Hormone Use, Reproductive History, and Risk of Lung Cancer: The Women's Health Initiative Studies

Summary of the 2023 Thai Menopause Society Clinical Practice Guideline on Menopausal Hormone Therapy

The Thai Menopause Society is an academic organization consisting of healthcare professionals engaged in menopause medicine. The position statement was first issued in 1994 and updated in 2003 and 2023. Herein, we reviewed the important updates of the 2023 position statement on menopausal hormone therapy (MHT) as an international reference for healthcare professionals in Thailand. An advisory panel of clinicians and research experts in the field of menopause reviewed the recommendation of published International Consensus Statements and updated the evidence using the MEDLINE database through PubMed. The evidence-based information and relevant publications were assessed, and a consensus on recommendations was subsequently achieved using the level of evidence to determine the recommendation strength and evidence quality. MHT remains the most effective treatment for vasomotor symptoms and genitourinary syndromes of menopause even after 20 years. Additionally, it is effective in preventing bone loss and fractures in postmenopausal women. The cardiovascular risk of MHT increased in women who initiated MHT after 60 years of age. Hormone therapy should be individualized following the hormone type, dose, administration route, use duration, and progestogen inclusion. The necessary pretreatment evaluation and appropriate follow-up recommendations were added for improved MHT standard care. The updated 2023 Clinical Practice Guideline on MHT is useful for gynecologists, general physicians, endocrinologists, and other healthcare professionals in treating menopausal women receiving hormone therapy in Thailand.

Reproductive factors and risk of lung cancer among 300,000 Chinese female never-smokers: evidence from the China Kadoorie Biobank study

BACKGROUND

Lung cancer is the leading cause of cancer mortality among Chinese females despite the low smoking prevalence among this population. This study assessed the roles of reproductive factors in lung cancer development among Chinese female never-smokers.

METHODS

The prospective China Kadoorie Biobank (CKB) recruited over 0.5 million Chinese adults (0.3 million females) from 10 geographical areas in China in 2004-2008 when information on socio-demographic/lifestyle/environmental factors, physical measurements, medical history, and reproductive history collected through interviewer-administered questionnaires. Cox proportional hazard regression was used to estimate adjusted hazard ratios (HRs) of lung cancer by reproductive factors. Subgroup analyses by menopausal status, birth year, and geographical region were performed.

RESULTS

During a median follow-up of 11 years, 2,284 incident lung cancers occurred among 282,558 female never-smokers. Ever oral contraceptive use was associated with a higher risk of lung cancer (HR = 1.16, 95% CI: 1.02-1.33) with a significant increasing trend associated with longer duration of use (p-trend = 0.03). Longer average breastfeeding duration per child was associated with a decreased risk (0.86, 0.78-0.95) for > 12 months compared with those who breastfed for 7-12 months. No statistically significant association was detected between other reproductive factors and lung cancer risk.

CONCLUSION

Oral contraceptive use was associated with an increased risk of lung cancer in Chinese female never-smokers. Further studies are needed to assess lung cancer risk related to different types of oral contraceptives in similar populations.

Lung cancer in females-sex-based differences from males in epidemiology, biology, and outcomes: a narrative review

Background and Objective

The role of biological sex is seldom considered in characterizing lung cancer, the deadliest cancer in both the United States and the world. Lung cancer has traditionally been regarded as a male disease; as such, research in female-specific phenomena is frequently conflicting or absent. Currently, disparities in lung cancer incidence are primarily driven by females, especially non-smokers and those of younger age. This narrative review provides insight into sex-specific characteristics of lung cancer, highlighting risk factors, diagnosis patterns, carcinogenesis, and treatment outcomes in females.

Methods

The PubMed database was searched on July 26, 2023 to identify research published between 2013 and 2023 in English. Sixty-three articles were considered relevant, and their full texts and citations were studied to compile information for this narrative review.

Key Content and Findings

Exposure-related risk factors, including personal tobacco use, are thought to impact female lung cancer risk more profoundly. However, studies on occupational exposures are underpowered to conclude risk in females. Data characterizing the effect of endogenous and exogenous hormonal exposures on female lung cancer risk remain two-sided. Screening guidelines are tailored to white males, exacerbating sex and race disparities. The effect of biological sex on carcinogenesis and the immune system response to cancer is not fully understood, though the female immune system clearly reacts more aggressively to lung cancer. In early-stage disease, females have greater survival in the perioperative setting and during follow-up of several years, attributed to favorable histopathology and healthier baseline status. Sex-specific response to systemic treatment continues to be optimized as lack of standardization in randomized trials makes interpreting results difficult when aggregated.

Conclusions

Biological sex plays a critical role in non-small cell lung cancer (NSCLC), though further study is needed to depict the complex web of factors that affect lung cancer risk, development, and outcomes. Female underrepresentation in studies has contributed to this lack of understanding. As these disparities are eliminated, we can move towards more effective treatment for both sexes in this pervasive yet deadly disease.

Lung Cancer in Women: The Past, Present, and Future

Lung cancer is the leading cause of cancer death for women in multiple countries including the United States. Women are exposed to unique risk factors that remain largely understudied such as indoor pollution, second-hand tobacco exposure, biological differences, gender differences in tolerability and response to therapy in lung cancer, and societal gender roles, that create distinct survivorship needs. Women continue to lack representation in lung cancer clinical trials and are typically treated with data generated from majority male patient study populations, which may be inappropriate to extrapolate and generalize to females. Current lung cancer treatment and screening guidelines do not incorporate sex-specific differences and physicians also often do not account for gender differences when choosing treatments or discussing survivorship needs. To best provide targeted treatment approaches, greater representation of women in lung cancer clinical trials and further research is necessary. Clinicians should understand the unique factors and consequences associated with lung cancer in women; thus, a holistic approach that acknowledges environmental and societal factors is necessary.

Age at Menarche, age at Natural Menopause, and Risk of Lung and Colorectal Cancers: A Mendelian Randomization Study

Background

The roles of age at menarche and age at menopause in the etiology of lung and colorectal cancers are unclear.

Objective

We aimed to investigate potential causal associations between age at menarche, age at natural menopause, and risk of lung and colorectal cancers using a Mendelian randomization (MR) approach.

Methods

From the Trøndelag Health Study in Norway, we defined two cohorts of 35 477 and 17 118 women to study the effects of age at menarche and age at natural menopause, respectively. We ran univariable MR to evaluate the potential causal associations. We performed multivariable MR adjusting for genetic variants of adult body mass index (BMI) to estimate the direct effect of age at menarche.

