Epidemiology of Lung Cancer in Korea: Recent Trends

Regional disparities in major cancer incidence in Korea, 1999-2018

OBJECTIVES

This study investigated regional disparities in the incidence of 8 major cancers at the municipal level in Korea during 1999-2018 and evaluated the presence or absence of hot spots of cancer clusters during 2014-2018.

METHODS

The Korea National Cancer Incidence Database was used. Age-standardized incidence rates were calculated by gender and region at the municipal level for 4 periods of 5 years and 8 cancer types. Regional disparities were calculated as both absolute and relative measures. The possibility of clusters was examined using global Moran's I with a spatial weight matrix based on adjacency or distance.

RESULTS

Regional disparities varied depending on cancer type and gender during the 20-year study period. For men, the regional disparities of stomach, colon and rectum, lung, and liver cancer declined, and those of thyroid and prostate cancer recently decreased, despite an overall increasing incidence. For women, regional disparities in stomach, colon and rectum, lung, liver, and cervical cancer declined, that of thyroid cancer recently decreased, despite an overall increasing incidence, and that of breast cancer steadily increased. In 2014-2018, breast cancer (I, 0.61; 95% confidence interval [CI], 0.53 to 0.70) showed a high probability of cancer clusters in women, and liver cancer (I, 0.48; 95% CI, 0.40 to 0.56) showed a high probability of cancer clusters in men.

CONCLUSIONS

Disparities in cancer incidence that were not seen at the national level were discovered at the municipal level. These results could provide important directions for planning and implementing local cancer policies.

Small Cell Lung Cancer: Emerging Targets and Strategies for Precision Therapy

Small cell lung cancer is an aggressive subtype of lung cancer with limited treatment options. Precision medicine has revolutionized cancer treatment for many tumor types but progress in SCLC has been slower due to the lack of targetable biomarkers. This review article provides an overview of emerging strategies for precision therapy in SCLC. Targeted therapies include targeted kinase inhibitors, monoclonal antibodies, angiogenesis inhibitors, antibody-drug conjugates, PARP inhibitors, and epigenetic modulators. Angiogenesis inhibitors and DNA-damaging agents, such as PARP and ATR inhibitors, have been explored in SCLC with limited success to date although trials are ongoing. The potential of targeting DLL3, a NOTCH ligand, through antibody-drug conjugates, bispecific T-cell engagers, and CAR T-cell therapy, has opened up new therapeutic options moving forward. Additionally, new research in epigenetic therapeutics in reversing transcriptional repression, modulating anti-tumor immunity, and utilizing antibody-drug conjugates to target cell surface-specific targets in SCLC are also being investigated. While progress in precision therapy for SCLC has been challenging, recent advancements provide optimism for improved treatment outcomes. However, several challenges remain and will need to be addressed, including drug resistance and tumor heterogeneity. Further research and biomarker-selected clinical trials are necessary to develop effective precision therapies for SCLC patients.

Methylated Circulating Tumor DNA in Blood as a Tool for Diagnosing Lung Cancer: A Systematic Review and Meta-Analysis

Lung cancer is the leading cause of cancer-related deaths, and early detection is crucial for improving patient outcomes. Current screening methods using computed tomography have limitations, prompting interest in non-invasive diagnostic tools such as methylated circulating tumor DNA (ctDNA). The PRISMA guidelines for systematic reviews were followed. The electronic databases MEDLINE, Embase, Web of Science, and Cochrane Library were systematically searched for articles. The search string contained three main topics: Lung cancer, blood, and methylated ctDNA. The extraction of data and quality assessment were carried out independently by the reviewers. In total, 33 studies were eligible for inclusion in this systematic review and meta-analysis. The most frequently studied genes were SHOX2, RASSF1A, and APC. The sensitivity and specificity of methylated ctDNA varied across studies, with a summary sensitivity estimate of 46.9% and a summary specificity estimate of 92.9%. The area under the hierarchical summary receiver operating characteristics curve was 0.81. The included studies were generally of acceptable quality, although they lacked information in certain areas. The risk of publication bias was not significant. Based on the findings, methylated ctDNA in blood shows potential as a rule-in tool for lung cancer diagnosis but requires further research, possibly in combination with other biomarkers.

Incidence disparities of obstructive sleep apnea-associated lung cancer by gender; Korean National Health Insurance data analysis

Introduction

Obstructive sleep apnea (OSA) is known to increase the risk of various cancers. By analyzing the Korea National Health Insurance Service (KNHIS) registry, the impact of OSA on the lung cancer incidence was analyzed in a retrospective cohort group.

Methods

A retrospective cohort of adult patients newly registered with OSA in the KNHIS data from 2007 to 2017 was included and observed until December 2019 (12 years). The main outcome measure was newly diagnosed lung cancer. The control group was set with age and sex that matched those in the OSA group.

Results

The hazard ratio (HR) of OSA for lung cancer incidence showed a significantly reduced HR of 0.87 (95% CI, 0.82-0.93). The observed significance of this finding was limited to male OSA patients [HR, 0.84 (95% CI, 0.78-0.90)], while no significant association was found in female OSA patients [HR, 1.05 (95% CI, 0.91-1.21)], irrespective of their age.

Discussion

OSA patients have a lower risk of developing lung cancer, but this risk reduction is gender-specific, as female OSA patients do not show a reduction in hazard ratio.

Economic Burden of Recurrence in Completely Resected Stage IB-IIIA Non-Small Cell Lung Cancer: A Retrospective Study Using Nationwide Claims Data of South Korea

INTRODUCTION

Although many patients with early stage non-small cell lung cancer (NSCLC) experience recurrence despite complete resection, few studies have reported on the corresponding economic burden. This study aimed to understand the economic impact of recurrence by measuring healthcare costs and resource utilization in patients with recurrent stage IB-IIIA NSCLC.

METHODS

Using Health Insurance Review and Assessment claims data from South Korea, we included patients who underwent complete resection for stage IB-IIIA NSCLC during the index period (January 1, 2012, to October 31, 2018). Patients who experienced recurrence were matched with those who did not using 1:1 propensity score (PS) matching. The mean healthcare costs and resource utilization were analyzed from the date of complete resection to the last claims for cancer treatment. A generalized linear model (GLM) was used to estimate the impact of covariates on healthcare costs. A difference-in-difference (DID) analysis was conducted to analyze the healthcare costs between the two groups before and after recurrence.

RESULTS

Patients with recurrence incurred higher healthcare costs, particularly in outpatient settings. The cost of targeted therapy and immune checkpoint inhibitors primarily contributed to cost differences, and medication costs increased over time after complete resection. Patients with recurrence were also hospitalized more frequently (9.3 vs. 5.0, p < 0.0001) for a longer period (74 days vs. 42 days, p < 0.0001) than those without recurrence. GLM analysis showed that the total cost was 2.31-fold higher in patients with recurrence (95% confidence interval: 2.19-2.44). The DID analysis showed significantly increased total costs in patients with recurrence (β = 26,269, p < 0.0001), which was mostly attributed to medication costs (β = 17,951, p < 0.0001).

CONCLUSION

Recurrence of completely resected NSCLC leads to a substantial increase in healthcare costs and resource utilization. The results of this study show the economic burden of recurrence, which may help future economic analyses and resource allocation.

Effects of scenario-based attribution on collective emotions and stigma toward persons with COVID-19: A cross-sectional survey

Background and Aims

During this COVID-19 pandemic, many people experience and share emotions such as fear, anxiety, sadness, anger, and disgust, which can be regarded as collective emotions. This study investigated the effects of scenario-based attribution for serious diseases on collective emotions and social stigma.

Methods

Participants were 297 healthy adults who met two conditions: (1) not having tested positive for COVID-19 (including their family members or close friends) and no experience of self-quarantine; and (2) not having been diagnosed with lung cancer, and not having family members or close friends diagnosed with it. Three hundred participants were recruited, through a company conducting online surveys. A total of 297 data sets were analyzed, excluding data supplied by three participants who might have responded unreliably to the filler question. Scenarios were recorded according to attribution type (internal vs. external) and disease (COVID-19 vs. lung cancer). A 2 × 2 factorial design was used, whereby participants were randomly assigned to one of four conditions.

Results

The COVID-19 condition showed higher scores on the perceived risk and fear of the disease compared to the lung cancer one. The COVID-19/internal attribution condition showed the highest scores for fear and anger toward scenario characters, and the lung cancer/external attribution condition showed higher sympathy scores than other conditions. Although attribution to COVID-19 was not directly related to social stigma, it could evoke negative emotions toward infected people.

Conclusion

The findings suggest that attributions of serious diseases such as COVID-19 to infected persons can influence collective emotions and the level of social stigma associated with the disease. Attention to the collective emotions and stigma associated with disease is a key component for communities and countries to recover from and respond to its impacts.

Risk-stratified Approach for Never- and Ever-Smokers in Lung Cancer Screening: A Prospective Cohort Study in China

Rationale: Over 40% of lung cancer cases occurred in never-smokers in China. However, high-risk never-smokers were precluded from benefiting from lung cancer screening as most screening guidelines did not consider them. Objectives: We sought to develop and validate prediction models for 3-year lung cancer risks for never- and ever-smokers, named the China National Cancer Center Lung Cancer models (China NCC-LC_m2021 models). Methods: 425,626 never-smokers and 128,952 ever-smokers from the National Lung Cancer Screening program were used as the training cohort and analyzed using multivariable Cox models. Models were validated in two independent prospective cohorts: one included 369,650 never-smokers and 107,678 ever-smokers (841 and 421 lung cancers), and the other included 286,327 never-smokers and 78,469 ever-smokers (503 and 127 lung cancers). Measurements and Main Results: The areas under the receiver operating characteristic curves in the two validation cohorts were 0.698 and 0.673 for never-smokers and 0.728 and 0.752 for ever-smokers. Our models had higher areas under the receiver operating characteristic curves than other existing models and were well calibrated in the validation cohort. The China NCC-LC_m2021 ⩾0.47% threshold was suggested for never-smokers and ⩾0.51% for ever-smokers. Moreover, we provided a range of threshold options with corresponding expected screening outcomes, screening targets, and screening efficiency. Conclusion: The construction of the China NCC-LC_m2021 models can accurately reflect individual risk of lung cancer, regardless of smoking status. Our models can significantly increase the feasibility of conducting centralized lung cancer screening programs because we provide justified thresholds to define the high-risk population of lung cancer and threshold options to adapt different configurations of medical resources.

