Is previous respiratory disease a risk factor for lung cancer?

Chronic obstructive pulmonary disease and lung cancer: inter-relationships

PURPOSE OF REVIEW

Chronic obstructive pulmonary disease (COPD) is a well established risk factor for lung cancer. Newer studies reveal a myriad of other mechanisms, some proven and some putative, which may contribute to their association.

RECENT FINDINGS

There is an ever-growing bundle of evidence that suggests a close association between persistent chronic inflammation and lung cancer. A few potential targets of genetic susceptibility locus for COPD and lung cancer have been suggested. Better characterization of immune dysregulation and identification of signaling pathways may assist the development of strategies to reduce risk of developing lung cancer in patients with COPD. Current lung cancer screening strategies may exclude some patients at high risk of having lung cancer. Prospective studies indicate that a screening criterion that includes variables reflecting the severity of COPD may increase the sensitivity of the screening program and reduce 'over-diagnosis bias' of indolent lung cancers. Examples of such variables include the emphysema score generated from computed tomography scans and diffusion capacity for carbon monoxide derived from lung function tests.

SUMMARY

A better understanding of the inter-relationship between lung cancer pathogenesis and COPD has been described recently. Improving lung cancer screening strategies by incorporating markers of COPD severity has recently been proposed.

Lung cancer risk by geologic coal deposits: A case-control study of female never-smokers from Xuanwei and Fuyuan, China

Coal types vary around the world because of geochemical differences in their source deposits; however, the influence of coal emissions from different deposits on human health remains unexplored. To address this issue, we conducted the first study of the relationship between coal use from various deposits and lung cancer risk in Xuanwei and Fuyuan, counties in China where lung cancer rates are among the highest in the world among female never-smokers due to use of bituminous ("smoky") coal for heating and cooking. We conducted a population-based case-control study of 1031 lung cancer cases and 493 controls among never-smoking women in Xuanwei and Fuyuan. Logistic regression models were used to estimate associations between coal use from various deposits across the lifecourse and lung cancer risk. There was substantial heterogeneity in risks by coal deposit (p = 7.8E-05). Compared to non-smoky coal users, risks by smoky coal deposit ranged from OR = 7.49 (95% CI: 3.43-16.38) to OR = 33.40 (95% CI: 13.07-85.34). Further, women born into homes that used smoky coal and subsequently changed to non-smoky coal had a higher risk (OR = 10.83 (95% CI: 4.61-25.46)) than women born into homes that used non-smoky coal and changed to smoky coal (OR = 4.74 (95% CI: 2.03-11.04, p_difference = 0.04)). Our study demonstrates that various sources of coal have considerably different impact on lung cancer in this population and suggests that early-life exposure to carcinogenic emissions may exert substantial influence on health risks later in life. These factors should be considered when evaluating the health risks posed by exposure to coal combustion emissions.

Lung cancer: a new frontier for microbiome research and clinical translation

The lung microbiome has been shown to reflect a range of pulmonary diseases—for example: asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis. Studies have now begun to show microbiological changes in the lung that correlate with lung cancer (LC) which could provide new insights into lung carcinogenesis and new biomarkers for disease screening. Clinical studies have suggested that infections with tuberculosis or pneumonia increased the risk of LC possibly through inflammatory or immunological changes. These have now been superseded by genomic-based microbiome sequencing studies based on bronchoalveolar lavage, sputum or saliva samples. Although some discrepancies exist, many have suggested changes in particular bacterial genera in LC samples particularly, Granulicatella, Streptococcus and Veillonella. Granulicatella is of particular interest, as it appeared to show LC stage-specific increases in abundance. We propose that these microbial community changes are likely to reflect biochemical changes in the LC lung, linked to an increase in anaerobic environmental niches and altered pyridoxal/polyamine/nitrogenous metabolism to which Granulicatella could be particularly responsive. These are clearly preliminary observations and many more expansive studies are required to develop our understanding of the LC microbiome.

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.

Management of co-existent tuberculosis and lung cancer

Tuberculosis (TB) and lung cancer are important global health threats, each accounting for 1.6 million deaths yearly. The incidence of both conditions remains high in many developing countries, especially in East Asia. There is now epidemiologic evidence that pre-existing TB poses an increased lung cancer risk. The clinical diagnosis of co-existent TB and lung cancer relies on symptoms of infection, typical radiological features and microbiological confirmation, and remains a challenge in both early and late stage lung cancer. The presence of histological granulomatous inflammation in resected lung specimens is not exclusively indicative of TB. The widely accepted systemic chemotherapy and immunotherapy for treating lung cancer are highly relevant to the occurrence of TB and its management. This review addresses the clinical approach to the diagnosis and treatment of TB that co-exists with lung cancer.