Results

Genetically predicted 1-year increase in age at menarche was associated with a lower risk of lung cancer overall (hazard ratio [HR, 0.64; 95% CI, 0.48-0.86), lung adenocarcinoma (HR, 0.61; 95% CI, 0.38-0.99), and lung non-adenocarcinoma (HR, 0.66; 95% CI, 0.45-0.95). After adjusting for adult BMI using a multivariable MR model, the direct effect estimates reduced to HR 0.72 (95% CI, 0.54-0.95) for lung cancer overall, HR 0.67 (95% CI, 0.43-1.03) for lung adenocarcinoma, and HR 0.77 (95% CI, 0.54-1.09) for lung non-adenocarcinoma. Age at menarche was not associated with colorectal cancer. Moreover, genetically predicted age at natural menopause was not associated with lung and colorectal cancers.

Conclusion

Our MR study suggested that later age at menarche was causally associated with a decreased risk of lung cancer overall and its subtypes, and adult BMI might be a mediator.

Temporal trends of tracheal, bronchus, and lung cancer between 2010 and 2019, in Asian countries by geographical region and sociodemographic index, comparison with global data

BACKGROUND

This study aimed to describe the trends in incidence, mortality, and burden of tracheal, bronchial and lung (TBL) cancer in Asia from 2010 through 2019 and compare with global and other continental data.

METHODS

We collected TBL cancer data from the 2019 Global Burden of Disease (GBD) study from 2010 to 2019 in 49 countries and territories in Asia. For all locations, annual case data and age-standardized rates (ASRs) were used to investigate the incidence, prevalence, mortality, and disability-adjusted life-years (DALYs) of TBL from 2010 to 2019. The relative difference (%) between years was used to show comparative variations of ASRs for the indicators studied.

RESULTS

In 2019, more than 55% of TBL cancer cases and deaths occurred in Asian countries. A total of 57% of lung cancer patients lived in Asia and almost 60% of the global burden of lung cancer was imposed on Asian countries. From 2010 to 2019, incidences, deaths, prevalence cases, and DALYs number of TBL cancer increased over 1.34-, 1.31-, 1.31-, and 1.26-fold, in Asia. During this period, the age-standardized incidence rate (ASIR), the age-standardized death rate (ASDR), the age-standardized prevalence rate (ASPR), and the age-standardized DALYs rate (DALYs ASR) of TBL cancer decreased by 1, 3, 4, and 4%, respectively. While at the same time, the decreasing trend of these rates globally and in America and in Europe happened faster. In 2019, age-specific incidence, death, prevalence, and DALY cases of TBL cancer were peaking at 65-74, 70-74, 65-69, and 65-69 years, respectively. In 2019, the highest ASIR, ASDR, and DALYs ASR of TBL cancer was observed in East Asia countries and the highest ASPR in high-income Asia Pacific countries. Central Asia and high-income Asia Pacific countries experienced a decreasing trend in ASIR and ASDR, and the South Asia countries experienced the highest increasing trend from 2010 to 2019. ASPR only decreased in Central Asia, and DALYs ASR only increased in South Asia. In 2019, among high sociodemographic index (SDI) Asian countries, Brunei Darussalam had the highest ASIR, ASDR, and DALYs ASR and the Republic of Korea had the highest ASPR. Among high-middle SDIs, Turkey and Georgia; among middle SDIs, China and Armenia; among low-middle SDIs, Mongolia and the Democratic People's Republic of Korea had the highest ASIR, ASDR, ASPR, and DALY ASR of TBL cancer. Among low SDI Asian countries, Pakistan had the highest ASIR, ASDR, ASPR, and DALY ASR of TBL cancer.

CONCLUSION

Most of the global burden of lung cancer occurs in Asian countries, and the decreasing trend of incidence, death, prevalence, and burden of this cancer in these countries is slower than in other regions. Therefore, the implementation of necessary measures in order to reduce the process of this cancer is considered urgent.

Management of pulmonary nodules in women with pregnant intention: A review with perspective

The process for the management of pulmonary nodules in women with pregnant intention remains a challenge. There was a certain proportion of targeted female patients with high-risk lung cancer, and anxiety for suspicious lung cancer in early stage also exists. A comprehensive review of hereditary of lung cancer, effects of sexual hormone on lung cancer, natural history of pulmonary nodules, and computed tomography imaging with radiation exposure based on PubMed search was completed. The heredity of lung cancer and effects of sexual hormone on lung cancer are not the decisive factors, and the natural history of pulmonary nodules and the radiation exposure of imaging should be the main concerns. The management of incidental pulmonary nodules in young women with pregnant intention is an intricate and indecisive problem we have to encounter. The balance between the natural history of pulmonary nodules and the radiation exposure of imaging should be weighed.

Female reproductive and hormonal factors and lung cancer mortality among never-smokers: A prospective cohort study of 287 408 Chinese women

There is growing, but inconsistent evidence suggesting oestrogen may play a key role in lung cancer development, especially among never-smoking women for whom lung cancer risk factors remain largely elusive. Using the China Kadoorie Biobank, a large-scale prospective cohort with 302 510 women aged 30 to 79 years recruited from 10 regions in China during 2004 to 2008, we assessed the risk of lung cancer death among self-reported never-smoking women who were cancer-free at baseline, in relation to age at menarche, age at menopause, time since menopause, prior use of oral contraceptives (OCP), number of livebirths, breastfeeding and age at first livebirth. Women were followed up to December 31, 2016 with linkage to mortality data. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox regression, adjusting for key confounders including several socio-demographic, environmental and lifestyle factors. Among 287 408 never-smoking women, 814 died from lung cancer with a median follow-up of 10.3 years. Women who had used OCP within 15 years prior to baseline had a significantly higher hazard of lung cancer death compared with never-users: HR = 1.85 (95% CI: 1.14-3.00) and risk increased by 6% with each additional year of use: HR = 1.06 (1.01-1.10). Among parous women, the hazard of lung cancer death increased by 13% with each single livebirth: HR = 1.13 (1.05-1.23); and among post-menopausal women, the risk increased by 2% with each year since menopause: HR = 1.02 (1.01-1.04). These results suggest that reproductive factors which were proxies for lower endogenous oestrogen level, for example, longer duration of OCP use, could play a role in lung cancer development.

The Causal Effect of Reproductive Factors on Breast Cancer: A Two-Sample Mendelian Randomization Study

Several studies have shown that female reproductive factors are associated with breast cancer (BC), but the results differ. We conducted two-sample MR in the present work. The raw data applied in the MR study were all from the Genome-wide association study (GWAS) database. The causal effect of reproductive factors on breast cancer were mainly estimated by the standard inverse variance weighted (IVW) method. Cochran's Q test and I² statistics were used to assess heterogeneity. The pleiotropy was evaluated by MR-Egger intercept test and MR-PRESSO. Finally, the leave-one-out analysis was performed to evaluate the robustness of the MR results. We found that there was a negative causal effect of the age at last live birth on BC (OR = 0.687, 95%CI = 0.539-0.875, p = 0.002) and positive effect of the age at menopause on BC (OR = 1.054, 95%CI = 1.034-1.075, p = 8.010 × 10^-8). Additionally, there were null effects of the age at menarche (OR = 0.977, 95%CI = 0.915-1.043, p = 0.484), the age at first sexual intercourse (OR = 1.053, 95%CI = 0.958-1.157, p = 0.284) and the age at first birth (OR = 0.981, 95%CI = 0.936-1.027, p = 0.404) on BC. All these results were reliable and stable. In conclusion, the present study showed that younger age at last birth and older age at menopause could increase the risk of BC.

