Abstract Rationale Rural populations in the US experience a higher lung cancer burden compared to urban residents, potentially due to differences in risk factors and access to preventative care and early detection. We sought to characterize tobacco use, smoking cessation, and lung cancer screening patterns by rurality to identify modifiable gaps in the lung cancer care continuum. Methods We analyzed data from current and former smoking adults in the Southern Community Cohort Study, a large prospective cohort recruited from community health centers across 12 southeastern states. Participants aged 65-80 years with at least 9 months of Medicare Part A/B and less than 3 months of Part C coverage between 2014 and 2020 were included. Data were linked with the National Death Index and Medicare claims for outcome ascertainment. Rurality was defined using Rural-Urban Commuting Area (RUCA) codes. We compared demographic characteristics, smoking patterns, use of smoking cessation interventions, and receipt of low-dose computed tomography (LDCT) screening between rural and urban participants over time. Results Among 10,114 adults included (56% urban; 46% rural), 54% were female, 55% identified as Black/African American, about a third reported less than a high school education, and 45% lived in areas in the highest quartile of deprivation. Urban residents were of similar age (66 vs 67 years), and more likely to currently smoke (42% vs 35%), but had fewer baseline smoking pack-years (27 vs 30 pack-years) than rural residents. Approximately 2% died of lung cancer during follow-up. Using the USPSTF 2013 lung cancer screening criteria, 27% of urban and 26% of rural residents were eligible. This increased unevenly to 38% urban and 35% rural under the USPSTF 2021 criteria. LDCT uptake was low, increasing from 0% in 2014 to 6% in 2020 among screening-eligible participants. Use of cessation interventions was similarly low. Among current smoking participants, 7% received smoking cessation counseling, and 3% had a varenicline prescription. These patterns remained relatively stable over time, with no significant rural-urban differences in LDCT and cessation intervention use. Conclusion Despite modest differences in smoking prevalence and screening eligibility, we found comparable lung cancer mortality and similarly low utilization of LDCT and cessation interventions among rural and urban residents. Our findings suggest that, among people in lower socioeconomic groups, shared socioeconomic constraints may extend beyond the rural-urban divide. Further research is needed to understand how social determinants of health may be addressed to improve lung cancer outcomes across the screening continuum. This abstract is funded by: NIH
Abstract 5045: Patterns of tobacco use, cessation interventions, and lung cancer screening in rural vs. urban areas over time; a 10-year retrospective cohort study
Abstract Introduction: Lung cancer rates differ across rural and urban areas, but few studies have evaluated rural-urban differences across the risk-screening continuum. We examined smoking, cessation interventions, and lung cancer screening patterns across the rural-urban continuum in a geographically defined area over 10 years. Materials and Methods: A retrospective cohort study (2014-2023) was conducted using clinical data from the Rochester Epidemiology Project, derived from healthcare encounters in a 27-county region of the midwestern United States. Patients ages 40-80 were included. We used Rural-Urban Commuting Area codes to assign residence as urban, rural, or highly rural. We examined yearly smoking prevalence, cessation intervention (pharmacotherapy, counseling), and low-dose computed tomography (LDCT) lung cancer screening. Results: Over the 10-year study period, the sample size ranged from 305,530 to 340,411 people annually with 36-38% urban, 56-57% rural, and 6-7% highly rural. Current smoking prevalence declined from 14 to 12% over the 10-year period (range=12-16%; p=0.06) and was consistently lower in urban areas (range=10-14%) than rural (range=12-17.0%) and highly rural areas (range=12-18%; p=<0.001). Among individuals who currently smoked with no history of lung cancer, yearly smoking cessation intervention ranged from 16% to 23%, increasing over the 10-year period (p=<0.001). Cessation medication (varenicline, bupropion, or nicotine replacement) prescription consistently increased overall over time but remained higher in urban than rural and highly rural areas (p=<0.001). Cessation counseling rates also increased overall over time and were similar between urban and rural areas and lower in highly rural areas (p=<0.001). Among people who had ever-smoked aged 50-80 years with no diagnosis of lung cancer, LDCT screening increased from 0.0% to 3.1% over the study period. Increases were higher in urban areas (0.0-3.6%) and similar in rural and highly rural areas (0.0-2.8% and 0.0-2.9%, respectively; p=<0.001). Among people who currently smoked, LDCT screening also increased over the study period (0.0-6.4%), with higher increases in urban (0.1-8.0%) than rural (0.0-5.7%) or highly rural (0.1-6.1%) areas (p=<0.001). After the new screening guidelines in 2021, rates in all areas increased year-on-year. Conclusion: In this cohort, we found that smoking prevalence, cessation interventions, and lung cancer screening improved from 2014-2023 across the rural-urban continuum. Unfortunately, smoking prevalence remained higher and cessation interventions and screening rates lower in rural compared to urban areas. The persistent patterns underscore the need for strategies to overcome barriers for rural residents and improve lung cancer prevention and early detection in all areas. Citation Format: Brianna Tranby, Paul A. Decker, Jiang Ruoxiang, David Midthun, Lori C. Sakoda, Melinda C. Aldrich, Debra Friedman, Adoma Manful, Oindrila Bhattacharyya, Christi Patten, Chyke A. Doubeni. Patterns of tobacco use, cessation interventions, and lung cancer screening in rural vs. urban areas over time; a 10-year retrospective cohort study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5045.
