Risk factors for lung cancer in young adults

Tackling Non-Small Cell Lung Cancer in Young Adults: From Risk Factors and Genetic Susceptibility to Lung Cancer Profile and Outcomes

Lung cancer has traditionally been associated with advanced age; however, its increasing incidence among young adults raises concerning questions regarding its etiology and unique considerations for this population. In contrast to the older population, the onset of lung cancer at younger age may be attributed to a complex interplay of incompletely understood individual susceptibility and prevalent environmental risk factors beyond tobacco smoke exposure, such as radon gas and air pollution, which are widespread globally. Consequently, this leads to distinct clinical and molecular profiles, requiring a tailored approach. Furthermore, a diagnosis of cancer represents a threatening event during the prime years of a young person's life, prompting concern about career development, social aspects, fertility aspirations, and physical independence. This poses significant additional challenges for health care professionals in a field that remains underexplored. This comprehensive review recognizes lung cancer in young adults as a distinct entity, exploring its clinical and molecular characteristics, diverse predisposing factors, and priorities in terms of quality of life, with the aim of providing practical support to oncologists and enhancing our understanding of this under-researched population.

Risk factors for early-onset lung cancer in Korea: analysis of a nationally representative population-based cohort

OBJECTIVES

We examined the associations of socioeconomic factors, health behaviors, and comorbidities with early-onset lung cancer.

METHODS

The study included 6,794,287 individuals aged 20-39 years who participated in a Korean national health check-up program from 2009 to 2012. During the follow-up period, 4,684 participants developed lung cancer. Multivariable Cox regression analysis was used to estimate the independent associations of potential risk factors with incident lung cancer.

RESULTS

Older age (multivariable hazard ratio [mHR], 1.13; 95% confidence interval [CI], 1.12 to 1.14) and female sex (mHR, 1.62; 95% CI, 1.49 to 1.75) were associated with increased lung cancer risk. Current smoking was also associated with elevated risk (<10 pack-years: mHR, 1.12; 95% CI, 1.01 to 1.24; ≥10 pack-years: mHR, 1.30; 95% CI, 1.18 to 1.45), but past smoking was not. Although mild alcohol consumption (<10 g/day) was associated with lower lung cancer risk (mHR, 0.92; 95% CI, 0.86 to 0.99), heavier alcohol consumption (≥10 g/day) was not. Higher income (highest vs. lowest quartile: mHR, 0.86; 95% CI, 0.78 to 0.94), physical activity for at least 1,500 metabolic equivalent of task-min/wk (vs. non-exercisers: mHR, 0.83; 95% CI, 0.69 to 0.99) and obesity (vs. normal weight: mHR, 0.89; 95% CI, 0.83 to 0.96) were associated with lower lung cancer risk, whereas metabolic syndrome was associated with increased risk (mHR, 1.13; 95% CI, 1.03 to 1.24).

CONCLUSIONS

In young adults, age, female sex, smoking, and metabolic syndrome were risk factors for early-onset lung cancer, while high income, physical activity, and obesity displayed protective effects.

Association between a family history of cancer and multiple primary lung cancer risks: a population-based analysis from China

OBJECTIVES

The incidence of multiple primary lung cancer (MPLC) has increased in recent years. The risk factors of MPLC are not well studied, especially in the Asian population. This case-control study investigated the association between a family history of cancer and MPLC risk.

METHODS

We used data from people who surgically confirmed MPLC with at least 2 nodes of Fujian Medical University Union Hospital and matched 1:2 normal individuals as controls between 2016 and 2017. Information on age, sex, lifestyle, personal history, and family history of cancer was collected using a self-administered questionnaire, and odds ratios (OR) were estimated using unconditional logistic regression.

RESULTS

We included 2 104 patients. In total, 321 patients with histologically confirmed MPLC and 642 healthy controls were studied. The significantly higher ratio of current smokers was observed for the cases than the controls (54.1% vs. 30.0%). A family history of LC in first-degree relatives of the cases reported a significantly higher proportion than in the controls (15.3% vs. 8.6%). Family history of all cancers and LC significantly increased the risk of MPLC (OR = 1.64, P = 0.009 and OR = 2.59, P = 0.000, respectively). The multivariate analysis identified a significantly increased risk of MPLC (OR = 2.45, P = 0.000) associated with parents and siblings influenced by LC history. The younger age (aged < 55 years) of LC cases at diagnosis exhibited a significantly increased risk of MPLC (OR = 2.39, P = 0.000). A significant association with a family history of LC was found for male squamous carcinoma and male adenocarcinoma (OR = 1.59, p = 0.037 and OR = 1.64, p = 0.032, respectively). A positive association with LC history was only observed for female adenocarcinoma (OR = 2.23, p = 0.028). The risk of MPLC was not significantly associated with A family history of cancers in non-smokers (OR = 0.91, P = 0.236). Ever-smokers with a positive family history of cancer or LC had a significantly elevated risk of MPLC (OR = 4.01, P = 0.000 and OR = 6.49, P = 0.000, respectively). We also observed a very elevated risk for smokers with no family history (OR = 3.49, P = 0.000). Such a positive association was also observed in ever-smokers with no family history of LC (OR = 3.55, P = 0.000). Adenocarcinoma in females was prevalent and significantly associated with a family history of LC in risk of MPLC compared with other histologic subtypes.

CONCLUSIONS

Our findings suggest an association between a family history of LC and MPLC risk among an Asian population. Smoking status and family history of LC have a synergistic effect on MPLC. These findings indicate that MPLC exhibits familiar aggregation and that inherited genetic susceptibility may contribute to the development of MPLC.

Lung Cancer Screening in Asia: An Expert Consensus Report

INTRODUCTION

The incidence and mortality of lung cancer are highest in Asia compared with Europe and USA, with the incidence and mortality rates being 34.4 and 28.1 per 100,000 respectively in East Asia. Diagnosing lung cancer at early stages makes the disease amenable to curative treatment and reduces mortality. In some areas in Asia, limited availability of robust diagnostic tools and treatment modalities, along with variations in specific health care investment and policies, make it necessary to have a more specific approach for screening, early detection, diagnosis, and treatment of patients with lung cancer in Asia compared with the West.

METHOD

A group of 19 advisors across different specialties from 11 Asian countries, met on a virtual Steering Committee meeting, to discuss and recommend the most affordable and accessible lung cancer screening modalities and their implementation, for the Asian population.

RESULTS

Significant risk factors identified for lung cancer in smokers in Asia include age 50 to 75 years and smoking history of more than or equal to 20 pack-years. Family history is the most common risk factor for nonsmokers. Low-dose computed tomography screening is recommended once a year for patients with screening-detected abnormality and persistent exposure to risk factors. However, for high-risk heavy smokers and nonsmokers with risk factors, reassessment scans are recommended at an initial interval of 6 to 12 months with subsequent lengthening of reassessment intervals, and it should be stopped in patients more than 80 years of age or are unable or unwilling to undergo curative treatment.

