Hormone replacement therapy and risk of epithelial ovarian cancer

Epidemiology and risk factors for ovarian cancer

Ovarian cancer is a complex disease, mostly observed in postmenopausal women, and is associated with poor survival rates. It is the sixth most common cancer and the fifth most common cause of death due to cancer among women in developed countries. Thus, despite representing less than one third of all gynaecologic cancers, deaths due to ovarian cancer account for more than two thirds of deaths due to gynaecologic cancers. Its prevalence is higher in Western Europe and Northern America than Asia and Africa. In sub-Saharan Africa, there is a considerably lower prevalence of ovarian cancer than other parts of Africa. Ovarian cancer is multifaceted, involving many factors, complex biological processes and unpredictable consequences. Unlike other female cancers that have early warning symptoms, ovarian cancer's symptoms are non-specific. As a result, ovarian cancers are normally undetected until advanced stages (III or IV). The major risk factors for ovarian cancer include older age, genetics, family history, hormone replacement therapy, nulliparity, and dietary fat. Controversial factors include obesity, infertility, talc powder, radiation exposure, fertility medications and in vitro fertilization. The current review discusses the aetiology, epidemiology and risk factors for ovarian cancer. Nevertheless, identification of the main risk factors for ovarian cancer may increase the awareness among women of the general population. This should help to decrease the incidence rate of ovarian cancer and increase the five-year survival rate.

Menopausal Hormone Replacement Therapy and the Risk of Ovarian Cancer: A Meta-Analysis

Background: Findings by epidemiologic studies on menopausal hormone replacement therapy (HRT) and the risk of ovarian cancer are inconsistent. This study aimed to assess the association of menopausal HRT with the risk of ovarian cancer by histological subtype. Methods: A literature search was performed in PubMed, Web of Science, and EmBase for relevant articles published from inception to August 2018. Pooled relative risk ratios (RRs) with 95% confidence intervals (CIs) were determined with a random-effects model. Results: Thirty-six studies involving 4, 229, 061 participants were included in this meta-analysis. The pooled RR of ovarian cancer was 1.29 (95%CI 1.19-1.40, I ² = 57.4%) for menopausal HRT. In subgroup analysis by study design, pooled RRs of ovarian cancer in cohort and case-control studies were 1.35 (95%CI 1.19-1.53) and 1.24 (95%CI 1.11-1.38), respectively. In subgroup analysis by continent, association of menopausal HRT with ovarian cancer was significant for North America (1.41 [1.23-1.61]), Europe (1.22 [1.12-1.34]), and Asia (1.76 [1.09-2.85]), but not Australia (0.96 [0.57-1.61]). Association differed across histological subtypes. Increased risk was only found for two common types, including serous (1.50 [1.35-1.68]) and endometrioid (1.48 [1.13-1.94]) tumors. Conclusion: This meta-analysis suggests that menopausal HRT may increase the risk of ovarian cancer, especially for serous and endometrioid tumors.

Regulation of semaphorin 4D expression and cell proliferation of ovarian cancer by ERalpha and ERbeta

Ovarian cancer is one of the most common malignancies in women. Semaphorin 4D (sema 4D) is involved in the progress of multiple cancers. In the presence of estrogen-like ligands, estrogen receptors (ERα and ERβ) participate in the progress of breast and ovarian cancers by transcriptional regulation. The aim of the study was to investigate the role of sema 4D and elucidate the regulatory pattern of ERα and ERβ on sema 4D expression in ovarian cancers. Sema 4D levels were up-regulated in ovarian cancer SKOV-3 cells. Patients with malignant ovarian cancers had significantly higher sema 4D levels than controls, suggesting an oncogene role of sema 4D in ovarian cancer. ERα expressions were up-regulated in SKOV-3 cells compared with normal ovarian IOSE80 epithelial cells. Conversely, down-regulation of ERβ was observed in SKOV-3 cells. Forced over-expression of ERα and ERβ in SKOV-3 cells was manipulated to establish ERα⁺ and ERβ⁺ SKOV-3 cell lines. Incubation of ERα⁺ SKOV-3 cells with ERs agonist 17β-estradiol (E2) significantly enhanced sema 4D expression and rate of cell proliferation. Incubated with E2, ERβ⁺ SKOV-3 cells showed lower sema 4D expression and cell proliferation. Blocking ERα and ERβ activities with ICI182-780 inhibitor, sema 4D expressions and cell proliferation of ERα⁺ and ERβ⁺ SKOV-3 cells were recovered to control levels. Taken together, the data showed that sema 4D expression was positively correlated with the progress of ovarian cancer. ERα positively regulated sema 4D expression and accelerated cell proliferation. ERβ negatively regulated sema 4D expression and inhibited cell multiplication.

Chronic lymphocytic leukemia-associated refractory immune thrombocytopenia successfully treated with eltrombopag

Chronic lymphocytic leukemia (CLL) may be associated with immune thrombocytopenia (ITP). The standard treatment for CLL-associated ITP is steroids. For refractory cases, various treatment strategies such as rituximab, splenectomy, and thrombopoietic mimetics are available. We report a patient with CLL who developed recurrent ITP and life-threatening pulmonary hemorrhage. Platelet counts remained extremely low despite massive platelet transfusion and treatment including steroids, immunoglobulin, and single-dose rituximab infusion. The bleeding stopped and platelet counts were increased to normal range 13 days after treatment with eltrombopag 25 mg per day. Our experience suggests that eltrombopag is an effective treatment option in CLL-associated, refractory ITP, especially during major bleeding, which requires relatively rapid improvement of thrombocytopenia.

Hormonal and surgical treatments for endometriosis and risk of epithelial ovarian cancer

OBJECTIVE

Whether hormonal or surgical treatment of endometriosis is associated with risk of epithelial ovarian cancer.

DESIGN

Nested case-control study.

SETTING

Sweden.

POPULATION

All women with a first-time discharge diagnosis of endometriosis in 1969-2007 were identified using the National Swedish Patient Register and constituted our study base.

METHODS

By linkage to the National Swedish Cancer Register we identified all women diagnosed with epithelial ovarian cancer at least one year after the endometriosis diagnosis (cases). Two controls per case with no ovarian cancer before the date of cancer diagnosis of the case were randomly selected from the study base and matched for year of birth. Two-hundred-and-twenty cases and 416 controls entered the study. Information on hormonal and surgical treatments and other reproductive factors was extracted from medical records according to pre-specified protocols. Conditional logistic regression was used for all calculations.

MAIN OUTCOME MEASURES

Crude and adjusted odds ratios (OR) with 95% confidence intervals (CI) for all hormonal as well as surgical treatments.

RESULTS

There was a significant association between one-sided oophorectomy, as well as for radical extirpation of all visible endometriosis, and ovarian cancer risk in both univariate analyses (crude OR 0.42, 95% CI 0.28-0.62 and OR 0.37, 95% CI 0.25-0.55, respectively) and multivariate analyses (adjusted OR 0.19, 95% CI 0.08-0.46 and OR 0.30, 95% CI 0.12-0.74, respectively).

CONCLUSIONS

One-sided oophorectomy as well as radical extirpation of all visible endometriosis is protective against later development of ovarian cancer.

Ovarian epithelial tumors and reproductive factors: a systematic review

PURPOSE

The aim of this systematic review is to summarize the current knowledge about the etiology and pathogenesis of borderline tumors ovarian cancer with special emphasis on the role of endocrine treatments and reproductive factors to establish a foundation for future studies.

