Non-small Cell Lung Cancer In Never-smokers Research Articles

Abstract 1467: Contribution of estrogen metabolites to never-smoking lung cancer

Abstract There has been a consistent rise in the incidence of non-small cell lung cancer (NSCLC) among individuals who have never smoked. Remarkably, over 50% of diagnosed female cases and 15-20% of male cases are never-smokers. Notably, NSCLC in never-smokers exhibits distinctive clinical and pathological features, notably a higher incidence of tumors with EGFR mutations, setting it apart from its counterpart in smokers. Despite the improved disease-free survival observed with EGFR-tyrosine kinase inhibitors, eventual relapse and limited responsiveness to immunotherapy are common, underscoring the urgency to comprehend the molecular mechanisms driving the escalating prevalence of NSCLC in never-smokers and develop targeted preventive and interceptive therapeutic strategies. The preponderance of females among NSCLC patients who never smoked has prompted an exploration into the potential contribution of estrogen to lung tumorigenesis. In contrast to prevailing research focused on estrogen receptor-mediated signaling, our investigations have yielded compelling evidence supporting the involvement of estrogen metabolism in lung carcinogenesis among never-smokers. This group is the first to report that estrogen is metabolized extensively in both mouse and human lungs, resulting in the generation of various derivatives, including the potential carcinogen 4-hydroxyestrogen (4-OHE). Notably, recent findings from our laboratory indicate that prolonged exposure of nonneoplastic human bronchial epithelial cells to 17β estradiol or 4-OHE, at concentrations approximating physiological levels, induces the accumulation of double-strand DNA breaks and cellular transformation. A comprehensive analysis was performed to further elucidate the mechanisms underlying the transformation process. Isolated transformed clones obtained after 9, 18, and 22 wks of exposure to 4-OHE were subjected to karyotyping, F.I.S.H., and RNA and exome sequencing. A longitudinal progression of aberrant chromosomal rearrangements and copy number alterations was observed, that increased with time of 4-OHE exposure. In addition, RNA-Seq analyses revealed the epithelial-mesenchymal transition pathway was highly enriched at the early timepoint (9 wks), while replicative stress-related signaling pathways were induced at all timepoints. To determine if the differentially expressed genes were also dysregulated in clinical lung cancer cases, TCGA lung adenocarcinoma (LUAD) data were examined. Interestingly, many of the genes upregulated after estrogen exposure were similarly overexpressed in the LUAD samples and often associated with a worse prognosis. In conclusion, our data support the role of estrogen metabolites in promoting lung cancer among never-smokers. (Supported by CA217161 and generous contributions from the Hellendall Family Foundation, Gregory G. Lawton and the Timothy and Aurora Hughes Cancer Research Fund.) Citation Format: Mitchell Cheung, Lisa A. Vanderveer, Daniel Krzizike, J. Nicholas Bodor, Joseph Treat, Joseph R. Testa, Margie L. Clapper. Contribution of estrogen metabolites to never-smoking lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1467.

EP16.03-020 High Tumor Mutational Burden by Whole-Genome Sequencing in Resected NSCLC in Never Smokers is Associated with Worse Prognosis

Tumor mutational burden (TMB) is a measure of the number of somatic mutations in a tumor. For all comers with non-small-cell lung cancer (NSCLC), high TMB defined as ≥ 10 mutations/megabase (mut/Mb) has been associated with positive and durable response to immunotherapy (IO). For never smokers with NSCLC, TMB is typically lower, but the clinical application of this biomarker remains to be established. In this study, using gold-standard whole-genome sequencing (WGS), we aimed to 1) test whether TMB is a prognostic biomarker of survival after surgery in never smokers with NSCLC, 2) define a prognostic TMB cutoff, and 3) compare TMB derived from WGS with exome sequencing (WES) and commercial NGS gene panels.