Trends and predictions of lung cancer incidence in Jiangsu Province, China, 2009–2030: a bayesian age-period-cohort modelling study

Background

Lung cancer is currently the most frequent cancer in Jiangsu Province, China, and the features of cancer distribution have changed continuously in the last decade. The aim of this study was to analyse the trend of the incidence of lung cancer in Jiangsu from 2009 to 2018 and predict the incidence from 2019 to 2030.

Methods

Data on lung cancer incidence in Jiangsu from 2009 to 2018 were retrieved from the Jiangsu Cancer Registry. The average annual percentage change (AAPC) was used to quantify the trend of the lung cancer age-standardized rate (ASR) using Joinpoint software. Bayesian age-period-cohort models were used to predict lung cancer incidence up to 2030.

Results

In Jiangsu, the lung cancer crude rate increased from 45.73 per 100,000 in 2009 to 69.93 per 100,000 in 2018. The lung cancer ASR increased from 29.03 per 100,000 to 34.22 per 100,000 during the same period (AAPC = 2.17%, 95% confidence interval [CI], 1.54%, 2.80%). Between 2019 and 2030, the lung cancer ASR is predicted to decrease slightly to 32.14 per 100,000 (95% highest density interval [HDI], 24.99, 40.22). Meanwhile, the ASR showed a downward trend in males and rural regions while remaining stable in females and urban regions.

Conclusion

We predict that the incidence of lung cancer in Jiangsu will decrease in the next 12 years, mainly due to the decrease in males and rural areas. Therefore, future lung cancer prevention and control efforts should be focused on females and urban regions.

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.

Concurrent Androgen Deprivation Therapy for Prostate Cancer Improves Survival for Synchronous or Metachronous Non-Small Cell Lung Cancer: A SEER-Medicare Database Analysis

Introduction: The crosstalk between receptor kinase signaling, such as EGFR and androgen receptor signaling, suggests a potential interaction between androgen deprivation therapy (ADT) and lung cancer outcome. Methods: We employed the SEER−Medicare data of lung cancer patients diagnosed between 1988 and 2005 to test for an association between ADT for prostate cancer and lung cancer outcome. We employed the Kaplan−Meier method and Cox proportional hazard with log-rank test model to assess any significant impact of ADT on survival. Results: We included data from 367,750 lung cancer patients; 17.4%, 2.9%, 33.6% and 46.1% with stages I, II, III and IV, respectively; 84.5% were >65 years; 57.2% males; 84.2% Caucasians and 9.3% Blacks. There were 11,061 patients (3%) with an initial prostate cancer diagnosis followed by lung cancer (P-L group); 3017 (0.8%) with an initial diagnosis of lung cancer and subsequent prostate cancer diagnosis (L-P group); the remainder had only lung cancer (L group). Stage I lung cancer was most common in the L-P group compared to the L and P-L groups—54% vs. 17.13% vs. 17.92%, p < 0.0001 for L-P, L and P-L, respectively. The median OS for lung cancer diagnosis was 93 months versus 10 and 9 months, respectively, for the L-P, L and P-L subgroups. ADT was associated with improved survival on multivariate analysis, especially in Caucasian patients (HR of death: 0.86; 95% CI: 0.76−0.97; p = 0.012). Conclusion: ADT was associated with improved outcome for NSCLC, in line with the hypothesis of a role for the androgen receptor in lung cancer. Our findings support a systematic evaluation of the potential benefit of ADT as a therapy for lung cancer.

Incidence of Lung Cancer Among Never-Smoking Asian American, Native Hawaiian, and Pacific Islander Females

BACKGROUND

Although lung cancer incidence rates according to smoking status, sex, and detailed race/ethnicity have not been available, it is estimated that more than half of Asian American, Native Hawaiian, and Pacific Islander (AANHPI) females with lung cancer have never smoked.

METHODS

We calculated age-adjusted incidence rates for lung cancer according to smoking status and detailed race/ethnicity among females, focusing on AANHPI ethnic groups, and assessed relative incidence across racial/ethnic groups. We used a large-scale dataset that integrates data from electronic health records from 2 large health-care systems-Sutter Health in Northern California and Kaiser Permanente Hawai'i-linked to state cancer registries for incident lung cancer diagnoses between 2000 and 2013. The study population included 1 222 694 females (n = 244 147 AANHPI), 3297 of which were diagnosed with lung cancer (n = 535 AANHPI).

RESULTS

Incidence of lung cancer among never-smoking AANHPI as an aggregate group was 17.1 per 100 000 (95% confidence interval [CI] = 14.9 to 19.4) but varied widely across ethnic groups. Never-smoking Chinese American females had the highest rate (22.8 per 100 000, 95% CI = 17.3 to 29.1). Except for Japanese American females, incidence among every never-smoking AANHPI female ethnic group was higher than that of never-smoking non-Hispanic White females, from 66% greater among Native Hawaiian females (incidence rate ratio = 1.66, 95% CI = 1.03 to 2.56) to more than 100% greater among Chinese American females (incidence rate ratio = 2.26, 95% CI = 1.67 to 3.02).

CONCLUSIONS

Our study revealed high rates of lung cancer among most never-smoking AANHPI female ethnic groups. Our approach illustrates the use of innovative data integration to dispel the myth that AANHPI females are at overall reduced risk of lung cancer and demonstrates the need to disaggregate this highly diverse population.

Menstrual factors, reproductive history, and risk of lung cancer: a multi-center population-based cohort study in Chinese females

Background

Female menstrual and reproductive factors, as remarkable indicators of hormone effect, were hypothesized to be associated with lung cancer risk, whereas the existed epidemiological evidence was inconsistent. Our study aims to investigate the association between menstrual and reproductive factors and lung cancer risk based on the Chinese Lung Cancer Screening Program.

Methods

This study was based on a large-scale multi-center population cohort across China recruiting individuals aged 40–74 years old between 2013–2018. Cox regression model was applied to estimate the HRs and 95% CIs. Restricted cubic spline (RCS) analysis was used to estimate dose-response relationships and test for nonlinear associations.

