Lung cancer and prior tuberculosis infection in Shanghai

Bioinformatics Study and Experimental Evaluation of miR-182, and miR-34 Expression Profiles in Tuberculosis and Lung Cancer

BACKGROUND

Lung cancer is one of the most dangerous cancers and tuberculosis is one of the deadliest infectious diseases in the world. Many studies have confirmed the connection between lung cancer and tuberculosis, and also the microRNAs (miRNAs) that play a major role in the development of these two diseases. This study aims to use different databases to find effective miRNAs and their role in different genes in lung and tuberculosis diseases. It also aims to determine the role of miR-34a and miR-182 in lung cancer and tuberculosis.

METHODS

Using the Gene Expression Omnibus (GEO) database, the influential miRNA databases were studied in the two diseases. Finally, considering bioinformatics results and literature studies, two miR-34a and miR-182 were selected. The role of these miRNAs and their target genes was carefully evaluated using bioinformatics. The expression of miRNAs in the plasma of patients with lung cancer and tuberculosis and healthy individuals was investigated.

RESULTS

According to the GEO database, miR-34a and miR-182 are miRNAs that affect tuberculosis and lung cancer. By checking the miRBase, miRcode, DIANA, miRDB, galaxy, Kyoto Encyclopedia of Genes and Genomes databases, the role of these miRNAs on genes and different molecular pathways and their effect on these miRNAs were mentioned. The results of the present study showed that the expression of miR-34a and miR-182 was lower than that of healthy people. The p-value for miR-182 was <0.0001 and for miR-34a was 0.3380.

CONCLUSION

Reducing the expression pattern of these miRNAs indicates their role in lung cancer and tuberculosis occurrence. Therefore, these miRNAs can be used as a biomarker for prognosis, diagnosis, and treatment methods.

Incidence of lung cancer among healthcare workers in Hunan Province and analysis of related risk factors

Background

The prevalence of lung cancer, a major type of malignant tumor, has been increasing over the years greatly impacting the health of Chinese residents. This study investigates the epidemiological characteristics of lung cancer among healthcare workers in the Hunan Province, as well as the occupational risk factors.

Methods

The data analyzed in this study was collected from the largest tumor hospital in the province: the Hunan Provincial Tumor Hospital affiliated with Central South University, School of Medicine. The data collected encompasses input collected between the years of 2004 to 2013 of the population of healthcare workers who were hospitalized for lung cancer treatments. Information was obtained through statistical analysis and telephonic interviews.

Results

The prevalence of lung cancer among healthcare workers was much higher than that of the general population, as revealed by the difference between number of healthcare worker cases per 1,000 cases and number of healthcare workers per 1,000 population in the decade from 2004 to 2013. Analysis of the data further demonstrates that lung cancer prevalence among healthcare workers increases exponentially with age. Although smoking has been shown to increase the incidence of lung cancer to some extent, it is most likely not the main cause of lung cancer. In addition, it appears that the highest rates of lung cancer incidence occurs in mainly in primary general practitioners, medical radiologists, and nurses. The lack of awareness of personal safety measures may place healthcare workers at a greater risk of lung cancer.

New progress of tuberculosis scar carcinoma

It has been demonstrated that scar tissue and fibrosis may increase the likelihood of developing malignancies. Specifically, scar tissue has been linked to the occurrence and progression of lung cancer (LC), though the precise mechanisms necessitate further research for explanation. Lung scarring can stem from various causes, with carcinogenesis on scarring lesions in pulmonary tuberculosis (PTB) being the most frequent (accounting for approximately 75% of cases). Notably, having previously cured, PTB is the second most common risk factor for LC after smoking, with approximately 3% of PTB patients experiencing LC as a secondary condition. This essay will delve into the mechanisms, treatment, and prognosis of tuberculosis scar carcinoma (TSC).

Lung cancer occurrence after an episode of tuberculosis: a systematic review and meta-analysis

INTRODUCTION

People with tuberculosis experience long-term health effects beyond cure, including chronic respiratory diseases. We investigated whether tuberculosis is a risk factor for subsequent lung cancer.

METHODS

We searched PubMed, Scopus, Cochrane, Latin American and Caribbean Health Sciences Literature and the Scientific Electronic Library Online for cohort and case-control studies providing effect estimates for the association between tuberculosis and subsequent lung cancer. We pooled estimates through random-effects meta-analysis. The study was registered in PROSPERO (CDR42020178362).

RESULTS

Out of 6240 records, we included 29 cohort and 44 case-control studies. Pooled estimates adjusted for age and smoking (assessed quantitatively) were hazard ratio (HR) 1.51 (95% CI 1.30-1.76, I²=81%; five studies) and OR 1.74 (95% CI 1.42-2.13, I²=59%; 19 studies). The occurrence of lung cancer was increased for 2 years after tuberculosis diagnosis (HR 5.01, 95% CI 3.64-6.89; two studies), but decreased thereafter. Most studies were retrospective, had moderate to high risk of bias, and did not control for passive smoking, environmental exposure and socioeconomic status. Heterogeneity was high.

CONCLUSION

We document an association between tuberculosis and lung cancer occurrence, particularly in, but not limited to, the first 2 years after tuberculosis diagnosis. Some cancer cases may have been present at the time of tuberculosis diagnosis and therefore causality cannot be ascertained. Prospective studies controlling for key confounding factors are needed to identify which tuberculosis patients are at the highest risk, as well as cost-effective approaches to mitigate such risk.

Challenges and Suggestions in Management of Lung and Liver Cancer in Uzbekistan: The Second Report of the Uzbekistan-Korea Oncology Consortium

The health burden of cancer increases in Uzbekistan as the country develops and the life expectancy increases. Management of such a burden requires efficient screening, treatment optimization, and investigation of the causes of cancer. The Ministry of Health of Uzbekistan formed an advisory consortium, including clinical oncology and healthcare management experts from Uzbekistan and South Korea, to design a strategy for cancer management. Our consortium has analyzed six cancer types with high morbidity and mortality in Uzbekistan by classifying them into three categories (breast, cervical (gynecologic cancers), lung, liver (cancer common in men), stomach, and colorectal cancers (gastrointestinal cancers)). Lung and liver cancers are common causes of death in men after middle age-they can yield a serious health burden on the country and ruin the livelihood of families. In this review, we will analyze the oncologic literature and suggest practical recommendations for the treatment and prevention of lung and liver cancer in Uzbekistan. Data from South Korea, which has conducted nationwide screening for two decades and made progress in improving prognosis, will be discussed as a comparative control.

Residential Radon Exposure in Patients with Advanced Lung Cancer in Lublin Region, Poland

Exposure to radon is the second most common factor causing lung cancer in smokers and the first among non-smokers. We aimed to measure the impact of the radon exposure on patients with different histological types of advanced lung cancer. The measurement of radon exposure was performed in 102 patients with lung cancer in stage 3B or higher (Poland). There were 78.4% of patients with non-small cell carcinoma and 21.6% of patients with small cell carcinoma. One month radon exposure measurement was performed with trace detectors in order to control whether high radon concentrations (>800 Bq/m3) were found in the homes of patients with cancer diagnosed. Results of the determinations were then compared with the representation of the most common types of lung cancer in the study population. In the analyzed group, the average concentration of radon during the exposure of the detector in the residential premises of the respondents accounted for 69.0 Bq/m3 [37.0−117.0] and had no statistically significant effect on the type of lung cancer developed in patients. The lack of statistical significance may result from the small study group and the accompanying exposure to other harmful components. As the incidence of lung adenocarcinoma is increasing and exposure to tobacco smoke is decreasing, the search for other modifiable causes of lung cancer should be the task in the future.