1276P Deep molecular characterization of never smoker non-small cell lung cancer (NSCLC) patients

Patients (Pts) with advanced NSCLC are eligible for treatments with immune checkpoint inhibitors (ICIs) as single agent or in combination with chemotherapy (ICI-CT), unless their tumor harbors actionable oncogenic drivers, more commonly observed in never-smokers. Next generation sequencing (NGS) is being increasingly employed in clinical practice in place of traditional molecular techniques, such as Real Time PCR (RT-PCR), mass spectrometry (MS) and fluorescence in situ hybridization (FISH), as ensures optimal levels of sensitivity and specificity.

Clinical and economic impact of current ALK rearrangement testing in Spain compared with a hypothetical no-testing scenario

BackgroundCurrently biomarkers play an essential role in diagnosis, treatment, and management of cancer. In non-small cell lung cancer (NSCLC) determination of biomarkers such as ALK, EGFR, ROS1 or PD-L1 is mandatory for an adequate treatment decision. The aim of this study is to determine the clinical and economic impact of current anaplastic lymphoma kinase testing scenario in Spain.MethodsA joint model, composed by decision-tree and Markov models, was developed to estimate the long-term health outcomes and costs of NSCLC patients, by comparing the current testing scenario for ALK in Spain vs a hypothetical no-testing. The current distribution of testing strategies for ALK determination and their sensitivity and specificity data were obtained from the literature. Treatment allocation based on the molecular testing result were defined by a panel of Spanish experts. To assess long-term effects of each treatment, 3-states Markov models were developed, where progression-free survival and overall survival curves were extrapolated using exponential models. Medical direct costs (expressed in €, 2019) were included. A lifetime horizon was used and a discount rate of 3% was applied for both costs and health effects. Several sensitivity analyses, both deterministic and probabilistic, were performed in order test the robustness of the analysis.ResultsWe estimated a target population of 7628 NSCLC patients, including those with non-squamous histology and those with squamous carcinomas who were never smokers. Over the lifetime horizon, the current ALK testing scenario produced additional 5060 and 3906 life-years and quality-adjusted life-years (QALY), respectively, compared with the no-testing scenario. Total direct costs were increased up to € 51,319,053 for testing scenario. The incremental cost-effectiveness ratio was 10,142 €/QALY. The sensitivity analyses carried out confirmed the robustness of the base-case results, being the treatment allocation and the test accuracy (sensitivity and specificity data) the key drivers of the model.ConclusionsALK testing in advanced NSCLC patients, non-squamous and never-smoker squamous, provides more than 3000 QALYs in Spain over a lifetime horizon. Comparing this gain in health outcomes with the incremental costs, the resulting incremental cost-effectiveness ratio reinforces that testing non-squamous and never-smoker squamous NSCLC is a cost-effective strategy in Spain.

Association between sex hormones regulation-related SNP rs12233719 and lung cancer risk among never-smoking Chinese women.

BackgroundThe mechanism of rapidly increased non‐small cell lung cancer (NSCLC) among never‐smoking Chinese women has not been elucidated. Ovarian sex steroid hormones have been suggested to counteract lung cancer development, and sex hormone‐binding globulin (SHBG) is essential in sex hormones regulation. This study aims to exploring single nucleotide polymorphisms (SNPs) in genomic regions associated with SHBG concentrations that contributed to never‐smoking female NSCLC.MethodsCandidate genes were selected by a genome‐wide association (GWAS) meta‐analysis and gene expression profiles of never‐smoking NSCLC of Chinese women. The candidate SNPs limited to common minor allele frequency (MAF), missense variant, ethnic heterogeneous distribution, and SNPs were genotyped using the TaqMan method. A two‐stage case‐control design was adopted for exploration and validation of associations between candidate SNPs and risk of NSCLC. All participants were never‐smoking Chinese women. Chi‐square test and multivariate logistic regression were applied.ResultsBeginning with 12 genomic regions associated with circulating SHBG concentrations and gene expression profiles from never‐smoking NSCLC in Chinese women, candidate SNP rs12233719 and rs7439366 both located in candidate gene UGT2B7, which may be related to circulating SHBG concentrations and cancer risk, were identified. A two‐stage case‐control study was conducted in Shenyang and Tianjin represented as the training stage and validation stage, respectively. Under the dominant model, compared to individuals with the wild G/G genotype, the adjusted OR of those with the T allele was 1.58 (95% CI: 1.15–2.16) in Chinese Shenyang training set, and was 1.49 (95% CI: 1.02–2.18) in Chinese Tianjin validation set, both accompanied with a significant trend relationship consistently. UGT2B7 was upregulated in female NSCLC patients’ tumor tissues and was associated with a poor prognosis in NSCLC.ConclusionOur findings indicated that a sex hormones regulation‐related SNP rs12233719 was associated with never‐smoking female lung cancer risk, which might partially explain NSCLC‐susceptibility in Chinese women.

