Use of exogenous hormones by women and lung cancer: evidence from the Royal College of General Practitioners' Oral Contraception Study
ABSTRACT The objective of this study was to assess the risk of lung cancer among women who have used oral contraception or hormone replacement therapy (HRT), especially those exposed to both classes of exogenous hormones.
This study is a nested case-control one using prospectively collected data from the Royal College of General Practitioners' Oral Contraception Study (OCS). The 162 case patients were women with a diagnosis of lung cancer recorded on the OCS database by August 2004. Each case patient was matched with 3 control subjects who were free of the disease at the time of the case patient's diagnosis, of similar age and with similar length of follow-up in the OCS.
Compared with never use, current use of oral contraception was associated with a statistically nonsignificant reduced risk of lung cancer, with an adjusted odds ratio (OR) of 0.47 and a 95% confidence interval (CI) of 0.08-2.95 (OR=0.86 and 95% CI=0.50-1.48 for former use; OR=0.84 and 95% CI=0.49-1.43 for ever use). Similar comparisons for HRT were current use (OR=1.21, 95% CI=0.23-6.37), former use (OR=0.62, 95% CI=0.23-1.68) and ever use (OR=0.71, 95% CI=0.28-1.78). The OR among women who had used both classes of hormones was 0.53 (95% CI=0.16-1.72), as compared with those who had used neither.
Our results are compatible with findings from other studies that suggest that oral contraceptives may reduce the risk of lung cancer. Evidence for a beneficial effect of HRT is less convincing. Further study is needed to determine how long any benefit lasts and whether it is stronger in women exposed to both classes of exogenous hormones. The small number of events occurring in this very large cohort, however, shows that any public health benefit is likely to be marginal.
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ABSTRACT: Several lines of evidence suggest that endocrine factors may play a role in the development of lung cancer, but the evidence is limited and inconsistent. We investigated the association of reproductive and hormonal factors with risk of lung cancer in the National Breast Screening Study, which included 89,835 Canadian women aged 40–59 years at recruitment between 1980 and 1985. Linkages to national cancer and mortality databases provided data on cancer incidence and deaths from all causes, respectively, with follow-up ending between 1998 and 2000. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI) for the association between hormonal factors and lung cancer. During a mean of 16.4 years of follow-up, we observed 750 incident lung cancer cases. After adjustment for covariates, parous women were not at increased risk of lung cancer (HR = 1.18, 95% CI 0.94–1.47) relative to nulliparous women; however, there was a modest increase in risk with increasing parity, reaching a HR of 1.42, 95% CI 1.06–1.88 in women who had 5 or more live births (p for trend 0.02). Among parous women, age at first live birth was inversely associated with risk. Women who had their first live birth at age 30 or older were at reduced risk relative to women who had their first live birth below age 23 (HR 0.68, 95% CI 0.50–0.93, p for trend 0.004). These associations did not differ by age at enrollment (40–49 vs. 50–59 years old), but were somewhat strengthened when attention was restricted to never smokers. Ever use of exogenous hormones showed little association with lung cancer risk; however, long-term users of hormone replacement therapy were at slightly increased risk. Our results add to the limited existing evidence that certain reproductive and hormonal factors may be associated with lung cancer risk in women. © 2007 Wiley-Liss, Inc.International Journal of Cancer 05/2007; 120(10):2214 - 2220. DOI:10.1002/ijc.22543 · 5.01 Impact Factor
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ABSTRACT: Introduction The incidence of lung cancer is increasing dramatically in women in France. It is now the leading cause of cancer deaths among women in the USA and the second in France. State of the art Lung cancer occurring in women displays some specific epidemiological, radiological, clinical and pathological characteristics. Moreover, both prognosis and response to treatment appear to be different from men. In line with these findings, lung carcinogenesis is, at least in part, distinct in women and involves different mechanisms and signalling pathways. We emphasize in this review genetic and hormonal specificities based upon epidemiological and biological studies. Moreover, we focus on lung cancer developing during pregnancy by reporting an individual case and discussing the published literature. Perspectives and conclusions Recent works suggest that lung cancer in women is a distinct entity with specific carcinogenesis. We propose that a better knowledge of this entity will permit the identification of specific genetic alterations or hormonal profiles that may serve as new therapeutic targets.Revue des Maladies Respiratoires 10/2007; 24(8):983-997. DOI:10.1016/S0761-8425(07)92763-1 · 0.49 Impact Factor
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ABSTRACT: BACKGROUND.The association between hormone replacement therapy (HRT) and a reduced lung cancer risk has been reported in previous studies. There is a high female to male ratio in Chinese lung cancer patients, and female patients have different clinicopathological characteristics compared with Western patient populations. The authors investigated whether HRT may reduce lung cancer risk in Taiwan.METHODS.The authors used a case-control study design to investigate 826 women with lung cancer and 531 healthy controls. Personal interviews based on a structured questionnaire were performed to collect information on HRT use of at least 3 months, age, ethnicity, active and passive smoking, exposure to air pollution, cooking or incense fumes, body mass index (BMI), menopause, and family history of cancers.RESULTS.HRT use was associated with reduced lung cancer risk with a multivariate, adjusted odds ratio of 0.70 (95% CI, 0.53–0.94; P = .019). HRT use was associated with reduced odds ratio of lung cancer in all subset analyses stratified by histology, active and passive cigarette smoking, BMI, history of incense burning, cooking, and motorcycle riding, as well as family history of certain cancers.CONCLUSIONS.This study confirmed that HRT is associated with a reduced lung cancer risk. The results appeared to be applicable to Chinese female population groups. Cancer 2007. © 2007 American Cancer Society.Cancer 10/2007; 110(8):1768 - 1775. DOI:10.1002/cncr.22987 · 4.90 Impact Factor