CONCLUSIONS

Asian countries face several challenges in implementing low-dose computed tomography screening, such as economic limitations, lack of efforts for early detection, and lack of specific government programs. Various strategies are suggested to overcome these challenges in Asia.

Risk of Presenting with Poor-Prognosis Metastatic Cancer in Adolescents and Young Adults: A Population-Based Study

Having metastatic disease at diagnosis poses the great risk of death among AYAs with cancer from all sociodemographic subgroups. This “landscape” study utilized United States Surveillance, Epidemiology, and End Results Program data from 2000−2016 to identify subgroups of AYAs at highest risk for presenting with metastases across twelve cancer sites having a poor-prognosis (5-year survival <50% with metastases). Adjusted odds ratios for risk of metastatic disease presentation were compared for AYAs in aggregate and by sociodemographic subgroup (race/ethnicity, sex, socioeconomic status [SES]). In general, AYAs who were male, racial/ethnic minorities, or low SES were at consistently greatest risk of metastases. Strikingly, having metastatic melanoma was independently associated with multiple AYA sociodemographic subgroups, including males (aOR 3.11 [95% CI 2.64−3.66]), non-Hispanic Blacks (4.04 [2.32−7.04]), Asian Pacific Islanders (2.99 [1.75−5.12]), Hispanics (2.37 [1.85−3.04]), and low SES (2.30 [1.89−2.80]). Non-Hispanic Blacks were more likely to present with metastatic cancer in all sites, except for bone, rhabdomyosarcoma, and stomach. Low SES AYAs are more likely to present with metastatic melanoma, bone tumors, soft tissue sarcomas, breast, cervical, lung, and stomach carcinomas. Building on these results, future cancer-specific studies should investigate the connection between sociodemographic risk factors and biological drivers of metastases. This line of research has potential to inform targeted public health and screening efforts to facilitate risk reduction and earlier detection of these deadly diseases.

Health effects associated with smoking: a Burden of Proof study

As a leading behavioral risk factor for numerous health outcomes, smoking is a major ongoing public health challenge. Although evidence on the health effects of smoking has been widely reported, few attempts have evaluated the dose-response relationship between smoking and a diverse range of health outcomes systematically and comprehensively. In the present study, we re-estimated the dose-response relationships between current smoking and 36 health outcomes by conducting systematic reviews up to 31 May 2022, employing a meta-analytic method that incorporates between-study heterogeneity into estimates of uncertainty. Among the 36 selected outcomes, 8 had strong-to-very-strong evidence of an association with smoking, 21 had weak-to-moderate evidence of association and 7 had no evidence of association. By overcoming many of the limitations of traditional meta-analyses, our approach provides comprehensive, up-to-date and easy-to-use estimates of the evidence on the health effects of smoking. These estimates provide important information for tobacco control advocates, policy makers, researchers, physicians, smokers and the public.

Older patients more likely to die from cancer-related diseases than younger with stage IA non-small cell lung cancer: a SEER database analysis

Background

Various reports showed some conflicting data on survival at different ages. This study aimed to investigate the main cause of death in older patients with lung cancer and to perform a comparison with younger patients in order to observe the differences between these two cohorts.

Methods

Outcomes of patients with stage IA non-small cell lung cancer (NSCLC) ≤3 cm who underwent lobectomy without induction therapy in the Surveillance, Epidemiology, and End Results-18 (SEER-18; January 2004 to December 2016) database were evaluated using multivariable Cox proportional hazards modeling and propensity score-matched analysis.

Results

A total of 16,672 eligible NSCLC cases were found in the SEER database. The number of patients aged ≤60, 61–70, and ≥71 years was 3,930, 6,391, and 6,351, respectively. Among these patient groups, 527 (13.4%), 1,018 (15.9%), and 1,235 (19.4%) died of lung cancer during follow-up, while 357 (9.1%), 964 (15.1%) and 1,579 (25.2%) died of non-lung cancer diseases, respectively. The overall survival (OS) and lung cancer-specific survival (LCSS) rates of younger patients showed a significant survival advantage over older patients. After propensity-score matching (PSM) of patients aged ≤60 and ≥71 years using a ratio of 1:1, we found that 403 (12.9%) and 584 (18.7%) patients in the ≤60 and ≥71 years age groups died of lung cancer, respectively. The OS and LCSS rates of younger patients still exhibited a significant survival advantage over older patients.

Conclusions

Older patients with stage IA NSCLC have a worse prognosis compared with younger patients. Also, cancer-related causes were more frequent in older patients than non-cancer-related causes.

Association between family history and lung cancer risk among Chinese women in Singapore

Risk factors of lung cancer unrelated to smoking are not well-studied, especially among women. Family history has been shown to play a role in predisposing individuals to lung cancer, but this relationship has not been investigated in the Southeast Asian population. A total of 1159 women were recruited in a case-control study conducted in public hospitals in Singapore from 2005 to 2008. After excluding participants with incomplete family history information, 374 cases and 785 controls remained in the final analysis. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated using logistic regression, adjusting for potential confounders. Overall, family history of lung cancer was associated with a higher risk for lung cancer (aOR 2.08, 95% CI 1.25-3.47). When stratified by smoking status, a significant association was observed among never-smokers (aOR 2.78, 95% CI 1.57-4.90). Further stratification by fruit consumption identified a significant association between family history of lung cancer and higher risk of lung cancer among never-smokers who had low fruit consumption (aOR 3.09, 95% CI 1.37-7.01). Our findings suggest that family history of lung cancer is a significant risk factor for lung cancer in Singaporean Chinese women, especially among never-smokers.

Association between family history of lung cancer and lung cancer risk: a systematic review and meta-analysis

BACKGROUND

Familial risk of lung cancer has been widely studied but the effects of sociodemographic factors and geographical regions are largely unknown.

METHODS

PubMed and Embase were systematically searched until 1^st October 2019. A total of 84 articles were identified and (19 cohort and 66 case control studies) included in this systematic review and meta-analysis. Pooled summary estimates and 95% confidence intervals were estimated, and the analysis was stratified by sociodemographic factors and geographical regions.

RESULTS

Geographical regions, sex, age of proband, smoking status, type of first-degree relatives, number of affected relatives, and early onset of lung cancer in affected relatives were significant determinants of familial risk of lung cancer. Higher risk of familial lung cancer was found among Asians as compared to non-Asians, younger individuals (age≤50) as compared with older individuals (age>50), individuals with ≥2 affected relatives as compared with individuals with one affected relative, ever-smokers as compared with never-smokers, Asian females as compared with Western females, and never-smokers in Asia as compared with never-smokers in the West.

CONCLUSIONS

Familial risk of lung cancer is influenced by both genetic and environmental factors. Future studies should control for environmental factors such as air pollution and environmental tobacco smoke which are prevalent in Asia.