Stratifying lung adenocarcinoma risk with multi-ancestry polygenic risk scores in East Asian never-smokers
Abstract Background Lung adenocarcinoma in never-smokers is a major public health burden, especially among East Asian women. Polygenic risk scores (PRSs) are promising for risk stratification but are primarily developed in European-ancestry populations. We aimed to develop and validate single- and multi-ancestry PRSs for East Asian never-smokers to improve lung adenocarcinoma risk prediction. Methods PRSs were developed using genome-wide association study summary statistics from East Asian (8002 cases; 20 782 controls) and European (2058 cases; 5575 controls) populations. Single-ancestry models included a PRS with 25 single nucleotide variants (PRS-25), PRS clumping and thresholding (CT), and LDpred2; multi-ancestry models included LDpred2 plus European PRS-128, PRS-CSx, and clumping and thresholding, super learning, empirical Bayes (CT-SLEB). Performance was evaluated in independent East Asian data from the Female Lung Cancer Consortium and externally validated in the Nanjing Lung Cancer Cohort. We assessed predictive accuracy via area under the curve operating procedure (AUC), with 10-year and (ages 30-80 years) absolute risks estimates. Results The best multi-ancestry PRS, using East Asian and European data via CT-SLEB, outperformed the best East Asian-only (LDpred2; AUC = 0.629, 95% confidence interval [CI] = 0.618 to 0.641), achieving an AUC of 0.640 (95% CI = 0.629 to 0.653) and odds ratio of 1.71 (95% CI = 1.61 to 1.82) per standard deviation increase. Nanjing Lung Cancer Cohort validation confirmed robust performance (AUC = 0.649, 95% CI = 0.623 to 0.676). The top 20% PRS group had a 3.92-fold higher lung adenocarcinoma risk than the bottom 20%. Further, the top 5% PRS group reached a 6.69% lifetime absolute risk. Notably, this group reached the average population 10-year lung adenocarcinoma risk at age 50 years (0.42%) by age 41 years, 9 years earlier. Conclusions Multi-ancestry PRS approaches enhance lung adenocarcinoma risk stratification in East Asian never-smokers, with consistent external validation, suggesting future clinical utility.
Lung Cancer in Ever- and Never-Smokers: Findings from Multi-Population GWAS Studies
Abstract Background: Clinical, molecular, and genetic epidemiology studies displayed remarkable differences between ever- and never-smoking lung cancer. Methods: We conducted a stratified multi-population (European, East Asian, and African descent) association study on 44,823 ever-smokers and 20,074 never-smokers to identify novel variants that were missed in the non-stratified analysis. Functional analysis including expression quantitative trait loci (eQTL) colocalization and DNA damage assays, and annotation studies were conducted to evaluate the functional roles of the variants. We further evaluated the impact of smoking quantity on lung cancer risk for the variants associated with ever-smoking lung cancer. Results: Five novel independent loci, GABRA4, intergenic region 12q24.33, LRRC4C, LINC01088, and LCNL1 were identified with the association at two or three populations (P < 5 × 10−8). Further functional analysis provided multiple lines of evidence suggesting the variants affect lung cancer risk through excessive DNA damage (GABRA4) or cis-regulation of gene expression (LCNL1). The risk of variants from 12 independent regions, including the well-known CHRNA5, associated with ever-smoking lung cancer was evaluated for never-smokers, light-smokers (packyear ≤ 20), and moderate-to-heavy-smokers (packyear > 20). Different risk patterns were observed for the variants among the different groups by smoking behavior. Conclusions: We identified novel variants associated with lung cancer in only ever- or never-smoking groups that were missed by prior main-effect association studies. Impact: Our study highlights the genetic heterogeneity between ever- and never-smoking lung cancer and provides etiologic insights into the complicated genetic architecture of this deadly cancer.
