

以经病理确诊的肺癌患者的家系作为研究人群，同时收集先证者的配偶家系作为对照家系，共收集先证者家系633例和对照家系565例。应用SPSS 17.0进行统计学分析。

结果

先证者家系一级亲属患肿瘤的风险性为对照组家系一级亲属的1.71倍（OR=1.71, P < 0.001）。家系中患癌个数分别为=1和≥2的两组与对照组比较有统计学差异（P=0.005, P=0.002）。建立回归模型后赋值得到与普通人群相比的肺癌风险度为0.38-63.08（倍）。风险度为普通人群10倍以上的群体，应用本模型的正确率为88.1%。

结论

如果一级亲属患癌个数越多，患肺癌的风险越高。根据本研究建立的风险度预测模型，风险度达普通人群10倍以上的主要为重度吸烟的吸烟人群，应加强筛查。特点为：有肺部既往疾病史的重度吸烟人群，加上男性、职业暴露和一级亲属肿瘤家族史三项中的任一项；有肺部既往疾病史或重度吸烟的人群中，有职业暴露的男性且一级亲属有不少于两位肿瘤患者。

[Gender-associated differences of lung cancer and mechanism]

肺癌是全球发病率、死亡率最高、治疗效果差的恶性肿瘤。肺癌在流行病学、病理类型、疗效和预后、甚至发病机制等多方面均表现出明显性别差异。对这些差异的深入剖析能更好地认识男女性别肺癌各自的特点，为肺癌防治采用不同的性别化措施提供新线索和思路；而对导致性别差异的具体机制进行深入研究，有助于阐明肺癌的发病机制。

Non-small cell lung cancer in never smokers as a representative 'non-smoking-associated lung cancer': epidemiology and clinical features

Recent interest in lung cancer without a history of tobacco smoking has led to the classification of a distinct disease entity of 'non-smoking-associated lung cancer'. In this review article, we have made an overview of the recent literature concerning both the epidemiology and clinical features of lung cancer in never smokers, and have brought 'non-smoking-associated lung cancer' into relief. The etiology of lung cancer in never smokers remains indefinite although many putative risk factors have been described including secondhand smoking, occupational exposures, pre-existing lung diseases, diet, estrogen exposure, etc. Non-small cell lung cancer (NSCLC) in never smokers is clinically characterized by an increased incidence in females and a higher occurrence of adenocarcinoma in comparison to NSCLC in ever smokers in both surgical patients and non-resectable advanced-stage patients. Furthermore, the prognosis of never-smoking NSCLC is better than that of smoking-related NSCLC in both surgical patients and non-resectable advanced-stage patients. Recently recognized novel gene mutations such as EGFR (epidermal growth factor receptor) mutations are largely limited to never smokers or light smokers, and the expression of this gene is responsible for the clinical efficacy of gefitinib, an epidermal growth factor receptor-tyrosine kinase inhibitor. NSCLC with the EML4 (echinoderm microtubule-associated protein-like 4)-ALK (anaplastic lymphoma kinase) fusion gene is also more likely to occur in never smokers and in those with adenocarcinoma histology, and is expected to benefit from ALK inhibitors. In consideration of the future increase in never-smoking NSCLC or 'non-smoking-associated lung cancer', both clinical trials and investigations are needed.

Lung cancer in never smokers: molecular profiles and therapeutic implications

The majority of lung cancers are caused by long term exposure to the several classes of carcinogens present in tobacco smoke. Although a significant fraction of lung cancers in never smokers may also be attributable to tobacco, many such cancers arise in the absence of detectable tobacco exposure, and may follow a very different cellular and molecular pathway of malignant transformation. Recent studies summarized here suggest that lung cancers arising in never smokers have a distinct natural history, profile of oncogenic mutations, and response to targeted therapy. The majority of molecular analyses of lung cancer have focused on genetic profiling of pathways responsible for metabolism of primary tobacco carcinogens. Limited research has been conducted evaluating familial aggregation and genetic linkage of lung cancer, particularly among never smokers in whom such associations might be expected to be strongest. Data emerging over the past several years show that lung cancers in never smokers are much more likely to carry activating mutations of the epidermal growth factor receptor (EGFR), a key oncogenic factor and direct therapeutic target of several newer anticancer drugs. EGFR mutant lung cancers may represent a distinct class of lung cancers, enriched in the never-smoking population, and less clearly linked to direct tobacco carcinogenesis. These insights followed initial testing and demonstration of efficacy of EGFR-targeted drugs. Focused analysis of molecular carcinogenesis in lung cancers in never smokers is needed, and may provide additional biologic insight with therapeutic implications for lung cancers in both ever smokers and never smokers.