Associations between history of chronic lung disease and non-small cell lung carcinoma in Maryland: variations by sex and race

PURPOSE

Lung cancer is a multifactorial malignancy for which some risk factors, such as chronic lung diseases, their interactions with smoking, and how they differ by race and sex, are not fully understood. We investigated the associations between chronic inflammatory lung disease and non-small cell lung carcinoma (NSCLC) and how sex and race may affect such associations.

METHODS

Using logistic regression, we analyzed 1660 lung cancer cases and 1959 population controls and estimated adjusted odds ratios (AORs) and 95% confidence intervals (CIs).

RESULTS

Chronic lung disease was significantly associated with higher odds of having NSCLC in never (AOR = 1.99; 95% CI = 1.19-3.34), former (AOR = 1.68; 95% CI = 1.29-2.20), and current smokers (AOR = 2.40; 95% CI = 1.62-3.57), after adjustment for relevant covariates. For each 5-year increment in chronic lung disease duration, the risk of lung cancer increased only among females (AOR = 1.07; 95% CI = 1.02-1.13). Females, but not males, with asthma were at risk for NSCLC (AOR = 2.08; 95% CI = 1.40-3.10).

CONCLUSIONS

This study provides support for chronic lung inflammation as a potential contributing factor to lung cancer risk and possible sex difference in the inflammatory events underlying disease mechanisms.

Impact of Pulmonary Tuberculosis on the EGFR Mutational Status and Clinical Outcome in Patients with Lung Adenocarcinoma

Purpose

Although it has been suggested that pulmonary tuberculosis (TB) is associated with increased risk of lung cancer, the exact mechanism is not clearly identified. We investigated the effect of pulmonary TB on the epidermal growth factor receptor (EGFR) mutational status and clinical outcome in patients with pulmonary adenocarcinoma.

Materials and Methods

We reviewed data of patients diagnosed with pulmonary adenocarcinoma harboring EGFR mutations and treated at our institution from 2008 to 2015. We divided our population into two groups: patients with pre-existing TB lesions on chest computed tomography scan (TB group) and those without the lesions (non-TB group). We compared the differences in EGFR mutational status, response to tyrosine kinase inhibitors (TKIs) and survival between the two groups.

Results

A total of 477 patients with pulmonary adenocarcinoma were analyzed. One hundred eighty-three patients (39%) had EGFR-mutated tumors and 100 (21%) patients had pre-existing TB lesions. The frequency of EGFR mutation was significantly higher in the TB group compared with the non-TB group (56% vs. 34%, p=0.038). Pre-existing TB lesions were independently associated with more frequent EGFR mutations in multivariate analysis (odds ratio, 1.43). In addition, both the progression-free survival (9.1 months vs. 11.6 months, p=0.020) and the overall survival (19.4 months vs. 24.5 months, p=0.014) after first-line EGFR-TKIs were significantly shorter in the TB group than in the non-TB group.

Conclusion

Previous pulmonary TB may be associated with more frequent EGFR mutations and poorer treatment response to EGFR-TKIs in patients with pulmonary adenocarcinoma.

Lung cancer: a brief review of epidemiology and screening

The global burden of lung cancer has been increasing over the past years, and is still a major threat to public health worldwide, leading to disabilities and premature mortality. Despite multifactorial cause, smoking remains as the major etiological factor, followed by occupational exposure to carcinogens, genetic predisposition and other concomitant diseases. In order to reduce the individual and social burden due to the direct and indirect costs related to the lung cancer treatment, accurate methods of screening are needed. Among those, x-ray with cytological analysis of sputum was first proposed. Nowadays, more sensitive methods such as low-dose computed tomography are being used to improve the early detection. In the future, molecular biomarkers may complement low-dose computed tomography and improve the robustness of early lung cancer detection.

Lung cancer and chronic obstructive pulmonary disease: From a clinical perspective

Chronic obstructive pulmonary disease (COPD) and lung cancer are devastating pulmonary diseases that commonly coexist and present a number of clinical challenges. COPD confers a higher risk for lung cancer development, but available chemopreventive measures remain rudimentary. Current studies have shown a marked benefit of cancer screening in the COPD population, although challenges remain, including the common underdiagnosis of COPD. COPD-associated lung cancer presents distinct clinical features. Treatment for lung cancer coexisting with COPD is challenging as COPD may increase postoperative morbidities and decrease survival. In this review, we outline current progress in the understanding of the clinical association between COPD and lung cancer, and suggest possible cancer prevention strategies in this patient population.