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

BackgroundThe proportion of never-smokers with non-small cell lung cancer (NSCLC) is increasing, but that in Korea has not been well addressed in a large population. We aimed to evaluate the proportion and clinical features of never-smokers with NSCLC in a large single institution.MethodsWe analyzed clinical data of 1860 consecutive patients who were newly diagnosed with NSCLC between June 2011 and December 2014.ResultsOf the 1860 NSCLC patients, 707 (38.0%) were never-smokers. The proportions of women (83.7% vs. 5.6%) and adenocarcinoma (89.8% vs. 44.9%) were higher among never-smokers than among ever-smokers. Significantly more never-smokers were diagnosed at a younger median age (65 vs. 68 years, P < 0.001) and earlier stage (stage I–II, 44.5% vs. 38.9%, P = 0.015) compared with ever-smokers. Epidermal growth factor receptor mutations (57.8% vs. 24.4%, P < 0.001) and anaplastic lymphoma kinase rearrangements (7.8% vs. 2.8%, P < 0.001) were more common in never-smokers, whereas Kirsten rat sarcoma viral oncogene homolog mutations (5.8% vs. 9.6%, P = 0.021) were less frequently encountered in never-smokers than in ever-smokers. Never-smokers showed longer survival after adjusting for the favorable effects of younger age, female sex, adenocarcinoma histology, better performance status, early stage disease, being asymptomatic at diagnosis, received antitumor treatment, and the presence of driver mutations (hazard ratio, 0.624; 95% confidence interval, 0.460–0.848; P = 0.003).ConclusionsMore than one-third of the Korean patients with NSCLC were never-smokers. NSCLC in never-smokers had different clinical characteristics and major driver mutations and resulted in longer overall survival compared with NSCLC in ever-smokers.

Proportion of Never-Smoker Non-Small Cell Lung Cancer Patients at Three Diverse Institutions.

Approximately 10% to 15% of lung cancer cases in the United States occur in never smokers, but there has been much debate about whether this rate is increasing. To determine whether the proportion of never smokers among lung cancer cases is increasing, we conducted a retrospective study using registries from The University of Texas Southwestern Medical Center, Parkland Hospital, and Vanderbilt University. Registries were queried for demographic information from 1990 to 2013 including sex, age, stage, and self-reported smoking history. Ten thousand five hundred ninety-three non-small cell lung cancer (NSCLC) case patients and 1510 small cell lung cancer (SCLC) case patients were captured, and logistic regression analysis was performed. All statistical tests were two-sided. The proportion of never-smoker NSCLC patients increased from 8.0% in the years 1990 to 1995 to 14.9% in 2011 to 2013 (P < .001). This increase was also observed using multivariable logistic regression after controlling for sex, stage at diagnosis, and race/ethnicity. The percentage of never smokers among SCLC case patients (1.5% in 1990-1995 to 2.5% in 2011-2013, P = .36) or squamous cell NSCLC case patients did not statistically significantly change during this period. This study demonstrates an increasing proportion of NSCLC patients who have never smoked in a large, diverse patient population between 1990 and 2013. Given that this increase appears independent of sex, stage, and race/ethnicity and also occurred in our county hospital, this trend is unlikely due to changes in referral patterns and suggests that the actual incidence of lung cancer in never smokers is increasing.

Association of CHEK2 polymorphisms with the efficacy of platinum-based chemotherapy for advanced non-small-cell lung cancer in Chinese never-smoking women.