Implications of the Immune Landscape in COPD and Lung Cancer: Smoking Versus Other Causes

Cigarette smoking is reported in about one third of adults worldwide. A strong relationship between cigarette smoke exposure and chronic obstructive pulmonary disease (COPD) as well as lung cancer has been proven. However, about 15% of lung cancer cases, and between one fourth and one third of COPD cases, occur in never-smokers. The effects of cigarette smoke on the innate as well as the adaptive immune system have been widely investigated. It is assumed that certain immunologic features contribute to lung cancer and COPD development in the absence of smoking as the major risk factor. In this article, we review different immunological aspects of lung cancer and COPD with a special focus on non-smoking related risk factors.

Advances in molecular mechanisms of interaction between Mycobacterium tuberculosis and lung cancer: a narrative review

Objective

We systematically review the molecular mechanism of the interaction between lung cancer (LC) and tuberculosis (TB), and put forward the existing problems in order to provide suggestions for early intervention and future research direction.

Background

TB and LC are two global public health problems affecting human health. LC is the main cause of cancer-related death worldwide and TB is one of the leading causes of death among infectious diseases, especially in resource-poor areas. Previous studies have suggested that a history of TB may be associated with an increased risk of LC. With the improvement of LC treatment, the occurrence of pulmonary tuberculosis in the course of LC treatment is also frequently reported recently.

Methods

The molecular immunological mechanisms of interaction between LC and TB, and related epidemiological literature are reviewed. The research progress and problems to be solved are summarized.

Conclusions

Chronic inflammation, immune abnormalities, scar formation, gene mutations and drug effects caused by TB may be associated with the occurrence of LC induced by abnormalities in various molecular pathways. LC and decreased immunity during treatment may also increase the risk of latent TB activation or new TB infection through immune pathways. Data on dual burden areas of TB and LC are still lacking, and more clinical studies are needed to elucidate the association.

Previous pulmonary tuberculosis enhances the risk of lung cancer: systematic reviews and meta-analysis

PURPOSE

The possible association between history of pulmonary tuberculosis (TB) and lung cancer (LC) has attracted researchers' attention for several decades. This systematic review and meta-analysis aim to assess the association between previous pulmonary TB infection and LC risk.

METHODS

A Systematic and comprehensive search was performed in the following databases: PubMed, Embase, clinical key, Web of Science and Google Scholar, in articles and abstracts published from 1987 to 2021. Thirty-two articles (involving 50,290 cases and 846,666 controls) met the inconclusive criteria. The Comprehensive Meta-Analysis version 2.2 software was used for this meta-analysis.

RESULTS

The result of this meta-analysis demonstrates that pre-existing active pulmonary TB increases the risk of LC (RR = 2.170, 95% confidence interval [CI] 1.833-2.569, p < .001, I² = 91.234%). The results showed that the risk of the history of active pulmonary TB infection in adenocarcinoma was 2.605 (95% CI 1.706-3.979, p < .001, I² = 55.583%), in small-cell carcinoma was 2.118 (95% CI 1.544-2.905, p < .001, I² = 0.0%), in squamous-cell carcinoma, was 3.570 (95% CI 2.661 - 4.791, p < .001, I² = 42.695%) and 2.746 (95% CI 2.300-3.279, p < .001, I² = 41.686%) for other histological types of LCs. According to these results, a history of active pulmonary TB increases the risk of LC.

CONCLUSIONS

This study emphasizes the importance of LC screening in pulmonary TB patients even after the infection is treated. With the increased chances of LC in a patient who had a history of active pulmonary TB, there could be a need for a further follow-up period after pulmonary TB recovery.

Is Mycobacterium tuberculosis carcinogenic to humans?

We highlight the ability of the tuberculosis (TB) causing bacterial pathogen, Mycobacterium tuberculosis (Mtb), to induce key characteristics that are associated with established IARC classified Group 1 and Group 2A carcinogenic agents. There is sufficient evidence from epidemiological case-control, cohort and meta-analysis studies of increased lung cancer (LC) risk in pre-existing/active/old TB cases. Similar to carcinogens and other pathogenic infectious agents, exposure to aerosol-containing Mtb sprays in mice produce malignant transformation of cells that result in squamous cell carcinoma. Convincing, mechanistic data show several characteristics shared between TB and LC which include chronic inflammation, genomic instability and replicative immortality, just to name a few cancer hallmarks. These hallmarks of cancer may serve as precursors to malignant transformation. Together, these findings form the basis of our postulate that Mtb is a complete human pulmonary carcinogen. We also discuss how Mtb may act as both an initiating agent and promoter of tumor growth. Forthcoming experimental studies will not only serve as proof-of-concept but will also pivot our understanding of how to manage/treat TB cases as well as offer solutions to clinical conundrums of TB lesions masquerading as tumors. Clinical validation of our concept may also help pave the way for next generation personalized medicine for the management of pulmonary TB/cancer particularly for cases that are not responding well to conventional chemotherapy or TB drugs.

Identification of Key Genes and Pathways in Gefitinib-Resistant Lung Adenocarcinoma using Bioinformatics Analysis

Gefitinib resistance is a serious threat in the treatment of patients with non-small cell lung cancer (NSCLC). Elucidating the underlying mechanisms and developing effective therapies to overcome gefitinib resistance is urgently needed. The differentially expressed genes (DEGs) were screened from the gene expression profile GSE122005 between gefitinib-sensitive and resistant samples. GO and KEGG analyses were performed with DAVID. The protein-protein interaction (PPI) network was established to visualize DEGs and screen hub genes. The functional roles of CCL20 in lung adenocarcinoma (LUAD) were examined using gene set enrichment analysis (GSEA). Functional analysis revealed that the DEGs were mainly concentrated in inflammatory, cell chemotaxis, and PI3K signal regulation. Ten hub genes were identified based on the PPI network. The survival analysis of the hub genes showed that CCL20 had a significant effect on the prognosis of LUAD patients. GSEA analysis showed that CCL20 high expression group was mainly enriched in cytokine-related signaling pathways. In conclusion, our analysis suggests that changes in inflammation and cytokine-related signaling pathways are closely related to gefitinib resistance in patients with lung cancer. The CCL20 gene may promote the formation of gefitinib resistance, which may serve as a new biomarker for predicting gefitinib resistance in patients with lung cancer.

Thiol-disulphide homoeostasis as a novel oxidative stress biomarker in lung tuberculosis patient

AIMS OF STUDY

To compare a novel oxidative stress biomarker dynamic thiol/disulphide homoeostasis between patients with lung tuberculosis and healthy controls.

METHODS

Our study included 50 patients with active lung tuberculosis and 50 healthy controls. Serum thiol/disulphide was measured with a new automated spectrometric method developed and results were compared statistically.

RESULTS

We found that native and total thiol levels were significantly decreased in patients with lung tuberculosis, disulphide/native thiol and disulphide/total thiol levels were found to be higher in lung tuberculosis patients when compared with the control group. However, disulphide levels were higher in the control group than in the patient group.

CONCLUSIONS

Based on the results of this study, it can be said that oxidative stress is closely associated with lung tuberculosis pathogenesis. There is a need for new studies that will show the possible effects of oxidative stress on lung tuberculosis pathogenesis.