New Targeted Therapy for Non-Small Cell Lung Cancer

Lung cancer ranks first in cancer mortality in Korea and cancer incidence in Korean men. More than half of Korean lung cancer patients undergo chemotherapy, including adjuvant therapy. Cytotoxic agents, targeted therapy, and immune checkpoint inhibitors are used in chemotherapy according to the biopsy and genetic test results. Among chemotherapy, the one that has developed rapidly is targeted therapy. The National Comprehensive Cancer Network (NCCN) guidelines have been updated recently for targeted therapy of multiple gene mutations, and targeted therapy is used not only for chemotherapy but also for adjuvant therapy. While previously targeted therapies have been developed for common genetic mutations, recently targeted therapies have been developed to overcome uncommon mutations or drug resistance that have occurred since previous targeted therapy. Therefore, this study describes recent, rapidly developing targeted therapies.

Lung cancer prediction using machine learning on data from a symptom e-questionnaire for never smokers, formers smokers and current smokers

PURPOSE

The aim of the present study was to investigate the predictive ability for lung cancer of symptoms reported in an adaptive e-questionnaire, separately for never smokers, former smokers, and current smokers.

PATIENTS AND METHODS

Consecutive patients referred for suspected lung cancer were recruited between September 2014 and November 2015 from the lung clinic at the Karolinska University Hospital, Stockholm, Sweden. A total of 504 patients were later diagnosed with lung cancer (n = 310) or no cancer (n = 194). All participants answered an adaptive e-questionnaire with a maximum of 342 items, covering background variables and symptoms/sensations suspected to be associated with lung cancer. Stochastic gradient boosting, stratified on smoking status, was used to train and test a model for predicting the presence of lung cancer.

RESULTS

Among never smokers, 17 predictors contributed to predicting lung cancer with 82% of the patients being correctly classified, compared with 26 predictors with an accuracy of 77% among current smokers and 36 predictors with an accuracy of 63% among former smokers. Age, sex, and education level were the most important predictors in all models.

CONCLUSION

Methods or tools to assess the likelihood of lung cancer based on smoking status and to prioritize investigative and treatment measures among all patients seeking care with diffuse symptoms are much needed. Our study presents risk assessment models for patients with different smoking status that may be developed into clinical risk assessment tools that can help clinicians in assessing a patient's risk of having lung cancer.

Identification of cuproptosis-related gene signature to predict prognosis in lung adenocarcinoma

Background: Studies have reported that coppers are involved in the tumorigenesis and development of tumor. In herein, we aimed to construct a prognostic classification system for lung adenocarcinoma (LUAD) associated with cuproptosis.

Methods: Samples information of LUAD were acquired from The Cancer Genome Atlas (TCGA) and GSE31210 dataset. Cuproptosis-related genes were screened from previous research. ConsensusClusterPlus was applied to determine molecular subtypes, which evaluated by genome analysis, tumor immune microenvironment analysis, immunotherapy, functional enrichment analysis. Furthermore, univariate Cox analysis combined with Lasso analysis were employed to construct a cuproptosis-related risk model for LUAD.

Results: 14 genes related to cuproptosis phenotype were identified, and 2 clusters (C1 and C2) were determined. Among which, C1 had better survival outcome, less advanced stages, enhanced immune infiltration and enriched in TCA related pathways. A 7 cuproptosis-associated genes risk model was constructed, and the performance was verified in the GSE31210 dataset. A higher RiskScore was significantly correlated with worse overall survival, advanced stages. Cox survival analysis showed that RiskScore was an independent predictor. High-risk group patients had weakened immune infiltration, less likely to benefit from immunotherapy and was more sensitived to immunotherapy.

Conclusion: The cuproptosis-related gene signature could serve as potential prognostic predictors for LUAD patients and may provide clues for the intervention of cuproptosis induced harm and targeted anti-tumor application.

Mechanism of Shishiwei Wendan Decoction in the Prevention and Treatment of Lung Adenocarcinoma Using Network Pharmacology and Molecular Docking

Objective

This study used network pharmacology and molecular docking technology to elucidate the mechanism of action of Shishiwei Wendan Decoction against lung adenocarcinoma.

Methods

By using the world's largest TCM System Pharmacology Database and Analysis Technology Platform (TCMSP) system to conduct in-depth mining analysis and data collection of the main active components of the medicinal components in Shishiwei Wendan Decoction and using the human gene card database (GeneCards), Human Mendelian Inheritance Online System (OMIM), and Human Disease-Related Gene and Mutation Information Database (DisGeNET) to collect the pathogenic targets of lung adenocarcinoma and build a PPI network; for the core drug targets, use GO enrichment analysis and KEGG pathway analysis; use Cytoscape software to build relevant network maps; and use AutoDock to achieve molecular docking.

Results

Shishiwei Wendan Decoction screened 144 active ingredients and 384 drug targets; 7680 lung adenocarcinoma disease targets were obtained, including 380 targets for Shishiwei Wendan Decoction in the treatment of lung adenocarcinoma. GO enrichment analysis demonstrated 2,299 downstream genes, and key target genes were closely related to nutrient levels, membrane rafts, and protein serine/threonine kinase activity; KEGG functional enrichment analysis yielded 179 related pathways, including tumor necrosis factor signaling pathway which is related to the target gene. Molecular docking showed that the core active ingredients and key targets could be well combined.

Conclusion

Through the network pharmacology analysis and molecular docking experiments of Shishiwei Wendan Decoction against lung adenocarcinoma, it is found that Shishiwei Wendan Decoction has multidimensional effects on the treatment of lung adenocarcinoma, and it is the first Shiwei Wendan Decoction to treat lung adenocarcinoma. Decoction in the treatment of lung adenocarcinoma provides biointellectual support and the oretical support.

Association between use of antacid medications (proton pump inhibitors and histamine-2 receptor antagonists) and the incidence of lung cancer: A population-based cohort analysis

This study investigated the association between antacid administration and lung cancer incidence in a real-world setting. This was a nationwide, retrospective cohort study. The cohort comprised random samples (n = 1,031,392) from the entire South Korean population in 2002. The duration of antacid administration between January 2006 and December 2010 was recorded for each participant. Newly developed lung cancers were counted during the 5-year observation period (January 1, 2006 to December 31, 2010). A total of 437,370 participants aged ≥ 40 years were included, of whom 301,201 (68.9%) had antacid exposure before the diagnosis of lung cancer. A total of 1230 (0.28%) antacid-exposed patients developed lung cancer. Among patients with no antacid exposure or underexposure (n = 136,171), 597 (0.44%) developed lung cancer. In the multivariable analysis, antacid exposure before the diagnosis of lung cancer was independently associated with a reduced incidence of lung cancer (hazard ratio: 0.64; 95% confidence interval: 0.55-0.74; P < .001). Antacid use might be independently associated with a decreased risk of lung cancer development in this cohort study.

The High Proportion of Discordant EGFR Mutations among Multiple Lung Tumors

The prevalence of multiple lung cancers has been increasing recently. Molecular analysis of epidermal growth factor receptor (EGFR) mutations in individual tumors of multiple lung cancers is essential for devising an optimal therapeutic strategy. The EGFR mutation status in multiple lung cancers was evaluated to determine its therapeutic implications. In total, 208 tumors from 101 patients who underwent surgery for multiple lung cancers were analyzed. Individual tumors were subjected to histological evaluation and EGFR analysis using a real-time polymerase chain reaction. Additionally, EGFR-wildtype tumors were subjected to next-generation sequencing (NGS). EGFR mutations were detected in 113 tumors from 72 patients, predominantly in females (p < 0.001) and non-smokers (p < 0.001). Among patients with at least one EGFR-mutant tumor, approximately 72% of patients (52/72) had different EGFR mutations in individual tumors. NGS analysis of EGFR-wildtype tumors from 12 patients revealed four and eight cases with concordant and discordant molecular alterations, respectively. These findings revealed a high proportion of discordant EGFR mutations among multiple lung tumors. Hence, EGFR analysis of individual tumors of multiple lung tumors is essential for the evaluation of clonality and the development of an optimal treatment strategy.

Lung Cancer Patients' Characteristics and Comorbidities Using the Korean National Hospital Discharge In-depth Injury Survey Data

Background

The aim of this study was to assess the incidence of lung cancer and comorbidities in Korea and analyze the lung cancer patient’s characteristics and their comorbidities over the past 12 years. This study also aimed to investigate factors related to death as treatment outcome in discharged lung cancer patients.

Methods

This study analyzed the data obtained from the Korean National Hospital Discharge In-depth Injury Survey from 2006 to 2017. The quantity of discharged lung cancer patients was assessed by year. Comorbidities were limited to those included in the Elixhauser Comorbidity Index (ECI). A Chi-square test was performed to determine statistically significant differences in the distributions of the ECI and ECI scores according to the presence or absence of metastatic cancer. Logistic regression analysis was used to analyze factors related to death as treatment outcome.