METHODS

We performed a systematic review on the relation between ovarian epithelial tumors (OET) and reproductive factors using the keywords: ovarian cancer, ovarian tumor, ovarian borderline tumor, age at menarche, age at menopause, parity, infertility, PCO syndrome, oral contraception, menopausal hormone therapy, fertility treatment. Totally, 3,290 abstracts were scanned for their relevance in this publication and 127 were finally included.

RESULTS

The incidence of ovarian epithelial cancer and ovarian borderline tumors is influenced by certain reproductive factors. The strongest protective effects are conferred by parity and use of oral contraceptive pills. Recent molecular biologic and histopathologic studies prove that OET represent a diverse group of tumors, each histologic type with a different genetic background. This is at least partly reflected in epidemiologic and clinical studies showing different risk modulating effects of reproductive factors and endocrine therapies on OET.

CONCLUSIONS

The etiology and pathogenesis of ovarian cancer are still not fully understood. None of the so far proposed hypothesis on the development of OET can fully account for the epidemiologic and clinical findings in the context of reproductive factors and OET development. Further research approaches are warranted and need to put more weight on the clinical and genetical diversity of OET to yield a more detailed insight into their pathogenesis.

Ovarian cancer: etiology, risk factors, and epidemiology

Little is known regarding the early aspects of ovarian carcinogenesis. As a consequence, the identification of women at risk for the disease is based primarily on clinical grounds, with family history being the most important risk factor. In this review, we will discuss the various hypotheses regarding ovarian etiology and pathogenesis. In addition, we will discuss the epidemiology of ovarian cancer, including hereditary, reproductive, hormonal, inflammatory, dietary, surgical, and geographic factors that influence ovarian cancer risk.

The 2012 hormone therapy position statement of: The North American Menopause Society

OBJECTIVE

This position statement aimed to update the evidence-based position statement published by The North American Menopause Society (NAMS) in 2010 regarding recommendations for hormone therapy (HT) for postmenopausal women. This updated position statement further distinguishes the emerging differences in the therapeutic benefit-risk ratio between estrogen therapy (ET) and combined estrogen-progestogen therapy (EPT) at various ages and time intervals since menopause onset.

METHODS

An Advisory Panel of expert clinicians and researchers in the field of women's health was enlisted to review the 2010 NAMS position statement, evaluate new evidence, and reach consensus on recommendations. The Panel's recommendations were reviewed and approved by the NAMS Board of Trustees as an official NAMS position statement.

RESULTS

Current evidence supports the use of HT for perimenopausal and postmenopausal women when the balance of potential benefits and risks is favorable for the individual woman. This position statement reviews the effects of ET and EPT on many aspects of women's health and recognizes the greater safety profile associated with ET.

CONCLUSIONS

Recent data support the initiation of HT around the time of menopause to treat menopause-related symptoms and to prevent osteoporosis in women at high risk of fracture. The more favorable benefit-risk ratio for ET allows more flexibility in extending the duration of use compared with EPT, where the earlier appearance of increased breast cancer risk precludes a recommendation for use beyond 3 to 5 years.

Hormone therapy and different ovarian cancers: a national cohort study

Postmenopausal hormone therapy use increases the risk of ovarian cancer. In the present study, the authors examined the risks of different histologic types of ovarian cancer associated with hormone therapy. Using Danish national registers, the authors identified 909,946 women who were followed from 1995-2005. The women were 50-79 years of age and had no prior hormone-sensitive cancers or bilateral oophorectomy. Hormone therapy prescription data were obtained from the National Register of Medicinal Product Statistics. The National Cancer and Pathology Register provided data on ovarian cancers, including information about tumor histology. The authors performed Poisson regression analyses that included hormone exposures and confounders as time-dependent covariates. In an average of 8.0 years of follow up, 2,681 cases of epithelial ovarian cancer were detected. Compared with never users, women taking unopposed oral estrogen therapy had increased risks of both serous tumors (incidence rate ratio (IRR) = 1.7, 95% confidence interval: 1.4, 2.2) and endometrioid tumors (IRR = 1.5, 95% confidence interval: 1.0, 2.4) but decreased risk of mucinous tumors (IRR = 0.3, 95% confidence interval: 0.1, 0.8). Similar increased risks of serous and endometrioid tumors were found with estrogen/progestin therapy, whereas no association was found with mucinous tumors. Consistent with results from recent cohort studies, the authors found that ovarian cancer risk varied according to tumor histology. The types of ovarian tumors should be given attention in future studies.

Ovarian cancer risk in postmenopausal women using estradiol-progestin therapy - a nationwide study

OBJECTIVE

While previous data link the use of postmenopausal hormone therapy to an increased risk for ovarian cancer, little is known about the impact of various progestins, modes or routes of administration of hormone therapy for this risk. In this nationwide study, we compared relations between different estradiol-progestin (EPT) formulations and epithelial ovarian cancer risk.

METHODS

All Finnish women over 50 years using EPT for at least 6 months (224 015 women with 602 ovarian cancers) during 1994-2006 were identified from the reimbursement register. The incidence of ovarian cancer in EPT users was compared to that in the age-matched background population by means of observed to expected ratio (standardized incidence ratio, SIR).

RESULTS

Ovarian cancer risk was not elevated for EPT use of < 5 years but it was elevated for EPT use of ≥5 years (SIR 1.21, 95% confidence interval (CI) 1.06-1.37). Medroxyprogesterone acetate and norethisterone acetate as components of EPT were associated with similar risks for use for ≥ 5 years (SIR 1.26, 95% CI 0.94-1.64 and SIR 1.42, 95% CI 1.11-1.77, respectively). The risk did not differ between sequential or continuous EPT regimens or between oral or transdermal EPT formulations. The risk elevation for EPT use for ≥ 5 years was seen only for serous (SIR 1.56; 95% CI 1.33-1.80) and mixed cancers (SIR 1.54; 95% CI 1.22-1.91), whereas the risk for mucinous cancer was decreased (SIR 0.47; 95% CI 0.22-0.86).

CONCLUSION

The elevated risk of non-mucinous ovarian cancer in users of EPT ≥ 5 years does not depend on progestin type, mode or route of administration of EPT.

Identification of common mechanisms between endometriosis and ovarian cancer

PURPOSE

To determine common molecular markers between endometriosis and ovarian cancer.

METHODS

Patients included women who underwent laparoscopic excision of ovarian endometriotic lesions (n = 7), healthy non-pregnant women with normal pelvises, who underwent excision of normal peritoneum (n = 7). Two epithelial ovarian cancer (EOC) cell lines were also utilized. Expression of transforming growth factor (TGF)-β1, cyclooxygenase (COX)-2, vascular endothelial growth factor (VEGF), estrogen receptor (ER)-1α, progesterone receptor (PR), androgen receptor (AR), and aromatase was evaluated by real-time RT-PCR.

RESULTS

Endometriosis and EOC cells manifested significantly higher mRNA levels of TGF-β1, COX-2, VEGF, ER-1α, AR, and aromatase, while they expressed significantly lower mRNA levels of PR.

CONCLUSIONS

Increased TGF-β1, COX-2, VEGF, ER-1α, AR, and aromatase and decreased PR in endometriotic as well as EOC cells suggests a potential association between these two disease processes. This association is important, as it may reveal common mechanisms for both diseases.