Cell cycle checkpoint kinase 2 (CHEK2) plays an essential role in the repair of DNA damage. Single nucleotide polymorphisms (SNPs) in DNA repair genes are thought to influence treatment effects and survival of cancer patients. This study aimed to investigate the relationship between polymorphisms in the CHEK2 gene and efficacy of platinum-based doublet chemotherapy in never-smoking Chinese female patients with advanced non-small-cell lung cancer (NSCLC). Using DNA from blood samples of 272 Chinese advanced NSCLC non-smoking female patients treated with first-line platinum-based chemotherapy, we have analyzed the relationships between four SNPs in the CHEK2 gene and clinical outcomes. We found that overall survival (OS) was significantly associated with CHEK2 rs4035540 (Log-Rank P=0.020), as well as the CHEK2 rs4035540 dominant model (Log-Rank P=0.026), especially in the lung adenocarcinoma group. After multivariate analysis, patients with rs4035540 A/G genotype had a significantly better OS than those with the G/G genotype (HR =0.67, 95% CI, 0.48-0.93; P=0.016). In the toxicity analysis, it was observed that patients with the CHEK2 rs4035540 A/A genotype had a higher risk of gastrointestinal toxicity than the G/G genotype group (P=0.009). However, there are no significant associations between chemotherapy treatments and genetic variations. Our findings indicate that SNPs in CHEK2 are related to Chinese advanced NSCLC never-smoking female patients receiving platinum-based doublet chemotherapy in China. Patients with rs4035540 A/G genotype have a better OS. And patients with rs4035540 A/A genotype have a higher risk of gastrointestinal toxicity. These results point to a direction for predicting the prognosis for Chinese never-smoking NSCLC female patients. However, there are no significant associations between chemotherapy treatments and SNPs in CHEK2, which need more samples to the further study.

EGFR, ALK, RET, KRAS and BRAF alterations in never-smokers with non-small cell lung cancer.

Non-small cell lung cancer (NSCLC), caused by various mutations in a spectrum of cancer driver genes, may have distinct pathological characteristics and drug responses. Extensive genetic screening and pathological characterization is required for the design of customized therapies to improve patient outcomes. Notably, NSCLC in never-smokers exhibits distinctive clinicopathological features, which are frequently associated with tumorigenic mutations, and thus may be treated as a unique disease entity. However, to the best of our knowledge, these mutations have not been extensively and accurately characterized in an NSCLC study with a large sample size. Therefore, the present study enrolled a large cohort of NSCLC patients, which consisted of 358 never-smokers, for the screening of genetic alterations in the epidermal growth factor receptor (EGFR), ret proto-oncogene (RET), anaplastic lymphoma kinase (ALK), Kirsten rat sarcoma viral oncogene homolog (KRAS) and B-Raf proto-oncogene serine/threonine kinase (BRAF) tumorigenic genes. It was identified that the mutation rate was 47.8, 7.5, 3.6, 1.4 and 0.3% for EGFR, ALK, KRAS, RET and BRAF, respectively. In addition, clinicopathological features associated with these mutations were characterized. EGFR mutations were more frequently observed in female and older patients. By contrast, KRAS mutations were more frequently detected in male patients, and ALK and RET translocations in younger patients. The cancer cells were frequently well-differentiated in carcinoma cases exhibiting EGFR mutations, however, were less differentiated in those with ALK translocations. In conclusion, the present study determined the frequency of oncogenic alterations and associated clinicopathological features in NSCLC exhibited by never-smokers using a large sample size. The results of the present study may enrich our knowledge of NSCLC in never-smokers and provide useful insights for improvement of the outcome of molecularly targeted therapies for the treatment of NSCLC.