Results

From 2006 to 2017, the number of discharged male and female patients with lung cancer increased from 31,720 to 42,016 and 10,897 to 18,197, respectively. The increase in the number of lung cancer patients was greater in women than in men (67.0% vs. 32.5%, respectively). The most common associated comorbidities were hypertension, diabetes, and chronic pulmonary disease. The factors related to death as treatment outcome were found to include sex, admission route, number of hospital beds, length of stay, presence or absence of metastatic cancer, and ECI score.

Conclusion

The number of lung cancer patients in Korea has increased, and a high proportion of these patients have chronic diseases, which negatively would impact the treatment and outcome of lung cancer patients as well as their quality of life. Thus, the management of chronic diseases needs to be prioritized in patients with lung cancer.

Factors Related to the Caregiving Burden on Families of Korean Patients With Lung Cancer

The purposes of this study were to describe caregiver burden on families of patients with lung cancer and to examine its associated factors, including patient symptoms and symptom clusters. In this cross-sectional study, 120 patient-caregiver dyads were recruited from an outpatient clinic in a tertiary care hospital. Patient symptoms and caregiver burden were measured with structured questionnaire. Descriptive and inferential statistics were used to analyze data. Three patient symptom clusters were identified. Hierarchical regression showed that a patient's smoking history; caregiver age, education, health status, depression, social support, monthly family income, relationship with patient, and time spent on nursing each day; and presence of another caregiver explained 41.4% of the total variance in caregiver burden. When patient symptom clusters were added to regression model, change in total variance in caregiver burden was significant. To reduce their burden, caregivers should be taught how cancer progresses and its major symptoms after chemotherapy.

Construction of a lung adenocarcinoma prognostic model based on N6-methyl-adenosine-related long noncoding RNA and screening of potential drugs based on this model

Lung adenocarcinoma (LUAD) has a high mortality rate. N6-methyl-adenosine (m6A)-related long noncoding RNA (lncRNA) is associated with tumor prognosis. Our objective was to construct an m6A-related lncRNA prognostic model and screen potential drugs for the treatment of LUAD. The LUAD sequencing data were randomly divided into Train and Test cohorts. In the Train group, the LASSO Cox regression was used to construct the m6A-related lncRNA prognostic model. The LUAD tumor immune dysfunction and exclusion model was used to evaluate immunotherapy efficacy in LUAD. The 'pRRophetic' package was utilized to screen potential drugs for the treatment of LUAD. Eleven m6A-related lncRNAs were identified by LASSO Cox regression and were used to construct the risk model to calculate sample risk scores. Patients were divided into high- and low-risk groups based on their median risk scores. The LUAD data of The Cancer Genome Atlas database showed that the overall survival (OS) of the high-risk group was significantly lower than that of the low-risk group in both cohorts. Multivariate Cox regression analysis showed that this risk model could serve as an independent prognostic factor of LUAD, and receiver operating characteristic curves suggested that m6A-related lncRNA prognostic signature has a good ability in predicting OS. Finally, nine potential drugs for LUAD treatment were screened based on this prognostic model. The prognostic model constructed based on the m6A-related lncRNAs facilitated prognosis prediction in LUAD patients. The screened therapeutic agents have potential application values and provide a reference for the clinical treatment of LUAD.

Exposure to Secondhand Smoke and a Tobacco-Specific Carcinogen in Non-Smokers

Background: The International Agency for Research on Cancer classifies 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) as a known carcinogen. This study aimed to investigate the association between exposure to secondhand smoke (SHS) and NNAL concentrations in non-smokers.Methods: This was a cross-sectional study based on data from the 2016 to 2018 Korea National Health and Nutrition Examination Survey. Urine NNAL concentrations were categorized into tertiles of 3,615 study participants who were non-smokers. All sampling and weight variables were stratified, and analyses to account for the complex sampling design were conducted.Results: The overall, male, and female percentages of SHS exposure among non-smokers were 22.4%, 29.2%, and 20.4%, respectively. The geometric means of urine NNAL concentrations were 1.896±0.098 pg/mL and 1.094±0.028 pg/mL in the SHS exposure and non-exposure groups, respectively. After adjusting for confounding variables, in the total group, the geometric mean of urine NNAL concentrations was significantly higher in the SHS exposure group than in the SHS non-exposure group (adjusted P-value <0.001). Compared with the non-exposure group, the adjusted odds ratios (95% confidence intervals) for the highest NNAL tertile group of overall SHS exposure in the total, men, and women groups were 2.44 (1.95–3.05), 1.65 (1.08–2.53), and 2.73 (2.11–3.52), respectively, after full adjustment.Conclusion: The urine NNAL concentration in the SHS exposure group was significantly higher than that in the non-exposure group. Exposure to SHS was associated with a higher risk of elevated urine NNAL concentrations in non-smokers.

Serum Reactive Oxygen Species Modulator 1 as a Novel Predictive Biomarker for Resected Lung Adenocarcinoma: A Retrospective Pilot Study

Purpose

Reactive oxygen species modulator 1 (Romo1) is a key regulator of intracellular reactive oxygen species production. Previous studies have shown that Romo1 overexpression in tumor tissue is associated with poor clinical outcomes in various clinical settings for lung cancer treatment. The aim of the present study was to assess the predictive value of serum Romo1 in patients received curative resection for lung cancer.

Methods

Serum samples were collected from patients with lung adenocarcinoma who underwent surgical resection. Baseline serum Romo1 and carcinoembryonic antigen (CEA) levels before surgery were measured. Univariate and multivariate analyses were performed to identify whether serum Romo1 was associated with disease-free survival (DFS).

Results

A total of 77 samples were analyzed. Using the cut-off value of 866 pg/mL, the population was classified into low (n = 42, 54.4%) and high (n = 35, 45.4%) Romo1 groups. The median DFS of the high Romo1 group was significantly shorter than that of the low Romo1 group (25.5 months vs not reached [NR], p = 0.0105). In addition, the median DFS of patients in the high CEA (>2.9 ng/mL) group was significantly shorter than those in the low CEA group (26.8 months vs NR, p = 0.0092). Multivariate analyses showed that both high Romo1 and CEA levels were independently associated with poor DFS (hazard ratio [HR] = 2.19; 95% confidence interval [CI]: 1.14–8.37, and HR = 2.95; 95% CI: 1.23–9.21, respectively). Moreover, combination of these two biomarkers resulted in higher HR of 4.11 (95% CI, 1.53–14.05) for DFS than those of Romo1 and CEA.

Conclusion

Elevated serum Romo1 levels were significantly associated with early recurrence in patients with lung adenocarcinoma treated with surgical resection. Serum Romo1 may be a promising predictive biomarker for this patient population.

Exosomal miR-375-3p breaks vascular barrier and promotes small cell lung cancer metastasis by targeting claudin-1

Background

High incidence of metastasis is the main cause of death for small cell lung cancer (SCLC), with its underlying molecular mechanisms remain unclear. Exosomal miRNAs are important regulators in metastatic processes of various tumors, but their specific role in SCLC metastasis is unknown.

Methods

Small RNA sequencing followed by qRT-PCR verification was used to screen the potential exosomal miRNAs that might mediate SCLC metastasis. SCLC-cell-secreted exosomes were labeled followed by incubating with vascular endothelial cells to evaluate exosome-mediated communication between SCLC cells and vascular endothelial cells. In vitro permeability assay and transendothelial migration assay were applied to investigate the function of exosomal miRNA on vascular endothelial cells. In vivo permeability assay and mouse lung colonization assay were used to verify the effects of exosomal miRNA on vascular barriers and SCLC metastasis in vivo. Proteomics technology, dual-luciferase reporter system together with rescue assays were conducted to excavate the downstream pathways of miRNA.

Results

Compared with 57 healthy volunteers and 46 non-small cell lung cancer patients, we identified that the level of exosomal miR-375-3p in 126 SCLC patients was obviously higher and was positively correlated with patient TNM stages. In vitro functional experiments found that SCLC-cell-secreted exosomal miR-375-3p could increase the permeability of vascular endothelial cells and facilitate the transendothelial migration of SCLC cells. In vivo, miR-375-3p-enriched exosomes also destroyed the barrier structure of lung, liver and brain tissues of mice, leaded to an increased blood vessel permeability and finally promoted SCLC metastasis. Mechanistically, SCLC-cell-secreted exosomal miR-375-3p was transferred to vascular endothelial cells. The internalized miR-375-3p broke the tight junction of vascular endothelial cells by directedly binding to the 3’UTR of tight junction protein claudin-1 and negatively regulating its expression. Overexpressing claudin-1 in vascular endothelial cells could rescue the broken vascular barriers induced by miR-375-3p.

Conclusions

Our findings underline the crucial roles of exosomal miRNA-375-3p in regulating vascular endothelial barrier integrity and SCLC metastasis. miRNA-375-3p has a great potential to be a novel biomarker monitoring metastasis and guiding clinical therapeutics of SCLC patients.