Single-nucleotide polymorphism rs17548629 in RIPK1 gene may be associated with lung cancer in a young and middle-aged Han Chinese population

Background

Genetic biomarkers of lung cancer (LC) susceptibility may provide a basis for treatment and prevention. This study analyzed an association between SNPs (single nucleotide polymorphisms) in the complementary region of the 3′-UTR (3′ untranslated region) of microRNAs of the gene RIPK1 (receptor-interacting serine/threonine-protein kinase 1) and LC among an adult Han Chinese population aged younger than 60 years. Also explored the effect of regulation of the RIPK1 gene via rs17548629 and microRNA-1197 on the occurrence of LC.

Methods

RIPK1 variants (rs17548629, rs77736895) were determined in a population of 571 adults (younger than 60 years) with LC, and 609 gender- and age-matched healthy individuals. Bioinformatics methods predicted the microRNAs bound to rs17548629. Dual luciferase reporter assay was performed to confirm the presence of both rs17548629 and the predicted microRNA.

Results

A mutation (T) of rs17548629 was associated with an increased risk for LC in this population under the codominant and recessive genetic models. The risk of lung adenocarcinoma in rs17548629 mutant carriers was 1.769-fold higher than that of the wildtype. In vitro, the luciferase activity of co-transfected mutant psiCHECK2-RIPK1 and microRNA-1197 mimics was less than that of the group transfected with microRNA-1197 mimics only. Factorial analysis indicated interactions between microRNA-1197 mimics and genotypes of rs17548629.

Conclusion

A mutation (T) of rs17548629 may increase the risk of LC/lung adenocarcinoma in adult Han populations younger than 60 years. When carrying the T allele, rs17548629 may be the target of hsa-miR-1197. This mutation may affect transcriptional level of the RIPK1, thereby promoting the occurrence of LC.

Young age increases risk for lymph node positivity but decreases risk for non-small cell lung cancer death

Non-small cell lung cancer (NSCLC) prognosis and risk of lymph node positivity (LN+) are reference points for reasonable treatments. The aim of the current study was to investigate the effect of age on LN+ and NSCLC death. Data from the Surveillance, Epidemiology, and End Results (SEER) registry were used to identify 82,253 patients with NSCLC diagnosed between 1988 and 2008. All the patients underwent standard lung cancer surgery with lymph node examination. Demographic and clinicopathological parameters were extracted and compared among each age group. Impact of age on LN+ and NSCLC death was evaluated by the Cochran-Armitage trend test and logistic univariate and multivariate analyses for all T stages. Overall, 22,711 (27.60%) patients of the entirety had lymph node metastasis and 28,968 (35.22%) patients died of NSCLC within 5 years. With the increase in age, LN+ rates decreased regardless of T stages (P<0.001), whereas NSCLC-specific mortality increased in stages T1-T3 (P<0.001). Controlling other covariates in multivariable logistic regression, age remained an independent risk factor for LN+ in all T stages (P<0.05) and in stages T1-T3 (P<0.05). Our SEER analysis demonstrated a higher rate of LN+ and lower mortality in younger patients with NSCLC, after accounting for other covariates.

Characteristics, survival, and risk factors of Chinese young lung cancer patients: the experience from two institutions

Limited data is available regarding lung cancer in Chinese young adults. This study was aimed to determine the characteristics, survival, and prognostic factors of young lung cancer patients in China. We reviewed demographic and clinical data, and survival information of 420 young patients (20-45 years old) diagnosed with lung cancer in two Chinese hospitals between 2000 and 2013. The results showed that lung cancer occurred more frequently (70%) and affected more males than females (43.8% vs 26.7%) in patients older than 36; whereas, more females were affected under age 35 (16.7% vs 12.8%). Most patients had adenocarcinoma (67.6%) and stage IV disease (72.4%) at presentation. The median survival of all young patients with lung cancer was 44 months (95% CI: 39-49), of which patients with stage I-IIIA disease had a longer survival than those with stage IIIB/IV disease (101 vs 22 months, p < 0.001). No significant difference in survival was found in patients having different histological subtypes or genders. Multivariate analysis revealed that high exposure risk occupations, smoking, family history of lung cancer were risk factors of young lung cancer patients. This study provides an overview of the clinical characteristics, patterns and prognostic factors of young patients with lung cancer in China.

Gene-set meta-analysis of lung cancer identifies pathway related to systemic lupus erythematosus

INTRODUCTION

Gene-set analysis (GSA) is an approach using the results of single-marker genome-wide association studies when investigating pathways as a whole with respect to the genetic basis of a disease.

METHODS

We performed a meta-analysis of seven GSAs for lung cancer, applying the method META-GSA. Overall, the information taken from 11,365 cases and 22,505 controls from within the TRICL/ILCCO consortia was used to investigate a total of 234 pathways from the Kyoto Encyclopedia of Genes and Genomes (KEGG) database.

RESULTS

META-GSA reveals the systemic lupus erythematosus KEGG pathway hsa05322, driven by the gene region 6p21-22, as also implicated in lung cancer (p = 0.0306). This gene region is known to be associated with squamous cell lung carcinoma. The most important genes driving the significance of this pathway belong to the genomic areas HIST1-H4L, -1BN, -2BN, -H2AK, -H4K and C2/C4A/C4B. Within these areas, the markers most significantly associated with LC are rs13194781 (located within HIST12BN) and rs1270942 (located between C2 and C4A).

CONCLUSIONS

We have discovered a pathway currently marked as specific to systemic lupus erythematosus as being significantly implicated in lung cancer. The gene region 6p21-22 in this pathway appears to be more extensively associated with lung cancer than previously assumed. Given wide-stretched linkage disequilibrium to the area APOM/BAG6/MSH5, there is currently simply not enough information or evidence to conclude whether the potential pleiotropy of lung cancer and systemic lupus erythematosus is spurious, biological, or mediated. Further research into this pathway and gene region will be necessary.

Non-Small Cell Lung Cancer in a Very Young Woman: A Case Report and Critical Review of the Literature

BACKGROUND

Lung cancer in young patients is quite uncommon; clinical presentation and outcome in this population compared to the older group are not yet well defined and data about this setting are mostly single-institutional retrospective analyses.

CASE REPORT

We report here a case of a very young woman with diagnosis of early-stage lung adenocarcinoma harboring EML4-ALK rearrangement; she underwent radical surgery and adjuvant chemotherapy according to the pathologic stage. Potential risk factors for lung cancer in our patient are discussed and clinico-pathologic features and outcomes of lung cancer in the young population compared to the elderly are reviewed through discussing studies with sample sizes larger than 100 patients.

CONCLUSIONS

A wide clinical overview should be performed when lung cancer is diagnosed in a young patient. Large-population studies are required to define the molecular signature and clinical behavior of lung cancer in young patients.