Family history and lung cancer risk: international multicentre case-control study in Eastern and Central Europe and meta-analyses

Lung cancer is the most common neoplastic disease in Eastern and Central Europe. The role of hereditary factors in lung carcinogenesis is not fully understood. Family history (FH) of lung cancer and other tobacco-related cancers might be a strong predictor of the lung cancer risk. We investigated family history of cancer among first-degree relatives of 2,861 patients with lung cancer and 3,118 controls from the Czech Republic, Hungary, Poland, Romania, Russia, Slovakia, and United Kingdom within the IARC Multicenter Case-Control Study. Odds ratios (ORs) and 95% CI were calculated using logistic regression, adjusting for age, gender, study center, education, tobacco smoking, and number of first-degree relatives. In addition, we conducted a meta-analysis of 41 studies on FH of cancer and lung cancer risk. Positive FH of lung cancer increased risk of lung cancer with OR of 1.63 (95%CI: 1.31-2.01), and having two or more affected relatives with lung cancer further increased the risk of lung cancer with OR 3.60 (95%CI: 1.56-8.31). Among subjects aged less than 50, the OR for FH of lung cancer was 2.08 (95%CI: 1.18-3.63). The associations were generally stronger for squamous cell carcinoma and large cell carcinoma subtypes. Heterogeneity in results was not found with respect to smoking status and gender. A significant association was not observed for FH of other smoking-related tumors. The results of meta-analysis were consistent with that of our study with regard to young onset, non-smokers and histology. FH of lung cancer is a predictor of an increased risk of lung cancer, especially in subjects aged less than 50.

Prediction of true positive lung cancers in individuals with abnormal suspicious chest radiographs: a prostate, lung, colorectal, and ovarian cancer screening trial study

INTRODUCTION

Chest radiographs are routinely employed in clinical practice. Radiographic findings that are abnormal suspicious (AS) for lung cancer occur commonly. The majority of AS radiographic abnormalities are not cancer. This study identifies predictors of true positive (TP) AS and presents models for estimating the probability of lung cancer.

METHODS

This is a prospective cohort study nested in the randomized National Cancer Institute's Prostate Lung Colorectal Ovarian Cancer Screening Trial (PLCO). First-time AS screens in the screening arm of the PLCO were studied. Associations between nonradiographic and radiographic factors, and TP AS were evaluated by multiple logistic regression.

RESULTS

The PLCO intervention arm had 77,465 individuals, of whom 12,314 were AS and of these 232 (1.9%) had lung cancer (were TP). Important independent predictors of TP were older age, lower education, greater pack years and duration smoking history, body mass index <30, family history of lung cancer, lung nodule, lung mass, unilateral mediastinal or hilar lymphadenopathy, lung infiltrate, and upper/middle chest AS location. The model including these variables had a receiver operator characteristic area under the curve (ROC AUC) of 86.4%. This model excluding the smoking variables had an ROC AUC of 77.1% and excluding all nonradiographic variables had an ROC AUC of 73.3% (p < 0.0001 for all these model differences). Smoking and nonsmoking nonradiographic variables significantly added to prediction.

CONCLUSION

This study identifies important nonradiographic and radiographic predictors of lung cancer, and presents an accurate model for estimating the probability of lung cancer in individuals with suspicious radiographs. These findings may be of value for screening, research, and patient and clinician decision-making.

Family history of cancer and nonmalignant lung diseases as risk factors for lung cancer

Family history (FH) of lung cancer is an established risk factor for lung cancer, but the modifying effect of smoking in relatives has been rarely examined. Also, the role of FH of nonmalignant lung diseases on lung cancer risk is not well known. We examined the role of FH of cancer and nonmalignant lung diseases in lung cancer risk overall, and by personal smoking, FH of smoking and histology in 1,946 cases and 2,116 population-based controls within the Environment And Genetics in Lung cancer Etiology (EAGLE) study. Odds ratios (ORs) and 95% CI from logistic regression were calculated adjusting for age, gender, residence, education and cigarette smoking. FH of lung cancer in any family member was associated with increased lung cancer risk (OR = 1.57, 95% CI = 1.25-1.98). The odds associated with fathers', mothers' and siblings' history of lung cancer were 1.41, 2.14 and 1.53, respectively. The associations were generally stronger in never smokers, younger subjects and for the adenocarcinoma and squamous cell carcinoma subtypes. FH of chronic bronchitis and pneumonia was associated with increased (OR = 1.49, 95% CI = 1.23-1.80) and decreased (OR = 0.73, 95% CI = 0.61-0.87) lung cancer risk, respectively. FH of lung cancer and nonmalignant lung diseases affected lung cancer risk independently, and did not appear to be modified by FH of smoking.