Consensus study on the health system and patient-related barriers for lung cancer management in South Africa

BACKGROUND

Lung cancer is the highest incident cancer globally and is associated with significant morbidity and mortality particularly if identified at a late stage. Poor patient outcomes in low- and middle-income countries (LMIC's) might reflect contextual patient and health system constraints at multiple levels, that act as barriers to prevention, disease recognition, diagnosis, and treatment. Lung cancer screening, even for high-risk patients, is not available in the public health sector in South Africa (SA), where the current HIV and tuberculosis (TB) epidemics often take precedence. Yet, there has been no formal assessment of the individual and health-system related barriers that may delay patients with lung cancer from seeking and accessing help within the public health care system and receiving the appropriate and effective diagnosis and treatment. This study aimed to derive consensus from health-system stakeholders in the urban Gauteng Province of SA on the most important challenges faced by the health services and patients in achieving optimum lung cancer management and to identify potential solutions.

METHODS

The study was undertaken among 27 participant stakeholders representing clinical managers, clinicians, opinion leaders from the public health sector and non-governmental organisation (NGO) representatives. The study compromised two components: consensus and engagement. For the consensus component, the Delphi Technique was employed with open-ended questions and item ranking from five rounds of consensus-seeking, to achieve collective agreement on the most important challenges faced by patients and the health services in achieving optimal lung cancer management. For the engagement component, the Nominal Group Technique was used to articulate ideas and reach an agreement on the group's recommendations for solution strategies and approaches.

RESULTS

Public health sector stakeholders suggested that a lack of knowledge and awareness of lung cancer, and the apparent stigma associated with the disease and its risk factors, as well as symptoms and signs, are critical to treatment delay. Furthermore, delays in up-referral of patients with suspected lung cancer from district health care level were attributed to inadequate knowledge arising from a lack of in-service training of nurses and doctors regarding oncologic symptoms, risk factors, need for further investigation, interpretation of x-rays and available treatments. At a tertiary level, participants suggested that insufficient availability of specialised diagnostic resources (imaging, cytological and pathological services including biomolecular assessment of lung cancer), theatres, cardiothoracic surgeons, and appropriate therapeutic modalities (chemotherapeutic agents and radiation oncology) are the main barriers to the provision of optimal care. It was suggested that a primary prevention programme initiated by the government that involves private-public partnerships may improve lung cancer management nationally.

CONCLUSIONS

Considerable barriers to the early identification and treatment of lung cancer exist. Finding solutions to overcome both individual and health-system level obstacles to lung cancer screening and management are vital to facilitate early identification and treatment, and to improve survival. Furthermore, research on inexpensive biomarkers for asymptomatic disease detection, the introduction of diagnostic imaging tools that utilise artificial intelligence to compensate for inadequate human resources and improving clinical integration across all levels of the healthcare system are essential.

Immune Modulation in Lung Cancer: Current Concepts and Future Strategies

Cancer immunotherapy represents the most dynamic field of biomedical research currently, with thoracic immuno-oncology as a forerunner. PD-(L)1 inhibitors are already part of standard first-line treatment for both non-small-cell and small-cell lung cancer, while unprecedented 5-year survival rates of 15-25% have been achieved in pretreated patients with metastatic disease. Evolving strategies are mainly aiming for improvement of T-cell function, increase of immune activation in the tumor microenvironment (TME), and supply of tumor-reactive lymphocytes. Several novel therapeutics have demonstrated preclinical efficacy and are increasingly used in rational combinations within clinical trials. Two overarching trends dominate: extension of immunotherapy to earlier disease stages, mainly as neoadjuvant treatment, and a shift of focus towards multivalent, individualized, mutatome-based antigen-specific modalities, mainly adoptive cell therapies and cancer vaccines. The former ensures ample availability of treated and untreated patient samples, the latter facilitates deeper mechanistic insights, and both in combination build an overwhelming force that is accelerating progress and driving the greatest revolution cancer medicine has seen so far. Today, immune modulation represents the most potent therapeutic modality in oncology, the most important topic in clinical and translational cancer research, and arguably our greatest, meanwhile justified hope for achieving cure of pulmonary neoplasms and other malignancies in the next future.

Cancer incidence attributable to tuberculosis in 2015: global, regional, and national estimates

Background

Tuberculosis is associated with increased risk of cancer. However, the impact of tuberculosis on global cancer burden is unknown.

Methods

We performed random-effects meta-analyses and meta-regressions of studies reporting the association between tuberculosis and cancer risks by searching PubMed, Web of Science, Embase, Cochrane library, and CINAHL from inception to 1 June 2019. Population attributable fractions (PAFs) of cancer incidence attributable to tuberculosis were calculated using relative risks from our meta-analyses and tuberculosis prevalence data from Global Health Data Exchange by age, sex, and country. The study has been registered with PROSPERO (CRD42016050691).

Results

Fourty nine studies with 52,480 cancer cases met pre-specified inclusion criteria. Tuberculosis was associated with head and neck cancer (RR 2.64[95% CI 2.00–3.48]), hepatobiliary cancer (2.43[1.82–3.25]), Hodgkin’s lymphoma (2.19[1.62–2.97]), lung cancer (1.69[1.46–1.95]), gastrointestinal cancer (1.62[1.26–2.08]), non-Hodgkin’s lymphoma (1.61[1.34–1.94]), pancreatic cancer (1.58[1.28–1.96]), leukaemia (1.55[1.25–1.93]), kidney and bladder cancer (1.54[1.21–1.97]), and ovarian cancer (1.43[1.04–1.97]). We estimated that 2.33%(1.14–3.81) or 381,035(187145–623,404) of global cancer incidences in 2015 were attributable to tuberculosis. The PAFs varied by Socio-demographic Index (SDI)—ranging from 1.28% (0.57–2.31%) in the high-SDI countries to 3.51% (1.84–5.42%) in the middle-SDI countries. Individually, China and India accounted for 47% of all tuberculosis-related cancer cases.

Conclusions

Tuberculosis is associated with increased risk of cancer at ten sites. The burden of tuberculosis attributable cancer skewed towards lower resource countries. Research priorities are to better understand regional disparities and underlying mechanism linking tuberculosis and cancer development.

Surgically treated lung cancer patients: do they all smoke and would they all have been detected with lung cancer screening?

Since publication of the National Lung Cancer Screening Trial (NLST) results early lung cancer detection has been widely studied, targeting individuals based on smoking history and age. However, over recent decades several changes in lung cancer epidemiology, including risk factors, have taken place. The aim of the current study was to explore smoking prevalence among lung cancer patients who had been treated surgically or undergone a diagnostic operation and whether these patients would have met the NLST inclusion criteria.

All patients operated on for lung cancer in a university hospital in Estonia between 2009 and 2015 were included. Data were collected from hospital records.

426 patients were operated on for lung cancer, with smoking history properly documented in 327 patients (87 females; median age 67 years). 170 (52%) patients were smokers, 97 (30%) patients were ex-smokers and 60 (18%) patients were nonsmokers. The proportion of females among smokers was 15%, among ex-smokers was 9% and among nonsmokers was 87%. 107 of our patients would not have met the NLST age criteria and 128 of our patients would not have met the NLST smoking criteria. In total, 183 patients (56% (79% of females and 48% of males)) would not have met the NLST inclusion criteria.

Only half of surgically treated lung cancer patients were current smokers and more than half did not meet the NLST inclusion criteria.