Chronic obstructive pulmonary disease in patients with lung cancer: prevalence, impact and management challenges

Chronic obstructive pulmonary disease (COPD) and lung cancer share a common etiological factor (cigarette smoking) and usually coexist in everyday clinical practice. The prevalence of COPD among newly diagnosed patients with lung cancer sometimes exceeds 50%. COPD is an independent risk factor (2-4 times higher than non-COPD subjects) for lung cancer development. The presence of emphysema in addition to other factors (e.g., smoking history, age) could be incorporated into risk scores in order to define the most appropriate target group for lung cancer screening using low-dose computed tomography. Clinical management of patients with coexistence of COPD and lung cancer requires a multidisciplinary oncology board that includes a pulmonologist. Detailed evaluation (lung function tests, cardiopulmonary exercise test) and management (inhaled drugs, smoking cessation, pulmonary rehabilitation) of COPD should be taken into account for lung cancer treatment (surgical approach, radiotherapy).

Mitochondria in chronic obstructive pulmonary disease and lung cancer: where are we now?

Recent advances in mitochondrial biogenesis have provided the emerging recognition that mitochondria do much more than 'simply providing energy for cellular function'. Currently, a constantly improving understanding of the mitochondrial structure and function has been providing valuable insights into the contribution of defects in mitochondrial metabolism to various human diseases, including chronic obstructive pulmonary disease and lung cancer. The growing interest in mitochondria research led to development of new biomedical fields in the two main smoking-related lung diseases. However, there is considerable paucity in our understanding of mechanisms by which mitochondrial dynamics regulate lung diseases. In this review, we will discuss our current knowledge on the role of mitochondrial dysfunction in the pathogenesis of chronic obstructive pulmonary disease and non-small-cell lung cancer.

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.

Atopy and Specific Cancer Sites: a Review of Epidemiological Studies

Mounting evidence appears to link asthma and atopy to cancer susceptibility. This review presents and discusses published epidemiological studies on the association between site-specific cancers and atopy. PubMed was searched electronically for publications between 1995 and 2015, and cited references were researched manually. Quantitative studies relating to atopy, allergy, or asthma and cancer were identified and tabulated. Despite many exposure-related limitations, patterns in the studies were observed. Asthma, specifically, has been observed to be a risk factor for lung cancer. A protective effect of atopic diseases against pancreatic cancer has been shown consistently in case-control studies but not in cohort studies. Allergy of any type appears to be protective against glioma and adult acute lymphoblastic leukemia. Most studies on atopic diseases and non-Hodgkin lymphoma or colorectal cancer reported an inverse association. The other sites identified had varying and non-significant outcomes. Further research should be dedicated to carefully defined exposure assessments of "atopy" as well as the biological plausibility in the association between atopic diseases and cancer.

Asthma and lung cancer, after accounting for co-occurring respiratory diseases and allergic conditions: a systematic review protocol

INTRODUCTION

Asthma is one of the most frequently diagnosed respiratory diseases in the UK, and commonly co-occurs with other respiratory and allergic diseases, such as chronic obstructive pulmonary disease (COPD) and atopic dermatitis. Previous studies have shown an increased risk of lung cancer related to asthma, but the evidence is mixed when accounting for co-occurring respiratory diseases and allergic conditions. A systematic review of published data that investigate the relationship between asthma and lung cancer, accounting for co-occurring respiratory and allergic diseases, will be conducted to investigate the independent association of asthma with lung cancer.

METHODS AND ANALYSIS

A systematic review will be conducted, and include original reports of cohort, cross-sectional and case-control studies of the association of asthma with lung cancer after accounting for co-occurring respiratory diseases. Articles published up to June 2016 will be included, and their selection will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A standardised data extraction form will be developed and pretested, and descriptive analyses will be used to summarise the available literature. If appropriate, pooled effect estimates of the association between asthma and lung cancer, given adjustment for a specific co-occurring condition will be estimated using random effects models. Potential sources of heterogeneity and between study heterogeneity will also be investigated.

ETHICS AND DISSEMINATION

The study will be a review of published data and does not require ethical approval. Results will be disseminated through a peer-reviewed publication.

TRIAL REGISTRATION NUMBER

International Prospective Register for Systematic Reviews (PROSPERO) number CRD42016043341.

The regional association between bronchiectasis and lung cancer in chest CT

Background

Limited studies have examined the association between lung cancer and bronchiectasis (BE). This study evaluated the regional association between BE and lung cancer by analyzing the lobar location of lung cancer in patients with underlying BE.

Methods

This clustered multi-level study enrolled patients who had underlying BE and were newly diagnosed with lung cancer between January 1, 2010 and May 30, 2013 in two referral hospitals in South Korea. By analyzing the presence of lung cancer and underlying BE as event variables at the level of lung lobes on chest computed tomography (CT), we evaluated the association of BE and lung cancer by the locations of the diseases.