Menopausal hormone therapy and risk of ovarian cancer in the European prospective investigation into cancer and nutrition

The association between menopausal hormone therapy (HT) and risk of ovarian cancer was assessed among 126,920 post-menopausal women recruited into the European Prospective Investigation into Cancer and Nutrition. After an average of 9-year follow-up, 424 incident ovarian cancers were diagnosed. Cox models adjusted for body mass index, smoking status, unilateral ovariectomy, simple hysterectomy, age at menarche, number of full-term pregnancies, and duration of oral contraceptives were used. Compared with baseline never use, current use of any HT was positively associated with risk (HR [hazard ratio], 1.29; 95% CI [confidence interval], 1.01-1.65), while former use was not (HR, 0.96; 95% CI, 0.70-1.30). Current estrogen-only HT was associated with a 63% higher risk (HR, 1.63; 95% CI, 1.08-2.47), while current estrogen plus progestin was associated with a smaller and non-significant higher risk (HR, 1.20; 95% CI, 0.89-1.62). Use of tibolone was associated with a twofold greater risk (HR, 2.19; 95% CI, 1.06-4.50), but was based on small numbers. In conclusion, women who currently use HT have a moderate increased risk of ovarian cancer, and which may be stronger for estrogen-only than estrogen plus progestin preparations.

[Ovarian carcinogenesis: recent and past hypotheses]

Ovarian carcinogenesis and the early stages of malignant transformation are limited because of the lack of a candidate precursor. There have been several proposed hypotheses: first, ovary and the ovarian surface epithelium and more recently observations have increasingly focused attention of the Fallopian tube. Moreover, molecular genetic analysis has designed two main pathways of tumorogenesis. In this review, we discuss the different and perhaps complementary hypotheses about ovarian carcinogenesis.

Molecular clustering based on ERα and EIG121 predicts survival in high-grade serous carcinoma of the ovary/peritoneum

Assessment of estrogen receptor (ER) expression by immunohistochemistry has yielded inconsistent results as a prognostic indicator in ovarian carcinoma. In breast and endometrial carcinomas, panels of estrogen-induced genes have shown improved prognostic capability over the use of ER immunohistochemistry alone. For both breast and endometrial cancers, overexpression of estrogen-induced genes is associated with better prognosis. We hypothesized that analysis of a panel of estrogen-induced genes can predict the outcome in ovarian carcinoma and potentially differentiate between tumors of varying hormonal responsiveness. From a cohort of 219 women undergoing ovarian cancer surgery from 2004 to 2007, 83 patients were selected for inclusion. All patients had advanced stage ovarian/primary peritoneal high-grade serous carcinoma and underwent primary surgical debulking, followed by adjuvant treatment with platinum and taxane agents. The expression of ERα and six genes known to be induced by estrogen in the female reproductive tract (namely EIG121, sFRP1, sFRP4, RALDH2, PR, and IGF-1) was measured using quantitative RT-PCR. Unsupervised cluster analyses were used to categorize patients as high or low gene expressors. Gene expression results were then compared with those for ER immunohistochemistry. Clusters were compared using χ(2) analyses, and Cox proportional hazards models were used to evaluate survival outcomes. The median follow-up time was 38.7 months (range: 1-68). A cluster defined by EIG121 and ERα segregated tumors into distinct groups of high and low gene expressors. Shorter overall survival (OS) was associated with high gene expression (HR 2.84 (1.11-7.30), P=0.03), even after adjustment for other covariates. No difference in ER immunohistochemistry expression was noted between gene clusters. In contrast to other hormonally driven cancers, high expression of ERα and the estrogen-induced gene EIG121 predicts shorter OS in patients with high-grade serous ovarian carcinoma. Such a biomarker panel may potentially be used to guide management with estrogen antagonists in this patient population.

Ovarian cancer in endometriosis: epidemiology, natural history, and clinical diagnosis

We review whether endometriosis-associated ovarian cancer is a specific entity compared with ovarian cancer not associated with endometriosis, with respect to epidemiology, natural history, and clinical diagnosis; we present a review of the English-language literature for ovarian cancer in endometriosis with respect to these three features. A recent prospective study in Japan directly showed that, during a follow-up of up to 17 years of an ovarian endometrioma cohort (n = 6398), 46 incident ovarian cancers were identified, showing that the ovarian cancer risk was significantly elevated in patients with ovarian endometrioma (standardized incidence ratio [SIR], 8.95; 95% confidence interval [CI], 4.12 to 15.3). Advancing age (>40 years) and the size of the endometriomas (>9 cm) were independent predictors of the development of ovarian cancer among the women with ovarian endometrioma. Although some endometriosis lesions may predispose to clear cell carcinoma (CCC) and endometrioid adenocarcinoma (EAC) of the ovary, both of these cancers differ from the other histological types with respect to their clinical characteristics and carcinogenesis. In patients with endometriosis-associated ovarian cancer, benign-appearing ovarian masses are typically present several years before the diagnosis of the cancer. A slightly elevated carbohydrate antigen [CA] 125 level is also typically present many years before the diagnosis in these patients. However, serous-type ovarian cancer may exhibit a rapid progression possibly through de-novo carcinogenesis. Ovarian endometrioma could be viewed as a neoplastic process, particularly in perimenopausal women. Understanding the mechanisms of the development of endometriosis and elucidating its pathogenesis and pathophysiology are intrinsic to the prevention of endometriosis-associated ovarian cancer and the search for effective therapies.

Endometrioid adenocarcinoma arising from endometriosis of the uterine cervix: a case report

Endometrioid adenocarcinoma arising from endometriosis of the uterine cervix is rare in premenopausal woman. We describe here a patient with this condition and review the clinical and pathological features of these tumors. A 48-yr-old woman complaining of severe dysmenorrhea was referred for investigation of a pelvic mass. Total abdominal hysterectomy and bilateral salpingo-oophorectomy were performed. Histological examination revealed an endometrioid adenocarcinoma directly adjacent to the endometriosis at the uterine cervix, with a transition observed between endometriosis and endometrioid adenocarcinoma. The patient was diagnosed as having endometrioid adenocarcinoma arising from endometriosis of the uterine cervix and underwent postoperative chemotherapy. Gynecologists and pathologists should be aware of the difficulties associated with a delay in diagnosis of endometrioid adenocarcinoma arising from endometriosis when the tumor presents as a benign looking endometrioma.

Current understanding of risk factors for ovarian cancer

OPINION STATEMENT

Ovarian cancer is the deadliest gynecologic cancer. Unlike many cancers such as breast, cervical and colon cancers, there is no easily clinically identifiable pre-malignant phase of this malignancy making early identification difficult. Similarly, unlike lung, head and neck, and skin cancers, there is not easily identifiable risk factor making prevention short of oophorectomy difficult. Even so, theories as to the causative factors of ovarian cancer continue to evolve making our understanding of the genesis of ovarian cancer more clear. Genetics, parity, environment, hormonal factors, and inflammation all play an important and pivotal role in the development of ovarian cancer. The most current understanding of these elements and their respective contribution to the development of this cancer are presented in this chapter.

Increased ovarian cancer risk associated with menopausal estrogen therapy is reduced by adding a progestin

BACKGROUND

It has become increasingly clear that use of menopausal hormone therapy (HT) is associated with an increased risk of ovarian cancer; however, the effects by type of formulation and duration of use are less clear. A systematic review of the HT and ovarian cancer literature was conducted to identify population-based case-control studies, cohort studies, and randomized trials that examined effects by formulation of HT (estrogen-alone [ET] and estrogen plus progestin [EPT]) and duration of use.

METHODS

Pub-Med (www.pubmed.gov) was used to identify relevant publications through December 2007; 14 studies were identified. The authors abstracted relative risks (RRs) and 95% confidence intervals (CIs) in relation to duration of HT use (ET and EPT separately). The authors used the risk estimates per year of HT use if these were provided; otherwise, they calculated a duration-response for a log-linear model of the duration of HT use against risk.