Results

Among 553,434 female participants, 1,529 incident lung cancer cases were identified with a median follow-up of 3.61 years. With adjustment for multiple covariates and all significant hormonal factors, elevated lung cancer risk was associated with later age (15, or ≥16 years) at menarche (HR =1.27, 95% CI: 1.04–1.56; HR =1.45, 95% CI: 1.19–1.76), later age (25–29, or ≥30 years) at first live birth (HR =1.27, 95% CI: 1.13–1.43; HR =1.23, 95% CI: 1.00–1.51), and benign breast disease history (HR =1.25, 95% CI: 1.10-1.41). For postmenopausal females specifically, surgical menopause (HR =1.62; 95% CI: 1.29–2.05) and other surgeries on the reproductive system (HR =1.19; 95% CI: 1.01–1.40) both appeared to be predictive of elevated lung cancer risk. Concerning age at menopause, a nonlinear association was observed (P-nonlinear =0.0126). Increased lung cancer risk was observed among females with age at menopause especially above 50. Although we observed no significant associations between longer time (≥13 months) of breastfeeding and lung cancer risk among all participants (HR =0.86; 95% CI: 0.71–1.04), significant decreased adenocarcinoma risk (HR =0.65; 95% CI: 0.53–0.81) was noted among nonsmoking females.

Conclusions

Our findings add some support for the role of menstrual and reproductive factors in lung carcinogenesis. However, these relationships were complex, and required further investigations addressing the biological mechanisms.

Phytoestrogens and lung cancer risk: a nested case-control study in never-smoking Chinese women

BACKGROUND

Since several lines of evidence suggest that estrogens may be involved in lung carcinogenesis, it has been hypothesized that intake of phytoestrogens, similar in molecular structure to mammalian estrogens, may be associated with lung cancer development.

OBJECTIVE

The aim was to prospectively evaluate the association between phytoestrogen exposure and lung cancer risk in never-smoking women.

METHODS

We conducted a nested case-control study within a population-based prospective cohort study of women. A total of 478 incident lung cancer cases and their individually matched controls were identified among never-smoking women after a mean follow-up of 15.6 years. Habitual intake of and internal exposure to phytoestrogens were assessed by repeated dietary surveys and urinary biomarkers, respectively. ORs and 95% CIs for lung cancer were estimated in conditional logistic regression models.

RESULTS

After adjustment for potential confounders, a moderate intake of dietary isoflavones was inversely associated with lung cancer risk in never-smoking women, with the OR for the second quartile vs. the lowest quartile of intake being 0.52 (95% CI: 0.35, 0.76). Further increasing intake did not convey additional benefits, with ORs (95% CI) for the third and fourth quartiles of 0.53 (0.36, 0.78) and 0.47 (0.31, 0.72), respectively (P-overall < 0.001 and P-nonlinearity = 0.006). A similar association was seen when exposure to isoflavones was assessed by urinary biomarkers. ORs (95% CI) for the second, third, and fourth quartiles compared with the lowest quartile of urinary isoflavone excretion were 0.57 (0.39, 0.83), 0.64 (0.44, 0.92), and 0.60 (0.41, 0.86), respectively. The inverse association reached a plateau beyond the second quartile, with P-overall = 0.04 and P-nonlinearity = 0.15. Urinary excretion of gut-microbiota-derived metabolites of lignans was not related to lung cancer risk.

CONCLUSIONS

This study suggests that moderately increasing intake of isoflavone-rich foods is associated with lower risk of lung cancer in never-smoking women.

Age at menopause and risk of lung cancer: A systematic review and meta-analysis

Previous reviews have found that menstrual and reproductive factors are associated with lung cancer risk, but evidence on a possible association with age at menopause is inconsistent. This review aimed to determine the association of early and late menopause with lung cancer risk. Publications were reviewed and obtained through PubMed, EMBASE and Scopus database search up to March 2021. The pooled relative risks (RRs) or odds ratios (ORs) and corresponding 95% CIs were estimated using a random-effects meta-analysis. Twenty-eight studies were included in at least one meta-analysis, of age at menopause (lowest vs highest; n=26), early menopause (≤45 vs ≥50/51 years or middle; n=11), late menopause (≥55 vs <50 years or middle; n=6), or continuous (per additional year; n=6). We found that early menopause was associated with lung cancer in both cohort studies (RR 1.26, 1.10-1.41; n=6) and case-control studies (OR 1.38, 1.11-1.66; n=5). Three large cohort studies showed that the increased risk was primarily evident among smokers (RR 1.38, 1.10-1.66) but not among non-smokers (RR 1.02, 0.63-1.40). Four case-control studies found that late menopause was also associated with lung cancer (OR 1.29, 1.08-1.51); conversely, the association was mainly observed among non-smokers (OR 1.35, 1.11-1.59) but not among smokers (OR 1.05, 0.75-1.36). In conclusion, evidence from this review indicates an increased risk of lung cancer in women who experience early menopause (≤45 years), although this risk is primarily among smokers. Large prospective cohort studies are needed to confirm the association between late menopause (≥55 years) and lung cancer risk among non-smokers. PROSPERO registration: CRD42020205429.

Uterine myoma is associated with an increased risk of lung cancer: A nationwide population-based cohort study

OBJECTIVE

The rate of lung cancer in female patients is increasing, with different features from male patients being displayed. Hormonal factors could play a role. The association between the development of uterine myoma (UM) and female hormones has also been reported. The relationship between female lung cancer and UM may be due to the effect of female hormones.

METHODS

Data from 50 711 Taiwanese women with UM were retrieved from the National Health Insurance Research Database between 2000 and 2012. They were propensity-score matched with 50 711 women without UM (control group). A multivariate Cox proportional hazard regression model was used to compare the incidence of lung cancer between groups and to determine the hazard ratio of lung cancer in the UM group.

RESULTS

The risk of lung cancer was significantly higher in women with myoma (adjusted hazard ratio: 1.62, 95% confidence ratio = 1.24-2.12). Stratified analyses demonstrated that the significantly increased risk of lung cancer was more likely to be found in certain groups, such as women who (a) are of younger age, (b) have a mid-level income, (c) have the highest urbanisation level, (d) are office workers and (e) with a longer follow-up period of myoma. Furthermore, myomectomy did not affect the risk pattern.

CONCLUSION

The results from this nationwide population-based cohort study suggested that UM is associated with a higher risk of developing lung cancer. However, the exact underlying mechanism accounted for this remains unclear, and our findings still need to be verified by further comprehensive studies elsewhere.

Reproductive Factors and Lung Cancer Risk among Never-Smoking Japanese Women with 21 Years of Follow-Up: A Cohort Study

BACKGROUND

Previous studies have reported inconsistent associations between reproductive factors and lung cancer.

METHODS

We used data from the Japan Public Health Center-based Prospective Study, which included 400 incident lung cancer cases (305 adenocarcinoma) among 42,615 never-smoking women followed for a median of 21 years, to examine the associations of reproductive and hormonal factors with lung cancer by histological type using Cox proportional hazards models.

RESULTS

Longer fertility span (≥36 years vs. ≤32 years) was associated with increased risk of lung adenocarcinoma (HR, 1.48; 95% CI, 1.07-2.06, P _trend = 0.01) but not with all lung cancer or nonadenocarcinoma. Similarly, late age at menopause (≥ 50 years) was associated with increased adenocarcinoma risk (vs. ≤ 47 years, HR, 1.41; 95% CI, 1.01-1.96, P _trend 0.04). Compared with premenopausal women, women with natural menopause (HR, 1.99; 95% CI, 1.02-3.88) or surgical menopause (HR, 2.75; 95% CI, 1.33-5.67) were at increased risk of adenocarcinoma. In contrast, breastfeeding was associated with reduced risk of nonadenocarcinoma (HR, 0.51; 95% CI, 0.28-0.92). No significant association with parity, age at first birth, exogenous hormone use, or length of menstrual cycle was detected.