Results

Eighty-one patients with BE and combined lung cancer were enrolled. Within 486 lung lobes of the patients, combined BE and lung cancer in the same lobe was found in 11 lobes (2.3 %). Using the general estimating equation assuming BE as a risk factor of lung cancer, the results indicated that the prevalence of lung cancer was significantly lower in the lobes with pre-existing BE (β = −1.09, p-value = 0.001).

Conclusions

Regionally, pre-existing BE was associated with a lower risk of the occurrence of lung cancer in the same lobe.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0311-4) contains supplementary material, which is available to authorized users.

Post-inhaled corticosteroid pulmonary tuberculosis and pneumonia increases lung cancer in patients with COPD

Background

Inhaled corticosteroids (ICS) have been associated with decreased lung cancer risk. However, they have been associated with pulmonary infections (tuberculosis [TB] and pneumonia) in patients with chronic obstructive pulmonary disease (COPD). TB and pneumonia have increased lung cancer risk. The association between post-ICS pulmonary infections and lung cancer remains unclear.

Methods

We conducted a retrospective cohort study from 2003 to 2010 using the Taiwan National Health Insurance Research Database. Among the 1,089,955 patients with COPD, we identified 8813 new users of ICS prescribed for a period of 3 months or more and 35,252 non-ICS users who were randomly matched for sex, age and date of ICS use from 2003 to 2005. Cox proportional hazard regression was used to estimate the hazard ratio (HR) of pulmonary infections in patients with/without ICS use.

Results

The HRs for lung cancer in ICS users with sequential lung infections were as follows; 2.42 (95 % confidence interval [CI], 1.28–4.58) for individuals with TB, 2.37 (95 % CI, 1.01–5.54) for TB and pneumonia, and 1.17(95 % CI, 0.69–1.98) for those with pneumonia. For non-ICS users with pulmonary infections, the HRs were 1.68 (95 % CI, 0.78–3.65) for individual with TB and pneumonia, 1.42 (95 % CI, 0.89–2.26) for TB, and 0.95 (95 % CI, 0.62–1.46) for individuals with pneumonia.

Conclusions

COPD patients with TB /or pneumonia who used ICS had increased risk of lung cancer. Because the overall prognosis of lung cancer remains poor, screening tests are recommended for patients with these conditions.

Using a chemiresistor-based alkane sensor to distinguish exhaled breaths of lung cancer patients from subjects with no lung cancer

BACKGROUND

Breath alkanes are reported to be able to discriminate lung cancer patients from healthy people. A simple chemiresistor-based sensor was designed to respond to alkanes by a change in resistance measured by a digital multimeter connected to the sensor. In preclinical experiments, the sensor response was found to have a strong positive linear relationship with alkane compounds and not responsive to water. This study aimed to determine the ability of the alkane sensor to distinguish the exhaled breaths of lung cancer patients from that of chronic obstructive pulmonary disease (COPD) patients and control subjects without lung cancer.

METHODS

In this cross-sectional study, 12 treatment-naive patients with lung cancer, 12 ex- or current smokers with COPD and 13 never-smokers without lung disease were asked to exhale through a drinking straw into a prototype breath-in apparatus made from an empty 125 mL Vitagen^® bottle with the chemiresistor sensor attached at its inside bottom to measure the sensor peak output (percentage change of baseline resistance measured before exhalation to peak resistance) and the time taken for the baseline resistance to reach peak resistance.

RESULTS

Analysis of multivariate variance and post-hoc Tukey test revealed that the peak output and the time to peak values for the lung cancer patients were statistically different from that for both the COPD patients and the controls without lung disease, Pillai's Trace =0.393, F=3.909, df = (4, 64), P=0.007. A 2.20% sensor peak output and a 90-s time to peak gave 83.3% sensitivity and 88% specificity in diagnosing lung cancer. Tobacco smoking did not affect the diagnostic accuracy of the sensor.

CONCLUSIONS

The alkane sensor could discriminate patients with lung cancer from COPD patients and people without lung disease. Its potential utility as a simple, cheap and non-invasive test for early lung cancer detection needs further studies.

Alcohol consumption and lung cancer risk in never smokers

OBJECTIVE

The main objective of this study is to analyse the role of alcohol consumption on lung cancer risk in people who have never smoked.