Many currently surgically treated lung cancer patients, especially females, are not a target for lung cancer screeninghttp://ow.ly/L9wY30kIQW0

Lung Cancer in Patients With Tuberculous Fibrothorax and Empyema: Computed Tomography and 18F-Fluorodeoxyglucose Positron Emission Tomography Findings

OBJECTIVE

The aim of this study was to describe the characteristics of lung cancers in patients with tuberculous fibrothorax or empyema.

METHODS

We retrospectively evaluated 138 consecutive patients with a diagnosis of lung cancer combined with fibrothorax (n = 127) or empyema (n = 11) from January 2005 to May 2015. All patients underwent computed tomography, and 105 underwent F-fluorodeoxyglucose positron emission tomography. Clinical, pathologic, and computed tomography characteristics and maximum standardized uptake values on positron emission tomography of 76 cancers ipsilateral to the fibrothorax or empyema (group 1) were compared with those of 62 contralateral cancers (group 2).

RESULTS

The median age at diagnosis of patients was 70 years, with a male-to-female ratio of 8.9:1. The most common type was squamous cell carcinoma (41.3%) followed by adenocarcinoma (39.1%). Most were in the peripheral lung (70.3%), and half abutted the pleura. The median maximum standardized uptake value was 8.9. Tumors in group 1 were larger (median, 48.5 vs 42.8 mm, P = 0.036) and more advanced (T3 or T4) (P = 0.014) than those in group 2.

CONCLUSIONS

Lung cancers ipsilateral to tuberculous fibrothorax or empyema presented larger and advanced T stages, and the diagnosis could be delayed. The most common type cancer was squamous cell carcinoma.

Effect of pre existing respiratory conditions on survival of lung cancer patients: A nationwide population-based cohort study

BACKGROUND

Common diseases with potential to increase the risk of death from lung cancer have so far not been studied in large populations.

METHODS

We did a population-based retrospective cohort study using nationwide health insurance claims data from 2005 to 2012 in Korea including 205 403 lung cancer patients. Multivariate-adjusted hazard ratios (aHRs) of lung cancer mortality by presence, time intervals with lung cancer diagnosis and combinations of pre-existing chronic obstructive pulmonary disease (COPD), pneumonia, asthma and tuberculosis were calculated using the Cox-proportional hazards model.

RESULTS

The total number of person-years of follow-up was 397 780 and 60.2% of patients died (mean survival 23.2 months after lung cancer diagnosis). Lung cancer patients with previous respiratory disease had increased aHR for mortality (COPD, hazard ratio [HR] = 1.32, CI 1.29-1.35; pneumonia, HR = 1.14, CI 1.08-1.19; and asthma, HR = 1.11, CI 1.06-1.16). Risks were positively associated with longer duration of pre-existing disease diagnosis; cases with >5 years since diagnosis compared to <2 years: COPD, HR = 2.91, CI 2.82-3.00; pneumonia, HR = 1.67, CI 1.51-1.85; asthma, HR = 1.56, CI 1.45-1.68; and tuberculosis, HR = 2.03, CI 1.90-2.17. Furthermore, elevated HRs of death were found among patients with multiple pre-existing co-morbidities.

CONCLUSION

Hazards of death from lung cancer are significantly increased in cases with pre-existing lung disease, and worse with longer durations, and with multiple combinations before cancer diagnosis. Patients and physicians should be aware of these meaningful risk/prognostic factors for lung cancer when identifying high-risk patient groups.

Tuberculosis, smoking and risk for lung cancer incidence and mortality

Among the exposures associated with risk for lung cancer, a history of tuberculosis (TB) is one potentially important factor, given the high prevalence of TB worldwide. A prospective cohort study was conducted to evaluate the associations of preexisting pulmonary TB with lung cancer incidence and mortality. The cohort consisted of 1,607,710 Korean adults covered by the National Health Insurance System who had a biennial national medical examination during 1997-2000. During up to 16 years of follow-up, there were 12,819 incident cases of lung cancer and 9,562 lung cancer deaths. Using Cox proportional hazards models and controlling for age, cigarette smoking and other covariates, the presence of underlying TB was significantly associated with increased risk for lung cancer incidence (HR 1.37 in men with 95% CI 1.29-1.45; HR 1.49 in women with 95% CI 1.28-1.74) and mortality (HR 1.43 in men with 95% CI 1.34-1.52; HR 1.53 in women with 95% CI 1.28-1.83). We also observed a dose-response relationship between number of cigarettes smoked daily and lung cancer risk. There was no evidence for synergism between a history of TB and smoking. The elevation in risk is relatively modest, particularly in comparison to that from smoking, and a prior history of TB is not likely to be useful risk indicator for clinical purposes. In populations with high prevalence of TB, it can be considered for incorporation into models for lung cancer risk prediction.

Risk factors for lung cancer worldwide

Lung cancer is the most frequent malignant neoplasm in most countries, and the main cancer-related cause of mortality worldwide in both sexes combined.The geographic and temporal patterns of lung cancer incidence, as well as lung cancer mortality, on a population level are chiefly determined by tobacco consumption, the main aetiological factor in lung carcinogenesis.Other factors such as genetic susceptibility, poor diet, occupational exposures and air pollution may act independently or in concert with tobacco smoking in shaping the descriptive epidemiology of lung cancer. Moreover, novel approaches in the classification of lung cancer based on molecular techniques have started to bring new insights to its aetiology, in particular among nonsmokers. Despite the success in delineation of tobacco smoking as the major risk factor for lung cancer, this highly preventable disease remains among the most common and most lethal cancers globally.Future preventive efforts and research need to focus on non-cigarette tobacco smoking products, as well as better understanding of risk factors underlying lung carcinogenesis in never-smokers.

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.

The coexistence of common pulmonary diseases on the histologic type of lung cancer in both genders in Taiwan: a STROBE-compliant article

Effects of pulmonary diseases [asthma, chronic obstructive pulmonary disease (COPD), and lung tuberculosis (TB)] on subsequent lung cancer development have been reported. However, whether patients with coexisting pulmonary diseases are at greater risk of developing various histologic types of lung cancer remains elusive. Patients newly diagnosed with lung cancer between 2004 and 2008 were identified from National Health Insurance Research Database (Taiwan). The histologic types of lung cancer were further confirmed using Taiwan Cancer Registry Database. Cox proportional hazard regression was used to calculate the hazard ratio (HR) of coexisting asthma, COPD and/or TB to estimate lung cancer risk by histologic type. During the study period, 32,759 cases of lung cancer were identified from 15,219,024 residents age 20 years and older, who were free from the disease before 2003. Coexisting pulmonary diseases showed stronger association with lung cancer than specific lung disorders. Specifically, among men, the HRs for squamous cell carcinoma (SqCC) were 3.98 (95% CI, 3.22-4.93), 2.68 (95% CI, 2.45-2.93), and 2.57 (95% CI, 2.10-3.13) for individuals with asthma+COPD+TB, asthma+COPD, and COPD+TB, respectively. Among women, the HRs for SqCC were 3.64 (95% CI, 1.88-7.05), 3.35 (95% CI, 1.59-7.07), and 2.21 (95% CI, 1.66-2.94) for individuals with TB, COPD+TB, and asthma+COPD, respectively. Adenocarcinoma HRs for men and women were 2.00 (95% CI, 1.54-2.60) and 2.82 (95% CI, 1.97-4.04) for individuals with asthma+COPD+TB, 2.28 (95% CI, 1.91-2.73) and 2.16 (95% CI, 1.57-2.95) for COPD+TB, and 1.76 (95% CI, 1.04-2.97) and 2.04 (95% CI, 1.02-4.09) for individuals with asthma+TB. Specifically, small cell carcinoma (SmCC) HRs among men were 3.65 (95% CI, 1.97-6.80), 2.20 (95% CI, 1.45-3.36), and 2.14 (95% CI, 1.86-2.47) for those with asthma+TB, asthma+COPD+TB, and asthma+ COPD, respectively. Among women, the HRs of SmCC were 8.97 (95% CI, 3.31-24.28), 3.94 (95% CI, 1.25-12.35) and 3.33 (95% CI, 2.23-4.97) for those with asthma+COPD+TB, COPD+TB, and asthma+COPD, respectively. Patients with coexistence of pulmonary diseases were more susceptible to lung cancer. Affected persons deserve greater attention while undergoing cancer screening.