CONCLUSIONS

Reproductive factors may play a role in lung carcinogenesis. Future studies that include estrogen and progesterone biomarkers may help clarify the role of endogenous hormones in lung carcinogenesis.

IMPACT

Fertility span and age at menopause may be useful variables in developing risk prediction models for lung adenocarcinoma among nonsmoking women.

High gene expression of estrogen and progesterone receptors is associated with decreased t cell infiltration in patients with NSCLC

OBJECTIVES

Prior studies have demonstrated that signaling via the estrogen and progesterone receptors (ER and PR) may affect prognosis in non-small cell lung cancer (NSCLC). The precise impact of hormone signaling on clinical outcomes in NSCLC, especially in the context of immune checkpoint blockade, remains unclear.

MATERIALS AND METHODS

We obtained RNA-Seq data from The Cancer Genome Atlas (TCGA) to determine mRNA expression levels of ESR1 (ER-α), ESR2 (ER-β), PGR (PR), CYP19A1 (aromatase), and immune-related genes. Tumor infiltration by activated T cells was predicted based on expression of immune metagenes.

RESULTS

High levels of both ESR1 and PGR were associated with significantly decreased tumor infiltration by CD4+ and CD8+ activated T cells. CYP19A1 expression was associated with decreased CD4+ but not CD8+ T cell infiltration. There were no significant differences based on ESR2. These findings persisted after stratifying patients based on sex and tumor histology. In addition, increased ESR1 was associated with high gene expression of immune checkpoint markers, while increased PGR was associated with high levels of TGF-β genes. In a multivariate logistic regression analysis, ESR1, PGR, TGFB1, and the total number of somatic variants were identified as independent factors predicting T cell infiltration.

CONCLUSIONS

Increased gene expression of ER-α and PR was associated with decreased activated T cell infiltration in patients with NSCLC. The relevance of hormone receptor status should be validated clinically, including in the context of immune checkpoint inhibitors.

Reproductive factors and lung cancer risk: a comprehensive systematic review and meta-analysis

BACKGROUND

A number of studies have investigated the association between reproductive factors and lung cancer risk, however findings are inconsistent. This meta-analysis aimed to evaluate the association between female reproductive factors and lung cancer risk.

METHODS

We conducted a comprehensive systematic search to identify relevant and eligible studies published before 18th December 2019. Inter-study heterogeneity was assessed using the Q test and I2 statistic. Based on the heterogeneity of each reproductive factor, fixed or random effects models were used to calculate the summary odds ratios (ORs) and 95% confidence intervals (CIs). Subgroup analyses by study design, lung cancer subtypes, smoking status, and ethnicity were also performed.

RESULTS

A total of 66 studies with 20 distinct reproductive factors were included in this meta-analysis. Comparing the highest and lowest categories (reference) of each reproductive factor, parity (OR = 0.83, 95% CI = 0.72-0.96), menstrual cycle length (OR = 0.79, 95% CI = 0.65-0.96), and age at first birth (OR = 0.85, 95% CI = 0.74-0.98), were significantly associated with a lower risk of overall lung cancer. On the contrary, non-natural menopause was significantly associated with higher lung cancer risk (OR = 1.52, 95% CI = 1.25-1.86). Among never-smokers, a significant negative association was found between parity and lung cancer risk. Both parity and non-natural menopause were statistically significant in case-control studies.

CONCLUSION

These results suggest that certain reproductive factors may be associated with lung cancer risk. Future studies should further validate the associations, and investigate the underlying mechanisms.

Epidemiological trends of tracheal, bronchus, and lung cancer at the global, regional, and national levels: a population-based study

Background

Investigations of disease incidence, mortality, and disability-adjusted life years (DALYs) are valuable for facilitating preventive measures and health resource planning. We examined the tracheal, bronchus, and lung (TBL) cancer burdens worldwide according to sex, age, and social development index (SDI) at the global, regional, and national levels.

Methods

We assessed the TBL cancer burden using data from the Global Burden of Disease (GBD) database, including 21 regions, 195 countries, and territories in the diagnostic period 1990–2017. The data of TBL cancer-related mortality and DALYs attributable to all known risk factors were also analyzed. Age-standardized rates (ASRs) and their estimated annual percentage changes (EAPCs) were calculated.

Results

Incident cases, deaths, and DALYs of TBL cancer increased worldwide (100.44%, 82.30%, and 61.27%, respectively). The age-standardized incidence rate (ASIR) was stable (EAPC = 0.02, 95% confidence interval [CI] − 0.03 to 0.08), but the age-standardized death (EAPC = − 0.34, 95%CI − 0.38 to − 0.3) and DALY rate decreased generally (EAPC = − 0.74, 95%CI − 0.8 to − 0.68). However, the change trend of ASIR and ASDR among sexes was on the contrary. China and the USA always had the highest incidence, mortality, and DALYs of TBL cancer. Significant positive correlations between ASRs and SDI were observed, especially among females. High (36.86%), high-middle (28.78%), and middle SDI quintiles (24.91%) carried the majority burden of TBL cancer. Tobacco remained the top cause of TBL cancer death and DALYs, followed by air pollution, the leading cause in the low-middle and low-SDI quintiles. Metabolic risk-related TBL cancer mortality and DALYs among females increased but was stable among males. The main ages of TBL cancer onset and death were > 50 years, and the DALYs concentrated in 50 − 69 years.

Conclusions

To significantly reduce the growing burden of TBL cancer, treatment resources need to be skewed according to factors such as risks and geography, especially for high-risk groups and high-burden areas. Asia had the greatest TBL cancer burden, followed by high-income North America. Tobacco remains the leading cause of death and DALYs, followed by air pollution. Effective prevention measures against tobacco and air pollution should be strengthened.

Female reproductive factors and the risk of lung cancer in postmenopausal women: a nationwide cohort study

Background

Reproductive factors and hormone use in postmenopausal women have been hypothesised to affect the risk of developing lung cancer, but the epidemiological evidence is inconsistent.

Methods

Using the Korean National Health Insurance System database, we identified 4,775,398 postmenopausal women older than 40 years who had undergone both cardiovascular health- and cancer screening between 1 January 2009 and 31 December 2014. Information about reproductive factors was obtained from a self-administered questionnaire. The risk of lung cancer was estimated using Cox proportional hazard regression models.