Non-small cell lung cancer in young adults: presentation and survival in the English National Lung Cancer Audit

BACKGROUND

Non-small cell lung cancer (NSCLC) in young adults is a rare but devastating illness with significant socioeconomic implications, and studies of this patient subgroup are limited.

AIM

This study employed the National Lung Cancer Audit to compare the clinical features and survival of young adults with NSCLC with the older age groups.

DESIGN

A retrospective cohort review using a validated national audit dataset.

METHODS

Data were analysed for the period between 1 January 2004 and 31 December 2011. Young adults were defined as between 18 and 39 years, and all others were divided into decade age groups, up to the 80 years and above group. We performed logistic and Cox regression analyses to assess clinical outcomes.

RESULTS

Of a total of 1 46 422 patients, 651 (0.5%) were young adults, of whom a higher proportion had adenocarcinoma (48%) than in any other age group. Stage distribution of NSCLC was similar across the age groups and 71% of young patients had stage IIIb/IV. Performance status (PS) was 0-1 for 85%. Young adults were more likely to have surgery and chemotherapy compared with the older age groups and had better overall and post-operative survival. The proportion with adenocarcinoma, better PS and that receiving surgery or chemotherapy diminished progressively with advancing decade age groups.

CONCLUSION

In our cohort of young adults with NSCLC, the majority had good PS despite the same late-stage disease as older patients. They were more likely to have treatment and survive longer than older patients.

Effect of smoking on survival from non-small cell lung cancer: a retrospective Veterans' Affairs Central Cancer Registry (VACCR) cohort analysis

Although a well-established risk factor for lung cancer, the impact of smoking on the survival of non-small cell lung cancer (NSCLC) is not well known. We performed a retrospective analysis of the Veteran's Affairs Comprehensive Cancer Registry of NSCLC patients. Smoking status was categorized as never smoker, past smoker and current smoker based on self-reported history. Multivariate analysis was performed to evaluate the impact of smoking on overall survival (OS) from NSCLC. The study population (n = 61,440) comprised predominantly of males (98 %) and Caucasians (81 %). The median age at diagnosis was 68 years (range 22-108 years). Current smokers were diagnosed with NSCLC at a younger age (65 years) compared to never smokers (71 years) and past smokers (72 years) (p < 0.001). On multivariate analysis, current smokers (n = 34,613) [Hazard ratio (HR) 1.059; 95 % confidence interval (CI) 1.012-1.108], but not past smokers (n = 23,864) (HR 1.008; 95 % CI 0.962-1.056), had worse OS for Stage III and IV NSCLC, compared to never smokers (n = 2,963). Smoking status was not prognostic in stages I and II NSCLC. Current smokers were diagnosed with NSCLC at a younger age than never smokers. Although current smoking was associated with worse prognosis, especially in stages III and IV, the impact of smoking status on OS was modest.

Long-term mortality in patients with pulmonary and extrapulmonary tuberculosis: a Danish nationwide cohort study

BACKGROUND

Long-term mortality and causes of death in patients with pulmonary tuberculosis (PTB) and extrapulmonary tuberculosis (EPTB) are poorly documented. In this study, long-term mortality and causes of death in PTB and EPTB patients were compared with the background population and it was investigated whether mortality was associated with family-related risk factors.

METHODS

A NATIONWIDE COHORT STUDY WAS CONDUCTED INCLUDING: all adult Danes notified with PTB or EPTB from 1977 to 2008 and alive 1 year after diagnosis; a randomly selected comparison cohort matched on birth date and sex; adult siblings of PTB patients; and population controls. Data were extracted from national registries. All-cause and cause-specific mortality rate ratios were calculated for patients and siblings and compared with their respective control cohorts. A total of 8,291 patients (6,402 PTB and 1,889 EPTB), 24,873 population controls, 1,990 siblings of PTB patients and 11,679 siblings of PTB population controls were included.

RESULTS

Overall, the mortality rate ratio was 1.86 (95% confidence interval [CI] 1.77-1.96) for PTB patients and 1.24 (95% CI 1.12-1.37) for EPTB patients. Both patient cohorts had significantly increased risk of death due to infectious diseases and diabetes. Further, the PTB patients had increased mortality due to cancers (mainly respiratory and gastrointestinal tract), liver and respiratory system diseases, and alcohol and drug abuse. The PTB patients had increased mortality compared with their siblings (mortality rate ratio 3.55; 95% CI 2.57-4.91) as did the siblings of the PTB patients compared with the siblings of population controls (mortality rate ratio 2.16; 95% CI 1.62-2.87).

CONCLUSION

We conclude that adult PTB patients have an almost two-fold increased long-term mortality whereas EPTB patients have a slightly increased long-term mortality compared with the background population. The increased long-term mortality in PTB patients stems from diseases associated with alcohol, tobacco, and drug abuse as well as immune suppression, and family-related factors.

Surgery for non-small cell lung cancer in younger patients: what are the differences?

BACKGROUND

Non-small cell lung cancer (NSCLC) in young adults is uncommon. The objective of this study was to evaluate the clinicopathological characteristics, outcomes and prognosis of people younger than 50 years old treated surgically for NSCLC.

METHODS

A retrospective study was conducted using the institutional database of four thoracic surgery units to collect patients with NSCLC younger than 50 years who had undergone surgery. These patients were compared with older patients (>75-years) operated in the same institutions and in the same period.

RESULTS

We identified 113 young patients and 347 older patients. Younger patients were more likely to be female, non-smokers, with fewer comorbidities. Younger patients were more likely to be symptomatic at the time of diagnosis. Risk factors for poor prognosis in younger patients were T-stage, and disease-free-interval less than 548 days. Kaplan-Meier analysis showed a lower five-year survival in older patients compared with the younger ones (66% vs 38%, p=0.001).

CONCLUSIONS

In conclusion NSCLC in younger patients has some distinct clinicopathological characteristics. The overall-survival of young patients is better than in older patients. Young patients receive more complete and aggressive treatment that could explain better survival. Further prospective studies with larger patient populations are required, to clarify the biological and genetic variance of NSCLC in younger patients.