Comparison of the clinical courses and chemotherapy outcomes in metastatic colorectal cancer patients with and without active Mycobacterium tuberculosis or Mycobacterium kansasii infection: a retrospective study

Background

Although active Mycobacterium tuberculosis (MTB) or Mycobacterium Kansasii (MK) infection could be present in patients with metastatic colorectal cancer (m-CRC), no study is available on the clinical courses and chemotherapy outcomes of these patients. The present study therefore aimed to retrospectively examine whether m-CRC patients with and without active MTB or MK infection could receive cancer chemotherapy similarly.

Methods

This study enrolled 30 m-CRC patients who received first-line chemotherapy between January 31, 2006 and January 31, 2013 at our institution, The clinical courses and tumor response of those with and without active MTB or MK infection were examined and compared.

Results

Of 30 m-CRC patients, 6 had active MTB infection, 1 with active MK and the other 23 had neither MTB nor MK. No significant demographic differences were observed between patients with MTB or MK and those without. Chemotherapy response rates of all patients, those with MTB or MK, and those without were 40.0%, 28.6% and 43.5%, respectively. Among patients with MTB or MK, 1 treated with bevacizumab experienced grade-3 hemoptysis while others did not report any severe toxicity. Median survival time of all studied patients, those with MTB or MK, and those without was 26.3, 36.7 and 22.6 months, respectively. No significant difference in overall survival was observed between patients with MTB or MK and those without. Multivariate analysis revealed that performance status and liver metastasis were significant prognostic factors of overall survival (P = 0.004 and 0.030, respectively), whereas other factors, including MTB or MK infection, were not. In our study, all 7 patients with MTB or MK did not experience infection relapse during or after cancer chemotherapy.

Conclusions

Our results indicate that m-CRC patients with MTB or MK should be able to safely and effectively continue cancer chemotherapy to subsequently achieve comparable survival duration to those without the infection if they receive proper MTB or MK treatment.

Latent TB infection in newly diagnosed lung cancer patients - A multicenter prospective observational study

OBJECTIVES

Lung cancer and tuberculosis (TB) share common risk factors and are associated with high morbidity and mortality. Coexistence of lung cancer and TB were reported in previous studies, with uncertain pathogenesis. The association between lung cancer and latent TB infection (LTBI) remains to be explored.

METHODS

Newly diagnosed, treatment-naïve lung cancer patients were prospectively enrolled from four referral medical centers in Taiwan. The presence of LTBI was determined by QuantiFERON-TB Gold In-Tube (QFT-GIT). Demographic characteristics and cancer-related factors associated with LTBI were investigated. The survival status was also analyzed according to the status of LTBI.

RESULTS

A total of 340 lung cancer patients were enrolled, including 96 (28.2%) LTBI, 214 (62.9%) non-LTBI, and 30 (8.8%) QFT-GIT results-indeterminate cases. Non-adenocarcinoma cases had higher proportion of LTBI than those of adenocarcinoma, especially in patients with younger age. In multivariate analysis, COPD (OR 2.41, 95% CI 1.25-4.64), fibrocalcified lesions on chest radiogram (OR 2.73, 95% CI 1.45-5.11), and main tumor located in typical TB areas (OR 2.02, 95% CI 1.15-3.55) were independent clinical predictors for LTBI. Kaplan-Meier survival analysis demonstrated patients with indeterminate QFT-GIT results had significantly higher 1-year all-cause mortality than those with LTBI (p<0.001) and non-LTBI (p=0.003). In multivariate analysis, independent predictors for 1-year all-cause mortality included BMI<18.5 (HR 2.09, 95% CI 1.06-4.14, p=0.033), advanced stage of lung cancer (RR 7.76, 95% CI 1.90-31.78, p=0.004), and indeterminate QFT-GIT results (RR 2.40, 95% CI 1.27-4.54, p=0.007).

CONCLUSIONS

More than one-quarter of newly diagnosed lung cancer patients in Taiwan have LTBI. The independent predictors for LTBI include COPD, fibrocalcified lesions on chest radiogram, and main tumor located in typical TB areas. The survival rate is comparable between LTBI and non-LTBI cases. However, indeterminate QFT-GIT result was an independent predictor for all-cause mortality in lung cancer patients.

Epidemiology of active tuberculosis in lung cancer patients: a systematic review

OBJECTIVES

The aim of this review article is to evaluate the available literature concerning the prevalence of active tuberculosis in lung cancer patients.

DATA SOURCE

MEDLINE, PubMed, EMBASE and Medscape databases were searched for studies with quantitative data on the interaction between tuberculosis (TB) and lung cancer, published since 1952. We used the Medical Subject Headings' term 'tuberculosis' and the text-word terms 'TB' and 'Mycobacterium infection', and also, the Medical Subject Headings' terms 'neoplasm' and 'lung neoplasm', or the text-word term 'lung cancer'.

DATA SELECTION

We selected studies with cases verified by bacteriological examinations and biopsies that contained enough data to estimate tuberculosis prevalence. We did not exclude any study on the basis of language.

RESULTS

The prevalence of active tuberculosis among lung cancer patients varies depending on spatial and regional factors. Lung cancer patients who are more prone to developing tuberculosis are Asian and Caucasian males, with an average age of 60 years old. The prevalence of tuberculosis is higher in patients with chest X-ray evidence of old tuberculosis and/or history of tuberculosis, chronic obstructive pulmonary disease, heavy cigarette smoking, increased alcohol consumption, and/or diabetes mellitus. A high mortality rate because of tuberculosis in lung cancer patients was also estimated.

CONCLUSION

Active tuberculosis complicating lung cancer is a significant clinical issue in countries with high prevalence of tuberculosis. However, as the there is a lack of reports from developed countries over the last 20 years, the significance of this interaction in countries with low tuberculosis burden remains controversial.

Evaluation of FLASH - PCR forrapid detection of Mycobacterium tuberculosis from clinical specimens

BACKGROUND AND OBJECTIVES

Tuberculosis (TB) is the oldest known bacterial disease in humans. Due to the rise of morbidity in recent years, early diagnosis of the disease is necessary.

MATERIALS AND METHODS

In this study we used Fluorescent Amplification-Based Specific Hybridization (FLASH) PCR to targetIS6110 for rapid detection of M. tuberculosis (MTB). To investigate the important factors influencing the risk of TB, data from patients and their medical records were analyzed.