The intersection of neighborhood-level disadvantage and overall lung cancer survival.
6551 Background: Despite recent advances in lung cancer therapeutics leading to considerable improvement in survival, disparities continue to persist among socially disadvantaged populations. Although the reasons underlying this phenomenon are uncertain, we posit that neighborhood-level factors could play a role. Furthermore, neighborhood disadvantage may lead to epigenetic changes which promote malignant progression. This study aimed to determine the effects of neighborhood-deprivation index (NDI), a validated 13-factor-based measure, that combines income, education, employment, and housing in a neighborhood, on lung cancer mortality. Methods: A retrospective cohort study assessed the relationship of NDI with survival weighted by age, stage, and DNA methylation among biopsy-proven lung cancer from two U.S. medical centers, Johns Hopkins University and the University of Illinois Chicago, between 2008-2020. In our analysis, U.S.-standardized NDI values for each year of sample collection were computed at the U.S. census tract level and categorized into quartiles. Participants’ residential addresses were geocoded to U.S. census tracts and linked to NDI quartiles. DNA extraction from liquid biopsy samples was performed for quantification of DNA methylation. Results: The study included 184 lung cancer patients, with 89 in the low-deprivation group and 95 in the high-deprivation group. The high-deprivation group had a higher percentage of females (57% vs. 48%), a higher percentage of African Americans (AA) (50% vs. 36%), a lower pack-year smoking history (30 vs. 39 median pack-years), and a higher percentage with stage IV disease (28% vs. 20%) than the low-deprivation group. Overall, NDI was significantly higher among AA when compared with Whites (p=0.003) and associated with lung cancer stage at diagnosis with an odds ratio of 1.17 (p=0.02). There was a significant correlation between DNA methylation and stage for HOXA7, SOX17, ZPF42, TAC1 and HOXA9. Only HOXA7 DNA methylation correlated with NDI (p=0.003).The high-deprivation group had a significantly shorter survival duration compared to the low-deprivation group, with a 1-year survival rate of 79% vs. 90%, a 2-year survival rate of 70% vs. 84%, and a 5-year-survival rate of 51% vs. 73% (p=0.02). After adjusting for age at diagnosis, stage, and DNA methylation status, belonging to the high-deprivation group was associated with a higher mortality risk with a hazard ratio of 2.02 (p=0.04). Conclusions: Neighborhood-level socioeconomic status and DNA methylation may be associated with late stage lung cancer at diagnosis; whereas NDI shows a potential association with shorter survival and increased mortality risk. Higher neighborhood deprivation among AA suggests that changes in health care policy that account for neighborhood-level indices of socioeconomic deprivation may enable more equitable improvement of lung cancer mortality.