Genetic factors in individual radiation sensitivity

Cancer risk and radiation sensitivity are often associated with alterations in DNA repair, cell cycle, or apoptotic pathways. Interindividual variability in mutagen or radiation sensitivity and in cancer susceptibility may also be traced back to polymorphisms of genes affecting e.g. DNA repair capacity. We studied possible associations between 70 polymorphisms of 12 DNA repair genes with basal and initial DNA damage and with repair thereof. We investigated DNA damage induced by ionizing radiation in lymphocytes isolated from 177 young lung cancer patients and 169 cancer-free controls. We also sought replication of our findings in an independent sample of 175 families (in total 798 individuals). DNA damage was assessed by the Olive tail moment (OTM) of the comet assay. DNA repair capacity (DRC) was determined for 10, 30 and, 60min of repair. Genes involved in the single-strand-repair pathway (SSR; like XRCC1 and MSH2) as well as genes involved in the double-strand-repair pathway (DSR; like RAD50, XRCC4, MRE11 and ATM) were found to be associated with DNA damage. The most significant association was observed for marker rs3213334 (p=0.005) of XRCC1 with basal DNA damage (B), in both cases and controls. A clear additive effect on the logarithm of OTM was identified for the marker rs1001581 of the same LD-block (p=0.039): BCC=-1.06 (95%-CI: -1.16 to -0.96), BCT=-1.02 (95%-CI: -1.11 to -0.93) and BTT=-0.85 (95%-CI: -1.01 to -0.68). In both cases and controls, we observed significantly higher DNA basal damage (p=0.007) for carriers of the genotype AA of marker rs2237060 of RAD50 (involved in DSR). However, this could not be replicated in the sample of families (p=0.781). An alteration to DRC after 30min of repair with respect to cases was observed as borderline significant for marker rs611646 of ATM (involved in DSR; p=0.055), but was the most significant finding in the sample of families (p=0.009). Our data indicate that gene variation impacts measurably on DNA damage and repair, suggesting at least a partial contribution to radiation sensitivity and lung cancer susceptibility.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Increased risk of lung cancer in individuals with a family history of the disease: a pooled analysis from the International Lung Cancer Consortium

BACKGROUND AND METHODS

Familial aggregation of lung cancer exists after accounting for cigarette smoking. However, the extent to which family history affects risk by smoking status, histology, relative type and ethnicity is not well described. This pooled analysis included 24 case-control studies in the International Lung Cancer Consortium. Each study collected age of onset/interview, gender, race/ethnicity, cigarette smoking, histology and first-degree family history of lung cancer. Data from 24,380 lung cancer cases and 23,305 healthy controls were analysed. Unconditional logistic regression models and generalised estimating equations were used to estimate odds ratios and 95% confidence intervals.

RESULTS

Individuals with a first-degree relative with lung cancer had a 1.51-fold increase in the risk of lung cancer, after adjustment for smoking and other potential confounders (95% CI: 1.39, 1.63). The association was strongest for those with a family history in a sibling, after adjustment (odds ratios (OR) = 1.82, 95% CI: 1.62, 2.05). No modifying effect by histologic type was found. Never smokers showed a lower association with positive familial history of lung cancer (OR = 1.25, 95% CI: 1.03, 1.52), slightly stronger for those with an affected sibling (OR = 1.44, 95% CI: 1.07, 1.93), after adjustment.

CONCLUSIONS

The occurrence of lung cancer among never smokers and similar magnitudes of the effect of family history on lung cancer risk across histological types suggests familial aggregation of lung cancer is independent of those risks associated with cigarette smoking. While the role of genetic variation in the aetiology of lung cancer remains to be fully characterised, family history assessment is immediately available and those with a positive history represent a higher risk group.

Cigarette Smoking and Lung Cancer: Pediatric Roots

A vast array of data suggests that early age of smoking onset enhances the risk for development of lung cancer in adulthood. Initiation of smoking at a young age may influence the development of lung cancer because of its effect on duration of smoking. Early onset of smoking also may serve as an independent risk factor. It may increase the likelihood that smoking occurs during a critical period of development that enhances susceptibility to the adverse effects of cancer causing agents in cigarette smoke, thereby facilitating the initiation of the carcinogenic process. While evidence for the latter hypothesis derives from a variety of sources, definitive proof has proven elusive. Whether or not early age of smoking serves as an independent risk factor for lung carcinogenesis, the consensus of the public health community is that prevention of smoking onset at a young age and early cessation are keys to stemming the current lung cancer pandemic. Population approaches to tobacco prevention and control, such as measures contained in the World Health Organization Framework Convention Tobacco Control Treaty, offer the best opportunity, on the scale needed, to create a smoke-free world and bring an end to the pandemic of tobacco-related disease.

Heritability of radiation response in lung cancer families

Radiation sensitivity is assumed to be a cancer susceptibility factor due to impaired DNA damage signalling and repair. Relevant genetic factors may also determine the observed familial aggregation of early onset lung cancer. We investigated the heritability of radiation sensitivity in families of 177 Caucasian cases of early onset lung cancer. In total 798 individuals were characterized for their radiation-induced DNA damage response. DNA damage analysis was performed by alkaline comet assay before and after in vitro irradiation of isolated lymphocytes. The cells were exposed to a dose of 4 Gy and allowed to repair induced DNA-damage up to 60 minutes. The primary outcome parameter Olive Tail Moment was the basis for heritability estimates. Heritability was highest for basal damage (without irradiation) 70% (95%-CI: 51%-88%) and initial damage (directly after irradiation) 65% (95%-CI: 47%-83%) and decreased to 20%-48% for the residual damage after different repair times. Hence our study supports the hypothesis that genomic instability represented by the basal DNA damage as well as radiation induced and repaired damage is highly heritable. Genes influencing genome instability and DNA repair are therefore of major interest for the etiology of lung cancer in the young. The comet assay represents a proper tool to investigate heritability of the radiation sensitive phenotype. Our results are in good agreement with other mutagen sensitivity assays.

Clinicopathological characteristics and prognosis of non-small cell lung cancer patients associated with a family history of lung cancer

INTRODUCTION

Clinicopathological characteristics and prognosis of non-small cell lung cancer (NSCLC) patients with a family history of lung cancer (FHLC) have not been well established.

METHODS

Clinical records of patients with NSCLC treated at our institute from 1982 to 2010 were reviewed with special reference to family history of lung cancer and clinicopathological factors including patient's outcome. Univariate analyses of the factors between the groups of FHLC and non-FHLC were performed using unpaired two-tailed t tests or the chi-square test. The Cox proportional hazards model was used to evaluate the hazard ratio of death.

RESULTS

Of the 1013 NSCLC patients, 124 (12.2%) had a FHLC of whom 119 (96%) were the first-degree relatives. The frequency of early stages of lung cancer was high in both groups of FHLC and non-FHLC patients. Patients with FHLC had a significantly higher frequency of early pathological stages and a prepomderance of adenocarcinoma, and a hazard ratio of death of 0.870 (95% confidence interval: 0.599-1.263, p value: 0.465) compared with the non-FHLC patients.

CONCLUSIONS

NSCLC patients with FHLC could be characterized by early pathological stages and preponderance of adenocarcinoma, however they were not at a decreased hazard ratio of death. These findings emphasize the importance of early detection of lung cancer and employment of less invasive therapeutic interventions.