RESULT

The sensitivity and specificity of FLASH-PCR for detecting MTB were determined as 93.33% and 92.5%, respectively. The findings of this study have suggested that removal of the contaminants in FLASH-PCR sign ificantly reduced the detection time, and MTB was much more rapidly detected in the clinical specimens compared to the conventional culture and smear examination. Results of the medical survey showed that the majority of TB patients were males, over 51 years old, smokers, with pulmonary TB and normal chest X-ray (CXR).

CONCLUSION

MTB can be rapidly detected inclinical specimens using FLASH-PCR in comparison with culture and smear examination.

Systematic review with meta-analysis of the epidemiological evidence in the 1900s relating smoking to lung cancer

BACKGROUND

Smoking is a known lung cancer cause, but no detailed quantitative systematic review exists. We summarize evidence for various indices.

METHODS

Papers published before 2000 describing epidemiological studies involving 100+ lung cancer cases were obtained from Medline and other sources. Studies were classified as principal, or subsidiary where cases overlapped with principal studies. Data were extracted on design, exposures, histological types and confounder adjustment. RRs/ORs and 95% CIs were extracted for ever, current and ex smoking of cigarettes, pipes and cigars and indices of cigarette type and dose-response. Meta-analyses and meta-regressions investigated how relationships varied by study and RR characteristics, mainly for outcomes exactly or closely equivalent to all lung cancer, squamous cell carcinoma ("squamous") and adenocarcinoma ("adeno").

RESULTS

287 studies (20 subsidiary) were identified. Although RR estimates were markedly heterogeneous, the meta-analyses demonstrated a relationship of smoking with lung cancer risk, clearly seen for ever smoking (random-effects RR 5.50, CI 5.07-5.96) current smoking (8.43, 7.63-9.31), ex smoking (4.30, 3.93-4.71) and pipe/cigar only smoking (2.92, 2.38-3.57). It was stronger for squamous (current smoking RR 16.91, 13.14-21.76) than adeno (4.21, 3.32-5.34), and evident in both sexes (RRs somewhat higher in males), all continents (RRs highest for North America and lowest for Asia, particularly China), and both study types (RRs higher for prospective studies). Relationships were somewhat stronger in later starting and larger studies. RR estimates were similar in cigarette only and mixed smokers, and similar in smokers of pipes/cigars only, pipes only and cigars only. Exceptionally no increase in adeno risk was seen for pipe/cigar only smokers (0.93, 0.62-1.40). RRs were unrelated to mentholation, and higher for non-filter and handrolled cigarettes. RRs increased with amount smoked, duration, earlier starting age, tar level and fraction smoked and decreased with time quit. Relationships were strongest for small and squamous cell, intermediate for large cell and weakest for adenocarcinoma. Covariate-adjustment little affected RR estimates.

CONCLUSIONS

The association of lung cancer with smoking is strong, evident for all lung cancer types, dose-related and insensitive to covariate-adjustment. This emphasises the causal nature of the relationship. Our results quantify the relationships more precisely than previously.

Peripheral DNA damage in active pulmonary tuberculosis

In pulmonary tuberculosis patients, little is known about peripheral DNA damage, although increased oxidative stress is a well documented entity. Therefore, we aimed to investigate DNA damage along with oxidative status parameters in pulmonary tuberculosis patients. Twenty-seven pulmonary tuberculosis patients and 26 controls were included. DNA damage was assessed by comet assay. Total oxidant and antioxidant status, and oxidative stress index were determined. DNA damage, total oxidant status and oxidative stress index were higher in pulmonary tuberculosis patients than controls (all P < 0.05), while total antioxidant status was lower (P < 0.05). DNA damage was correlated with total oxidant and antioxidant status, and oxidative stress index (r = 0.69, P < 0.05; r = 0.48, P < 0.05, r = -0.47, P < 0.05; respectively) in pulmonary tuberculosis patients. Oxidative stress and DNA damage are increased in pulmonary tuberculosis patients. Increased oxidative stress associated DNA damage may be one of the pathogenetic mechanisms involved in the disorders suggested to be associated with pulmonary tuberculosis.

[COPD and lung cancer: epidemiological and biological links]

Lung cancer and chronic obstructive lung disease (COPD) are two common fatal diseases. Apart from their common link to tobacco, these two diseases are usually considered to be the result of separate distinct mechanisms. In the past 15 years, numerous studies have produced arguments in favour of a relationship between these two pathologies that goes beyond a simple addition of risk factors. At the epidemiological level, there are data that demonstrate an increased incidence of bronchial carcinoma in patients with COPD. The links between these two pathologies are still unexplained but there are numerous arguments supporting a common physiopathology. Common genetic and epigenetic abnormalities, mechanical factors and signalisation pathways have been quoted. COPD and lung cancer appear to be two diseases possessing a genetic basis that creates a predisposition to environmental or toxic assaults, resulting in a different clinical manifestation in each disease. Consequently, improvements in the management of these two diseases will involve a more intensive investigation of their physiopathology, and require a closer collaboration between research centres and clinical units.

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.

Differential proteome profiling of pleural effusions from lung cancer and benign inflammatory disease patients

The pleural effusion proteome has been found containing information that directly reflects pathophysiological status and represents a potential diagnostic value for pulmonary diseases. However, the variability in protein composition between malignant and benign effusions is not well understood. Herein, we investigated the changes of proteins in pleural effusions from lung adenocarcinoma and benign inflammatory disease (pneumonia and tuberculosis) patients by two-dimensional difference gel electrophoresis (2D-DIGE). Twenty-eight protein spots displayed significantly different expression levels were positively identified by MALDI-TOF-MS representing 16 unique proteins. Five identified protein candidates were further validated and analyzed in effusions, sera or tissues. Among them, hemopexin, fibrinogen gamma and transthyretin (TTR) were up-regulated in cancer samples. The effusion concentration of serum amyloid P component (SAP) was significantly lower in lung cancer patients than in benign inflammatory patients, but no differences were found in sera samples. Moreover, a Jumonji C (JmjC)-domain-containing protein, JMJD5, was observed to be down-regulated in malignant effusions, lung cancer tissues and cancer cells. These results shed light on the altered pleural effusion proteins as a useful and important complement to plasma or other routine clinical tests for pulmonary disease diagnosis.

MAGE A1-A6 RT-PCR and MAGE A3 and p16 methylation analysis in induced sputum from patients with lung cancer and non-malignant lung diseases

The melanoma antigen gene (MAGE) A1-A6 RT-PCR system was developed for the detection of lung cancer cells in the sputum. However, we identified MAGE expression in some patients with non-malignant lung diseases. To understand these patterns of MAGE expression, we performed MAGE A3 methylation-specific PCR (MSP) and p16 MSP. We collected 24 biopsy specimens of lung cancer tissue and performed MAGE A1-A6 RT-PCR, MAGE A3 MSP and p16 MSP. RNA and DNA were simultaneously extracted from induced sputum specimens of 133 patients with lung diseases and 30 random sputum specimens of healthy individuals and the 3 molecular analyses were performed. The patients were diagnosed as 65 cases of lung cancer and 68 of benign lung diseases. Positive rates of MAGE A1-A6 RT-PCR, MAGE A3 MSP and p16 MSP were as follows: in lung cancer tissue, 87.5, 58.3 and 70.8%; in the sputum of lung cancer patients, 50.8, 46.2 and 63.1%; benign lung diseases, 10.3, 30.9 and 39.7%; and healthy individuals, 3.3, 6.7 and 3.3%. Of the 40 MAGE-positive cases, 33 were diagnosed with lung cancer and 7 as having benign lung diseases. From the 7 cases of MAGE-positive benign lung diseases, 6 cases showed methylation abnormalities. The MAGE-positive group revealed significantly higher rates of methylation abnormalities. Of the 40 MAGE-positive cases, 39 cases were found to be lung cancer or benign lung diseases with abnormal methylation. Thus, MAGE expression in the sputum suggests the presence of lung cancer cells or pre-cancerous cells.