Genome-wide analyses characterize shared heritability among cancers and identify novel cancer susceptibility regions
Abstract Background The shared inherited genetic contribution to risk of different cancers is not fully known. In this study, we leverage results from 12 cancer genome-wide association studies (GWAS) to quantify pairwise genome-wide genetic correlations across cancers and identify novel cancer susceptibility loci. Methods We collected GWAS summary statistics for 12 solid cancers based on 376 759 participants with cancer and 532 864 participants without cancer of European ancestry. The included cancer types were breast, colorectal, endometrial, esophageal, glioma, head and neck, lung, melanoma, ovarian, pancreatic, prostate, and renal cancers. We conducted cross-cancer GWAS and transcriptome-wide association studies to discover novel cancer susceptibility loci. Finally, we assessed the extent of variant-specific pleiotropy among cancers at known and newly identified cancer susceptibility loci. Results We observed widespread but modest genome-wide genetic correlations across cancers. In cross-cancer GWAS and transcriptome-wide association studies, we identified 15 novel cancer susceptibility loci. Additionally, we identified multiple variants at 77 distinct loci with strong evidence of being associated with at least 2 cancer types by testing for pleiotropy at known cancer susceptibility loci. Conclusions Overall, these results suggest that some genetic risk variants are shared among cancers, though much of cancer heritability is cancer-specific and thus tissue-specific. The increase in statistical power associated with larger sample sizes in cross-disease analysis allows for the identification of novel susceptibility regions. Future studies incorporating data on multiple cancer types are likely to identify additional regions associated with the risk of multiple cancer types.
Genome-wide interaction analysis identified low-frequency variants with sex disparity in lung cancer risk
Abstract Differences by sex in lung cancer incidence and mortality have been reported which cannot be fully explained by sex differences in smoking behavior, implying existence of genetic and molecular basis for sex disparity in lung cancer development. However, the information about sex dimorphism in lung cancer risk is quite limited despite the great success in lung cancer association studies. By adopting a stringent two-stage analysis strategy, we performed a genome-wide gene–sex interaction analysis using genotypes from a lung cancer cohort including ~ 47 000 individuals with European ancestry. Three low-frequency variants (minor allele frequency < 0.05), rs17662871 [odds ratio (OR) = 0.71, P = 4.29×10−8); rs79942605 (OR = 2.17, P = 2.81×10−8) and rs208908 (OR = 0.70, P = 4.54×10−8) were identified with different risk effect of lung cancer between men and women. Further expression quantitative trait loci and functional annotation analysis suggested rs208908 affects lung cancer risk through differential regulation of Coxsackie virus and adenovirus receptor gene expression in lung tissues between men and women. Our study is one of the first studies to provide novel insights about the genetic and molecular basis for sex disparity in lung cancer development.
Genome-wide interaction analysis identified low-frequency variants with sex disparity in lung cancer risk
Abstract There is growing evidence showing that sex disparity in lung cancer risk cannot be fully explained by sex differences in smoking behavior, implying existence of genetic and molecular basis for sex disparity in lung cancer development. However, the information about sex dimorphism in lung cancer risk is quite limited despite the great success in lung cancer association studies. By adopting a stringent two-stage analysis strategy, we performed a genome-wide gene-sex interaction analysis using genotype from a lung cancer cohort including ~ 47,000 individuals with European ancestry. Three low-frequency variants (minor allele frequency < 0.05), rs17662871 (OR=0.71, p=4.29x10-8); rs79942605 (OR=2.17, p=2.81x10-8); and rs208908 (OR=0.70, p=4.54x10-8), were identified with different risk effect of lung cancer between men and women. Further eQTL and functional annotation analysis suggested rs208908 affect lung cancer risk through differential regulation of CXADR (Coxsackie Virus And Adenovirus Receptor) gene expression in lung tissues between men and women. Our study is one of the first studies to provide novel insights about the genetic and molecular basis for sex disparity in lung cancer development.
Accuracy of FDG-PET to diagnose lung cancer in the ACOSOG Z4031 trial.