RESULTS

Ovarian cancer risk was increased among ET users (RR per 5 years of use, RR(5) = 1.22; 95% CI, 1.18-1.27; P < .0001), and a lower but still statistically significant increased risk was seen with EPT use (RR(5) = 1.10; 95% CI, 1.04-1.16; P = .001). The increased risk in ET users was statistically significantly higher than the increased risk in EPT users (P = .004).

CONCLUSIONS

ET use increases risk of ovarian cancer in a duration-dependent manner, and it appears that the addition of progestins blocks this effect, at least to some extent. Whether the effect of estrogens would be completely blocked if progestins were given every day is unclear.

Hormone therapy for endometriosis and surgical menopause

BACKGROUND

Endometriosis is characterized by the presence of ectopic endometrial tissue that might lead to many distressing and debilitating symptoms. Despite available studies supporting standard hormone therapy for women with endometriosis and post-surgical menopause, there is still a concern that estrogens may induce a recurrence of the disease and its symptoms.

OBJECTIVES

This review aimed to look at pain and disease recurrence in women with endometriosis who used hormone therapy for post-surgical menopause.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders and Subfertility Group Specialized Register (March 2008), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2008, Issue 3), MEDLINE (1966 to March 2008), EMBASE (1980 to March 2008), and references lists of articles. Relevant journals and conference proceedings were handsearched.

SELECTION CRITERIA

Randomized controlled trials studying hormone therapy for women with endometriosis in post-surgical menopause.

DATA COLLECTION AND ANALYSIS

Review authors assessed the eligibility of trials and their quality.

MAIN RESULTS

Two studies fulfilled our inclusion criteria. One trial compared the nonstop transdermal application of 17beta-estradiol (0.05 mg/day) combined with cyclic medroxy progesterone acetate (10 mg per day) for 12 days per month in women with a conserved uterus with nonstop tibolone (2.5 mg/day). The second trial used sequential administration of estrogens and progesterone with two 22 cm(2) patches applied weekly to produce a controlled release of 0.05 mg/day. Micronized progesterone was administered orally (200 mg/day) for 14 days with a 16-day interval free of treatment. Pain and dyspareunia The first trial reported recurrence of pain in the estrogen and progesterone arm in 4/10 of women compared with 1/11 in the tibilone arm. In the latter, 4/115 women reported recurrence of pain in the treatment group compared with 0/57 patients in the no-treatment arm. Neither finding was statistically different.Confirmed recurrence or exacerbation of endometriosis This outcome was not reported in the first trial. The second found that 2/115 of the treatment group developed recurrence of endometriosis with no recurrence reported in the no-treatment group. This was not statistically significant. No woman was re-operated on in the no-treatment group compared with 2/115 in the treatment group.

AUTHORS' CONCLUSIONS

Hormone replacement therapy for women with endometriosis in post-surgical menopause could result in pain and disease recurrence. However, the evidence in the literature is not strong enough to suggest depriving severely symptomatic patients from this treatment. There is a need for more randomised controlled studies.

Aromatase inhibitors in ovarian cancer: is there a role?

Estrogen plays a role in ovarian tumorigenesis. Aromatase is the enzyme required for the synthesis of estrogen via conversion of androgen to estrogen, which is the major source of estrogen in postmenopausal women. Aromatase is present in normal ovaries and other tissues (e.g., fat and muscle) as well as in 33-81% tumor tissues of ovarian cancer. Aromatase inhibitors (AIs) block estrogen synthesis by inhibiting aromatase activity. In patients with recurrent ovarian cancer, single-agent AI therapy has been shown to elicit clinical response rates of up to 35.7% and stable disease rates of 20-42%. Given the limited treatment options for recurrent ovarian cancer and the favorable safety profile and convenient use, AI is a rational option for prolonging platinum-free interval in recurrent ovarian cancer. Further studies are required to determine the efficacy of combination treatment with AIs and biological agents, determine the benefit of AIs for treating special types of ovarian cancer (e.g., endometrioid type), and identify biomarkers for targeted patient selection. This review summarizes the current epidemiologic, preclinical, and clinical data regarding estrogen's role in ovarian cancer, the expression and regulation of aromatase in this disease, the development and characteristics of the three generations of AIs, and the preclinical and clinical studies of AIs in the treatment of ovarian cancer.

Menopausal hormone therapy and risk of epithelial ovarian cancer

Substantial increase in the use of menopausal hormone therapy (HT) throughout the 1990s, followed by widespread discontinuation after the 2002 publication of the Women's Health Initiative findings, has resulted in large numbers of former HT users among U.S. women. However, few studies have examined whether ovarian cancer risk varies according to recency and duration of specific HT regimens. We assessed risk of epithelial ovarian cancer among users of unopposed estrogen (ET) and combined estrogen/progestogen (EPT). In a population-based study in Washington state, 812 women with ovarian cancer diagnosed in 2002 to 2005 and 1,313 controls were interviewed in person about the use of HT and other characteristics. Women who used a single form of therapy (ET or EPT) were compared with women who never used HT using logistic regression to calculate odds ratios (OR) and 95% confidence intervals (95% CIs). Risk was increased among current or recent (within the last 3 years) users of ET with > or = 5 years of use (ORs, 95% CIs: 1.6, 1.1-2.5 and 1.8, 0.8-3.7, respectively). Little increase in risk was noted among long-term ET users who discontinued use in the more distant past (OR, 1.2; 95% CI, 0.6-2.6). No increase in risk was noted among women who used only EPT, regardless of duration. Compared with women who never used HT, current users of EPT had an OR of 1.1 (95% CI, 0.8-1.5), and risk declined with increasing time since stopping; the OR was 0.7 (95% CI, 0.4-1.0) among women who had discontinued EPT within the last 3 years and 0.5 (95% CI, 0.3-0.7) among women who stopped at an earlier point. Long-term ET may be associated with an increased ovarian cancer risk that wanes after use ceases. We did not observe an increased risk with EPT, and with increasing time after stopping, a reduction in risk became increasingly evident. The progestogen component of HT may confer a risk reduction that is masked by an opposing effect of estrogen until, among former users, estrogenic influences have diminished. These findings, if replicated, may have implications both for public health and development of chemoprevention strategies.

Hormone therapy and ovarian cancer: incidence and survival

OBJECTIVE

We conducted a population-based case-control study to investigate the association between hormone therapy (HT) and ovarian cancer incidence, and followed all these cancer cases to determine the association of HT use with ovarian cancer mortality.

METHODS

Seven hundred fifty-one incident cases of invasive epithelial ovarian cancer aged 40-79 years were diagnosed in Massachusetts and Wisconsin between 1993-1995 and 1998-2001 and matched to similarly aged controls (n = 5,808). Study subjects were interviewed by telephone, which ascertained information on HT use and specific preparation, estrogen alone (E-alone) or estrogen plus progestin (EP). Ovarian cancer cases were followed-up for mortality through December 2005. Multivariate logistic regression was used to estimate odds ratios and 95% confidence intervals (CI) for ovarian cancer incidence, and Cox proportional hazards modeling was used to estimate hazard ratios and corresponding confidence intervals for ovarian cancer mortality.

RESULTS

Ever use of HT was significantly associated with an increased risk of ovarian cancer (odds ratio 1.57, 95% CI 1.31-1.87). The excess risk was confined to women who used E-alone preparations (OR 2.33, 95% CI 1.85-2.95). No significant associations were detected between pre-diagnosis HT use and ovarian cancer survival.