Incidence trends and risk factors of lung cancer in never smokers: Pooled analyses of seven cohorts

The trends in incidence of lung cancer in never smokers are unclear as well as the significance of risk factors. We studied time trends in the incidence and risk factors of lung cancer in never smokers in Finland in a large, pooled cohort. We pooled data from seven Finnish health cohorts from the period between 1972 and 2015 with 106 193 never smokers. The harmonised risk factors included education, alcohol consumption, physical activity, height and BMI. We retrieved incident lung cancers from the nation-wide Finnish Cancer Registry. We estimated average annual percent change (AAPC) and the effects of risk factors on cause-specific hazard ratios (HRs) of lung cancer using Poisson regression. We detected 47 lung cancers in never smoking men (n = 31 859) and 155 in never smoking women (n = 74 334). The AAPC of lung cancer incidence was -3.30% (95% confidence interval [CI]: -5.68% to -0.88%, P = .009) in never smoking men and 0.00% (95% CI: -1.57% to 1.60%, P = .996) in never smoking women. Of the five studied risk factors only greater height in women had a statistically significant increased risk of lung cancer (multivariate HR = 1.84, 95%CI: 1.08 to 3.12). It is plausible that tobacco control measures focused on working places have reduced passive smoking among men more than among women, which could explain the declining trend in lung cancer incidence in never smoker men but not in never smoker women. As tobacco control measures have not been targeted to domestic environments, it is likely that women's exposure to passive smoking has continued longer.

Depressive symptoms among cancer patients: Variation by gender, cancer type, and social engagement

Prior literature has documented an association between cancer and depressive symptoms. There has been a limited understanding about whether the association between cancer and depressive symptoms varies by gender and whether social engagement moderates this association. Using seven waves of the Korean Longitudinal Study of Ageing (N = 10,055), we examine the association between cancer and depressive symptoms among middle- and older-aged adults in Korea. We conduct fixed-effects regression models to account for unobserved characteristics of individuals that may confound this association. We first investigate whether the association between cancer and depressive symptom differs by gender. We distinguish among cancer types to assess potentially distinctive mental health consequences of different types of cancer. Then, we explore whether social engagement moderates the cancer-depressive symptoms association. Naive OLS models yielded significant associations between cancer and depressive symptoms for both men and women. However, our preferred fixed effects estimates revealed that the association was statistically significant only for men, and not for women. This association was especially pronounced for lung cancer. We also found that one's level of social engagement including informal connections and formal social activities moderates the link between cancer and depressive symptoms. Cancer is not only a leading cause of death, but also a serious threat to one's mental health. This study sheds light on gender differences in psychological reactions to cancer among Korean adults. Findings of this study hold important implications for programs aiming to improve the mental health and quality of life of cancer patients.

Association between long-term exposure to high levels of ambient air pollution and incidence of lung cancer in a population-based cohort

Although outdoor air pollution including particulate matter (PM) was classified as carcinogenic to humans based on accumulating epidemiological evidence, these findings were suggested mostly from low-dose environments in North America and Europe. We aimed to examine the association of long-term exposure to PM ≤ 10 and 2.5 μm in diameter (PM₁₀ and PM_2.5) and nitrogen dioxide (NO₂) with lung cancer incidence using a population-based cohort in the Seoul Metropolitan Area (SMA), South Korea. Our study included 83,478 people residing in the SMA and followed up for 2007-2015 from the National Health Insurance Service-National Sample Cohort. This cohort was constructed based on the National Health Insurance database that contains sociodemographic and medical information under universal health coverage. Individual long-term concentrations of PM₁₀, PM_2.5, and NO₂ were estimated at people's district-level and annually-updated residential addresses for the previous 5 years by using previously-validated prediction models. We applied a time-dependent Cox proportional hazards model and estimated hazard ratios (HRs) per 10 μg/m³ and 10 ppb increases in PM and NO₂, respectively, after adjusting for individual characteristics. During 9 years of follow-up, 489 lung cancer new cases occurred (714,012 person-year). The adjusted HRs for PM₁₀ were greater than 1 but statistically non-significant (HR = 1.15; 95% CI = 0.88-1.52). We also did not find associations for PM_2.5 and NO₂. Despite null associations for the total population, our subgroup analysis suggested associations with PM in family members with cancer (PM₁₀: HR = 2.59, 95% CI = 1.26-5.32; PM_2.5: 5.55, 1.09-27.91) and in those who have smoked more than 1 pack per day (1.77, 0.96-3.25; 3.81, 1.00-14.44) or for less than 20 years (2.81; 1.13-7.07; 2.02, 0.21-19.23). Our study based on a highly urbanized population exposed to relatively high air pollution provides no evidence of the association between PM and lung cancer incidence in the total population but indicates the potential susceptibility in heavy smokers for relatively short periods and family members of cancer patients. Future studies should re-examine the association using improved exposure assessment and extended population.

Clinical Characteristics and Outcome of Pathologic N0 Non-small Cell Lung Cancer Patients With False Positive Mediastinal Lymph Node Metastasis on FDG PET-CT

BACKGROUND/AIM

Preoperative fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET-CT) is a non-invasive and useful diagnostic tool to evaluate mediastinal lymph node (LN) metastasis in lung cancer. However, there are often false-positive LN cases in FDG PET-CT. This study aimed to explore the clinical characteristics and outcome of pathologic N0 non-small cell lung cancer patients with false-positive mediastinal LN on FDG PET-CT.

PATIENTS AND METHODS

We enrolled 147 patients who underwent preoperative FDG PET-CT scan and mediastinal LN dissection. These patients were re-evaluated for post-operative pathologic nodal metastasis and divided into a false-positive group and a group of others.

RESULTS

Among 40 patients diagnosed with clinical N1-3 on FDG PET-CT, 19 (47.5%) patients were pathologic N0, meaning false-positive LN by PET-CT. Preoperative absolute platelet count and platelet-lymphocyte ratio were significantly higher in patients with pathologic N0. The presence of lymphatic invasion was significantly lower in patients with pathologic N0 than in the group of others. Recurrence-free survival was significantly shorter in patients with false positive LN than in patients with true positive LN or true negative LN at the same pathologic stage.

CONCLUSION

Higher absolute platelet count and PLR, lower proportion of lymphatic invasion and shorter recurrence-free survival were associated with false positive mediastinal LN on preoperative FDG PET-CT.

Colonic Metastasis of Primary Lung Cancer

The colon is an uncommon secondary site for metastasis of lung adenocarcinoma. Distinguishing primary colonic carcinoma from metastatic spread of lung carcinoma can be difficult. We present a case of a patient with lung adenocarcinoma who, on abdominal computed tomography scan examination, was found to have a sigmoid tumor that was thought to represent a synchronous primary colorectal adenocarcinoma. Histological examination of endoscopic sigmoid tumor biopsies confirmed this to be metastasis from the lung adenocarcinoma. The patient subsequently developed major rectal bleeding and deteriorated significantly. This case also illustrates the poor prognosis association with colorectal metastasis of lung cancer.

Inter-regional multimedia fate analysis of PAHs and potential risk assessment by integrating deep learning and climate change scenarios

Polycyclic aromatic hydrocarbons (PAHs) are hazardous compounds associated with respiratory disease and lung cancer. Increasing fossil fuel consumption, which causes climate change, has accelerated the emissions of PAHs. However, potential risks by PAHs have not been predicted for Korea, and appropriate PAH regulations under climate change have yet to be developed. This study assesses the potential risks posed by PAHs using climate change scenarios based on deep learning, and a multimedia fugacity model was employed to describe the future fate of PAHs. The multimedia fugacity model describes the dynamics of sixteen PAHs by reflecting inter-regional meteorological transportation. A deep neural network predicts future environmental and economic conditions, and the potential risks posed by PAHs, in the year 2050, using a prediction model and climate change scenarios. The assessment indicates that cancer risks would increase by more than 50%, exceeding the lower risk threshold in the southern and western regions. A mix of strategies for developing PAH regulatory policies highlighted the necessity of increasing PAHs monitoring stations and controlling fossil fuel usage based on the domestic and global conditions under climate change scenarios.

Clinical Spectrum of Uveal Metastasis in Korean Patients Based on Primary Tumor Origin

PURPOSE

To describe the clinical features and prognosis of patients with uveal metastasis in Korea.

DESIGN

Retrospective, observational case series.

PARTICIPANTS

Patients diagnosed at 2 tertiary high-volume centers between November 2005 and November 2019.

METHODS

Evaluation of multimodal imaging and electronic medical records.

MAIN OUTCOME MEASURES

The clinical features and outcomes were assessed based on the primary cancer site.

RESULTS

A total of 134 uveal metastases (128 choroidal, 3 iris, and 3 ciliary body tumors) were diagnosed in 95 eyes of 80 patients. Mean age at diagnosis was 56 years (median, 55 years; range, 24-86 years), with a minor preponderance of women (61%). Tumors were bilateral in 15 patients (19%) and the primary origin was established in 49 patients (61%) before ocular detection. The primary tumor originated in the lung (48%), breast (24%), gastrointestinal tract (10%), liver (3%), pancreas (3%), kidney (1%), cervix (1%), and nasopharynx (1%), with some remaining unknown (10%). The overall 5-year survival rate was 21%. Kaplan-Meier analysis revealed that the worst survival was found in pancreatic cancers (mean survival, 5.9 months; P = 0.045), and the best survival was found in gastrointestinal tract cancers (mean survival, 44.5 months).

CONCLUSIONS

The primary tumor origins in Korean patients with uveal metastases differed from those reported in primarily population-based studies of White patients, with a higher prevalence of lung and gastrointestinal tract cancers.