METHODS

We conducted a systematic review of the scientific literature following the PRISMA statement. We searched Medline, EMBASE and CINAHL using different combinations of MeSH terms and free text. We included cohort studies, pooled cohort studies and case-control studies comprising at least 25 anatomopathologically-confirmed diagnoses of lung cancer cases, a sample size larger than 100 individuals and more than five years of follow-up for cohort studies. We excluded studies that did not specifically report results for never smokers. We developed a quality score to assess the quality of the included papers and we ultimately included 14 investigations with a heterogeneous design and methodology.

RESULTS

Results for alcohol consumption and lung cancer risk in never smokers are inconclusive; however, several studies showed a dose-response pattern for total alcohol consumption and for spirits. Heterogeneous results were found for wine and beer.

CONCLUSION

No clear effect is observed for alcohol consumption. Due to the limited evidence, no conclusion can be drawn for beer or wine consumption. There is little research available on the effect of alcohol on lung cancer risk for people who have never smoked, and more studies are urgently needed on this topic.

Exposure to Mycobacterium tuberculosis during Flexible Bronchoscopy in Patients with Unexpected Pulmonary Tuberculosis

OBJECTIVE

Recent guidelines recommend the use by healthcare personnel of a fit-tested N95 particulate respirator or higher-grade respiratory precaution in a patient undergoing bronchoscopy when pulmonary tuberculosis (PTB) is suspected. However, PTB may be unexpectedly diagnosed in this setting and therefore not evaluated, resulting in the unexpected exposure to Mycobacterium tuberculosis (MTB) of healthcare workers in the bronchoscopy suite. Here, we examined the incidence of unexpected exposure to MTB during flexible bronchoscopy and determined the exposure-related factors.

METHODS

Between 2011 and 2013, a retrospective study was conducted to evaluate unexpected diagnoses of PTB in the bronchoscopy suite. During the study period, 1650 consecutive patients for whom previous CT scans were available and who underwent bronchoscopy for respiratory disease other than PTB were included. The results of bronchial washing, bronchoalveolar lavage, and post-bronchoscopic sputum were reviewed.

RESULTS

PTB was unexpectedly diagnosed in 76 patients (4.6%). The presence of anthracofibrosis [odds ratio (OR), 3.878; 95% confidence interval (CI), 1.291-11.650; P = 0.016), bronchiectasis (OR, 1.974; 95% CI, 1.095-3.557; P = 0.024), or atelectasis (OR, 1.740; 95% CI, 1.010-2.903; P = 0.046) as seen on chest CT scan was independently associated with unexpected PTB. Patients with both anthracofibrosis and atelectasis were at much higher risk of unexpected PTB (OR, 4.606; 95% CI, 1.383-15.342; P = 0.013).

CONCLUSIONS

The risk of MTB exposure by healthcare personnel in the bronchoscopy suite due to patients with undiagnosed PTB has been underestimated. Therefore, in geographic regions with an intermediate PTB prevalence, such as South Korea (97/100,000 persons per year), higher-grade respiratory precaution, such as a fit-tested N95 particulate respirator, should be considered to prevent occupational exposure to MTB during routine bronchoscopy, especially in patients with CT-confirmed anthracofibrosis, bronchiectasis, or atelectasis.

Association between cooking oil fume exposure and lung cancer among Chinese nonsmoking women: a meta-analysis

Lung cancer has been the main cause of cancer death around the world. Cigarette smoking has been identified as a risk factor for lung cancer in males. However, the etiological factors in nonsmoking women remain elusive. A meta-analysis was conducted to evaluate the relationship between cooking oil fume exposure and lung cancer among Chinese nonsmoking women. Thirteen articles containing three population-based case-control and ten hospital-based case-control studies were included in this meta-analysis. These studies with a total of 3,596 lung cancer women and 6,082 healthy controls were analyzed by RevMan 5.3. Fixed effects model or random effects model was used to obtain pooled estimates of risk ratio. The risk ratios with a 95% CI were 1.74 (95% CI =1.57-1.94) and 2.11 (95% CI =1.54-2.89), respectively. Cooking oil fume exposure as well as not using a kitchen ventilator when cooking was significantly associated with lung cancer among nonsmoking women (Z=10.07, P<0.00001; Z=4.65, P<0.00001). Cooking oil fume exposure, especially lacking a fume extractor, may increase the risk of lung cancer among Chinese nonsmoking women.