The impact of positive cancer family history on the clinical features and outcome of patients with non-small cell lung cancer

The purpose of this study is to investigate the impact of positive cancer/lung cancer family history (FH) on clinical features and outcome in non-small cell lung cancer (NSCLC) patients. We analyzed 4,491 NSCLC patients with NSCLC who presented from January 1999-December 2005. Chi-square test and Wilcoxon test were used for univariate comparisons, while Cox Proportional Hazards regression analysis was performed to evaluate the adjusted risk of death. Univariate probability of survival was calculated using Kaplan-Meier estimate and compared using the log-rank test. Of 4,491 patients, 579 patients (12.89%) had positive FH, including 233 patients (5.19%) with FH of lung cancer. Patients with positive lung cancer FH, compared to those with negative FH, were diagnosed at earlier age (57 vs. 60; P < 0.001), presented more cases of adenocarcinoma (58.80 vs. 50.69%; P = 0.016), and at more advanced stage (Stage IIIB/IV 45.74 vs. 36.79%; P < 0.001). These differences were also detected in patients with positive cancer FH. In addition, more females and non-smokers were among patients with positive cancer FH (30.05 vs. 26.15%; P = 0.045 and 39.90 vs. 33.82%; P = 0.008, respectively). Furthermore, patients with advanced cancer (stage IIIB/IV) who had positive FH had lower response rate to chemotherapy (CR&PR 24.68 vs. 34.42%; P = 0.024). Nevertheless, patients with positive lung cancer FH had better prognosis (P = 0.015), especially if diagnosed at an early stage (P = 0.035), and their adjusted relative risk of death was lower (RR 0.69; 95% CI: 0.51-0.93; P = 0.015). Definite epidemiologic and survival differences exist between NSCLC patients with positive or negative FH of cancer. Our results suggest that cancer FH is an important factor of clinical features, and could serve as a prognostic indicator for NSCLC.

The WST survival assay: an easy and reliable method to screen radiation-sensitive individuals

An easy, fast and reliable method was developed to screen hundreds of Epstein-Barr virus-transformed cell lines (lymphoblastoid cell lines, LCLs) for radiation sensitivity that were generated from lymphocytes isolated from young lung cancer patients. The WST-1 test explores the metabolic activity of the mitochondria as an indicator for the vital status of cells. Cell proliferation as well as indirect cell death can be quantified by this method on a large scale in microtiter plates. Cell survival was measured at 24- and 48-h post-irradiation with 10 Gy ((137)Cs source) by the WST-1 assay and Trypan blue staining. To set up the experimental screening conditions and to establish a positive and a negative control, an ATM-mutated cell line from a radiation-sensitive ATM patient and an ATM proficient cell line from a healthy brother were compared. An optimal differentiation between the two cell lines was demonstrated for 10 Gy and 24- and 48-h cell growth after irradiation. Upon screening 120 LCLs of young lung cancer patients under these conditions, 5 of them were found to be radiation sensitive to a high degree of statistical significance. The results have been confirmed by a second laboratory by means of Trypan blue testing. The WST-1 test represents an efficient and reliable method by means of screening for radiation-sensitive cell lines.

Smoking reduces survival in young females with lung adenocarcinoma after curative resection

The aim of this study was to investigate effects of smoking on the overall survival of young female lung adenocarcinoma patients after curative resection. A total of 282 surgically treated young females (younger than 40) with histologically confirmed primary lung adenocarcinoma were studied retrospectively. Overall survivals (OS) and related prognostic factors were analyzed. The 5-year OS of current-smokers and non-smokers were 20 and 36.6%, respectively (P = 0.03). As for patients with stage I disease, the 5-year OS of current-smokers and non-smokers were 50 and 68.8%, respectively, (P = 0.02). Smoking (RR = 3.15, CI 1.726-8.786) was identified as an independent prognostic factor. Current-smokers (21.4 vs. 14.5%, P = 0.03) and non-smokers (37.9 vs. 28.8%, P = 0.02) all benefited from adjuvant chemotherapy. Among young female patients with adenocarcinoma, current-smokers have a lower survival rate than non-smokers, especially patients with stage I disease.

[Systematic review of the relationship between family history of lung cancer and lung cancer risk]

背景与目的

四十多年前Tokuhata和Lilienfeld首次从流行病学的角度证实肺癌的家族聚集现象。随后的多个研究也证实了家族聚集现象是肺癌危险性的一个家族性成分，但研究结果并不完全一致。本研究旨在进一步分析和评价一级亲属患肺癌者在肺癌发生中的作用。

方法

检索PubMed、CENTRAL、中国生物医学文献数据库系统（CBM）、中国期刊全文数据库（CNKI）、中文科技期刊全文数据库（VIP）等收集国内外公开发表的肺癌家族聚集性的病例对照研究。采用RevMan version 4.2统计软件对各研究结果进行分析，计算其合并优势比和95%可信区间。

结果

纳入合并分析的文献共有28篇，分析结果表明：肺癌先证家系一级亲属患肺癌的风险是对照家系一级亲属的1.88倍（P < 0.001)。分层分析，先证家系的父亲、母亲及兄弟姐妹患肺癌的风险分别是对照家系的1.62倍（P < 0.001）、1.96倍（P < 0.001）和1.92倍（P < 0.001）；吸烟和非吸烟先证者一级亲属患肺癌的风险分别是对照组中吸烟者和非吸烟者一级亲属患肺癌的1.73倍（P < 0.001）和1.42倍（P=0.02）；女性和男性肺癌先证者一级亲属患肺癌的风险性分别是对照组中女性和男性一级亲属患肺癌的1.89倍（P < 0.001）和1.99倍（P < 0.001）。

结论

先证家系一级亲属患肺癌的风险性增加，肺癌存在明显的家族聚集现象。

Family history and lung cancer risk: international multicentre case-control study in Eastern and Central Europe and meta-analyses

Lung cancer is the most common neoplastic disease in Eastern and Central Europe. The role of hereditary factors in lung carcinogenesis is not fully understood. Family history (FH) of lung cancer and other tobacco-related cancers might be a strong predictor of the lung cancer risk. We investigated family history of cancer among first-degree relatives of 2,861 patients with lung cancer and 3,118 controls from the Czech Republic, Hungary, Poland, Romania, Russia, Slovakia, and United Kingdom within the IARC Multicenter Case-Control Study. Odds ratios (ORs) and 95% CI were calculated using logistic regression, adjusting for age, gender, study center, education, tobacco smoking, and number of first-degree relatives. In addition, we conducted a meta-analysis of 41 studies on FH of cancer and lung cancer risk. Positive FH of lung cancer increased risk of lung cancer with OR of 1.63 (95%CI: 1.31-2.01), and having two or more affected relatives with lung cancer further increased the risk of lung cancer with OR 3.60 (95%CI: 1.56-8.31). Among subjects aged less than 50, the OR for FH of lung cancer was 2.08 (95%CI: 1.18-3.63). The associations were generally stronger for squamous cell carcinoma and large cell carcinoma subtypes. Heterogeneity in results was not found with respect to smoking status and gender. A significant association was not observed for FH of other smoking-related tumors. The results of meta-analysis were consistent with that of our study with regard to young onset, non-smokers and histology. FH of lung cancer is a predictor of an increased risk of lung cancer, especially in subjects aged less than 50.