Impact of idiopathic pulmonary fibrosis on clinical outcomes of lung cancer patients

The clinical characteristics of lung cancer in patients with idiopathic pulmonary fibrosis (IPF) differ from those of lung cancer in patients without IPF. Thus, we aimed to evaluate the impact of IPF on the clinical course of patients with lung cancer. Clinical data of IPF patients with lung cancer (n = 122) were compared with those of patients with lung cancer without IPF (n = 488) matched by age, sex, histopathology, stage, and date of diagnosis of lung cancer. The median follow-up period after diagnosis of lung cancer was 16 months. Among patients with IPF, the mean age was 68 years, 95.9% were male, 93.2% were ever-smokers, and squamous cell carcinoma was the most common cancer type (48.4%). The IPF group had poorer lung function and lower lobe predominance of lung cancer than the no-IPF group. The IPF group showed a poorer prognosis than the no-IPF group (5-year survival rate: 14.5% vs. 30.1%, respectively; P < 0.001), even after adjusting for lung function and regardless of the treatment method. Among patients with IPF, 16.8% experienced acute exacerbation within 1 month after treatment of lung cancer. The treatment outcome of patients with lung cancer and IPF was generally unfavorable, and acute exacerbation triggered by treatment frequently occurred.

Recent Trends of Lung Cancer in Korea

Lung cancer is one of the leading causes of cancer-related deaths in Korea. Although the smoking rate has decreased over time, the prevalence of lung cancer still remains high. In this study, we reviewed recent trends on the incidence, epidemiology, screening, diagnosis, and treatment of lung cancer in Korea by analyzing data from the national lung cancer registry and recently-published studies. Although approximately 40% of patients with non-small cell lung cancer (NSCLC) were diagnosed as stage IV, the 5-year relative survival rate improved from 11.3% (1993-1995) to 30.2% (2013-2017), possibly due to advances in methods of diagnosis and therapy. In addition, the 2019 implementation of the national lung cancer screening program with low-dose computed tomography may have also contributed to these improvements in survival rates. Recently, molecular diagnosis has become more widely used in the identification of genetic mutations in tissue specimens. Target therapy and immune checkpoint inhibitors have also been successfully used, particularly in cases of advanced NSCLC. In the future, further research on the optimal management of lung cancer remains necessary.

Long-term progression-free survival in a patient with advanced non-small-cell lung cancer treated with low-dose gefitinib and traditional herbal medicine: A case report

RATIONALE

Gefitinib is a first-line palliative chemotherapy drug used to treat advanced non-small-cell lung cancer (NSCLC) in patients who have an epidermal growth factor receptor (EGFR) mutation. However, approximately two-thirds of NSCLC patients with EGFR-tyrosine kinase inhibitor experience dermatological toxicity. Cutaneous toxicity is usually not life threatening but can necessitate modification or discontinuation of medication in severe cases. In this case, despite a reduction in the dose of gefitinib due to side effects, combined treatment with modified Bojungikki-tang (BJKIT) increased progression-free survival (PFS) in an advanced NSCLC patient.

PATIENT CONCERNS

An 83-year-old Asian woman presented with chief complaints of chronic cough, dyspnea, weight loss, and anorexia.

DIAGNOSES

The patient was diagnosed with stage IV NSCLC (T2aN3M1), adenocarcinoma with metastasis to the lymph node, brain, and bone based on image scan and biopsy. An EGFR deletion was detected in exon 19.

INTERVENTIONS

The patient was treated with gefitinib (250 mg/d) and traditional herbal medicine, modified Bojungikki-tang (BJIKT). However, after 1 year of combination therapy, gefitinib was tapered down to once per week while modified BJIKT was maintained.

OUTCOMES

A partial response was achieved, but after 3 months severe papulopustular skin rashes developed and became aggravated with time. Thus, the gefitinib dose was reduced. However, the PFS has been maintained for approximately 78 months.

LESSONS

Despite the reduction in gefitinib dose due to side effects, the combined treatment of gefitinib and the modified BJIKT has maintained a PFS of over 78 months, indicating that modified BJIKT enhanced the anti-cancer effect of gefitinib in a patient with advanced NSCLC harboring the EFGR mutation, and may have delayed acquired resistance, the main limitation on the efficacy of gefitinib. Further investigations including clinical trials are needed to confirm these effects.

GC-MS metabolomics identifies novel biomarkers to distinguish tuberculosis pleural effusion from malignant pleural effusion

Background

Tuberculous pleural effusions (TBPEs) and malignant pleural effusions (MPEs) are two of the most common and severe forms of exudative effusions. Clinical differentiation is challenging; however, metabolomics is a collection of powerful tools currently being used to screen for disease‐specific biomarkers.

Methods

17 TBPE and 17 MPE patients were enrolled according to the inclusion criteria. The normalization gas chromatography‐mass spectrometry (GC‐MS) data were imported into the SIMCA‐P + 14.1 software for multivariate analysis. The principal component analysis (PCA) and orthogonal partial least‐squares discriminant analysis (OPLS‐DA) were used to analyze the data, and the top 50 metabolites of variable importance projection (VIP) were obtained. Metabolites were qualitatively analyzed using the National Institute of Standards and Technology (NIST) databases. Pathway analysis was performed by MetaboAnalyst 4.0. The detection of biochemical indexes such as urea and free fatty acids in these pleural effusions was also verified, and significant differences were found between these two groups.

Results

1319 metabolites were screened by non‐targeted metabonomics of GC‐MS. 9 small molecules (urea, L‐5‐oxoproline, L‐valine, DL‐ornithine, glycine, L‐cystine, citric acid, stearic acid, and oleamide) were found to be significantly different (p < 0.05 for all). In OPLS‐DA, 9 variables were considered significant for biological interpretation (VIP≥1). However, after the ROC curve was performed, it was found that the metabolites with better diagnostic value were stearic acid, L‐cystine, citric acid, free fatty acid, and creatinine (AUC > 0.8), with good sensitivity and specificity.

Conclusion

Stearic acid, L‐cystine, and citric acid may be potential biomarkers, which can be used to distinguish between the TBPE and the MPE.

Excess Mortality of Males Due to Malignant Lung Cancer in OECD Countries

Excess mortality of men has been observed since the beginning of the 20th century. One of the main causes of this phenomenon is malignant cancers, with lung cancer as the main reason. At the turn of the 20th and 21st centuries, a decline in male excess mortality was observed in most developed countries. This study aimed to analyze the changes in the level of excess mortality of men caused by lung cancer between 2002 and 2017 in the countries associated with the Organization for Economic Cooperation and Development (OECD). In order to compare changes in male mortality rates across countries, the annual average percent change (AAPC) in male excess mortality rate for a given country was calculated. A decrease in excess male mortality due to lung cancer between 2002 and 2017 was recorded in 33 of the 35 countries analyzed. The highest rate of decline was observed in Spain (4.9% per year), Belgium (4.7% per year), Slovakia (4.4% per year) and other European OECD member countries. In most OECD countries, the decrease in excess male mortality was the result of a decrease in mortality in the male population as well as the increase in female mortality. In 10 member countries of the OECD, there was a simultaneous increase in the mortality of men and women, though the increase was higher in the female population. Only in two countries was the decrease in excess mortality of males due to a greater decline in the mortality of men. The decline in male mortality from lung cancer primarily associated with a reduction in tobacco consumption in this population initiated in the 1980s or 1990s (depending on the country) was not observed in the female population.

Targeted inhibition of c-MET by podophyllotoxin promotes caspase-dependent apoptosis and suppresses cell growth in gefitinib-resistant non-small cell lung cancer cells

BACKGROUND

Lung cancer has the highest incidence and cancer-related mortality of all cancers worldwide. Its treatment is focused on molecular targeted therapy. c-MET plays an important role in the development and metastasis of various human cancers and has been identified as an attractive potential anti-cancer target. Podophyllotoxin (PPT), an aryltetralin lignan isolated from the rhizomes of Podophyllum species, has several pharmacological activities that include anti-viral and anti-cancer effects. However, the mechanism of the anti-cancer effects of PPT on gefitinib-sensitive (HCC827) or -resistant (MET-amplified HCC827GR) non-small cell lung cancer (NSCLC) cells remains unexplored.

PURPOSE

In the present study, we investigated the underlying mechanisms of PPT-induced apoptosis in NSCLC cells and found that the inhibition of c-MET kinase activity contributed to PPT-induced cell death.

METHODS

The regulation of c-MET by PPT was examined by pull-down assay, ATP-competitive binding assay, kinase activity assay, molecular docking simulation, and Western blot analysis. The cell growth inhibitory effects of PPT on NSCLC cells were assessed using the MTT assay, soft agar assay, and flow cytometry analysis.

RESULTS

PPT could directly interact with c-MET and inhibit kinase activity, which further induced the apoptosis of HCC827GR cells. In contrast, PPT did not significantly affect EGFR kinase activity. PPT significantly inhibited the cell viability of HCC827GR cells, whereas the PPT-treated HCC827 cells showed a cell viability of more than 80%. PPT dose-dependently induced G2/M cell cycle arrest, as shown by the downregulation of cyclin B1 and cdc2, and upregulation of p27 expression in HCC827GR cells. Furthermore, PPT treatment induced Bad expression and downregulation of Mcl-1, survivin, and Bcl-xl expression, subsequently activating multi-caspases. PPT thereby induced caspase-dependent apoptosis in HCC827GR cells.

CONCLUSION

These results suggest the potential of PPT as a c-MET inhibitor to overcome tyrosine kinase inhibitor resistance in lung cancer.

Awareness and Use of Complementary and Alternative Medicine in Korean Lung Cancer Patients

Background

Complementary and alternative medicine (CAM) has been used frequently, and its use continues to increase in lung cancer patients, despite insufficient scientific of its efficacy. To investigate this situation, we analyzed the current awareness and use of CAM in Korean lung-cancer patients.

Methods

This prospective survey–based study was performed at seven medical centers in South Korea between August and October 2019. The survey assessed general patient characteristics and the awareness and use of CAM. We analyzed differences in the clinical parameters of patients aware and not aware of CAM and of CAM non-users and users.