Results

During a median follow-up of 4.4 years, 16,556 women (15,223 non-smokers) were diagnosed with lung cancer. The risk of lung cancer was not significantly influenced by early menarche age (adjusted hazard ratio [aHR] 1.03 for menarche ≥18 vs. ≤14; 95% confidence interval [CI], 0.98–1.09) or late age at menopause (aHR 1.02 for menopause ≥55 vs. <40; 95% CI, 0.91–1.14). Furthermore, the number of children, duration of breastfeeding and use of hormone replacement therapy were not associated with the risk of lung cancer.

Conclusions

No statistically significant association was found between reproductive factors and the risk of lung cancer in postmenopausal Korean women.

Expression Profiling of Driver Genes in Female Never-smokers With Non-adenocarcinoma Non-small-cell Lung Cancer in China

BACKGROUND

Although smoking is a primary cause of lung cancer, females are overrepresented among never-smokers with the disease. The mutational landscape of adenocarcinoma in never-smoking females has been extensively profiled; however, there is little knowledge about genomic alterations in non-adenocarcinoma non-small-cell lung cancer (NA-NSCLC). In the study, we reviewed the status of oncogenic drivers of NA-NSCLC in these populations.

MATERIALS AND METHODS

Comprehensive genomic profiling was performed on DNA extracted from formalin-fixed, paraffin-embedded sections of 52 NA-NSCLC tissues, including 35 squamous cell carcinomas (SQCCs), 11 adenosquamous carcinomas, 5 pulmonary sarcomatoid carcinoma, and 1 large cell carcinoma by next-generation sequencing within a panel of 68 cancer-related genes.

RESULTS

Mutations of the common oncogenic drivers (EGFR, KRAS, ALK, ROS1, MET, RET, and ERBB2) occurred in 61.5% of cases. The frequency of well-established targets (EGFR and ALK), new targets without widely available therapies (MET and ERBB2), and potentially actionable targets (RET and DDR2) in SQCCs of female never-smokers was significantly higher than that in The Cancer Genome Atlas dataset. There were 31%, 82%, and 80% of cases with SQCC, adenosquamous carcinoma, and pulmonary sarcomatoid carcinoma, respectively, harboring at least one of the following targets: EGFR, ALK, ERBB2, and MET. Approximately 78% (7/9) of the patients responded to various targeted treatments.

CONCLUSION

Female never-smokers with NA-NSCLC in this study had a high frequency of currently known or potentially actionable oncogenic alterations and could benefit from targeted therapy. Our study also provides evidence for the recommendation of molecular analysis in never-smoking female SQCC.

Hormone replacement therapy and lung cancer risk in women: a meta-analysis of cohort studies: Hormone replacement therapy and lung cancer risk

BACKGROUND

Discordant results about the causal relationship between hormone replacement therapy use (HRT) and lung cancer risk in women had been reported. We therefore conducted a meta-analysis of cohort studies to evaluate this association.

METHODS

The PubMed and Embase databases were searched. Fixed- or random-effects model was used to pool the study-specific relative risks (RRs) with corresponding 95% confidence intervals (CIs). Sensitivity analysis, publication bias, and subgroup analysis were performed.

RESULTS

A total of 13 cohort studies met the inclusion criteria. Combined results indicated that compared with nonusers, women with HRT use were at a decreased risk (RR: 0.95, 95% CI: 0.91-0.99, I = 30.8%, P for heterogeneity = .137). In subgroup analysis by geographic area, smoking statue, type of hormones, and histology type of lung cancer, no significant association between HRT use and lung cancer was observed in most subgroups except in those studies which reported risk estimates adjusted for age, body mass index, smoking, and other confounders (RR: 0.95, 95 CI: 0.91-0.99, I = 33.0%, P for heterogeneity = .214). Both Begg funnel plot and Egger test (P = .243) suggested no evidence for publication bias.

CONCLUSION

Our meta-analysis suggests ever use of HRT is associated with a decreased risk of lung cancer in women.

Smoking, Sex, and Non-Small Cell Lung Cancer: Steroid Hormone Receptors in Tumor Tissue (S0424)

Background

To what extent steroid hormones contribute to lung cancer in male and female never smokers and smokers is unclear. We examined expression of hormone receptors in lung tumors by sex and smoking.

Methods

Patients with primary non-small cell lung cancer were recruited into an Intergroup study in the United States and Canada, led by SWOG (S0424). Tumors from 813 cases (450 women and 363 men) were assayed using immunohistochemistry for estrogen receptor (ER)-α, ER-β, progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Linear regression was used to examine differences in expression by sex and smoking status. Cox proportional hazard models were used to estimate survival associated with the receptors. All statistical tests were two-sided.

Results

In ever smokers, postmenopause and oral contraceptive use were associated with lower nuclear ER-β (P = .02) and total (nuclear + cytoplasmic) PR expression (P = .02), respectively. Women had lower cytoplasmic ER-α (regression coefficient [β], or differences in H-scores = -15.8, P = .003) and nuclear ER-β (β = -12.8, P = .04) expression than men, adjusting for age, race, and smoking. Ever smokers had both higher cytoplasmic ER-α (β = 45.0, P < .001) and ER-β (β = 25.9, P < .001) but lower total PR (β = -42.1, P < .001) than never smokers. Higher cytoplasmic ER-α and ER-β were associated with worse survival (hazard ratio = 1.73, 95% confidence interval [CI] = 1.15 to 2.58, and HR = 1.59, 95% CI = 1.08 to 2.33, respectively; quartiles 4 vs 1).

Conclusions

Lower expression of nuclear ER-β in women supports the estrogen hypothesis in lung cancer etiology. Increasing cytoplasmic ER-α and ER-β and decreasing PR protein expression may be mechanisms whereby smoking disrupts hormone pathways.

Reproductive and Hormonal Factors in Relation to Lung Cancer Among Nepali Women

Background: Of the 1.8 million global incident lung cancer cases estimated in 2012, approximately 60% occurred in less developed regions. Prior studies suggest sex differences in lung cancer risk and a potential role for reproductive and hormonal factors in lung cancer among women. However, the majority of these studies were conducted in developed regions. No prior study has assessed these relationships among Nepali women.

Methods: Using data from a hospital-based case-control study conducted in B. P. Koirala Memorial Cancer Hospital (Nepal, 2009–2012), relationships between reproductive and hormonal factors and lung cancer were examined among women aged 23–85 years. Lung cancer cases (n = 268) were frequency-matched to controls (n = 226) based on age (±5 years), ethnicity and residential area. The main exposures in this analysis included menopausal status, age at menarche, age at menopause, menstrual duration, gravidity, and age at first live-birth. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression.

Results: Among postmenopausal women, those with a younger age at menopause (<45 years; 45–49 years) had an increased odds of lung cancer compared to those with an older (≥50 years) age at menopause [OR (95%CI): 2.14 (1.09, 4.17); OR (95% CI): 1.93 (1.07, 3.51)], after adjusting for age and cumulative active smoking years. No statistically significant associations were observed with the other reproductive and hormonal factors examined.

Conclusion: These results suggest that Nepali women with prolonged exposure to endogenous ovarian hormones, via later age at menopause, may have a lower odds of lung cancer.