Measles virus: evidence for association with lung cancer

In recent years the frequency of nonsmokers among lung cancer patients has increased to 10% to 15%. The measles virus has rarely been evoked as an etiological agent in malignant tumors and its role in carcinogenesis remains doubtful. It has been suggested that measles virus phosphoprotein may inhibit ubiquitination of Pirh2, which has been reported to be overexpressed in lung carcinoma and is responsible for degrading the cell cycle regulator p53. The authors conducted a clinicopathological study of newly diagnosed patients with non-small cell lung carcinoma of all stages seen in a 10-year period. Immunohistochemical studies for measles virus antigens, p53, and Pirh2 were performed using the avidin-biotin peroxidase complex. The authors found expression of measles virus antigens in 54 of 65 cases of non-small cell lung carcinoma. This finding is associated with the older age of the patients and with expression of Pirh2. The presence of Pirh2 itself was associated with improved survival.

Family history of cancer and nonmalignant lung diseases as risk factors for lung cancer

Family history (FH) of lung cancer is an established risk factor for lung cancer, but the modifying effect of smoking in relatives has been rarely examined. Also, the role of FH of nonmalignant lung diseases on lung cancer risk is not well known. We examined the role of FH of cancer and nonmalignant lung diseases in lung cancer risk overall, and by personal smoking, FH of smoking and histology in 1,946 cases and 2,116 population-based controls within the Environment And Genetics in Lung cancer Etiology (EAGLE) study. Odds ratios (ORs) and 95% CI from logistic regression were calculated adjusting for age, gender, residence, education and cigarette smoking. FH of lung cancer in any family member was associated with increased lung cancer risk (OR = 1.57, 95% CI = 1.25-1.98). The odds associated with fathers', mothers' and siblings' history of lung cancer were 1.41, 2.14 and 1.53, respectively. The associations were generally stronger in never smokers, younger subjects and for the adenocarcinoma and squamous cell carcinoma subtypes. FH of chronic bronchitis and pneumonia was associated with increased (OR = 1.49, 95% CI = 1.23-1.80) and decreased (OR = 0.73, 95% CI = 0.61-0.87) lung cancer risk, respectively. FH of lung cancer and nonmalignant lung diseases affected lung cancer risk independently, and did not appear to be modified by FH of smoking.

Cancer diagnosis in first-degree relatives and non-small cell lung cancer risk: results from a multi-centre case-control study in Europe

Because aggregation of cancers at different sites can occur in families, cancer could be considered as a broad phenotype with shared genetic factors. Here, we report results from a multi-centre case-control study of non-small cell lung cancer (NSCLC), with particular emphasis on a history of cancer in first-degree relatives and the risk of lung cancer. From 2002 to 2006, 733 NSCLC patients treated surgically were recruited in 8 European countries and matched to 1312 controls, by centre, sex and age. We used multivariate conditional logistic regression models to test the association between a history of cancer in first-degree relatives and risk of NSCLC. A family history of lung cancer was associated with an odds ratio (OR) for early-onset (54 years or younger) NSCLC of 4.72 (95% confidence interval [CI]=1.02-21.90). A family history of gastric cancer was associated with an OR for NSCLC of 1.82 (95% CI=1.08-3.06) and for late-onset (55 years or older) NSCLC of 2.92 (95% CI=1.10-7.75). Our findings provide further evidence of a familial predisposition to lung cancer and support the hypothesis that family history is a significant risk factor for the disease. Because of the inherent potential for bias in familial case-control study design, cautious interpretation is warranted.

Matrix metalloproteinase 1 (MMP1) is associated with early-onset lung cancer

Matrix metalloproteinases (MMP) play a key role in the breakdown of extracellular matrix and in inflammatory processes. MMP1 is the most highly expressed interstitial collagenase degrading fibrillar collagens. Overexpression of MMP1 has been shown in tumor tissues and has been suggested to be associated with tumor invasion and metastasis. Nine haplotype tagging and additional two intronic single nucleotide polymorphisms (SNP) of MMP1 were genotyped in a case control sample, consisting of 635 lung cancer cases with onset of disease below 51 years of age and 1,300 age- and sex-matched cancer-free controls. Two regions of linkage disequilibrium (LD) of MMP1 could be observed: a region of low LD comprising the 5' region including the promoter and a region of high LD starting from exon 1 to the end of the gene and including the 3' flanking region. Several SNPs were identified to be individually significantly associated with risk of early-onset lung cancer. The most significant effect was seen for rs1938901 (P = 0.0089), rs193008 (P = 0.0108), and rs996999 (P = 0.0459). For rs996999, significance vanished after correction for multiple testing. For each of these SNPs, the major allele was associated with an increase in risk with an odds ratio between 1.2 and 1.3 (95% confidence interval, 1.0-1.5). The haplotype analysis supported these findings, especially for subgroups with high smoking intensity. In summary, we identified MMP1 to be associated with an increased risk for lung cancer, which was modified by smoking.

Association of positive family history with survival of patients with lung cancer

BACKGROUND

Risk factors for development of lung cancer include a family history of the disease. The effect of family history on lung cancer outcomes is unknown. A study was conducted to investigate this.

METHODS

The medical records of all patients with lung cancer seen in an academic medical oncology lung cancer clinic between 1999 and 2006 were reviewed for outcomes and family history of lung cancer. chi(2)-test and Wilcoxon test were used for univariate comparisons, while Cox Proportional Hazards regression analysis was used to evaluate the adjusted risk of death. Univariate probability of survival was computed using Kaplan-Meier estimate and compared using the log-rank test.

RESULTS

Of the 560 patients evaluated, 289 (51%) were male and 519 (93%) had a smoking history. Of the 148 patients (26%) with a family history of lung cancer, 115 had an affected first-degree relative. No association between family history and histology or stage at diagnosis was detected. Median survival in patients with a family history of lung cancer was 53 months compared to 58 months in patients without such a history (p=0.06). Patients with a positive family history had an adjusted relative risk of death of 1.65 (95% CI: 1.07-2.56; p=0.02) compared to those without a family history. This risk was especially increased in those with an affected first-degree relative (RR: 1.72; 95% CI: 1.08-2.75, p=0.02).

CONCLUSIONS

Lung cancer patients with a first-degree relative with lung cancer have a poorer outcome than those without such a history.