Results

Of the 434 patients included in this study, 68.8% responded that they were aware of CAM and 30.9% said they had experienced it. In univariate analysis, the patients aware of CAM were younger with poor performance status, had advanced-stage lung cancer, received more systemic therapy, and received concurrent chemoradiation therapy (CCRT). By multiple logistic regression, younger age, poor performance status, advanced stage, and prior CCRT were identified as independent risk factors for CAM awareness. There were no significant differences in the general characteristics and cancer-associated clinical parameters of CAM non-users and users.

Conclusion

Specific clinical parameters were associated with patients’ awareness of CAM, although there were no significantly different characteristics between CAM users and non-users.

Glutathione Peroxidase 3 as a Biomarker of Recurrence after Lung Cancer Surgery

We aimed to examine the usefulness of serum glutathione peroxidase 3 (GPx3) as a biomarker of lung cancer recurrence after complete resection. We prospectively collected serial serum samples at the baseline, as well as 3, 6 and 12 months after surgery from complete resection cases in 2013. GPx3 levels were measured by enzyme-linked immunosorbent assay. Statistical tests including t-tests and Cox proportional hazard regression analyses were performed. Totally, 135 patients were enrolled, and 39 (28.9%) showed relapse during the median follow-up period (63.60 months; range, 0.167–81.867). The mean GPx3 change was significantly higher in the recurrence group at 6 months (0.32 ± 0.38 vs. 0.15 ± 0.29, p = 0.016) and 12 months (0.40 ± 0.37 vs. 0.13 ± 0.28, p = 0.001). The high GPx3 change group showed significantly higher 60-months recurrence rates than the low group (48.1% vs. 25.2% at 3 months, p = 0.005; 54.5% vs. 28.9% at 6 months, p = 0.018; 38.3% vs. 18.3% at 12 months, p = 0.035). High GPx3 change at 3 months were independent risk factors of recurrence (hazard ratio (HR) 3.318, 95% confidence interval (CI), 1.582–6.960, p = 0.002) and survival (HR 3.150, 95% CI, 1.301–7.628, p = 0.011). Therefore, serum GPx3 changes after surgery may be useful predictive biomarkers for recurrence in lung cancer. Larger-scale validation studies are warranted to confirm these findings.

An examination of two dichotomies: Women with lung cancer and living with lung cancer as a chronic disease

Lung cancer remains the leading cause of cancer death globally, yet with many recent advances in the diagnosis and treatment of lung cancer, the face of the disease is shifting. Historically, lung cancer is often thought of as a predominantly male disease with more than twice as many men as women being diagnosed worldwide-mostly due to the influence of smoking as the leading risk factor. However, lung cancer is also the second leading cause of cancer death in women and there is a growing population of young women who have never smoked and are being diagnosed. The past decade has seen groundbreaking innovations in both the early detection and treatment of lung cancer. In this new era, survival rates are beginning to increase and many of those diagnosed are finding themselves in a new situation-living long term with a deadly cancer. Here, we review pertinent aspects of women and lung cancer as well as the concept of living with lung cancer as a chronic disease to give a new perspective on the changing face of lung cancer treatment and care.

DNA Methylation Markers in Lung Cancer

Lung cancer is the most common cancer and the leading cause of cancer-related morbidity and mortality worldwide. As early symptoms of lung cancer are minimal and non-specific, many patients are diagnosed at an advanced stage. Despite a concerted effort to diagnose lung cancer early, no biomarkers that can be used for lung cancer screening and prognosis prediction have been established so far. As global DNA demethylation and gene-specific promoter DNA methylation are present in lung cancer, DNA methylation biomarkers have become a major area of research as potential alternative diagnostic methods to detect lung cancer at an early stage. This review summarizes the emerging DNA methylation changes in lung cancer tumorigenesis, focusing on biomarkers for early detection and their potential clinical applications in lung cancer.

Active Treatment Improves Overall Survival in Extremely Older Non-Small Cell Lung Cancer Patients: A Multicenter Retrospective Cohort Study

PURPOSE

As the aging of society progresses, the proportion of extremely older lung cancer patients has also increased; However, studies of these patients with non-small cell lung cancer are limited. Therefore, we investigated the initial treatment modalities and survival outcomes for patients aged 80 years or over.

Materials and Methods

We included a multicenter retrospective cohort from the Korean Association for Lung Cancer Registry, which surveys 10% of the newly diagnosed lung cancer patients across 52 hospitals in Korea. We analyzed and compared the 2014-2016 data of the non-small cell lung cancer patients aged ≥ 80 years and those aged < 80 years.

RESULTS

Of the 6,576 patients reviewed, 780 patients were aged ≥ 80 years, and 5,796 patients were aged < 80 years. In the patients aged ≥ 80 years, surgery and radiation therapy resulted in longer patient survival among those with a resectable tumor (stage I-II) than the best supportive care (median survival, not reached [surgery] vs. 32.2 months [radiation therapy] vs. 11.43 months [best supportive care]). The duration of survival in patients with advanced-stage (IV) lung cancers was higher after chemotherapy than after the best supportive care (median survival, 8.63 months vs. 2.5 months). Patients with stage IV adenocarcinoma who received targeted therapy had better survival than those who did not (median survival, 9.0 months vs. 4.3 months).

CONCLUSION

Even in extremely older patients, active treatments, such as surgery, radiation therapy, and chemotherapy, can result in better survival outcomes than the best supportive care.

CT features and disease spread patterns in ROS1-rearranged lung adenocarcinomas: comparison with those of EGFR-mutant or ALK-rearranged lung adenocarcinomas

The purpose of this study was to investigate the differences in CT characteristics and disease spread patterns between ROS1-rearranged adenocarcinomas and epidermal growth factor receptor (EGFR)-mutant or anaplastic lymphoma kinase (ALK)-rearranged adenocarcinomas. Patients with stage IIIb/IV adenocarcinoma with ROS1 rearrangement, EGFR mutations, or ALK rearrangement were retrospectively identified. Two radiologists evaluated CT features and disease spread patterns. A multivariable logistic regression model was applied to determine the clinical and CT characteristics that can discriminate between ROS1-rearranged and EGFR-mutant or ALK-rearranged adenocarcinomas. A cohort of 169 patients was identified (ROS1 = 23, EGFR = 120, and ALK = 26). Compared to EGFR-mutant adenocarcinomas, ROS1-rearranged adenocarcinomas were less likely to have air-bronchogram (p = 0.011) and pleural retraction (p = 0.048) and more likely to have pleural effusion (p = 0.025), pericardial metastases (p < 0.001), intrathoracic and extrathoracic nodal metastases (p = 0.047 and 0.023, respectively), and brain metastases (p = 0.017). Following multivariable analysis, age (OR = 1.06; 95% CI: 1.01, 1.12; p = 0.024), pericardial metastases (OR = 10.50; 95% CI: 2.10, 52.60; p = 0.005), and nodal metastases (OR = 8.55; 95% CI: 1.14, 62.52; p = 0.037) were found to be more common in ROS1-rearranged tumors than in non-ROS1-rearranged tumors. ROS1-rearranged adenocarcinomas appeared as solid tumors and were associated with young age, pericardial metastases and advanced nodal metastases relative to tumors with EGFR mutations or ALK rearrangement.

Lifetime survival and medical costs of lung cancer: a semi-parametric estimation from South Korea

Background

It is essential to have information on the disease burden of lung cancer at an individual level throughout the life; however, few such results have been reported. Thus, this study aimed to assess the lifetime disease burden in patients with lung cancer by assessing various factors, such as survival, years of life lost (YLL) and medical expenditure in South Korea based on real-world data and extrapolation.

Methods

Newly diagnosed lung cancer patients (n = 2919) in 2004–2010 were selected and observed until the end of 2015 using nationwide reimbursement claim database. The patients were categorised into the Surgery group, Chemo and/or Radiotherapy group (CTx/RTx), and Surgery+CTx/RTx according to their treatment modality. Age- and sex-matched control subjects were selected from among general population using the life table. The survival and cost data after diagnosis were analysed by a semi-parametric method, the Kaplan–Meier analysis for the first 100 months and rolling extrapolation algorithm for 101–300 months. YLL were derived from the difference in survival between patients and controls.

Results

Lifetime estimates (standard error) were 4.5 (0.2) years for patients and 14.5 (0.1) years for controls and the derived YLL duration was 10.0 (0.2) years. Lifetime survival years showed the following trend: Surgery (14.2 years) > Surgery+CTx/RTx (8.5 years) > CTx/RTx group (3.0 years), and YLL were increased as lifetime survival years decreased (2.3, 8.7, 12.2 years, respectively). The mean lifetime medical cost was estimated at 30,857 USD/patient. Patients in the Surgery group paid higher treatment cost in first year after diagnosis, but the overall mean cost per year was lower at 4359 USD compared with 7075USD of Surgery+CTx/RTx or 7626USD of CTx/RTx group.

Conclusions

Lung cancer has resulted in about 10 years of life lost in overall patients. The losses were associated with treatment modality, and the results indicated that diagnosing lung cancer in patients with low stage disease eligible for surgery is beneficial for reducing disease burden in terms of survival and treatment cost per year throughout the life.

High PD-L1 Expression is Associated with Unfavorable Clinical Outcome in EGFR-Mutated Lung Adenocarcinomas Treated with Targeted Therapy

Purpose

Although programmed death-ligand 1 (PD-L1) expression is widely accepted as a predictive and prognostic biomarker in immunotherapy, its implications in lung cancer patients with driving mutations are still unclear. The objective of this study is to determine the association between PD-L1 expression and treatment outcome in epidermal growth factor receptor (EGFR)-mutated lung cancer treated with tyrosine kinase inhibitors (TKIs).