A Favorable Treatment Response of Erlotinib in Lung Adenocarcinoma with Concomitant ActivatingEGFRMutation andROS1Rearrangement

The rearrangement of c-ros oncogene 1 (ROS1) has been recently identified as an important molecular target in non small cell lung cancer (NSCLC). ROS1 rearrangement and epidermal growth factor receptor (EGFR) mutation were mutually exclusive each other in previous studies, and the clinical implication of co-existence of the two genetic alterations has not been determined. We report a case of 46-year-old female never-smoker NSCLC patient whose tumor harbored ROS1 rearrangement and EGFR mutation concomitantly. She had undergone curative surgery for stage IIIA NSCLC, and the recurrence in left pleura and brain occurred at 2 years after the surgery. She received several lines of chemotherapy including docetaxel plus carboplatin, erlotinib, pemetrexed, and gemcitabine. Erlotinib therapy showed a favorable treatment response with progression-free survival of 9.5 months and partial response of tumor on radiologic evaluations. This case represents a successful erlotinib treatment in a NSCLC patient with concurrent ROS1 rearrangement and EGFR mutation. (Ewha Med J 2014;37(1):46-51) Received September 27, 2013, Accepted January 14, 2014

Molecular profiles of non-small cell lung cancers in cigarette smoking and never-smoking patients

Molecular features of non-small cell lung cancer (NSCLC) in never-smokers are not well recognized. We assessed the expression of genes potentially related to lung cancer etiology in smoking vs. never-smoking NSCLC patients. We assayed frozen tumor samples from surgically resected 31 never-smoking and 54 clinically pair-matched smoking NSCLC patients, and from corresponding normal lung tissue from 27 and 43 patients, respectively. Expression of 21 genes, including cell membrane kinases, sex hormone receptors, transcription factors, growth factors and others was assessed by reverse transcription - quantitative PCR. Expression of 5 genes was significantly higher in tumors of non-smokers vs. smokers: CSF1R (p<0.0001), RRAD (p<0.0001), PR (p=0.0004), TGFBR2 (p=0.0027) and EPHB6 (p=0.0033). Expression of AKR1B10 (p<0.0001), CDKN2A (p<0.0001), CHRNA6 (p<0.0001), SOX9 (p<0.0001), survivin (p<0.0001) and ER2 (p=0.002) was significantly higher in tumors compared to normal lung tissue. Expression of AR (p<0.0001), EPHB6 (p<0.0001), PR (p<0.0001), TGFBR2 (p<0.0001), TGFBR3 (p<0.0001), ER1 (p=0.0006) and DLG1 (p=0.0016) was significantly lower in tumors than in normal lung tissue. Expression of IGF2 was higher in tumors than in healthy lung tissue in never-smokers (p=0.003), and expression of AHR (p<0.0001), CSF1R (p<0.0001) and RRAD (p<0.0001) was lower in tumors than in healthy lung tissue in smokers. Expression of several genes in NSCLC is strongly related to smoking history. Lower expression of PR and higher expression of ER2 in tumors suggests a possibility of hormonal therapeutic intervention in selected NSCLC patients. Distinct molecular features of NSCLC in never-smokers, e.g. CHRNA6 upregulation, may prompt new treatment strategies.

1225O - A Randomized Phase 2 Study of Erlotinib Plus Pemetrexed vs Erlotinib or Pemetrexed Alone as Second-Line Treatment for Never-Smoker Patients with Non-Squamous Advanced Non-Small Cell Lung Cancer (NSCLC)