Family history of cancer and risk of lung cancer among nonsmoking Chinese women

The relationship between family cancer history in first-degree relatives and risk of lung cancer was evaluated among a population-based cohort of 71,392 female nonsmokers in Shanghai, China. A total of 179 newly diagnosed lung cancer patients were identified during 441,410 person-years of follow-up. Lung cancer risk was not elevated among those with a family history of lung cancer. However, risk of lung cancer was increased among subjects who had two or more first-degree relatives with any type of cancers {rate ratio [RR], 1.95 [95% confidence intervals (95% CI), 1.08-3.54] for two relatives with any cancers and RR, 3.17 [95% CI, 1.00-10.03] for three or more relatives with any cancer}. Having a family history of colorectal cancer (RR, 2.38; 95% CI, 1.21-4.70) and having siblings with stomach cancer (RR, 2.16; 95% CI, 1.01-4.65) and pancreatic cancer (RR, 4.19; 95% CI, 1.04-16.95) were also found to be associated with lung cancer risk. This cohort study indicated a moderate association of lung cancer risk with a family cancer history in general, but not with a family history of lung cancer specifically. The associations were stronger when a sibling, rather than a parent, was affected. The apparent link between lung cancer risk and a family history of colorectal, stomach, and pancreas cancers may be worth further investigation.

Do genetic factors protect for early onset lung cancer? A case control study before the age of 50 years

BACKGROUND

Early onset lung cancer shows some familial aggregation, pointing to a genetic predisposition. This study was set up to investigate the role of candidate genes in the susceptibility to lung cancer patients younger than 51 years at diagnosis.

METHODS

246 patients with a primary, histologically or cytologically confirmed neoplasm, recruited from 2000 to 2003 in major lung clinics across Germany, were matched to 223 unrelated healthy controls. 11 single nucleotide polymorphisms of genes with reported associations to lung cancer have been genotyped.

RESULTS

Genetic associations or gene-smoking interactions was found for GPX1(Pro200Leu) and EPHX1(His113Tyr). Carriers of the Leu-allele of GPX1(Pro200Leu) showed a significant risk reduction of OR = 0.6 (95% CI: 0.4-0.8, p = 0.002) in general and of OR = 0.3 (95% CI:0.1-0.8, p = 0.012) within heavy smokers. We could also find a risk decreasing genetic effect for His-carriers of EPHX1(His113Tyr) for moderate smokers (OR = 0.2, 95% CI:0.1-0.7, p = 0.012). Considered both variants together, a monotone decrease of the OR was found for smokers (OR of 0.20; 95% CI: 0.07-0.60) for each protective allele.

CONCLUSION

Smoking is the most important risk factor for young lung cancer patients. However, this study provides some support for the T-Allel of GPX1(Pro200Leu) and the C-Allele of EPHX1(His113Tyr) to play a protective role in early onset lung cancer susceptibility.

Aggregation of cancer among relatives of never-smoking lung cancer patients

The authors evaluated the familial aggregation of lung and other cancers in first-degree relatives of lung cancer patients self-reported to be lifetime never smokers. The data, derived from a large lung cancer case-control study, included 2,465 first-degree relatives of 316 never smoker lung cancer cases and 2,441 first-degree relatives of 318 never smoker controls, frequency matched to the cases on age, gender and ethnicity. The median age of the cases and the controls was 61 years, about 2/3 were women, and about 80% were Caucasian. Overall, there was a 25% excess risk [95% CI (1.05-1.50)] of any type of cancer among the first-degree relatives of cases, and case offspring exhibited a 2-fold excess cancer risk (1.03-4.10) compared with control offspring. There was also a 44% excess risk (1.05-1.97) of young onset cancers (before age 50) among relatives of cases. Smoking case relatives had an increased risk of any cancer [odds ratio (OR) = 1.36 (1.03-1.81)] and a 5.52-fold risk (1.19-25.51) of young onset lung cancer compared with smoking control relatives. Female case relatives had a 58% excess breast cancer risk (1.04-2.43), and case mothers a 2.57-fold breast cancer risk (1.16-4.24). A significant excess of testicular cancer was observed among case male relatives [OR = 12.32 (1.71-88.90)], although based on only 9 cases. The age at lung cancer diagnosis tended to be earlier in case relatives (61.4, SD = 12.9) compared with control relatives (66.2, SD = 11.4; p = 0.07). Our analysis provides further evidence for the importance of genetic factors for lung cancer in never smokers.

Lung cancer disparities in African Americans: health versus health care

African Americans with lung cancer have disproportionately worse outcomes than other ethnic groups. The incidence of lung cancer in blacks has remained well above the rates seen for the general population and the 5-year and overall survival rates for blacks with lung cancer are among the lowest of all racial groups. Many studies have focused on socioeconomic status of African Americans as the sole cause of these disparities. Other stu-dies, however, have identified additional factors related to risks for poor outcomes in blacks with lung cancer. This article reviews data on these risks and their relationships to the health and health care of African Americans with lung cancer.

Association Between Lung Cancer Incidence and Family History of Lung Cancer

STUDY OBJECTIVES

To clarify the possibility of a hereditary predisposition to lung cancer, we investigated the association between a family history of lung cancer and subsequent risk of lung cancer in a large-scale, population-based cohort study.

DESIGN

We investigated 102,255 middle-aged and older Japanese subjects (48,834 men and 53,421 women) with 13-year follow-up. A total of 791 cases of lung cancer were newly diagnosed during the follow-up period.

RESULTS

A family history of lung cancer in a first-degree relative was associated with a significantly increased risk of lung cancer (hazard ratio [HR], 1.95; 95% confidence interval [CI], 1.31 to 2.88). The association was stronger in women than in men (HR, 2.65; 95% CI, 1.40 to 5.01 and HR, 1.69; 95% CI, 1.03 to 2.78, respectively), and in never-smokers than in current smokers (HR, 2.48; 95% CI, 1.27 to 4.84 and HR, 1.73; 95% CI, 0.99 to 3.00, respectively). In addition, family history was more strongly associated with the risk of squamous cell carcinoma than with other histologic types (HR, 2.79; 95% CI, 1.37 to 5.68), while no clear increase in risk was observed in adenocarcinoma and small cell carcinoma. A family history of overall cancer was not associated with an increased risk of lung cancer.

CONCLUSIONS

These results suggest that those with a family history of lung cancer are more likely to acquire lung cancer themselves.

Family history and risk of lung cancer: age-at-diagnosis in cases and first-degree relatives

To investigate the little known risk of lung cancer at an early age when a first-degree relative has had such a diagnosis, 579 incident cases and 1157 population controls were studied in Liverpool between 1998 and 2004 using standardised questionnaires covering demography and lifestyle. A history of lung cancer in first-degree relatives was associated with a significantly increased risk in the proband where in both individuals the cancers were diagnosed before the age of 60 years (odds ratio (OR)=4.89; 95% confidence interval (CI): 1.47–16.25). A significantly elevated risk of lung cancer was also observed in association with a relative affected before the age of 60 years, regardless of age-at-onset of the disease (OR=2.08; 95% CI: 1.20–3.59). This finding is strongly consistent with a genetic component in early-onset lung cancer risk.