Methods

We retrospectively enrolled EGFR-mutant, advanced lung adenocarcinoma patients who received first-line EGFR-TKIs and evaluated the PD-L1 tumor proportion score (TPS) using the 22C3 pharmDx assay. We investigated the distribution of patients with different PD-L1 TPS values, followed by the analysis of response rate (RR), survival rate, and incidence of secondary T790M mutation according to the PD-L1 TPS group.

Results

Among the 131 patients analyzed, the proportion of patients with PD-L1 TPS ≥ 50%, 1–49%, and <1%, was 17.6%, 32.8%, and 49.6%, respectively. The RR was significantly lower in the group with PD-L1 TPS ≥ 50% than in the other groups (43.5% vs 72.1% vs 78.5%, all p = 0.001). In multivariate analysis, PD-L1 TPS ≥ 50% was independently associated with a significantly shorter PFS in the overall population (hazard ratio [HR] = 2.64, p = 0.004) and associated with shorter OS in patients with exon 19 deletion (HR = 2.55, p = 0.041) compared with PD-L1 TPS < 50%. In addition, the frequency of secondary T790M mutation after TKI failure was significantly lower in the group with PD-L1 TPS ≥ 50% than in the other groups (13.3% vs 40.0% vs 53.3%, all p = 0.001). PD-L1 TPS ≥ 50% was an independent predictor of a lower frequency of this mutation (HR = 0.63, p = 0.043).

Conclusion

High PD-L1 expression was associated with unfavorable clinical outcome and less development of secondary T790M mutation, suggesting a distinct subgroup warranting active surveillance and tailored therapeutic approach.

Reactive Oxygen Species Modulator 1 is Associated with Poor Survival in Patients with Non-Small Cell Lung Cancer After Stereotactic Fractionated Radiosurgery: A Retrospective Pilot Study

Purpose

It has been reported that the overexpression of reactive oxygen species modulator 1 (Romo1) is significantly associated with poor survival outcomes in patients with lung cancer who received surgical resection, conventional fractionated radiotherapy, and chemotherapy. In this study, we investigated whether Romo1 expression is associated with survival outcomes in patients with early-stage lung cancer who were treated with radiosurgery.

Methods

Romo1 protein expression was evaluated and scored in the tumor tissue specimens of 40 patients with non-small cell lung cancer by immunohistochemistry. An optimal cut-off for Romo1 expression was determined and used to allocate patients to low or high Romo1 expression groups. Survival outcomes were compared between the two groups.

Results

Romo1 expression was significantly associated with distant metastasis-free survival. The 1- and 2-year distant metastasis-free survival rates were 96.4% and 92.6% in the low Romo1 expression group and 87.5% and 46.7% in the high Romo1 expression group (P=0.041), respectively. The overall, local recurrence-free, regional recurrence-free, and disease progression-free survival rates were higher in the low Romo1 expression group than the high Romo1 expression group. However, the differences were not statistically significant.

Conclusion

Romo1 overexpression is associated with poor distant metastasis-free survival in patients with non-small cell lung cancer treated with radiosurgery. Further, large-scale prospective studies are required to identify the clinical efficacy of Romo1 as a potential adverse prognostic factor in lung cancer.

PDX models of human lung squamous cell carcinoma: consideration of factors in preclinical and co-clinical applications

Background

Treatment of human lung squamous cell carcinoma (LUSC) using current targeted therapies is limited because of their diverse somatic mutations without any specific dominant driver mutations. These mutational diversities preventing the use of common targeted therapies or the combination of available therapeutic modalities would require a preclinical animal model of this tumor to acquire improved clinical responses. Patient-derived xenograft (PDX) models have been recognized as a potentially useful preclinical model for personalized precision medicine. However, whether the use of LUSC PDX models would be appropriate enough for clinical application is still controversial.

Methods

In the process of developing PDX models from Korean patients with LUSC, the authors investigated the factors influencing the successful initial engraftment of tumors in NOD scid gamma mice and the retainability of the pathological and genomic characteristics of the parental patient tumors in PDX tumors.

Conclusions

The authors have developed 62 LUSC PDX models that retained the pathological and genomic features of parental patient tumors, which could be used in preclinical and co-clinical studies.

Trial registration Tumor samples were obtained from 139 patients with LUSC between November 2014 and January 2019. All the patients provided signed informed consents. This study was approved by the institutional review board (IRB) of Samsung Medical Center (2018-03-110)

Diagnostic and Predictive Values of 18F-FDG PET/CT Metabolic Parameters in EGFR-Mutated Advanced Lung Adenocarcinoma

Purpose

The clinical implications of the metabolic parameters of ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET/CT) in epidermal growth factor receptor (EGFR)-mutated lung cancer are not fully understood. The aim of this study was to evaluate the diagnostic and prognostic utility of the parameters in EGFR-mutated lung cancer patients.

Patients and Methods

We retrospectively enrolled 134 patients with advanced lung adenocarcinoma (72 EGFR-negative and 62 EGFR-positive). We evaluated the correlation between EGFR mutational status and the maximum standardized uptake value (SUVmax), as well as the associations between treatment outcomes in EGFR-mutated patients and various metabolic parameters of primary tumors. For the best predictive parameters, we calculated the metabolic tumor volume (MTV) and total lesion glycolysis (TLG) using two SUV cutoffs: 1.5 (MTV_1.5, TLG_1.5) and 2.5 (MTV_2.5, TLG_2.5).

Results

Mean SUVmax was lower for EGFR-mutated tumors compared with EGFR wild-type (6.11 vs 10.41, p < 0.001) tumors. Low SUVmax was significantly associated with positive EGFR mutation (odds ratio = 1.74). Multivariate analysis for survival demonstrated that high MTV_1.5, TLG_1.5, MTV_2.5, and TLG_2.5 were independently associated with shorter progression-free survival (PFS) and overall survival (OS), and the highest hazard ratios were found in TLG_1.5 (3.26 for PFS and 4.62 for OS).

Conclusion

SUVmax may be predictive for EGFR mutational status, and MTV and TLG of primary tumors may be promising prognostic parameters; ¹⁸F-FDG PET/CT has potential utility for the risk stratification of EGFR-mutated patients treated with targeted therapy.

Patterns of percutaneous transthoracic needle biopsy (PTNB) of the lung and risk of PTNB-related severe pneumothorax: A nationwide population-based study

Background

As percutaneous transthoracic needle biopsy (PTNB) of the lung is a well-established diagnostic method for the evaluating pulmonary lesions, evidence of safety based on representative data is limited. This study investigated the practice patterns of PTNB of the lung and assessed the incidence and risk factors of PTNB-related severe pneumothorax in Korea.

Methods

We used a national-level health insurance database between January 1, 2007 and December 31, 2015. Patients who underwent PTNB of the lung were identified using procedure codes for organ biopsy, fluoroscopy, computed tomography, chest radiography, and lung-related diagnosis codes. The annual age-/sex-standardized rate of PTNB and the incidence of PTNB-related severe pneumothorax were calculated. We defined severe pneumothorax as the pneumothorax requiring intervention. The odds ratios of risk factors were assessed by a generalized estimating equation model with exchangeable working correlation matrix to address clustering effect within institution.

Results

A total of 66,754 patients were identified between 2007 and 2015. The annual age-/sex-standardized rate of PTNB per 100,000 population was 19.6 in 2007 and 22.4 in 2015, and it showed an increasing trend. The incidence of severe pneumothorax was 2.4% overall: 2.5% in men and 1.2% in women, and 2.6%, 2.7%, 2.1%, 2.1%, 1.9%, 2.4%, and 2.4% from 2009 to 2015. Older age (≥60), male sex, presence of chronic obstructive pulmonary disease, receiving treatment in an urban or rural area versus a metropolitan area, and receiving treatment at a general hospital were significantly associated with the risk of severe pneumothorax.

Conclusions

Considering the increasing trend of PTNB, more attention needs to be paid to patients with risk factors for severe pneumothorax.

Cancer development in patients with COPD: a retrospective analysis of the National Health Insurance Service-National Sample Cohort in Korea

BACKGROUND

COPD is a well-known risk factor for lung cancer, independent of smoking behavior. By investigating the retrospective National Health Insurance Service-National Sample Cohort (NHIS-NSC) in Korea, this study attempted to prove the hypothesis that COPD is a risk factor for major cancers developing outside of the lungs. We also aimed to investigate the environmental factors associated with the development of lung cancer in COPD patients.

METHODS

This study analyzed data from the NHIS-NSC over a 12-year period. Among the 514,795 subjects in the NHIS-NSC, 16,757 patients who were diagnosed with any cancer from 2002 to 2003 were excluded. This cohort enrolled six arms consisting of never-smokers without COPD (N = 313,553), former smokers without COPD (N = 41,359), smokers without COPD (N = 112,627), never-smokers with COPD (N = 7789), former smokers with COPD (N = 1085), and smokers with COPD (N = 2677).

RESULTS

Incident rate of lung cancer per 100,000 person-year was higher according to smoking and COPD (216 in non-COPD and 757 in COPD among never-smokers, 271 in non-COPD and 1266 in COPD among former smokers, 394 in non-COPD and 1560 in COPD among smokers, p <  0.01). Old age, male sex, lower BMI, low exercise level, history of diabetes mellitus, smoking, and COPD were independent factors associated with the development of lung cancer (p <  0.01). Multi-variable analyses showed that COPD, regardless of smoking status, contributed to the development of lung cancer, and colorectal cancer and liver cancer among other major cancers (p <  0.01).