Tobacco Smoking Modifies the Association between Hormonal Factors and Lung Cancer Occurrence among Post-Menopausal Chinese Women

Inconsistent evidence has been reported on the role of female hormonal factors in the development of lung cancer. This population-based case–control study evaluated the main effect of menstrual/reproductive factors on the risk of lung cancer, and the effect modification by smoking status. Multivariable unconditional logistic regression models were applied adjusted for age, income, education, county of residence, body mass index, smoking status, pack-years of smoking, and family history of lung cancer. Among 680 lung cancer cases and 1,808 controls, later menopause (at >54 vs. <46 years old) was associated with increased risk of lung cancer (SBOR, semi-Bayes adjusted odds ratio = 1.61, 95% PI, posterior interval = 1.10–2.36). More pregnancies (2 or 3 vs. 0 or 1) was associated with decreased risk (SBOR = 0.71, 95% PI = 0.53, 0.95). Ever being a smoker and having two or fewer pregnancies in one's lifetime could jointly increase the odds of lung cancer (RERI, relative excess risk due to interaction = 1.71, 95% CI = 0.03, 3.38). An increased number of ovulatory cycles was associated with increased risk of lung cancer (SBOR for 13 ovulatory cycles = 1.02, 95% CI = 1.00+, 1.04).

Association of Combined Estrogen-Progestogen and Progestogen-Only Contraceptives with the Development of Cancer

Combined estrogen-progestogen contraceptives (oral contraceptives or OCs) and progestogen-only contraceptives (POCs) are synthetic steroids that bind to steroid hormone receptors, which are widespread throughout the body. They have a profound effect on cellular physiology. Combined OCs have been classified by the International Agency for Research on Cancer (IARC) as Group 1 carcinogens, but their findings have not been updated recently. In order to update the information and better understand the impact that OCs and POCs have on the risk of development of cancers, a comprehensive literature search was undertaken, focusing on more recently published papers. In agreement with the IARC, the recent literature confirms an increased risk of breast cancer and cervical cancer with the use of OCs. The recent literature also confirms the IARC conclusion that OCs decrease the risk of ovarian and endometrial cancers. However, there is little support from recent studies for the IARC conclusion that OCs decrease the risk of colorectal cancer or increase the risk of liver cancer. For liver cancer, this may be due to the recent studies having been performed in areas where hepatitis is endemic. In one large observational study, POCs also appear to increase the overall risk of developing cancer. OCs and POCs appear to increase the overall risk of cancer when carefully performed studies with the least intrinsic bias are considered.

Summary

OCs have been classified as cancer-causing agents, especially leading to increases in breast cancer and cervical cancer. A review of the recent scientific literature was performed to see whether this still appears to be the case. The recent literature supports the cancer-causing role of OCs especially for breast cancer and cervical cancer. Studies also indicate that progesterone-only contraceptives (such as implants and vaginal rings) also can cause cancer. This is especially true for breast cancer and cervical cancer.

Sex specific function of epithelial STAT3 signaling in pathogenesis of K-ras mutant lung cancer

Lung adenocarcinomas (LUADs) with mutations in the K-ras oncogene display dismal prognosis. Proinflammatory and immunomodulatory events that drive development of K-ras mutant LUAD are poorly understood. Here, we develop a lung epithelial specific K-ras mutant/Stat3 conditional knockout (LR/Stat3^Δ/Δ) mouse model. Epithelial Stat3 deletion results in intriguing sex-associated discrepancies; K-ras mutant tumors are decreased in female LR/Stat3^Δ/Δ mice whereas tumor burdens are increased in males. RNA-sequencing and tumor microenvironment (TME) analysis demonstrate increased anti-tumor immune responses following Stat3 deletion in females and, conversely, elevated pro-tumor immune pathways in males. While IL-6 blockade in male LR/Stat3^Δ/Δ mice reduces lung tumorigenesis, inhibition of estrogen receptor signaling in female mice augments K-ras mutant oncogenesis and reprograms lung TME toward a pro-tumor phenotype. Our data underscore a critical sex-specific role for epithelial Stat3 signaling in K-ras mutant LUAD, thus paving the way for developing personalized (e.g. sex-based) immunotherapeutic strategies for this fatal disease.

Proinflammatory and immunomodulatory events that drive development of K-ras mutant lung adenocarcinoma (LUAD) are poorly understood. Here they develop a lung epithelial specific K-ras mutant/Stat3 conditional knockout mouse model and show a sex-specific role for epithelial Stat3 signaling in K-ras-mutant LUAD.

Candidate SNP markers of reproductive potential are predicted by a significant change in the affinity of TATA-binding protein for human gene promoters

BACKGROUND

The progress of medicine, science, technology, education, and culture improves, year by year, quality of life and life expectancy of the populace. The modern human has a chance to further improve the quality and duration of his/her life and the lives of his/her loved ones by bringing their lifestyle in line with their sequenced individual genomes. With this in mind, one of genome-based developments at the junction of personalized medicine and bioinformatics will be considered in this work, where we used two Web services: (i) SNP_TATA_Comparator to search for alleles with a single nucleotide polymorphism (SNP) that alters the affinity of TATA-binding protein (TBP) for the TATA boxes of human gene promoters and (ii) PubMed to look for retrospective clinical reviews on changes in physiological indicators of reproductive potential in carriers of these alleles.

RESULTS

A total of 126 SNP markers of female reproductive potential, capable of altering the affinity of TBP for gene promoters, were found using the two above-mentioned Web services. For example, 10 candidate SNP markers of thrombosis (e.g., rs563763767) can cause overproduction of coagulation inducers. In pregnant women, Hughes syndrome provokes thrombosis with a fatal outcome although this syndrome can be diagnosed and eliminated even at the earliest stages of its development. Thus, in women carrying any of the above SNPs, preventive treatment of this syndrome before a planned pregnancy can reduce the risk of death. Similarly, seven SNP markers predicted here (e.g., rs774688955) can elevate the risk of myocardial infarction. In line with Bowles' lifespan theory, women carrying any of these SNPs may modify their lifestyle to improve their longevity if they can take under advisement that risks of myocardial infarction increase with age of the mother, total number of pregnancies, in multiple pregnancies, pregnancies under the age of 20, hypertension, preeclampsia, menstrual cycle irregularity, and in women smokers.

CONCLUSIONS

According to Bowles' lifespan theory-which links reproductive potential, quality of life, and life expectancy-the above information was compiled for those who would like to reduce risks of diseases corresponding to alleles in own sequenced genomes. Candidate SNP markers can focus the clinical analysis of unannotated SNPs, after which they may become useful for people who would like to bring their lifestyle in line with their sequenced individual genomes.