Increased lung cancer risk among patients with pulmonary tuberculosis: a population cohort study

INTRODUCTION

Given one third of the human population have been infected with tuberculosis, it is important to delineate the relationship between tuberculosis and lung cancer. This study explored whether contracting pulmonary tuberculosis is associated with an increased risk of developing lung cancers.

METHODS

In a cohort of 716,872 insured subjects, free from cancers, aged 20 years and older, 4480 patients with newly diagnosed tuberculosis were identified from the universal insurance claims in 1998-2000 and tracked until 2007 with the remaining insured without tuberculosis. We compared the incidence of lung cancers between the two cohorts and measured the associated hazard of developing lung cancer.

RESULTS

The incidence of lung cancers was approximately 11-fold higher in the cohort of patients with tuberculosis than nontuberculosis subjects (26.3 versus 2.41 per 10,000 person-years). Cox proportional hazard regression analysis showed a hazard ratio of 4.37 (95% confidence interval [CI]: 3.56-5.36) for the tuberculosis cohort after adjustment for the sociodemographic variables or 3.32 (95% CI: 2.70-4.09) after further adjustment for chronic obstructive pulmonary disease (COPD), smoking-related cancers (other than lung cancer), etc. The hazard ratio increased to 6.22 (95% CI: 4.87-7.94) with the combined effect with COPD or to 15.5 (95% CI: 2.17-110) with the combined effect with other smoking-related cancers.

CONCLUSIONS

This study provides a compelling evidence of increased lung cancer risk among individuals with tuberculosis. The risk may increase further with coexisting COPD or other smoking-related cancers.

Scar carcinoma of the lung: a historical perspective

Lung scar carcinoma (SC) was first described by Friedrich in 1939 as a type of lung cancer that originates around peripheral scars in the lung. Scarring in the lung can result from a variety of infections, injuries, and lung diseases. Scars can also be due to repeated episodes of tumor necrosis and healing. SCs are typically found as subpleural adenocarcinomas with retraction or puckering of the overlying pleura. They were considered a histologic curiosity that was promoted for decades until doubts about their existence were raised in the 1980s. Finding type III collagen, type V collagen, and myofibroblasts characteristic of fibrosis in the scars, finally reversed the original SC concept. The presence of type III collagen and extracellular matrix suggested an ongoing fibrosing process secondary to host response to the neoplasm. The high concentration of type III collagen in SC indicates that the fibrous tissue is in an active immature state compared with noneuplastic fibrous tissue, which is mature and contains type I and type V collagen. A recent cohort analysis of data from the PLCO (Prostate, Lung, Colorectal and Ovarian) cancer screening trial demonstrated a correlation between the presence of scar and the development of carcinoma, but the causation of this association has to be determined by future studies. The role of inflammation, infections, and smoking in the development of cancer is discussed in this article. Additional research is necessary to determine if lung scarring detected by imaging requires clinical monitoring in the context of the development of lung cancer when a defined set of risk factors is identified.

Previous lung diseases and lung cancer risk: a systematic review and meta-analysis

BACKGROUND

In order to review the epidemiologic evidence concerning previous lung diseases as risk factors for lung cancer, a meta-analysis and systematic review was conducted.

METHODS

Relevant studies were identified through MEDLINE searches. Using random effects models, summary effects of specific previous conditions were evaluated separately and combined. Stratified analyses were conducted based on smoking status, gender, control sources and continent.

RESULTS

A previous history of COPD, chronic bronchitis or emphysema conferred relative risks (RR) of 2.22 (95% confidence interval (CI): 1.66, 2.97) (from 16 studies), 1.52 (95% CI: 1.25, 1.84) (from 23 studies) and 2.04 (95% CI: 1.72, 2.41) (from 20 studies), respectively, and for all these diseases combined 1.80 (95% CI: 1.60, 2.11) (from 39 studies). The RR of lung cancer for subjects with a previous history of pneumonia was 1.43 (95% CI: 1.22-1.68) (from 22 studies) and for subjects with a previous history of tuberculosis was 1.76 (95% CI=1.49, 2.08), (from 30 studies). Effects were attenuated when restricting analysis to never smokers only for COPD/emphysema/chronic bronchitis (RR=1.22, 0.97-1.53), however remained significant for pneumonia 1.36 (95% CI: 1.10, 1.69) (from 8 studies) and tuberculosis 1.90 (95% CI: 1.45, 2.50) (from 11 studies).

CONCLUSIONS

Previous lung diseases are associated with an increased risk of lung cancer with the evidence among never smokers supporting a direct relationship between previous lung diseases and lung cancer.

The role of inflammation in the pathogenesis of non-small cell lung cancer

The link between chronic immune activation and tumorigenesis is well established. Compelling evidence has accumulated that histologic assessment of infiltration patterns of different host immune response components in non-small cell lung cancer specimens helps identify different prognostic patient subgroups. This review provides an overview of recent insights gained in the understanding of the role played by chronic inflammation in lung carcinogenesis. The usefulness of quantification of different populations of lymphocytes, natural killer cells, macrophages, and mast cells within the tumor microenvironment in non-small cell lung cancer is also discussed. In particular, the importance of assessment of inflammatory cell microlocalization within both the tumor islet and surrounding stromal components is emphasized.

Pulmonary tuberculosis increases the risk of lung cancer: a population-based cohort study

BACKGROUND

The possible effect of pulmonary tuberculosis (TB) on subsequent lung cancer development has been suspected, but the evidence remains inconsistent. The purpose of this study was to perform a nationwide population-based cohort study to investigate the risk of lung cancer after pulmonary TB infection.

METHODS

This nationwide population-based cohort study was based on data obtained from the Taiwan National Health Insurance Database. In total, 5657 TB patients and 23,984 controls matched for age and sex were recruited for the study from 1997 to 2008.

RESULTS

The incidence rate of lung cancer (269 of 100,000 person-years) was significantly higher in the pulmonary TB patients than that in controls (153 of 100,000 person-years) (incidence rate ratio [IRR], 1.76; 95% confidence interval [CI], 1.33-2.32; P < .001). Compared with the controls, the IRRs of lung cancer in the TB cohort were 1.98 at 2 to 4 years, 1.42 at 5 to 7 years, and 1.59 at 8 to 12 years after TB infections. The multivariate Cox proportional hazards model revealed pulmonary TB infections (hazard ratio [HR], 1.64; 95% CI, 1.24-2.15; P < .001) and chronic obstructive pulmonary disease (HR, 1.09; 95% CI, 1.03-1.14; P = .002) to be independent risk factors for lung cancer.

CONCLUSIONS

Pulmonary infection with TB is associated with an increased risk of lung cancer.

Tuberculosis and malignancy

BACKGROUND

Tuberculosis (TB) and malignancy represent global threats claiming millions of lives and inflicting formidable suffering worldwide. Surprisingly, the pathophysiological and practical implications of their co-existence have received little attention.