CONCLUSIONS

Hormone therapy increases risk of ovarian cancer among E-alone users, but there is no substantial impact on survival after diagnosis.

Menopausal hormone therapy and risk of ovarian cancer: systematic review and meta-analysis

Knowledge about the impact of menopausal hormone therapy (MHT) on the risk of ovarian cancer (OvC) is insufficient, and studies are inconsistent. Mortality from OvC ranks highest among cancer sites in female reproductive organs. We performed meta-analyses to assess the impact of specified types of MHT on the risk of OvC in cohort studies (CS), case-control studies (CCS), randomized controlled trials (RCT) and cancer registry studies (CRS). We used data published 1966-2006 on estrogen therapy (ET), estrogen/progestin therapy (EPT) or MHT (unspecified regimen) identified by a structured, computerized and manual literature search. We identified 42 studies (30CCS, 7CS, 1 RCT and 4 CRS) with 12 238 cases. The risk of OvC (ever-use, annual risk) is increased 1.28-fold by ET [confidence interval (CI) 1.18-1.40] and 1.11-fold by EPT (CI 1.02-1.21) with a suggestion of greater risks with ET. There appears to be no differential impact of any therapy on histological subtypes. Risks were greater in European than North American studies for both ET and EPT. In conclusion, ET as well as EPT, are risk factors for OvC. Given the widespread use of MHT, known benefits should be weighed against the increased risk of OvC, and more studies are warranted, particularly on factors with the greatest apparent risks.

Ovarian cancer and hormone replacement therapy in the Million Women Study

BACKGROUND

Ovarian cancer is the fourth most common cancer in women in the UK, with about 6700 developing the malignancy and 4600 dying from it every year. However, there is limited information about the risk of ovarian cancer associated with the use of hormone replacement therapy (HRT).

METHODS

948,576 postmenopausal women from the UK Million Women Study who did not have previous cancer or bilateral oophorectomy were followed-up for an average of 5.3 years for incident ovarian cancer and 6.9 years for death. Information on HRT use was obtained at recruitment and updated where possible. Relative risks for ovarian cancer were calculated, stratified by age and hysterectomy status, and adjusted by area of residence, socioeconomic group, time since menopause, parity, body-mass index, alcohol consumption, and use of oral contraceptives.

FINDINGS

When they last reported HRT use, 287,143 women (30%) were current users and 186 751 (20%) were past users. During follow-up, 2273 incident ovarian cancers and 1591 deaths from the malignancy were recorded. Current users were significantly more likely to develop and die from ovarian cancer than never users (relative risk 1.20 [95% CI 1.09-1.32; p=0.0002] for incident disease and 1.23 [1.09-1.38; p=0.0006] for death). For current users of HRT, incidence of ovarian cancer increased with increasing duration of use, but did not differ significantly by type of preparation used, its constituents, or mode of administration. Risks associated with HRT varied significantly according to tumour histology (p<0.0001), and in women with epithelial tumours the relative risk for current versus never use of HRT was greater for serous than for mucinous, endometroid, or clear cell tumours (1.53 [1.31-1.79], 0.72 [0.52-1.00], 1.05 [0.77-1.43], or 0.77 [0.48-1.23], respectively). Past users of HRT were not at an increased risk of ovarian cancer (0.98 [0.88-1.11] and 0.97 [0.84-1.11], respectively, for incident and fatal disease). Over 5 years, the standardised incidence rates for ovarian cancer in current and never users of HRT were 2.6 (2.4-2.9) and 2.2 (2.1-2.3) per 1000, respectively-ie, one extra ovarian cancer in roughly 2500 users; death rates were 1.6 (1.4-1.8) and 1.3 (1.2-1.4) per 1000, respectively-ie, one extra ovarian cancer death in roughly 3300 users.

INTERPRETATION

Women who use HRT are at an increased risk of both incident and fatal ovarian cancer. Since 1991, use of HRT has resulted in some 1300 additional ovarian cancers and 1000 additional deaths from the malignancy in the UK.

Risk of developing ovarian cancer among women with ovarian endometrioma: a cohort study in Shizuoka, Japan

Although some studies have indicated that endometriosis may increase the risk of developing ovarian cancer, there are no data from epidemiologic studies in Japan. We prospectively analyzed all cases of ovarian endometrioma enrolled in the prefecture-wide Shizuoka Cohort Study on Endometriosis and Ovarian Cancer Programme, which was initiated in 1985. To evaluate the risk of ovarian cancer by time periods subsequent to ovarian endometrioma diagnosis, a cohort of 6,398 women with a clinically documented ovarian endometrioma in Shizuoka between 1985 and 1995 was identified from the Shizuoka Cancer Registry (SCR), with follow-up through 2002. Ovarian cancer incidence among cohort members was ascertained by linkage to the SCR using a unique person-identification number. Standardized incidence ratios (SIR) and their 95% confidence intervals (CI) were computed by a use of prefecture-wide rates of ovarian cancer, adjusted for age and calendar year. During follow-up of up to 17 years of the ovarian endometrioma cohort, 46 incident ovarian cancers were identified, yielding that the ovarian cancer risk was elevated significantly among patients with ovarian endometrioma (SIR = 8.95, 95% CI = 4.12-15.3). The SIR did not increase with increasing follow-up duration. The risk increased with increasing age at ovarian endometrioma diagnosis, with a SIR equal to 13.2 (95% CI = 6.90-20.9) in women above 50 years of age. Our findings for the first time support the hypothesis that ovarian endometrioma increases the subsequent risk of developing ovarian cancer in Shizuoka, Japan.

Endometriosis and the development of malignant tumours of the pelvis. A review of literature

For several decades, endometriosis has been suspected of playing a role in the aetiology of ovarian cancer. The literature concerning a possible histogenesis of ovarian cancer from benign endometriosis is reviewed in this chapter. Epidemiological evidence from large-cohort studies confirms endometriosis as an independent risk factor for ovarian cancer. Further circumstantial evidence for this link was found in the common risk factors for ovarian cancer and endometriosis. These risk factors influence retrograde menstruation and endometriosis in the same positive or negative way. Based on data in the literature, the prevalence of endometriosis in epithelial ovarian cancer has been calculated to be 4.5, 1.4, 35.9, and 19.0% for serous, mucinous, clear-cell and endometrioid ovarian carcinoma, respectively. The risk of malignant transformation in ovarian endometriosis was calculated at 2.5% but this might be an underestimate. In addition, some authors described atypical endometriosis in a spatial and chronological association with ovarian cancer. Finally, molecular studies have detected common alterations in endometriosis and ovarian cancer. These data suggest that some tumours, especially endometrioid and clear-cell carcinomas, can arise from endometriosis. Moreover, endometriosis-associated ovarian cancer represents a distinct clinical entity, with a more favourable biological behaviour, given a lower stage distribution and better survival than non-endometriosis-associated ovarian cancer.

Estrogen–progestogen replacement therapy and ovarian cancer: an update

Hormone replacement therapy in menopause has been associated with a moderate increase in ovarian cancer risk. Data on combined estrogen-progestin therapy, based on one randomized trial, two cohort and four case-control studies, do not provide definite evidence of an association between combined hormone replacement therapy and ovarian cancer. These data do not suggest, however, substantial differences between the effect of estrogen only or unspecified hormone replacement therapy and combined hormone replacement therapy on ovarian cancer risk.