The relationship of lung cancer with menstrual and reproductive factors may be influenced by passive smoking, cooking oil fumes, and tea intake: A case-control study in Chinese women

The aim of this study was to investigate the association of menstrual and reproductive factors with risk of lung cancer in women. Potential etiological clues related to lung cancer in women are identified to inform preventive strategies.Case-control study of 477 newly diagnosed women with lung cancer and 479 age-matched (±2 years) controls. Data on menstrual and reproductive factors and history of oral contraceptive use were obtained on personal interviews using a structured questionnaire. Risk factors were analyzed by unconditional logistic regression analysis.Maternal age ≥25 years at first birth appeared to protect against female lung cancer [odds ratios (ORs): 0.511, 95% confidence interval (CI), 0.376-0.693]. Age at menopause > 50 years and use of contraceptives was associated with an increased risk of lung cancer in women (OR: 1.471, 95% CI, 1.021-2.119 and OR: 1.844, 95% CI: 1.111-3.061, respectively). Age ≥13 years at menarche was associated with a decreased risk of lung adenocarcinoma (OR: 0.563, 95% CI, 0.317-0.997). There was significant heterogeneity in the levels of cooking oil fume (COF) exposure (Pheterogeneity = .015). Higher levels of exposure to passive smoking, COF, and lack of tea intake were associated with an increased risk of lung cancer.Menstrual and reproductive factors are considered to play a role in the development of lung cancer in women. Exposure to passive smoking, COF, and lack of tea intake appeared to significantly modify the relationship.

Menstrual and reproductive factors and lung cancer risk: A pooled analysis from the international lung cancer consortium

Many clinical features of lung cancer are different in women and men. Sex steroid hormones exert effects in nonreproductive organs, such as the lungs. The association between menstrual and childbearing factors and the risk of lung cancer among women is still debated. We performed a pooled analysis of eight studies contributing to the International Lung Cancer Consortium (4,386 cases and 4,177 controls). Pooled associations between menstrual or reproductive factors and lung cancer were estimated using multivariable unconditional logistic regression. Subgroup analyses were done for menopause status, smoking habits and histology. We found no strong support for an association of age at menarche and at menopause with lung cancer, but peri/postmenopausal women were at higher risk compared to premenopausal (OR 1.47, 95% CI 1.11-1.93). Premenopausal women showed increased risks associated with parity (OR 1.74, 95% CI 1.03-2.93) and number of children (OR 2.88, 95% CI 1.21-6.93 for more than 3 children; p for trend 0.01) and decreased with breastfeeding (OR 0.54, 95% CI 0.30-0.98). In contrast, peri/postmenopausal subjects had ORs around unity for the same exposures. No major effect modification was exerted by smoking status or cancer histology. Menstrual and reproductive factors may play a role in the genesis of lung cancer, yet the mechanisms are unclear, and smoking remains the most important modifiable risk factor. More investigations in large well-designed studies are needed to confirm these findings and to clarify the underlying mechanisms of gender differences in lung cancer risk.

Exon 7 splicing variant of estrogen receptor α is associated with pathological invasiveness in smoking-independent lung adenocarcinoma

Patients with smoking-independent lung cancer mainly consist of females, yet the molecular background of this epidemiological feature, other than epidermal growth factor receptor (EGFR) mutation, remains unclear. Several studies have revealed the association between female hormone-associated factors and the prognosis of lung cancer, however the data remain inconsistent. The present study focused on the expression of estrogen receptor (ER)α in order to elucidate this association in smoking-independent lung cancer. Immunohistochemistry staining (IHC) of aromatase, ERα and ERβ was performed against formalin-treated tissues from 38 patients who had never-smoked who underwent complete surgical resection between 2012 and 2013. Among them, adequate RNA of the tumor and adjacent normal lung cancer was extracted from 31 matching deep frozen samples. Considering the IHC results, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to measure the expression level of 2 different exons of ERα, exon 6 and exon 7, which are part of the ligand binding domain of ERα, using the Taqman gene expression assay. Extra-nuclear expression of ERα using IHC demonstrated a statistically significant association with pathological invasiveness. RT-qPCR results exhibited a decreased expression of ERα exon 7 in invasive tumor tissues, compared with their adjacent normal tissues. This is consistent with the findings of previous in vitro studies indicating that extra-nuclear ERα were exon 7 splicing variants. No difference was observed in ERα exon 7 expression between normal and tumor tissues in non-invasive lung cancer tissues. When considering the EGFR mutation status, EGFR wild-type lung cancers exhibited decreased ERα exon 7 expression levels compared with EGFR mutated lung cancers. Extra-nuclear expression of ERα, which may represent exon 7 splicing variants of ERα, showed statistical association with pathological invasiveness in smoking-independent lung cancer. The post-translational splicing mechanism of ERα may be involved in the acquired invasiveness of smoking independent lung cancer.

Menopausal Hormone Therapy, Age, and Chronic Diseases: Perspectives on Statistical Trends

The release of the Women's Health Initiative (WHI) study in 2002 was a shock to the medical community. Hormone therapy (HT) had generally been considered to be highly beneficial for postmenopausal women since it was the gold standard for relief of menopausal symptoms (hot flashes, night sweats, vaginal atrophy) and it was thought to protect women from osteoporosis, heart disease, and cognitive decline and to generally improve quality of life. However, WHI showed a statistically significant increase in a number of disease states, including breast cancer, cardiovascular disease, and stroke. One problem with the WHI study was that the average age of women in the study was 63, which is considerably older than the age at which most women enter menopause (about 51). The timing hypothesis attempts to rationalize the effect of age on response to HT and risk of various diseases. The data suggests that younger women (50-60) may be protected from heart disease with only a slight increase in breast cancer risk. In contrast, older women (>65) are more susceptible to breast cancer and heart disease and should avoid HT. This Perspective on Statistical Trends evaluates the current data on HT and risk for chronic diseases as a function of age.

Reproductive factors and lung cancer risk among women in the Singapore Breast Cancer Screening Project

OBJECTIVES

A growing body of literature suggests that female hormones play a role in lung cancer risk. Our study aims to examine the relationship between reproductive factors and lung cancer incidence in a large prospectively enrolled cohort in Singapore.

MATERIALS AND METHODS

Multivariate Cox proportional hazard regression models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of lung cancer for each exposure, adjusting for smoking, age at entry, ethnicity and body mass index.

RESULTS

Among 28,222 women aged 50-64 years enrolled in the Singapore Breast Cancer Screening Project from October 1994 to February 1997, we identified 311 incident lung cancer cases (253 in non-smokers) over an average of 15.8 years of follow-up to 31 December 2011. Higher parity was associated with decreased lung cancer risk. Compared with nulliparous women, those with 1-2, 3-4, and ≥5 deliveries had a hazard ratio (HR) of 0.56, 0.55 and 0.45, respectively (P(trend)<0.01). This association was observed in both smokers and non-smokers, and in both adenocarcinomas and non-adenocarcinomas. Reproductive period, breastfeeding, oral contraceptive and hormone replacement therapy use did not seem to influence the risk of getting lung cancer.

CONCLUSION

Our findings add to the existing evidence that parous women have a lower lung cancer risk than nulliparous women.