ABSTRACT Background Erlotinib (E) and Pemetrexed (P) are approved second-line treatments in patients (pts) with relapsed NSCLC and may be effective in combination. This randomized phase 2 study compared the efficacy and safety of E + P vs either agent alone, as second-line treatment in never-smoker pts with advanced non-squamous NSCLC. Methods From Nov 2007 to Jul 2010, never-smoker NSCLC, ECOG Performance Status (PS) ≤2 pts who had failed 1 prior chemotherapy regimen were enrolled and randomized to either: E 150 mg daily, P 500 mg/m2 day 1, or P 500 mg/m2 day 1 plus E 150 mg daily on days 2 to 14 of a 21-day cycle, continued until discontinuation criteria were met. The primary endpoint of progression-free survival (PFS) was analyzed using a sequential approach. A multivariate Cox model was used to perform a global comparison across the 3 arms with pairwise comparisons between treatments using contrasts within the model. If the global null hypothesis was rejected at a 2-sided 0.2 significance level (SL), then 2 pairwise comparisons of E + P vs E or P were conducted. Statistical significance was claimed if both pairwise and global null hypotheses were rejected at a 2-sided 0.05 SL. Results A total of 240 non-squamous pts (Male, 34.6%; East Asian, 55.4%; ECOG PS 0-1, 92.9%) were included. A statistically significant difference in PFS was found across the 3 arms (global p = 0.003), with E + P significantly better than both single agents (HR (95% CI) for E + P vs E was 0.57 (0.40, 0.81), p = 0.002; for E + P vs P was 0.58 (0.39, 0.85), p = 0.005). Median PFS (95% CI) was 7.4 months (4.4, 12.9) in E + P, 3.8 (2.7, 6.3) in E and 4.4 (3.0, 6.0) in P. Safety analyses showed a higher number of pts with ≥1 TEAE with CTCAE grade 3/4 toxicity in E + P (n = 45; 60.0%) than in P (n = 10; 28.9%) or E (n = 22; 12.0%), the majority being neutropenia, anemia, rash and diarrhea. Conclusions Erlotinib + Pemetrexed significantly improved PFS compared to either agent alone in this clinically selected population. E + P had more toxicity, but was clinically manageable. Further analysis of the EGFR mutational status will help to understand and predict which pts will benefit most from this approach. Disclosure X. Wang: I am employee of Eli Lilly and Company. S. Altug: I am employee of, and hold stock/stock options in, Eli Lilly and Company. M. Orlando: “I am employed by and hold stock in Eli Lilly & Company”. All other authors have declared no conflicts of interest.

The 18p11.22 locus is associated with never smoker non-small cell lung cancer susceptibility in Korean populations

The proportion of never smoker non-small cell lung cancer (NSCLC) in Asia is about 30-40%. Despite the striking demographics and high prevalence of never smoker NSCLC, the exact causes still remain undetermined. Although several genome wide association (GWA) studies were conducted to find susceptibility loci for lung cancer in never smokers, no regions were replicated except for 5p15.33, suggesting locus heterogeneity and different environmental toxic effects. To identify genetic loci associated with susceptibility of lung cancer in never smokers, we performed a GWA analysis using the Affymetrix 6.0 SNP array. For discovery GWA set, we recruited 446 never smoking Korean patients with NSCLC and 497 normal subjects. We tested association of SNPs with lung cancer susceptibility using the Cochran-Armitage trend test. For validation, 39 SNPs were selected from the top 50 SNPs and five additional SNPs were selected in the DAB1 gene region which showed significant associations in the GWA analysis. The validation SNPs were genotyped in an independent sample including 434 patients and 1,000 controls. Among the 44 validation SNPs, two SNPs (rs11080466 and rs11663246) near the APCDD1, NAPG and FAM38B genes in the 18p11.22 region were replicated. P value of rs11080466 was 1.08 × 10(-6) in the combined sets (2.68 × 10(-5) in the discovery set and 2.60 × 10(-3) in the validation set) and odds ratio was 0.68 (0.58-0.79). We observed similar association for rs11663246. Our result suggests the 18p11.22 region as a novel lung cancer susceptibility locus in never smokers.

XPC mRNA Level May Predict Relapse in Never-smokers with Non-Small Cell Lung Cancers

Disease recurrence and distant metastasis are the major causes of death in resected non-small cell lung cancer (NSCLC). The prognostic marker for never-smokers with this disease remains to be identified. To improve patient outcome, establishing an adjacent molecular marker to predict relapse of NSCLC in never-smokers is needed. Three hundred two lung tumors from NSCLC patients and normal lung tissues from 68 noncancer subjects were enrolled to evaluate XPC (xeroderma pigmentosum group C) mRNA expression by quantitative real-time reverse transcriptase polymerase chain reaction. Receiver operating characteristic curve analysis was used to search for a feasible cutoff point of XPC mRNA levels for predicting recurrence-free survival. Of the 326 patients, 214 were confirmed as only receiving surgical resection. Kaplan-Meier and multivariate Cox regression analysis were used to assess the prognostic value of XPC mRNA level in lung tumors from patients who only received surgical resection. Receiver operating characteristic curve analysis indicated 30.28 as a cutoff point, and thus 150 and 64 tumors with low- and high-XPC mRNA expression were categorized in this study population. Low-XPC mRNA appeared with more frequency in never-smokers and in late-stage (stage II-III) disease than smokers and early-stage disease (stage I). Kaplan-Meier analysis indicated that patients with low-XPC mRNA had shorter recurrence-free survival than that found in never-smokers (P = 0.002), but not in smokers (P = 0.296). Cox regression analysis further revealed that low-XPC mRNA may independently predict relapse in lung cancer of never-smokers (hazard ratio 2.34, 95% confidence interval 1.21-4.51, P = 0.011). Low-XPC mRNA may predict relapse in lung cancer patients who are never-smokers.

