Sex hormones, hormonal interventions, and gastric cancer risk: a meta-analysis.
Estrogens may influence gastric cancer risk, but published studies are inconclusive. We therefore carried out a meta-analysis addressing the associations of gastric cancer in women with menstrual and reproductive factors and with use of estrogen- and antiestrogen-related therapies. Searches of PubMed up to June, 2011 and review of citations yielded a total of 28 independent studies, including at least one exposure of interest. Random effects pooled estimates of relative risk (RR) and corresponding 95% CIs were calculated for eight exposures reported in at least five studies, including: age at menarche, age at menopause, years of fertility, parity, age at first birth, oral contraceptive use, hormone replacement therapy (HRT), and tamoxifen treatment. Longer years of fertility (RR = 0.74, 95% CI: 0.63-0.86) and HRT (RR = 0.77; 95% CI: 0.64-0.92) were each associated with decreased gastric cancer risk. Conversely, tamoxifen treatment was associated with increased risk (RR = 1.82; 95% CI: 1.39-2.38). The other five exposures were not significantly associated. Our analysis supports the hypothesis that longer exposure to estrogen effects of either ovarian or exogenous origin may decrease risk of gastric cancer. Additional studies are warranted to extend this finding and to identify the underlying mechanisms.
Infections and Immunoepidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, 6120 Executive Blvd, EPS/6116, Rockville, MD 20852, USA. camargomc@mail.nih.gov
M Constanza
MC
Camargo
Yasuyuki
Y
Goto
Jovanny
J
Zabaleta
Douglas R
DR
Morgan
Pelayo
P
Correa
Charles S
CS
Rabkin
D015914:Estrogen Replacement Therapy / Q000009:adverse effects / Q000706:statistics & numerical data*; D005260:Female; D012739:Gonadal Steroid Hormones / Q000008:administration & dosage* / Q000009:adverse effects; D006801:Humans; D017584:Reproductive History; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000453:epidemiology* / Q000209:etiology
D012739:Gonadal Steroid Hormones