7008 Background: Fluoro-deoxyglucose positron emission tomography (FDG-PET) is recommended for diagnosis and staging of known or suspected NSCLC. Meta-analyses examining the accuracy of FDG-PET to diagnose lung cancer demonstrated high sensitivity 94% and specificity 83% but were performed in select centers. The purpose of this study is to evaluate the accuracy of FDG-PET to diagnose NSCLC and examine enrolling site differences in the national prospective ACOSOG Z4031 trial. Methods: 1,074 patients with clinical stage I (cT1-2N0M0) known or suspected NSCLC were enrolled between 2004 and 2006 in the Z4031 study and underwent surgical resection. The final diagnosis was determined by pathological examination. FDG-PET results were abstracted from radiology interpretations included in the case report forms. FDG-PET avidity was categorized based on either radiologist description or reported maximum standard uptake value (SUV). The four categories were: not avid and not cancerous (SUV=0), low avidity and likely not cancerous (SUV>0 and <2.5), avid and probably cancerous (SUV>2.5 and <5) and highly avid and likely cancerous (SUV>5). Sensitivity analysis of FDG-PET diagnostic accuracy was performed for varying levels of avidity and by preoperative lesion size. Differences in accuracy by enrolling site were examined. Results: There were 51 enrolling sites in 39 cities with 969 eligible participants. Preoperative FDG-PET results were available for 682 participants. Lung cancer prevalence was 83%. FDG-PET sensitivity was 82% (95% CI: 79-85), and specificity was 31% (95% CI: 23-40). Positive and negative predictive values were 85% and 26%, respectively and accuracy improved with lesion size. There were 80 false positive scans and 69% were granulomas. False negative scans occurred in 101 patients (11were ≤10mm) with adenocarcinoma, squamous, bronchoalveolar cell and neuroendocrine tumors responsible for 64%, 12%, 10% and 8% of false negative results, respectively. Specificity did not differ between the 8 sites with >25 patients (p=0.74). Conclusions: In a national surgical population with clinical stage I NSCLC, FDG-PET to diagnose lung cancer performed poorly compared to published studies. Reasons for poor test performance should be explored.
Abstract LB-296: FDG-PET avidity negatively impacts survival in pStage I NSCLC in the ACOSOG Z4031 trial.
Abstract Background: Fluoro-deoxyglucose positron emission tomography (FDG-PET) scans are used for diagnosis and staging of known or suspected non-small cell lung cancer (NSCLC). Single institution studies examining the impact of avidity on survival have reported mixed results. The purpose of this study is to evaluate the association between FDG-PET avidity and survival in the national prospective ACOSOG Z4031 trial in patients with pathological Stage I NSCLC. Methods: Between 2004 and 2006, 1074 patients with known or suspected clinical stage I (cT1-2N0M0) NSCLC were enrolled in the ACOSOG Z4031 trial and underwent surgical resection. FDG-PET results were abstracted from radiology interpretations included in the case report forms. FDG-PET avidity was categorized based on either radiologist description or reported maximum standard uptake value (SUV). The four categories were: 1) not avid and not cancerous (SUV=0), 2) low avidity and likely not cancerous (SUV>0 and <2.5), 3) avid and probably cancerous (SUV≥2.5 and <5) and 4) highly avid and likely cancerous (SUV≥5). The lesion was classified as avid if in categories 3 or 4. The final diagnosis was determined by pathological examination and all cause mortality was reported. Cox proportional hazard regression was used to assess the impact of FDG-PET avidity on survival. The covariates used in the model included pStage, gender, age, race, and preoperative lesion size. Kaplan-Meier survival curves were calculated and the log-rank test was used to determine differences in survival based on FDG-PET avidity. Results: There were 51 enrolling sites in 39 cities with 969 eligible participants. Preoperative FDG-PET results were available for 540 participants with NSCLC and 81% had FDG-PET avid or highly avid lesions. 400 patients had pStage I NSCLC and the 5 year survival was 70% with 95%CI (65%, 75%). FDG-PET avidity, male gender, age, and lesion size negatively impacted survival. FDG-PET avidity in pStage I disease still negatively impacted survival (p=0.03) when controlling for lesion size. The 5 year survival for Stage I disease was 80% with 95%CI (68%, 88%) in FDG-PET negative patients and 67% with 95% CI (61%, 72%) in FDG-PET positive patients (p=0.02). Conclusions: In a national surgical population with pathological stage I NSCLC, FDG-PET avidity negatively impacted five year survival, independently of lesion size. Further work should be done to determine if chemotherapy would be beneficial in patients with PET avid lesions and pStage I NSCLC. Citation Format: Eric L. Grogan, Stephen A. Deppen, Heidi Chen, Karla V. Ballman, Francys C. Verdial, Melinda C. Aldrich, Paul A. Decker, David H. Harpole, Robert J. Cerfolio, Robert J. Keenan, David R. Jones, Thomas A. D'Amico, Joseph B. Shrager, Bryan F. Meyers, Joe B. Putnam. FDG-PET avidity negatively impacts survival in pStage I NSCLC in the ACOSOG Z4031 trial. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-296. doi:10.1158/1538-7445.AM2013-LB-296