METHODS

Therefore, we sought to review the available literature on the field and identify data regarding the association between TB and malignancy in order to highlight the neglected aspects of this association and probably derive clinically useful information. We searched PubMed up to June 2008 for case reports, case series, non-comparative and comparative studies that were written in English and reported data on the occurrence of both TB infection and a neoplastic disorder in the same patient(s). The development of mycobacterial infections in patients with immunocompromized conditions is well known and was considered outside the scope of this review.

EVIDENCE SYNTHESIS

The synthesis of the available evidence enabled us to establish three different types of association between malignancy and TB: (i) the development of cancer on the background of a previous tuberculous infection; (ii) the concurrent existence of TB and malignancy in the same patient(s) or clinical specimen(s); and (iii) the diagnostic challenges arising from the multi-faceted presentations of these two disorders.

CONCLUSION

We conclude that clinicians need to be aware of the protean manifestations of TB and cancer and maintain a high index of suspicion for simultaneous and/or misleading presentations. In addition, further research is required to determine if a tuberculous infection, being similar to other chronic infections and inflammatory conditions, may facilitate carcinogenesis.

Lung cancer risk in never-smokers: a population-based case-control study of epidemiologic risk factors

BACKGROUND

We conducted a case-control study in the greater Toronto area to evaluate potential lung cancer risk factors including environmental tobacco smoke (ETS) exposure, family history of cancer, indoor air pollution, workplace exposures and history of previous respiratory diseases with special consideration given to never smokers.

METHODS

445 cases (35% of which were never smokers oversampled by design) between the ages of 20-84 were identified through four major tertiary care hospitals in metropolitan Toronto between 1997 and 2002 and were frequency matched on sex and ethnicity with 425 population controls and 523 hospital controls. Unconditional logistic regression models were used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI) for the associations between exposures and lung cancer risk.

RESULTS

Any previous exposure to occupational exposures (OR total population 1.6, 95% CI 1.4-2.1, OR never smokers 2.1, 95% CI 1.3-3.3), a previous diagnosis of emphysema in the total population (OR 4.8, 95% CI 2.0-11.1) or a first degree family member with a previous cancer diagnosis before age 50 among never smokers (OR 1.8, 95% CI 1.0-3.2) were associated with increased lung cancer risk.

CONCLUSIONS

Occupational exposures and family history of cancer with young onset were important risk factors among never smokers.

Risk of lung cancer following nonmalignant respiratory conditions among nonsmoking women living in Shenyang, Northeast China

BACKGROUND

There has been conflicting evidence about possible associations between nonmalignant respiratory conditions (NMRCs) and subsequent risk of lung cancer. Determination of whether or not there is such an association has potential importance for managing NMRCs, for screening of lung cancer, and for understanding mechanisms of carcinogenesis.

METHODS

A hospital-based, case-control study involving interviews with 226 female nonsmoking lung cancer patients and 279 matching population controls was conducted in Shenyang, Northeast China, between January 2004 and December 2007. A standardized interview collected information on a variety of potential risk factors, including a history of physician-diagnosed NMRCs (pulmonary tuberculosis, chronic bronchitis, emphysema, asthma, and bronchiectasis), and age/year in which each condition was first diagnosed. Multivariate logistic regression analyses were applied to assess the associations between NMRCs and subsequent lung cancer risk.

RESULTS

Compared with those without, subjects with a history of NMRC experience greater risk of lung cancer (OR=2.0, 95% CI 1.2-3.4), particularly following a diagnosis of pulmonary tuberculosis (OR=4.7, 95% CI 1.6-13.2). The results from subgroup analysis, when limited to small cell lung cancer, showed a 6.2-fold increase in lung cancer risk among asthmatics (95% CI 1.5-25.8). However, there was no evidence of a significant association between chronic bronchitis and lung cancer.

CONCLUSIONS

This study strengthens the evidence linking NMRCs, especially pulmonary tuberculosis, to lung cancer even in lifelong nonsmoking women.

Lower risk of lung cancer after multiple pneumonia diagnoses

BACKGROUND

Although pneumonia has been suggested as a risk factor for lung cancer, previous studies have not evaluated the influence of number of pneumonia diagnoses in relation to lung cancer risk.

METHODS

The Environment And Genetics in Lung cancer Etiology (EAGLE) population-based study of 2,100 cases and 2,120 controls collected information on pneumonia more than 1 year before enrollment from 1,890 cases and 2,078 controls.

RESULTS

After adjusting for study design variables, smoking, and chronic bronchitis, pneumonia was associated with decreased risk of lung cancer [odds ratio (OR), 0.79; 95% confidence interval (CI), 0.64-0.97], especially among individuals with three or more diagnoses versus none (OR, 0.35; 95% CI, 0.16-0.75). Adjustment for chronic bronchitis contributed to this inverse association. In comparison, pulmonary tuberculosis was not associated with lung cancer (OR, 0.96; 95% CI, 0.62-1.48).

CONCLUSIONS

The apparent protective effect of pneumonia among individuals with multiple pneumonia diagnoses may reflect an underlying difference in immune response and requires further investigation and confirmation. Therefore, careful evaluation of the number of pneumonia episodes may shed light on lung cancer etiology.

Silica exposure, smoking, silicosis and lung cancer--complex interactions

BACKGROUND

Establishing a clear relationship between workplace exposures and cancer is often difficult. The latent period for cancer development can make it difficult to establish a definite cause-effect relationship. The picture is further complicated by variable job histories, concomitant exposure to other carcinogens and other factors such as genetic susceptibility and poor nutrition. The lack of accurate and detailed record keeping may potentially mask informative differences among group of workers. Removing or reducing exposures to probable and known carcinogens, however, can prevent workplace cancer.

AIM

This paper gives an overview of the literature reporting investigations of the relationship between exposure to silica and development of lung cancer with a focus on the controversy concerning the roles of silicosis and smoking in the development of cancer.

METHOD

A literature search was conducted to identify epidemiologic papers on silica, silicosis and lung cancer using electronic databases (MEDLINE, PubMed, Web of Science) from 1996 onwards and paper bibliographies.

RESULTS

If silicosis were the necessary step leading to lung cancer, enforcing the current silica standards would protect workers against lung cancer risk as well. Alternatively, a direct silica-lung cancer association that has been suggested implies that regulatory standards should be revised accordingly.

CONCLUSION

Further research is needed in order to understand the complex pattern of interactions leading to lung cancer among silica-exposed workers (and cancers and workplace exposures in general) and to understand whether and to what extent other workplace lung carcinogens, total respirable dust and total surface size and age of silica particles affect the carcinogenic potential of silica. In addition, the apparent paradox of a lower lung cancer risk in some workplaces with high-level silica exposure needs further investigation.

Human papilloma virus and female lung adenocarcinoma

Lung cancer is the leading cause of cancer among women worldwide, and adenocarcinoma is the most common histological subtype among non-smoking women. Previous studies showed that human papillomavirus (HPV) infection may relate to the tumorigenesis of pulmonary adenocarcinoma. Women with anogenital malignancy have a higher risk of lung cancer, which raises the possibility of HPV transmission from the cervix to the lung. Two postulated pathways are discussed in this work. First, HPV may infect the female cervix and then move to the lung by blood circulation. The second transmission route is the HPV infection of oral cavity resulting from dangerous sexual contacts, and subsequently transmitted to the lung. This chapter also reviews the techniques for detecting the existence, subtypes, and viral load of HPV. Future studies are needed to demonstrate the causal inference between HPV infection and the risk of female lung adenocarcinoma.