Elliott AM, Hannaford PC.. Use of exogenous hormones by women and lung cancer: Evidence from the Royal College of General Practitioners’ Oral Contraception Study
Department of General Practice and Primary Care, University of Aberdeen, Foresterhill Health Center, AB25 2AY Aberdeen, Scotland. Contraception
(Impact Factor: 2.34).
05/2006; 73(4):331-5. DOI: 10.1016/j.contraception.2005.10.003
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.
Available from: Eric Duell
- "However, the limited number of observed cases precluded firm conclusions. Most of the scientific literature on oral contraceptive use (OC) points to no association with lung cancer risk (Taioli and Wynder, 1994; Elliott and Hannaford, 2006; Kabat et al, 2007; Schwartz et al, 2007; Weiss et al, 2008; Seow et al, 2009; Hannaford et al, 2010; Vessey et al, 2010; Meinhold et al, 2011), with two possible exceptions showing, however, opposite results: a reduced lung cancer risk among ever OC users in a case–control study (Kreuzer et al, 2003) and a slightly increased risk among women using OC for 45 years in a cohort study (Baik et al, 2010). "
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The association between oral contraceptive (OC) use, hormone replacement therapy (HRT) and lung cancer risk in women is still debated.
We performed a pooled analysis of six case–control studies (1961 cases and 2609 controls) contributing to the International Lung Cancer Consortium. Potential associations were investigated with multivariable unconditional logistic regression and meta-analytic models. Multinomial logistic regressions were performed to investigate lung cancer risk across histologic types.
A reduced lung cancer risk was found for OC (odds ratio (OR)=0.81; 95% confidence interval (CI): 0.68–0.97) and HRT ever users (OR=0.77; 95% CI: 0.66–0.90). Both oestrogen only and oestrogen+progestin HRT were associated with decreased risk (OR=0.76; 95% CI: 0.61–0.94, and OR=0.66; 95% CI: 0.49–0.88, respectively). No dose-response relationship was observed with years of OC/HRT use. The greatest risk reduction was seen for squamous cell carcinoma (OR=0.53; 95% CI: 0.37–0.76) in OC users and in both adenocarcinoma (OR=0.79; 95% CI: 0.66–0.95) and small cell carcinoma (OR=0.37; 95% CI: 0.19–0.71) in HRT users. No interaction with smoking status or BMI was observed.
Our findings suggest that exogenous hormones can play a protective role in lung cancer aetiology. However, given inconsistencies with epidemiological evidence from cohort studies, further and larger investigations are needed for a more comprehensive view of lung cancer development in women.
Available from: Yan-Wen Yao
- "Females in studies of Blackman et al., Kabat et al., Liu et al., Olsson et al. and Smith et al. included young females, who were less than 50 years old , , , , . Estrogen was used alone as HRT in seven studies , , , , , , , estrogen plus progestin were used as HRT in three studies , ,  and estrogen or estrogen plus progestin or the combination of both was used in the left 15 studies. The status of oral contraceptive use in patients was also investigated in nine studies , , , , , –, . "
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ABSTRACT: The purpose of the present meta-analysis was to determine the relationship between hormone replacement therapy (HRT) and lung cancer risk in females. Publications were reviewed and obtained through a PubMed, EMBASE database and Cochrane Library literature search up to May, 2012. The detailed numbers of patients in different groups, odd ratios (ORs) and corresponding 95% confidence intervals (CIs) were collected and estimated using a random-effects model. Twenty five studies entered into the meta-analysis. The total number of participates and lung cancer patients was 656,403 and 11,442, respectively. The OR of all 25 studies was 0.91 (95%CI = 0.83 to 0.99) and P value was 0.033. In stratified analyses, the positive association between HRT use and decreased lung cancer risk was also found in the patients with BMI<25 kg/m(2) (OR = 0.65, P = 0.000), and never smokers patients (OR = 0.86, P = 0.042). However, HRT use in patients with artificial menopause could increase the lung cancer risk, OR = 1.51(P = 0.001). The result of Egger's test did not show any evidence of publican bias (P = 0.069). In conclusion, our meta-analysis on HRT and lung cancer risk suggests that HRT use is correlated with decreased lung cancer risk in female, especially in female with BMI<25 kg/m(2) and never smokers.
Available from: Geoffrey C Kabat
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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.
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