Menopausal hormone therapy and ovarian cancer risk in the National Institutes of Health-AARP Diet and Health Study Cohort

BACKGROUND

Recent studies offer conflicting data on risks of ovarian cancer in users of menopausal hormone therapy. Some findings of increased risks associated with unopposed estrogen use are based on older studies of women with intact uteri, and small sample size and incomplete exposure information have limited the data on estrogen plus progestin associations.

METHODS

The National Institutes of Health-AARP Diet and Health Study Cohort included 97,638 women aged 50-71 years at baseline who completed two questionnaires (1995-1996 and 1996-1997). We identified 214 incident ovarian cancers among these women through the year 2000 using data from state cancer registries and mortality indexes. We estimated relative risks (RRs) of ovarian cancer for detailed hormone therapy exposures using multivariable proportional hazards regression models. All statistical tests were two-sided.

RESULTS

Use of unopposed estrogen for fewer than 10 years was not associated with ovarian cancer. Compared with use of no hormone therapy, use of unopposed estrogen for 10 or more years was statistically significantly associated with ovarian cancer among all women (RR = 1.89, 95% confidence interval [CI] = 1.22 to 2.95; P = .004; 56 versus 72 ovarian cancers per 100,000 person-years, respectively) and, albeit not statistically significantly, among women with hysterectomy (n = 19,359, RR = 1.70, 95% CI = 0.87 to 3.31; P = .06). Among the 73,483 women with intact uteri, 51,698 had used no hormone therapy or only estrogen plus progestin. Compared with no hormone therapy use, 5 or more years of use of sequential (progestin for < 15 days per cycle; RR = 3.09, 95% CI = 1.68 to 5.68; P < .001; 49 versus 108 per 100,000 person-years) or continuous (progestin for > or = 15 days per cycle; RR = 1.82, 95% CI = 1.03 to 3.23; P = .02; 49 versus 66 per 100,000 person-years) estrogen plus progestin regimens were statistically significantly associated with ovarian cancer.

CONCLUSIONS

Long durations of use of unopposed estrogen and of estrogen plus progestin, especially sequential regimens, are associated with increased ovarian cancer risk. These data expand the range of possible risks associated with menopausal hormone therapy.

Malignant extraovarian endometriosis: A review

AIMS

Malignant transformation in extra-ovarian endometriosis is a rare but known complication. This distinct pathological entity is reviewed with a specific focus on aetiology and treatment.

METHODS

Studies were identified by searching the English language literature in the MEDLINE database and by an extensive review of bibliographies from articles found through that search.

FINDINGS

Up to 1% of women with endometriosis will develop endometriosis-associated neoplasm. Almost a quarter of the reported cases of malignancy in endometriosis have involved extra-ovarian tissues. In many cases, hormonal factors may play a role in its pathogenesis. Estrogen monotherapy in obese patients significantly increase the risk of malignant extra-gonadal endometrial transformation. Genetic anomalies have also been reported such as loss of heterozygosity on chromosome 5q. For patients with disease confined to the site of origin, a 82-100% 5-year survival has been noted for endometrioid cell type; disseminated intraperitoneal disease, however, has a very poor associated prognosis, with a 0-12% 5-year survival overall.

CONCLUSIONS

Women with endometriosis-associated cancers most likely represent a different class of patients than traditional ovarian cancer patients and may require different therapeutic options.

Does hormone replacement therapy prevent epithelial ovarian cancer?

Two much-debated hypotheses regarding the aetiology of epithelial ovarian cancer (EOC) are incessant ovulation and gonadotrophin stimulation. A significant inverse correlation is found between the risk of EOC and number of pregnancies, duration of oral contraceptive use (about 10% risk reduction per year) and duration of breastfeeding. Whereas ovulation in the 20-29 year age group was associated with a 20% increase in risk for each year of ovulation, maximum protective effect was noticed in late childbirth (>35 years). Although both in-vitro and in-vivo studies showed that gonadotrophins may initiate and stimulate the growth of EOC, it is not known whether gonadotrophins promote EOC. FSH and LH receptors have been detected by ligand-binding assay and by reverse transcriptase polymerase chain reaction in ovarian surface epithelium (OSE) and in malignant epithelial ovarian tissue. Key aetiological events for this cancer may occur in the premenopausal period. Although hormone replacement therapy (HRT) can lower FSH and LH concentrations substantially, it cannot reduce EOC. The ideal time of ovulation and/or gonadotrophin suppression for prevention of EOC, and why oral contraceptives (OC) can but HRT cannot reduce EOC effectively, are unknown. Various growth-related genes, factors, adhesion molecules and angiogenic factors are present in OSE. Pituitary ovarian axis hormones seem to maintain a delicate balance towards growth control whilst the resultant chain of abnormal growth-promoting events occur at cellular level. Reports regarding the relation of exogenous and endogenous hormones, especially oestrogen, and post-menopausal EOC are reviewed.

Hormonal treatments and epithelial ovarian cancer risk

Exogenous sex hormones are widely used by women either for pregnancy prevention, as part of infertility treatment, or for treatment of menopausal symptoms. The role of these hormones in the development of ovarian cancer has been vastly explored. The protective effect of combined oral contraceptive pill is confirmed in multiple studies, but it is not clear whether this protection also covers women with a genetic predisposition to ovarian cancer. There is no conclusive evidence of infertility treatments increasing ovarian cancer risk, but infertility as such is a risk factor. Currently available data suggest that long-term users of hormone replacement therapy may have a slightly increased risk for ovarian cancer compared to women who have never used estrogen. The risk might particularly involve the endometrioid type of ovarian cancer. Most data on ovarian cancer and estrogen comes from epidemiological studies, since the normally high concentrations of estrogens in ovarian tissue and follicular fluid make direct biologic studies on the effects of exogenous estrogens on the ovarian cell difficult. This review discusses the risk of ovarian cancer associated with the use of sex steroid hormones, with special emphasis on the possible risk associated with estrogens.

Hormone replacement therapy (HRT) and endometrial morphology under consideration of the different molecular pathways in endometrial carcinogenesis

The majority of modern hormone replacement therapy (HRT) regimens contain estrogen and progestogens, given either in a cyclical or continuous manner. About 15% of the endometrial biopsies taken from women on sequential HRT show proliferative activity including atypical endometrial hyperplasia in up to 1% of the cases. The majority of biopsies from women under continuous combined HRT show an endometrial atrophy. About 2-3% of these women will present proliferative activity, usually without atypical hyperplasia. Contrary to breast cancer, an increased risk of endometrial cancer has not been reported in the WHI- and HERS-studies. However, endogenous factors, such as obesity, diabetes mellitus, the distribution of estrogen receptors alpha and beta and genetic polymorphisms for receptors and enzymes might alter the endometrial stimulation under different types of HRT. There should be a liberal indication for endometrial biopsies in Hereditary Non-Polyposis Colorectal Cancer (HNPCC). HNPCC-patients under HRT as well as for ultrasonographic evaluation of the endometrium. The risk of atypical hyperplasias or carcinoma under unopposed estrogen-therapy varies from 2 to 10%. So, this kind of HRT should not be used in non-hysterectomised women. As far as the risk of endometrial cancer under any kind of HRT is concerned, the different molecular pathways of endometrial carcinogenesis (type 1 and 2 cancers) should be taken into account. The use of tibolone leaves the endometrium unaffected.