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

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

Miliary Never-Smoking Adenocarcinoma of the Lung: Strong Association with Epidermal Growth Factor Receptor Exon 19 Deletion

Miliary pattern of pulmonary metastases is a rarity in patients with lung cancer. We report five cases of patients with a never-smoking adenocarcinoma of the lung with such a pattern of metastases. In the tumor cells of all five patients, epidermal growth factor receptor (EGFR) mutation gene sequencing identified a deletion in exon 19 of the EGFR gene, and all five patients had a dramatic response to EGFR tyrosine kinase inhibitors. No echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) translocation was detected. We believe that the miliary never-soking adenocarcinoma of the lung is a distinct clinically relevant subgroup of the never-smoking non-small cell lung cancer. Physician should recognize this subgroup of patients with lung cancer when facing a picture of miliary pulmonary metastases in chest x-ray or computed tomography scan in patients with a history of never smoking and consider upfront therapy with EGFR tyrosine kinase inhibitors.

Nonsmall cell lung cancer in never smokers

To summarize the available knowledge about nonsmall cell lung cancer (NSCLC) in never smokers in terms of biological and clinical-pathological findings. Overall in newly diagnosed NSCLC, 10% of men and 20% of women, with a much higher proportion among Asiatic women, are never smokers and among them an overwhelming proportion have adenocarcinoma. Several environmental, genetic, hormonal and viral factors have been associated with an increased risk of NSCLC in never smokers, but for none of them there is definitive evidence. The incidence of epidermal growth factor receptor mutations is higher in never smokers, whereas K-ras mutations are rarely detected in this group of never smoking patients. The role of never smoking status in NSCLC as a positive prognostic factor or predictive of a better chemosensitivity to systemic treatments is still undefined. Epidemiological, molecular and clinical-pathological features indicate NSCLC in never smokers as a distinct entity. Future preclinical studies should address more deeply the biological differences between NSCLC in smokers and never smokers and, to avoid biased results due to differences in survival outcomes, smoking status should be considered among stratification factors in future clinical studies.

Never‐smoking nonsmall cell lung cancer as a separate entity

To propose 'never-smoking nonsmall cell lung cancer (NSCLC)' as a separate entity, the clinicopathologic differences of operable NSCLC between never-smoking patients and patients with a history of smoking were investigated. The medical records of 1405 patients with primary NSCLC who underwent a complete resection at the study institution from 1974 through 2004 were reviewed for clinicopathologic variables and postoperative survival. The proportion of never-smoking patients with NSCLC has been significantly increasing over 30 years, from 15.9% in the 1970s to 32.8% in the 2000s. A significantly greater proportion of female patients or adenocarcinoma patients was found in the 'never-smoking NSCLC' group in comparison to the 'smoking NSCLC' group (85.8% vs 11.2% and 87.8% vs 49.1%, respectively). The proportion of pathologic stage IA disease for the 'never-smoking NSCLC' group was significantly higher than that for the 'smoking NSCLC' group (40.1% vs 25.4%; P < .0001). With regard to both overall and cancer-specific survival, the 'never-smoking NSCLC' patient group was significantly superior to the 'smoking NSCLC' group. In addition to smoking status, the factors found to be significantly associated with the postoperative survival rate were sex, histologic type, T classification, and N classification by univariate analyses. A multivariate analysis revealed never-smoking status to be an independent prognostic factor in addition to pathologic T and N classification. The differences in the clinicopathologic factors and survivals between the 'never-smoking NSCLC' patient group and the 'smoking NSCLC' group suggest that NSCLC in never-smokers should be considered a separate disease entity.