Cancer diagnosis in first-degree relatives and non-small cell lung cancer risk: results from a multi-centre case-control study in Europe

Because aggregation of cancers at different sites can occur in families, cancer could be considered as a broad phenotype with shared genetic factors. Here, we report results from a multi-centre case-control study of non-small cell lung cancer (NSCLC), with particular emphasis on a history of cancer in first-degree relatives and the risk of lung cancer. From 2002 to 2006, 733 NSCLC patients treated surgically were recruited in 8 European countries and matched to 1312 controls, by centre, sex and age. We used multivariate conditional logistic regression models to test the association between a history of cancer in first-degree relatives and risk of NSCLC. A family history of lung cancer was associated with an odds ratio (OR) for early-onset (54 years or younger) NSCLC of 4.72 (95% confidence interval [CI]=1.02-21.90). A family history of gastric cancer was associated with an OR for NSCLC of 1.82 (95% CI=1.08-3.06) and for late-onset (55 years or older) NSCLC of 2.92 (95% CI=1.10-7.75). Our findings provide further evidence of a familial predisposition to lung cancer and support the hypothesis that family history is a significant risk factor for the disease. Because of the inherent potential for bias in familial case-control study design, cautious interpretation is warranted.

The International Epidemiology of Lung Cancer: geographical distribution and secular trends

This review presents the latest available international data for lung cancer incidence, mortality and survival, emphasizing the established causal relationship between smoking and lung cancer. In 2002, it was estimated that 1.35 million people throughout the world were diagnosed with lung cancer, and 1.18 million died of lung cancer-more than for any other type of cancer. There are some key differences in the epidemiology of lung cancer between more developed and less developed countries. In more developed countries, incidence and mortality rates are generally declining among males and are starting to plateau for females, reflecting previous trends in smoking prevalence. In contrast, there are some populations in less developed countries where increasing lung cancer rates are predicted to continue, due to endemic use of tobacco. A higher proportion of lung cancer cases are attributable to nonsmoking causes within less developed countries, particularly among women. Worldwide, the majority of lung cancer patients are diagnosed after the disease has progressed to a more advanced stage. Despite advances in chemotherapy, prognosis for lung cancer patients remains poor, with 5-year relative survival less than 14% among males and less than 18% among females in most countries. Given the increasing incidence of lung cancer in less developed countries and the current lack of effective treatment for advanced lung cancers, these results highlight the need for ongoing global tobacco reform to reduce the international burden of lung cancer.

Lung cancer and women

In the early 1900s, lung cancer was a rare malignancy in women, but starting from the 1960s it has progressively reached epidemic proportions, surpassing breast cancer in 1987 and becoming the leading cause of cancer deaths in many countries. Retrospective data show that the 5-year survival rate for women who have lung cancer is 15.6%, compared with 12.5% for men, and this improved survival could have important implications in the design and interpretation of lung cancer trials. Women have major responses to therapy regardless of stage, therapeutic modalities or histology. The increase of lung cancer incidence among women is reflected in their clinical trial participation, causing a survival improvement and suggesting the need of stratification by sex in future studies. No specific drugs for women with lung cancer are currently available, but researchers are devoting energies in this area in order to better understand the implication of gender differences in epidemiology, pathogenesis, prognosis and tumor response.

Adenocarcinoma with epidermal growth factor receptor gene mutations in three siblings

Sensitivity to an inhibitor of epidermal growth factor receptor (EGFR) kinase strongly correlates with EGFR somatic mutations in non-small cell lung cancer. These mutations are frequently found in patients with adenocarcinoma, never- or light-smokers, women, and East Asians. In this study, we show an aggregation of three non-small cell lung cancer cases with EGFR gene mutations in one family. The subjects were all female, never- or light-smokers with adenocarcinoma. Two of the patients responded to treatment with gefitinib. A genetic study of these cases would be useful in elucidating genetic susceptibility to lung cancer in persons with EGFR mutations.

Inflammation and lung cancer: roles of reactive oxygen/nitrogen species

The lung is a highly specialized organ that facilitates uptake of oxygen and release of carbon dioxide. Due to its unique structure providing enormous surface area to outside ambient air, it is vulnerable to numerous pathogens, pollutants, oxidants, gases, and toxicants that are inhaled continuously from air, which makes the lung susceptible to varying degrees of oxidative injury. To combat these unrelenting physical, chemical, and biological insults, the respiratory epithelium is covered with a thin layer of lining fluid containing several antioxidants and surfactants. Inhaled toxic agents stimulate the generation of reactive oxygen/nitrogen species (ROS/RNS), which in turn provoke inflammatory responses resulting in the release of proinflammatory cytokines and chemokines. These subsequently stimulate the influx of polymorphonuclear leukocytes (PMNs) and monocytes into the lung so as to combat the invading pathogens or toxic agents. In addition to the beneficial effects, persistent inhalation of the invading pathogens or toxic agents may result in overwhelming production of ROS/RNS, producing chronic inflammation and lung injury. During inflammation, enhanced ROS/RNS production may induce recurring DNA damage, inhibition of apoptosis, and activation of proto-oncogenes by initiating signal transduction pathways. Therefore, it is conceivable that chronic inflammation-induced production of ROS/RNS in the lung may predispose individuals to lung cancer. This review describes the complex relationship between lung inflammation and carcinogenesis, and highlights the role of ROS/RNS in cancer development.