Hormone replacement therapy and invasive and borderline epithelial ovarian cancer risk

Risk of epithelial ovarian cancer (EOC) attendant to use of hormone replacement therapy (HRT) was evaluated in a population-based case-control study of newly diagnosed EOC cases (n=256) and randomly selected population controls (n=1122). Telephone interviews were conducted to obtain information on history of HRT and several other covariates. Multivariate adjusted odds ratio (OR) and 95% confidence intervals (CI) were derived from unconditional logistic regression. The OR for ever use of HRT was 1.39 (95% CI: 1.01-1.93) compared to never use. Long-term use (>10 years) increased risk (OR: 1.62, CI: 1.05-2.50) although the trend p-value for duration of use was of only borderline significance (p=0.08). The relationship was stronger in women without hysterectomy (OR: 1.66, 95% CI: 1.14-2.41) or tubal ligation (OR: 1.56, 95% CI: 1.08-2.26). In this study, use of HRT is associated with an increased risk of EOC.

Ovarian Conservation at the Time of Hysterectomy for Benign Disease

OBJECTIVE

Prophylactic oophorectomy is often recommended concurrent with hysterectomy for benign disease. The optimal age for this recommendation in women at average risk for ovarian cancer has not been determined.

METHODS

Using published age-specific data for absolute and relative risk, both with and without oophorectomy, for ovarian cancer, coronary heart disease, hip fracture, breast cancer, and stroke, a Markov decision analysis model was used to estimate the optimal strategy for maximizing survival for women at average risk of ovarian cancer. For each 5-year age group from 40 to 80 years, 4 strategies were compared: ovarian conservation or oophorectomy, and use of estrogen therapy or nonuse. Outcomes, as proportion of women alive at age 80 years, were measured. Sensitivity analyses were performed, varying both relative and absolute risk estimates across the range of reported values.

RESULTS

Ovarian conservation until age 65 benefits long-term survival for women undergoing hysterectomy for benign disease. Women with oophorectomy before age 55 have 8.58% excess mortality by age 80, and those with oophorectomy before age 59 have 3.92% excess mortality. There is sustained, but decreasing, benefit until the age of 75, when excess mortality for oophorectomy is less than 1%. These results were unchanged following multiple sensitivity analyses and were most sensitive to the risk of coronary heart disease.

CONCLUSION

Ovarian conservation until at least age 65 benefits long-term survival for women at average risk of ovarian cancer when undergoing hysterectomy for benign disease.

Epithelial ovarian cancer risk by invasiveness and cell type in the Central Valley of California

OBJECTIVE

To evaluate epithelial ovarian cancer (EOC) risk factors by level of invasiveness and histology.

METHODS

A population-based epidemiologic case-control study of EOC was conducted over a 2-year period (January 2000 to December 2001) in 22 counties of Central California that comprise the reporting area for two regional cancer registries. Telephone interviews were conducted with 256 cases and 1122 control frequencies matched on age and ethnicity. The interview obtained information on demographic factors as well as information pertinent to the respondent's menstrual and reproductive experience, use of exogenous hormones, surgical history, and family history of cancer. Adjusted odds ratios were calculated using stratification as well as Logistic regression methods. Analyses were completed by level of invasiveness and cell type.

RESULTS

Strong protective associations were observed for use of oral contraceptives and parity. Risk increased with a family history of ovarian, but not breast cancer and age at first birth was positively associated with increased risk. Hormone replacement therapy was associated with increased risk only in long-term users. Many of the relationships were observed only in specific histologic subtypes of EOC.

CONCLUSION

Risk of EOC is associated with several lifestyle and environmental exposures but the impact of these effects appears to be dependent upon level of invasiveness and histologic subtypes of EOC. However, the sample size available for analysis limits our statistical power and our ability to analyze data by histologic subtype, thus limiting interpretation of our results.

Prevention of cancers of the breast, endometrium and ovary

A central epidemiological feature of cancers of the breast, endometrium and ovary is the sharp slowing down in their rate of increase with age around the time of menopause. The incidence of these tumors by the age of 70 years would be between fourfold and eightfold increased if the rapid increase with age seen in young women continued into old age. These phenomena can be explained by the different effects of ovarian hormones on cell division rates in the relevant tissues. Models of these effects provide a plausible explanation of most of the known epidemiology of each of the cancers, including the increase in breast cancer risk from menopausal estrogen-progestin therapy. Some recent epidemiological findings in endometrial and ovarian cancer suggest new avenues for possible chemoprevention of these cancers.

Review of epidemiological evidence for reproductive and hormonal factors in relation to the risk of epithelial ovarian malignancies

Ovarian cancer is the leading cause of mortality related to gynecologic malignancies in Sweden but there is no current screening program. Based upon epidemiological research there is evidence that certain reproductive factors are associated with ovarian cancer risk. Most studies generally indicate that each childbirth incurs a 15-20% risk reduction. Women who have used oral contraceptives for 5 years or longer experience about half the risk of ovarian cancer compared with never users. Breastfeeding seems to be protective while age at menarche and at menopause are less consistent risk predictors. Tubal ligation and hysterectomy seem to reduce ovarian cancer risk by up to 80%. Although some studies found endometriosis, polycystic ovarian syndrome (PCOS) and pelvic inflammatory disease (PID) to be positively related to ovarian cancer, the role of these factors is not yet established. Most recent studies observed an approximately 50% ovarian cancer risk increase among ever users of hormone replacement therapy (HRT) compared with never users, and the risk increased further with long-term use. There is less information concerning separate estrogen and progestin effects of HRT and ovarian cancer risk. Although the cause of ovarian cancer remains obscure, hypotheses relating to "incessant" ovulation, excessive gonadotropin secretion, retrograde carcinogen transportation, apoptosis and estrogen/progestin imbalance have been invoked as etiological explanations. All these hypotheses find various epidemiological support. The aim of this review is to summarize the epidemiological findings on reproductive factors and ovarian cancer risk. These findings are considered in the context of etiologic hypotheses and some new research areas are suggested.

Hormone replacement therapy in postmenopausal women

BACKGROUND

For many years, hormone replacement therapy (HRT) was considered an effective method of restoring the relative protection from coronary artery disease enjoyed by premenopausal women compared with men of similar age. This view has been supported by a substantial number of basic science and observational studies.

DATA SOURCES

Results of recent randomized controlled trials have seriously challenged the concept of the protective value of HRT by showing that rather than decreasing the risk of coronary artery disease, HRT actually appears to increase it. In addition, it increases the risk for breast cancer, stroke, venous thromboembolism, and cholecystitis.

RESULTS

Despite some benefits such as increased bone mineral density and decreased risk of fracture and colorectal cancer, these data suggest that the risks of HRT outweigh the benefits.

CONCLUSIONS

HRT is no longer routinely recommended for prevention of chronic disease. We present the current scientific data, benefits, risks, and consequent clinical recommendations regarding HRT use in postmenopausal women.

Association of cigarette smoking with the risk of ovarian cancer

Cigarette smoking may be associated with ovarian cancer risk. This association may differ by histological type. The authors conducted a population-based case-control study in Canada of 442 incident cases of ovarian cancer and 2,135 controls 20-76 years of age during 1994-1997 to examine this association, overall and by histological type. Compared to women who never smoked, those who smoked had higher odds (odds ratio [OR] = 1.22; 95% confidence interval [CI] = 0.98-1.53) of having ovarian cancer, and the OR was larger for ex-smokers (1.30; 95% CI = 1.01-1.67) than for current smokers (1.10; 95% CI = 0.81-1.49). The association with cigarette smoking was stronger for mucinous tumors (OR = 1.77; 95% CI = 1.06-2.96) than for nonmucinous tumors (OR = 1.13; 95% CI = 0.89-1.44). In addition, the odds of smokers having mucinous tumors increased with years of smoking (OR = 1.36, 1.88, 1.19, 4.89 for <20, 21-30, 31-40 and >40 years, respectively; p for trend = 0.002), number of cigarettes smoked per day (OR = 1.55, 1.89, 2.28 for <10, 11-20 and >20 cigarettes/day, respectively; p for trend = 0.014) and smoking pack-years (OR = 1.13, 2.65, 1.77 and 2.39 for <10, 11-20, 21-30 and >30 pack-years, respectively; p for trend = 0.004). Our data suggest that cigarette smoking is associated with an increased risk of ovarian cancer, especially for mucinous types.