Surgical results of non-small cell lung cancer in never-smokers as a separate entity

7505 Background: Recent information about epidermal growth factor receptor gene mutations suggests that there are two etiologically different forms of lung cancer based on the smoking status. In order to propose ‘never-smoking non-small cell lung cancer (NSLC)‘ as a separate entity, the clinico-pathologic differences of operable NSLC between never smoking patients and patients with a history of smoking were investigated. Methods: The medical records of 1405 patients with primary NSLC who underwent a complete resection at our institution from 1974 through 2004 were reviewed for the clinico-pathologic variables and postoperative survival. Results: The proportion of never-smoking patients with NSLC has been significantly increasing over 30 years from 15.9% in the 1970's to 32.8% in the 2000's. A significantly greater proportion of female patients or adenocarcinoma patients was found in the ‘never-smoking NSLC‘ group in comparison to the ‘smoking NSLC’ group (85.8% vs. 11.2%; 87.8% vs. 49.1%, respectively). The distribution of the pathologic T status was significantly different between the never-smoking NSLC group and the smoking NSLC group (more T1 patients in the never-smoking NSLC group), although that of the pathologic N status was not different. In both the overall and cancer-specific survivals, the ‘never-smoking NSLC’ patient group was significantly superior to the ‘smoking NSLC’ group. In addition to the smoking status, the factors significantly associated with the postoperative survival rate were gender, histologic type, T-status and N-status by the univariate analyses. A multivariate analysis revealed the never-smoking status to be an independent prognostic factor, besides a pathologic T and N status. Conclusions: From now on, ‘never-smoking NSLC’ should therefore be both clinically and basically investigated as a distinct entity from ‘smoking-associated NSLC’. No significant financial relationships to disclose.

Clinical and biological effects of gefitinib in EGFR FISH positive/phospho-akt positive or never smoker non-small cell lung cancer (NSCLC): Preliminary results of the ONCOBELL trial

7023 Background: Effectiveness of gefitinib, a tyrosine kinase inhibitor of the epidermal growth factor receptor (EGFR), in never smokers and/or EGFR FISH positive NSCLC patients has been evaluated only in retrospective studies and few data exist on the biological effects of gefitinib therapy in tumor samples. Methods: The ONCOBELL trial is a multicenter prospective phase II study designed to include 39 patients EGFR FISH positive/phospho-Akt (p-AKT) positive and/or never smokers with advanced or metastatic NSCLC. Gefitinib is given at the daily dose of 250 mg. When feasible, primary tumor biopsy was repeated immediately before therapy, during therapy and at progression. Specimens were evaluated for EGFR and HER2 gene copy number by FISH, EGFR gene mutation by DNA sequencing, and EGFR and p-AKT protein expression by immunohistochemistry. Results: Data from the first 28 enrolled patients are available: median age was 60 years (range, 43–80); male/female: 7/21; stage IIIB/IV: 2/26; ECOG PS 0/1/2: 18/6/4; 25 patients had a diagnosis of adenocarcinoma and/or bronchioloalveolar carcinoma; 13 patients had brain metastases, and in 10 cases gefitinib was offered as first-line therapy. Twenty-four patients were never smokers and 19 were EGFR FISH positive. Overall response rate was 54%, including 1 complete and 14 partial responses. Median time to progression was 6.45 months, and median survival was not reached. Response to therapy was not influenced by previous therapies or presence of brain metastases. Toxicity was mild, and consisted in grade 1–2 skin rash (68%) and diarrhea (57%). One patient developed grade 3 diarrhea and another patient was hospitalized for acute interstitial lung disease. In patients exposed to previous chemotherapy, no difference in EGFR or HER2 FISH results were observed in specimens collected at the time of original diagnosis compared to specimens collected immediately before gefitinib therapy. In 14 cases primary tumor biopsy was repeated during gefitinib therapy. Conclusions: These preliminary data indicate that gefitinib is highly effective in patients with trial characteristics. Clinical and biological data for the entire cohort will be available in June 2006. No significant financial relationships to disclose.