CONCLUSION

Our data suggested that COPD was an independent risk factor for the development of lung cancer, and colorectal cancer and liver cancer among other major cancers in the Korean population, regardless of smoking status.

Impact of Sarcopenia on Early Postoperative Complications in Early-Stage Non-Small-Cell Lung Cancer

Background

Risk assessment for pulmonary resection in patients with early-stage non–small-cell lung cancer (NSCLC) is important for minimizing postoperative morbidity. Depletion of skeletal muscle mass is closely associated with impaired nutritional status and limited physical ability. We evaluated the relationship between skeletal muscle depletion and early postoperative complications in patients with early-stage NSCLC.

Methods

Patients who underwent curative lung resection between 2016 and 2018 and who were diagnosed with pathological stage I/II NSCLC were included, and their records were retrospectively analyzed. The psoas volume index (PVI, cm³/m³) was calculated based on computed tomography images from routine preoperative positron emission tomography-computed tomography. Early postoperative complications, defined as those occurring within 90 days of surgery, were compared between the lowest sex-specific quartile for PVI and the remaining quartiles.

Results

A strong correlation was found between the volume and the cross-sectional area of the psoas muscle (R²=0.816). The overall rate of complications was 57.6% among patients with a low PVI and 32.8% among those with a normal-to-high PVI. The most common complication was prolonged air leak (low PVI, 16.9%; normal-to-high PVI, 9.6%), followed by pneumonia (low PVI, 13.6%; normal-to-high PVI, 7.9%) and recurrent pleural effusion (low PVI, 11.9%; normal-to-high PVI, 6.8%). The predictors of overall complications were low PVI (odds ratio [OR], 2.18; 95% confidence interval [CI], 1.07–4.09; p=0.03), low hemoglobin level (OR, 0.686; 95% CI, 0.54–0.87; p=0.002), and smoking history (OR, 3.93; 95% CI, 2.03–7.58; p<0.001).

Conclusion

Low PVI was associated with a higher rate of early postoperative complications in patients with early-stage NSCLC.

Artificial intelligence and lung cancer treatment decision: agreement with recommendation of multidisciplinary tumor board

Background

IBM Watson for Oncology (WFO) is a cognitive computing system helping physicians quickly identify key information in a patient’s medical record, surface relevant evidence, and explore treatment options. This study assessed the possibility of using WFO for clinical treatment in lung cancer patients.

Methods

We evaluated the level of agreement between WFO and multidisciplinary team (MDT) for lung cancer. From January to December 2018, newly diagnosed lung cancer cases in Chonnam National University Hwasun Hospital were retrospectively examined using WFO version 18.4 according to four treatment categories (surgery, radiotherapy, chemoradiotherapy, and palliative care). Treatment recommendations were considered concordant if the MDT recommendations were designated ‘recommended’ by WFO. Concordance between MDT and WFO was analyzed by Cohen’s kappa value.

Results

In total, 405 (male 340, female 65) cases with different histology (adenocarcinoma 157, squamous cell carcinoma 132, small cell carcinoma 94, others 22 cases) were enrolled. Concordance between MDT and WFO occurred in 92.4% (k=0.881, P<0.001) of all cases, and concordance differed according to clinical stages. The strength of agreement was very good in stage IV non-small cell lung carcinoma (NSCLC) (100%, k=1.000) and extensive disease small cell lung carcinoma (SCLC) (100%, k=1.000). In stage I NSCLC, the agreement strength was good (92.4%, k=0.855). The concordance was moderate in stage III NSCLC (80.8%, k=0.622) and relatively low in stage II NSCLC (83.3%, k=0.556) and limited disease SCLC (84.6%, k=0.435). There were discordant cases in surgery (7/57, 12.3%), radiotherapy (2/12, 16.7%), and chemoradiotherapy (15/129, 11.6%), but no discordance in metastatic disease patients.

Conclusions

Treatment recommendations made by WFO and MDT were highly concordant for lung cancer cases especially in metastatic stage. However, WFO was just an assisting tool in stage I–III NSCLC and limited disease SCLC; so, patient-doctor relationship and shared decision making may be more important in this stage.

Ten-year patient journey of stage III non-small cell lung cancer patients: A single-center, observational, retrospective study in Korea (Realtime autOmatically updated data warehOuse in healTh care; UNIVERSE-ROOT study)

INTRODUCTION

Until the recent approval of immunotherapy after completing concurrent chemoradiotherapy (CCRT), there has been little progress in treating unresectable stage III non-small cell lung cancer (NSCLC). This prompted us to search real-world data (RWD) to better understand diagnosis and treatment patterns, and outcomes.

METHODS

This non-interventional observational study used a unique, novel algorithm for big data analysis to collect and assess anonymized patient electronic medical records from a clinical data warehouse (CDW) over a 10-year period to capture real-world patterns of diagnosis, treatment, and outcomes of stage III NSCLC patients. We describe real-world patterns of diagnosis and treatment of patients with newly-diagnosed stage III NSCLC, and patients' characteristics, and assessment of treatment outcomes.

RESULTS

We analyzed clinical variables from 23,735 NSCLC patients. Stage III patients (N = 4138, 18.2 %) were diagnosed as IIIA (N = 2,547, 11.2 %) or IIIB (N = 1,591. 7.0 %). Treated stage III patients (N = 2530, 61.1 %) had a median age of 64.2 years, were mostly male (78.5 %) and had an ECOG performance status of 1 (65.2 %). Treatment comprised curative-intent surgery (N = 1,254, 49.6 %) with 705 receiving neoadjuvant therapy; definitive CRT (N = 648, 25.6 %); palliative CT (N = 270, 10.7 %), or thoracic RT (N = 170, 6.7 %). Median OS (range) for neoadjuvant, surgery, CRT, palliative chemotherapy, lung RT alone, and supportive care was 49.2 (42.0-56.5), 52.5 (43.1-61.9), 30.3 (26.6-34.0), 14.7 (13.0-16.4), 8.8 (6.2-11.3), and 2.0 (1.0-3.0) months, respectively.

CONCLUSIONS

This unique in-house algorithm enabled a rapid and comprehensive analysis of big data through a CDW, with daily automatic updates that documented real-world PFS and OS consistent with the published literature, and real-world treatment patterns and clinical outcomes in stage III NSCLC patients.

Risk factors for primary lung cancer among never-smoking women in South Korea: a retrospective nationwide population-based cohort study

BACKGROUND/AIMS

We performed a large-scale, retrospective, nationwide, cohort study to investigate the risk factors for lung cancer among never-smoking Korean females.

METHODS

The study data were collected from a general health examination and questionnaire survey of eligible populations conducted between January 1, 2003 and December 31, 2004; the data were acquired from the tailored big data distribution service of the National Health Insurance Service. After a 1-year clearance period, 5,860,922 of 6,318,878 never-smoking female participants with no previous history of lung cancer were investigated. After a median follow-up of 11.4 years, 43,473 (0.74%) participants were defined as "newly diagnosed lung cancer".

RESULTS

After adjusting for all variables at baseline, the variables older age, lower body mass index (BMI), less exercise, frequent alcohol drinking, meat-based diet, rural residence, and previous history of cancer were associated with a higher incidence of lung cancer. Low BMI (< 18.5 kg/m2: hazard ratio [HR], 1.33; 95% confidence interval [CI], 1.27 to 1.40) was a significant independent risk factor; as BMI decreased, HR increased. Negative associations between BMI and lung-cancer development were also observed after controlling for age (p for trend < 0.001). Drinking alcohol one to two times a week (HR, 1.25; 95% CI, 1.21 to 1.28) and eating a meat-based diet (HR, 1.08; 95% CI, 1.01 to 1.15) were associated with lung-cancer incidence.

CONCLUSION

Modifiable baseline characteristics, such as BMI, exercise, alcohol consumption, and diet, are risk factors for lung-cancer development among never- smoking females. Thus, lifestyle modifications may help prevent lung cancer.

Epidemiology of lung cancer in northeast of Iran: A 25-year study of 939 patients

Background: Lung cancer (LC) is a global public health priority. In this study, the epidemiology and current trends of primary LCs were investigated in northeast of Iran.

Methods: Demographic and pathologic records of primary LCs during 1985-2012 in Mashhad (capital of northeast of Iran) were reviewed. Data were obtained from archives of the largest referral oncologic hospital and the only private outpatient radiation-oncologic clinic in the region. To investigate trends, study duration was classified into 3 periods: 1985-1995, 1995-2005, and 2005-2012. Patients were placed in one of these 3 groups, based on the date of their pathologic diagnosis. Data were analyzed by SPSS 16 software. T test, chi-squared, and ANOVA tests were used for data analysis, and statistical significant level was set at < 0.05.

Results: Among 939 cases with pathologic diagnosis of primary LC, male-to-female ratio was 2.36. Mean±SD age at diagnosis was 61.47±12.01 years in males and 58.45±12.75 in females (p=0.001). Squamous cell carcinoma (SCC) was the most frequent pathologic subtype. Mean age at diagnosis and rate of smokers were unchanged during the study (p= 0.978 and 0.153, respectively). Relative frequency of leading pathologic subtypes changed in 3 intervals (p<0.001): it was increasing in adenocarcinoma and large cell carcinoma and decreasing in SCC and small cell lung cancer (SCLC). There were statistically significant differences in the mean age at diagnosis (p<0.001), rate of smokers (p<0.001), and male-to-female ratio (p=0.011) between leading pathologic subtypes.

Conclusion: Similar to universal picture, rate of adenocarcinoma in northeast of Iran was rising during recent decades, especially among younger patients, women, and nonsmokers. These trends are indicative of changes in exposures and smoking habits and reveal the need for regional studies in these contexts.