Lung cancer screening in patients with chronic obstructive pulmonary disease

Lung cancer and chronic obstructive pulmonary disease (COPD) are two intimately related diseases, with great impact on public health. Annual screening using low-dose computed tomography (LDCT) of the chest significantly reduces mortality due to lung cancer, and several scientific societies now recommend this technique. COPD, defined by the presence of airflow obstruction [forced expiratory volume and forced vital capacity (FVC) ratio less than 0.70], and their clinical phenotypes, namely emphysema and chronic bronchitis, have been associated with increased lung cancer risk. Several epidemiological studies, including lung cancer screening trials, have found a 2- to 4-fold increase in lung cancer risk in patients with COPD when compared to individuals without airflow obstruction. Part of the risk attributed to airflow obstruction appears to be derived from the presence of radiographic emphysema. The latter has proven to be an important lung cancer risk factor in smokers without airflow obstruction and even in never smokers. This evidence supports the idea of including patients with COPD and/or emphysema in lung cancer screening programs. There is evidence that lung cancer screening in this population is effective and can potentially reduce mortality. Specific lung cancer risk scores have been developed for patients with COPD [COPD lung cancer screening score (LUCSS) and COPD-LUCSS-diffusing capacity for carbon monoxide (DLCO)] to identify those at high risk. A multidisciplinary approach for an adequate patient selection, especially of patients with severe disease, is key to maximize benefits and reduce harms from lung cancer screening in this population. Patients with COPD included in lung cancer screening programs could also benefit from other interventions, such as smoking cessation and adequate treatment.

Leisure-time physical activity and lung cancer risk: A systematic review and meta-analysis

OBJECTIVES

We conducted a systematic review and meta-analysis of the association between recreational physical activity and lung cancer risk to update previous analyses and to examine population subgroups of interest defined by smoking status and histology.

MATERIALS AND METHODS

We searched the PubMed database for studies up to May 2015. Individual study characteristics were abstracted including study design, number of cases, assessment of recreational physical activity and type and level of adjustment for confounding factors. Combined effect estimates were calculated for the overall associations and across subgroups of interest.

RESULTS

We identified 28 studies that were eligible for inclusion in the meta-analysis. The overall analysis indicated an inverse association between recreational physical activity and lung cancer risk (Relative Risk (RR), 0.76; 95% Confidence Interval (CI), 0.69-0.85, p-value: <0.001). Similar inverse associations with risk were also noted for all evaluated histological subtypes, including adenocarcinoma (RR, 0.80; 95% CI, 0.72-0.88), squamous (RR, 0.80; 95% CI, 0.71-0.90) and small cell (RR, 0.79; 95% CI, 0.66-0.94). When we examined effects by smoking status, inverse associations between recreational physical activity and lung cancer risk were observed among former (RR, 0.77; 95% CI, 0.69-0.85) and current smokers (RR, 0.77; 95% CI, 0.72-0.83), but not among never smokers (RR, 0.96; 95% CI, 0.79-1.18).

CONCLUSION

Results from this meta-analysis suggest that regular recreational physical activity may be associated with reduced risk of lung cancer. Only four studies examining never smokers were identified, suggesting the need for additional research in this population.

Epidemiology of Lung Cancer in Korea: Recent Trends

Lung cancer causes the most cancer deaths in Korea. Although the smoking rate has begun to decrease, the prevalence of lung cancer is still increasing. We reviewed the national lung cancer registry data and the data published about lung cancer in Korea. In 2012, the crude incidence rate of lung cancer was 43.9 per 100,000. The age-standardized mortality rate of lung cancer was 19.8 per 100,000. The 5-year relative survival rate for lung cancer was 11.3% from 1993 to 1995 and increased to 21.9% in the period from 2008 to 2012. Lung cancer occurring in never-smokers was estimated to increase in Korea. Adenocarcinoma is steadily increasing in both women and men and has replaced squamous cell carcinoma as the most common type of lung cancer in Korea. In patients with adenocarcinoma, the frequency of EGFR mutations was 43% (range, 20%–56%), while that of the EMK4-ALK gene was less than 5%.

Chronic Obstructive Pulmonary Disease Is Not Associated with KRAS Mutations in Non-Small Cell Lung Cancer

Mutations in epithelial growth factor receptor (EGFR), as well as in the EGFR downstream target KRAS are frequently observed in non-small cell lung cancer (NSCLC). Chronic obstructive pulmonary disease (COPD), an independent risk factor for developing NSCLC, is associated with an increased activation of EGFR. In this study we determined presence of EGFR and KRAS hotspot mutations in 325 consecutive NSCLC patients subjected to EGFR and KRAS mutation analysis in the diagnostic setting and for whom the pulmonary function has been determined at time of NSCLC diagnosis. Information about age at diagnosis, sex, smoking status, forced vital capacity (FVC) and forced expiratory volume in 1 sec (FEV₁) was collected. Chronic obstructive pulmonary disease(COPD) was defined according to 2013 GOLD criteria. Chi-Square, student t-test and multivariate logistic regression were used to analyze the data. A total of 325 NSCLC patients were included, 193 with COPD and 132 without COPD. COPD was not associated with presence of KRAS hotspot mutations, while EGFR mutations were significantly higher in non-COPD NSCLC patients. Both female gender (HR 2.61; 95% CI: 1.56–4.39; p<0.001) and smoking (HR 4.10; 95% CI: 1.14–14.79; p = 0.03) were associated with KRAS mutational status. In contrast, only smoking (HR 0.11; 95% CI: 0.04–0.32; p<0.001) was inversely associated with EGFR mutational status. Smoking related G>T and G>C transversions were significantly more frequent in females (86.2%) than in males (61.5%) (p = 0.008). The exon 19del mutation was more frequent in non-smokers (90%) compared to current or past smokers (36.8%). In conclusion, KRAS mutations are more common in females and smokers, but are not associated with COPD-status in NSCLC patients. EGFR mutations are more common in non-smoking NSCLC patients.