Neoplasms of the reproductive tract: the role of hormone exposure

Cancers of the reproductive system are a major source of morbidity and mortality among women worldwide. Because the uterus, ovaries, and cervix are hormonally responsive tissues, exposure to endogenous or exogenous sex steroids can profoundly affect the carcinogenic process. Animal models developed to date provide valuable but imperfect systems in which to study neoplasms of the reproductive tract. Nonhuman primate models share the unique primate-specific endometrial physiology of humans, but rarely develop neoplasms of the reproductive tract. Therefore a surrogate marker approach is required for the study of hormonally induced cancer risk in primates. Rodents provide practical models in which tumorigenesis can be assayed in a short time and, with appropriate interpretation, can be used for assessment of risk, prevention, and therapeutic strategies. In addition to the spontaneous strain-dependent incidence of female reproductive cancers, the classical chemical and hormonal carcinogenesis models, and the use of xenograft approaches, novel genetically modified animals provide unique insights into relevant molecular mechanisms. Caveats in the use of rodent models include anatomical differences from the human reproductive tract, the greater possibility of different metabolic responses to hormonal agents than humans, strain variations in tumor type and hormonal responsiveness, and unexpected tumor phenotypes in genetically modified animals. Reported nonmammalian models are limited primarily to the study of ovarian carcinogenesis. Recent progress in the understanding of cervical carcinogenesis is encouraging. Unmet needs in this area of research include models of early events in ovarian carcinogenesis and strongly predictive models of endometrial cancer risk. Nonhuman primates remain indispensable for the study of some aspects of reproductive pathophysiology, but the best understanding of carcinogenesis in the reproductive tract requires a broad approach using complementary human, nonhuman primate, and nonprimate studies.

Estrogens and epithelial ovarian cancer

OBJECTIVE

Molecular mechanisms involved in ovarian carcinogenesis are still unclear, but there is growing evidence that estrogens promote tumor progression in an epithelial ovarian cancer (EOC) subgroup.

METHODS

We reviewed current knowledge on the effects of estrogens in ovarian carcinogenesis and new potential research focuses concerning hormonal therapy of EOC.

RESULTS

Experimentally, estrogen stimulates the growth of ovarian tumor cell lines expressing estrogen receptors (ER). We and other authors have demonstrated differential expression of ERalpha or beta during ovarian carcinogenesis, with overexpression of ERalpha as compared to ERbeta in cancer. This differential expression in ER suggests that estrogen-induced proteins may act as ovarian tumor-promoting agents. Among these proteins, c-myc, fibulin-1, cathepsin-D, or several kallikreins may play a role, since high expression levels have been found in EOC. Consistently, recent prospective epidemiological studies have indicated that estrogen replacement therapy in postmenopausal women may increase ovarian cancer incidence and mortality.

CONCLUSION

Questions on the estrogen-sensitivity and potential benefits of new hormone therapies in an EOC subgroup should be readdressed in the light of recent experimental and clinical data.

Hormonal factors and the risk of invasive ovarian cancer: a population-based case-control study

OBJECTIVE

To examine the influence of hormone-related factors on the risk of invasive epithelial ovarian cancer (ovarian cancer).

DESIGN

Population-based case-control study using in-person interviews.

SETTING

Academic department of preventive medicine.

PATIENT(S)

Four hundred seventy-seven ovarian cancer patients and 660 controls.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Numbers of and ages at births, oral contraceptive use, and use of menopausal hormone therapy.

RESULT(S)

Compared with nulliparous women, women whose only (last) birth was after age 35 years had an estimated 51% (95% confidence interval: 21%-70%) reduction in risk. If this birth occurred earlier, the reduction in risk was progressively less. Additional (earlier) births reduced the risk further. Oral contraceptive use also reduced risk. Increased body mass index increased risk, but this effect was confined to localized disease and is likely to be a diagnostic bias, as a consequence of other problems associated with being overweight and in itself having no etiological significance.

CONCLUSION(S)

If the major protective effect of a late birth can be confirmed, our most challenging task will be to understand the mechanism to develop a chemoprevention approach to exploit this finding.

Ovarian cancer and high-risk women—implications for prevention, screening, and early detection

OBJECTIVE

The aim of this study was to understand the strengths and limitations of current prevention, detection, and screening methods for ovarian cancer and to identify research areas to improve prevention, screening, and detection of the disease for all women as well as for women carrying a mutation in the BRCA1/2 genes.

METHODS

We convened an ovarian cancer symposium at the University of Pittsburgh in May 2002. Nineteen leading scientists representing disciplines such as epidemiology, molecular biology, pathology, genetics, bioinformatics, and psychology presented the latest data on ovarian cancer prevention, screening, and early detection.

RESULTS

Ovarian cancer is the most common cause of death from a gynecologic malignancy in the United States. Because survival depends on stage of diagnosis, early detection is critical in improving clinical outcome. However, existing screening techniques (CA125, transvaginal ultrasound) have not been shown to reduce morbidity or mortality. Moreover, with the exception of oral contraceptives, there are no available chemopreventive agents. Bilateral salpingo-oophorectomy also has been shown to reduce incidence, but this procedure has several drawbacks in terms of a woman's reproductive, cardiovascular, skeletal, and mental health.

CONCLUSIONS

Better methods to prevent, detect, and screen for ovarian cancer in all women, but particularly in high-risk women carrying mutations in BRCA1/2, are urgently needed. This article reviews the current state of knowledge in the etiology, prevention, and early detection of ovarian cancer and suggests several areas for future clinical, epidemiologic, and laboratory-based research.

The prohibitin 3' untranslated region polymorphism is not associated with risk of ovarian cancer

OBJECTIVE

The 3' untranslated region of the prohibitin gene encodes an RNA molecule that arrests cell proliferation between the G(1) and S phases of the cell cycle, and a C-to-T transition within this region creates a variant lacking antiproliferative activity. The T allele was reported to be associated with an increased risk of breast cancer in North American women, specifically in those under age 50 years reporting a first-degree family history of breast cancer. We assessed the association of the prohibitin 3' untranslated region polymorphism with risk of ovarian cancer in the Australian population by case-control comparison.

METHODS

We examined 553 cases of epithelial ovarian cancer and 300 unaffected controls to assess whether this polymorphism was associated with risk of ovarian cancer in Australian women. Genotyping was carried out using the Perkin-Elmer ABI Prism 7700 Sequence Detection System for fluorogenic polymerase chain reaction allelic discrimination. Genotype distributions were compared by logistic regression.

RESULTS

Stratification of the ovarian cancer cases according to tumour behavior (low malignant potential or invasive), histology, grade, stage, or p53 immunohistochemical status failed to reveal any heterogeneity with respect to prohibitin genotype. There was no difference in genotype distribution between cases and controls, with an odds ratio (95% confidence interval) of 0.99 (0.72-1.35) for the CT/TT genotype.

CONCLUSION

The prohibitin T variant does not appear to be associated with risk of ovarian cancer in Australian women.