36
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Oestrogen exposure and breast cancer risk

      review-article
      1 , , 1
      Breast Cancer Research
      BioMed Central
      breast cancer, epidemiology, oestrogen, prevention, risk factors

      Read this article at

      ScienceOpenPublisherPMC
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Epidemiological and experimental evidence implicates oestrogens in the aetiology of breast cancer. Most established risk factors for breast cancer in humans probably act through hormone-related pathways, and increased concentrations of circulating oestrogens have been found to be strongly associated with increased risk for breast cancer in postmenopausal women. This article explores the evidence for the hypothesis that oestrogen exposure is a major determinant of risk for breast cancer. We review recent data on oestrogens and breast cancer risk, consider oestrogen-related risk factors and examine possible mechanisms that might account for the effects of oestrogen. Finally, we discuss how these advances might influence strategies for reducing the incidence of breast cancer.

          Related collections

          Most cited references95

          • Record: found
          • Abstract: found
          • Article: not found

          Endogenous sex hormones and breast cancer in postmenopausal women: reanalysis of nine prospective studies.

          Reproductive and hormonal factors are involved in the etiology of breast cancer, but there are only a few prospective studies on endogenous sex hormone levels and breast cancer risk. We reanalyzed the worldwide data from prospective studies to examine the relationship between the levels of endogenous sex hormones and breast cancer risk in postmenopausal women. We analyzed the individual data from nine prospective studies on 663 women who developed breast cancer and 1765 women who did not. None of the women was taking exogenous sex hormones when their blood was collected to determine hormone levels. The relative risks (RRs) for breast cancer associated with increasing hormone concentrations were estimated by conditional logistic regression on case-control sets matched within each study. Linear trends and heterogeneity of RRs were assessed by two-sided tests or chi-square tests, as appropriate. The risk for breast cancer increased statistically significantly with increasing concentrations of all sex hormones examined: total estradiol, free estradiol, non-sex hormone-binding globulin (SHBG)-bound estradiol (which comprises free and albumin-bound estradiol), estrone, estrone sulfate, androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate, and testosterone. The RRs for women with increasing quintiles of estradiol concentrations, relative to the lowest quintile, were 1.42 (95% confidence interval [CI] = 1.04 to 1.95), 1.21 (95% CI = 0.89 to 1.66), 1.80 (95% CI = 1.33 to 2.43), and 2.00 (95% CI = 1.47 to 2.71; P(trend)<.001); the RRs for women with increasing quintiles of free estradiol were 1.38 (95% CI = 0.94 to 2.03), 1.84 (95% CI = 1.24 to 2.74), 2.24 (95% CI = 1.53 to 3.27), and 2.58 (95% CI = 1.76 to 3.78; P(trend)<.001). The magnitudes of risk associated with the other estrogens and with the androgens were similar. SHBG was associated with a decrease in breast cancer risk (P(trend) =.041). The increases in risk associated with increased levels of all sex hormones remained after subjects who were diagnosed with breast cancer within 2 years of blood collection were excluded from the analysis. Levels of endogenous sex hormones are strongly associated with breast cancer risk in postmenopausal women.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Projecting individualized probabilities of developing breast cancer for white females who are being examined annually.

            To assist in medical counseling, we present a method to estimate the chance that a woman with given age and risk factors will develop breast cancer over a specified interval. The risk factors used were age at menarche, age at first live birth, number of previous biopsies, and number of first-degree relatives with breast cancer. A model of relative risks for various combinations of these factors was developed from case-control data from the Breast Cancer Detection Demonstration Project (BCDDP). The model allowed for the fact that relative risks associated with previous breast biopsies were smaller for women aged 50 or more than for younger women. Thus, the proportional hazards models for those under age 50 and for those of age 50 or more. The baseline age-specific hazard rate, which is the rate for a patient without identified risk factors, is computed as the product of the observed age-specific composite hazard rate times the quantity 1 minus the attributable risk. We calculated individualized breast cancer probabilities from information on relative risks and the baseline hazard rate. These calculations take competing risks and the interval of risk into account. Our data were derived from women who participated in the BCDDP and who tended to return for periodic examinations. For this reason, the risk projections given are probably most reliable for counseling women who plan to be examined about once a year.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Prophylactic oophorectomy in carriers of BRCA1 or BRCA2 mutations.

              Data concerning the efficacy of bilateral prophylactic oophorectomy for reducing the risk of gynecologic cancer in women with BRCA1 or BRCA2 mutations are limited. We investigated whether this procedure reduces the risk of cancers of the coelomic epithelium and breast in women who carry such mutations. A total of 551 women with disease-associated germ-line BRCA1 or BRCA2 mutations were identified from registries and studied for the occurrence of ovarian and breast cancer. We determined the incidence of ovarian cancer in 259 women who had undergone bilateral prophylactic oophorectomy and in 292 matched controls who had not undergone the procedure. In a subgroup of 241 women with no history of breast cancer or prophylactic mastectomy, the incidence of breast cancer was determined in 99 women who had undergone bilateral prophylactic oophorectomy and in 142 matched controls. The length of postoperative follow-up for both groups was at least eight years. Six women who underwent prophylactic oophorectomy (2.3 percent) received a diagnosis of stage I ovarian cancer at the time of the procedure; two women (0.8 percent) received a diagnosis of papillary serous peritoneal carcinoma 3.8 and 8.6 years after bilateral prophylactic oophorectomy. Among the controls, 58 women (19.9 percent) received a diagnosis of ovarian cancer, after a mean follow-up of 8.8 years. With the exclusion of the six women whose cancer was diagnosed at surgery, prophylactic oophorectomy significantly reduced the risk of coelomic epithelial cancer (hazard ratio, 0.04; 95 percent confidence interval, 0.01 to 0.16). Of 99 women who underwent bilateral prophylactic oophorectomy and who were studied to determine the risk of breast cancer, breast cancer developed in 21 (21.2 percent), as compared with 60 (42.3 percent) in the control group (hazard ratio, 0.47; 95 percent confidence interval, 0.29 to 0.77). Bilateral prophylactic oophorectomy reduces the risk of coelomic epithelial cancer and breast cancer in women with BRCA1 or BRCA2 mutations.
                Bookmark

                Author and article information

                Journal
                Breast Cancer Res
                Breast Cancer Research
                BioMed Central (London )
                1465-5411
                1465-542X
                2003
                28 July 2003
                : 5
                : 5
                : 239-247
                Affiliations
                [1 ]Cancer Research UK, Epidemiology Unit, University of Oxford, Oxford, UK
                Article
                bcr628
                10.1186/bcr628
                314432
                12927032
                1d6ea56e-1e0a-490c-a9d8-3c2c7d1dfb03
                Copyright © 2003 BioMed Central Ltd
                History
                Categories
                Review

                Oncology & Radiotherapy
                oestrogen,prevention,epidemiology,risk factors,breast cancer
                Oncology & Radiotherapy
                oestrogen, prevention, epidemiology, risk factors, breast cancer

                Comments

                Comment on this article