The effects of pulmonary diseases on histologic types of lung cancer in both sexes: a population-based study in Taiwan

Background

The associations between pulmonary diseases (asthma, chronic obstructive pulmonary disease [COPD], and tuberculosis [TB]) and subsequent lung cancer risk have been reported, but few studies have investigated the association with different histologic types of lung cancer.

Methods

Patients newly diagnosed with lung cancer from 2004 to 2008 were identified from the National Health Insurance Research Database in Taiwan. Histologic types of lung cancer were further confirmed using the Taiwan Cancer Registry Database. Cox proportional hazards regression was used to calculate the hazard ratio (HR) of asthma, COPD, and TB and to estimate the risk of specific types of lung cancer.

Results

During the study period, 32,759 cases of lung cancer were identified from 15,219,024 insurants aged 20 years and older. In men and women, the adjusted HR estimates of squamous cell carcinoma were respectively 1.37 (95 % confidence interval [CI], 1.21–1.54) and 2.10 (95 % CI, 1.36–3.23) for TB, 1.52 (95 % CI, 1.42–1.64) and 1.50 (95 % CI, 1.21–1.85) for asthma, and 1.66 (95 % CI, 1.56–1.76) and 1.44 (95 % CI, 1.19–1.74) for COPD. Similarly, the adjusted HR estimates of adenocarcinoma were respectively 1.33 (95 % CI, 1.19–1.50) and 1.86 (95 % CI, 1.57–2.19) for TB, 1.13 (95 % CI, 1.05–1.21) and 1.18 (95 % CI, 1.09–1.28) for asthma, and 1.50 (95 % CI, 1.42–1.59) and 1.33 (95 % CI, 1.25–1.42) for COPD. The HRs of small cell carcinoma were respectively 1.24 (95 % CI, 1.01–1.52) and 2.23 (95 % CI, 1.17–4.25) for TB, 1.51 (95 % CI, 1.35–1.69) and 1.63 (95 % CI, 1.16–2.27) for asthma, and 1.39 (95 % CI, 1.26–1.53) and 1.78 (95 % CI, 1.33–2.39) for COPD.

Conclusions

Asthma, COPD, and TB were associated with an increased risk of all major subtypes of lung cancer. The risk was the highest among women with TB.

Update in Lung Cancer 2014

In the past 2 years, lung cancer research and clinical care have advanced significantly. Advancements in the field have improved outcomes and promise to lead to further reductions in deaths from lung cancer, the leading cause of cancer death worldwide. These advances include identification of new molecular targets for personalized targeted therapy, validation of molecular signatures of lung cancer risk in smokers, progress in lung tumor immunotherapy, and implementation of population-based lung cancer screening with chest computed tomography in the United States. In this review, we highlight recent research in these areas and challenges for the future.

The association between combined non-cystic fibrosis bronchiectasis and lung cancer in patients with chronic obstructive lung disease

BACKGROUND

Whereas the epidemiological association between lung cancer and chronic obstructive pulmonary disease (COPD), a chronic inflammatory respiratory disease, is well known, limited studies have examined the association between lung cancer and non-cystic fibrosis bronchiectasis, a representative chronic airway inflammatory disease. This study evaluated the association between bronchiectasis and lung cancer in patients with COPD.

METHODS

A matched case-control study was conducted in a referral hospital in South Korea. Among COPD patients with moderate to very severe airflow limitation (forced expiratory volume in one second/forced vital capacity <0.7 and forced expiratory volume in one second ≤70% [% predicted]) who underwent chest computed tomography (CT) between January 1, 2010 and May 30, 2013, patients with lung cancer and controls matched for age, sex, and smoking history were selected. The risk of lung cancer was assessed according to the presence of underlying bronchiectasis confirmed by chest CT.

RESULTS

The study enrolled 99 cases and 198 controls. Combined bronchiectasis on chest CT was inversely associated with the risk of lung cancer compared with controls (odds ratio [OR] 0.25, 95% confidence interval [CI] 0.12-0.52, P<0.001). Significant associations were found in patients with squamous cell carcinoma (OR 0.11, 95% CI 0.03-0.49, P=0.001) and history of smoking (OR 0.27, 95% CI 0.12-0.57, P<0.001). However, the severity and location of bronchiectasis were not associated with the risk of lung cancer.

CONCLUSION

Interestingly, the concomitant presence of bronchiectasis in COPD patients was associated with a lower risk of lung cancer.

Causes of death in patients with asthma and asthma-chronic obstructive pulmonary disease overlap syndrome

Background

The administration of inhaled corticosteroids and worldwide usage of several asthma guidelines have improved asthma mortality. Elderly patients with asthma show high mortality rates, and may have several comorbidities, including overlap with chronic obstructive pulmonary disease (COPD). Among patients showing asthma overlapped with COPD (asthma–COPD overlap syndrome; ACOS), mortality is worse than for asthma alone. Therefore, we investigated comorbidities, malignancies, and causes of death in patients with asthma and ACOS.

Methods

This was a retrospective study. From January 2000 to March 2012, 650 patients were followed up at Tottori University Hospital. Medical records were reviewed to collect data regarding patient characteristics and comorbidities, and causes of death were recorded for patients who died during the study period.

Results

Eighty-seven patients died during the study period. The most frequent cause of death was malignancy. The proportion of malignant disease was 21.7% in all patients, 19.4% in patients with asthma alone, and 32.4% in patients with ACOS. One patient died from an asthma attack during this period.

Conclusion

The most frequent cause of death in patients with asthma and ACOS was malignant disease. It is necessary to control not only asthma but also comorbidities in patients with asthma, especially in those with ACOS.

Low oxygen saturation and mortality in an adult cohort: the Tromsø study

Background

Oxygen saturation has been shown in risk score models to predict mortality in emergency medicine. The aim of this study was to determine whether low oxygen saturation measured by a single-point measurement by pulse oximetry (SpO₂) is associated with increased mortality in the general adult population.

Methods

Pulse oximetry was performed in 5,152 participants in a cross-sectional survey in Tromsø, Norway, in 2001–2002 (“Tromsø 5”). Ten-year follow-up data for all-cause mortality and cause of death were obtained from the National Population and the Cause of Death Registries, respectively. Cause of death was grouped into four categories: cardiovascular disease, cancer except lung cancer, pulmonary disease, and others. SpO₂ categories were assessed as predictors for all-cause mortality and death using Cox proportional-hazards regression models after correcting for age, sex, smoking history, body mass index (BMI), C-reactive protein level, self-reported diseases, respiratory symptoms, and spirometry results.

Results

The mean age was 65.8 years, and 56% were women. During the follow-up, 1,046 (20.3%) participants died. The age- and sex-adjusted hazard ratios (HRs) (95% confidence intervals) for all-cause mortality were 1.99 (1.33–2.96) for SpO₂ ≤ 92% and 1.36 (1.15–1.60) for SpO₂ 93–95%, compared with SpO₂ ≥ 96%. In the multivariable Cox proportional-hazards regression models that included self-reported diseases, respiratory symptoms, smoking history, BMI, and CRP levels as the explanatory variables, SpO₂ remained a significant predictor of all-cause mortality. However, after including forced expiratory volume in 1 s percent predicted (FEV₁% predicted), this association was no longer significant. Mortality caused by pulmonary diseases was significantly associated with SpO₂ even when FEV₁% predicted was included in the model.

Conclusions

Low oxygen saturation was independently associated with increased all-cause mortality and mortality caused by pulmonary diseases. When FEV₁% predicted was included in the analysis, the strength of the association weakened but was still statistically significant for mortality caused by pulmonary diseases.

Collagenolytic matrix metalloproteinases in chronic obstructive lung disease and cancer

Chronic obstructive pulmonary disease (COPD) and lung cancer result in significant morbidity and mortality worldwide. In addition to the role of environmental smoke exposure in the development of both diseases, recent epidemiological studies suggests a connection between the development of COPD and lung cancer. Furthermore, individuals with concomitant COPD and cancer have a poor prognosis when compared with individuals with lung cancer alone. The modulation of molecular pathways activated during emphysema likely lead to an increased susceptibility to lung tumor growth and metastasis. This review summarizes what is known in the literature examining the molecular pathways affecting matrix metalloproteinases (MMPs) in this process as well as external factors such as smoke exposure that have an impact on tumor growth and metastasis. Increased expression of MMPs provides a unifying link between lung cancer and COPD.