Long-term effects of oral contraceptives on ovarian cancer risk

Contraception as chemoprevention of ovarian cancer in BRCA1 and BRCA2 women

Ovarian cancer is the seventh most common cancer in women in the world, with an estimated worldwide mortality of over 207'000 women every year. This cancer, due to the current lack of adequate screening techniques, is commonly diagnosed late and has a poor prognosis. The oral contraceptive pill is considered the most effective prevention strategy for ovarian cancer in the general population, being associated with a decreased incidence while also having a substantial positive impact on the mortality rate, which is reduced by up to 50%. BRCA1 and BRCA2 germline mutated women have an augmented risk of ovary and breast cancer: despite international guidelines that consider prophylactic surgery as the gold standard for ovarian cancer prevention, there are currently no effective non-invasive preventive methods. In BRCA1\2 mutated patients, clinicians should weigh the benefits of contraceptive pills against the risk of long-term thromboembolic side effects and hormonal malignancies such as breast and cervical cancer. A multidisciplinary team should counsel patients on the most appropriate risk-reduction strategy tailored to their needs and expectations, proposing the oral contraceptive pill to selected patients after balancing the risks of adverse effects and the benefits on both contraception and chemoprevention.

Executive Summary of the Ovarian Cancer Evidence Review Conference

The Centers for Disease Control and Prevention awarded funding to the American College of Obstetricians and Gynecologists to develop educational materials for clinicians on gynecologic cancers. The American College of Obstetricians and Gynecologists convened a panel of experts in evidence review from the Society for Academic Specialists in General Obstetrics and Gynecology and content experts from the Society of Gynecologic Oncology to review relevant literature, best practices, and existing practice guidelines as a first step toward developing evidence-based educational materials for women's health care clinicians about ovarian cancer. Panel members conducted structured literature reviews, which were then reviewed by other panel members and discussed at a virtual meeting of stakeholder professional and patient advocacy organizations in February 2022. This article is the executive summary of the relevant literature and existing recommendations to guide clinicians in the prevention, early diagnosis, and special considerations of ovarian cancer. Substantive knowledge gaps are noted and summarized to provide guidance for future research.

Contraception in Adolescents

Adolescents are at risk for unwanted pregnancy when they become sexually active, and contraception is an important part of mitigating this risk. Use of contraceptive methods, and long-acting reversible contraceptive methods such as implants and intrauterine devices in particular, has increased among adolescents. Although sexual activity has declined and contraceptive use has increased among adolescents in the United States in recent years, the unintended pregnancy rate remains high. All of the currently available contraceptive methods are safe and effective for adolescents to use; however, adolescents may have specific concerns about side effect profiles and unscheduled bleeding that should be addressed during contraceptive counseling. Healthcare providers should prioritize adolescents' needs and preferences when approaching contraceptive counseling, and also consider the unique access and confidentiality issues that adolescents face when accessing contraception.

A Review of Principal Studies on the Development and Treatment of Epithelial Ovarian Cancer in the Laying Hen Gallus gallus

Often referred to as the silent killer, ovarian cancer is the most lethal gynecologic malignancy. This disease rarely shows any physical symptoms until late stages and no known biomarkers are available for early detection. Because ovarian cancer is rarely detected early, the physiology behind the initiation, progression, treatment, and prevention of this disease remains largely unclear. Over the past 2 decades, the laying hen has emerged as a model that naturally develops epithelial ovarian cancer that is both pathologically and histologically similar to that of the human form of the disease. Different molecular signatures found in human ovarian cancer have also been identified in chicken ovarian cancer including increased CA125 and elevated E-cadherin expression, among others. Chemoprevention studies conducted in this model have shown that decreased ovulation and inflammation are associated with decreased incidence of ovarian cancer development. The purpose of this article is to review the major studies performed in laying hen model of ovarian cancer and discuss how these studies shape our current understanding of the pathophysiology, prevention, and treatment of epithelial ovarian cancer.

Characterizing Endocrine Status, Tumor Hypoxia and Immunogenicity for Therapy Success in Epithelial Ovarian Cancer

Epithelial ovarian cancer is predominantly diagnosed at advanced stages which creates significant therapeutic challenges. As a result, the 5-year survival rate is low. Within ovarian cancer, significant tumor heterogeneity exists, and the tumor microenvironment is diverse. Tumor heterogeneity leads to diversity in therapy response within the tumor, which can lead to resistance or recurrence. Advancements in therapy development and tumor profiling have initiated a shift from a "one-size-fits-all" approach towards precision patient-based therapies. Here, we review aspects of ovarian tumor heterogeneity that facilitate tumorigenesis and contribute to treatment failure. These tumor characteristics should be considered when designing novel therapies or characterizing mechanisms of treatment resistance. Individual patients vary considerably in terms of age, fertility and contraceptive use which innately affects the endocrine milieu in the ovary. Similarly, individual tumors differ significantly in their immune profile, which can impact the efficacy of immunotherapies. Tumor size, presence of malignant ascites and vascular density further alters the tumor microenvironment, creating areas of significant hypoxia that is notorious for increasing tumorigenesis, resistance to standard of care therapies and promoting stemness and metastases. We further expand on strategies aimed at improving oxygenation status in tumors to dampen downstream effects of hypoxia and set the stage for better response to therapy.

Natural history of ovarian high-grade serous carcinoma from time effects of ovulation inhibition and progesterone clearance of p53-defective lesions

High-grade serous carcinoma is the most common and devastating type of ovarian cancer; its etiology, mechanism of malignant transformation, and origin remain controversial. Recent studies have identified secretory cells at the fimbria of the fallopian tube as the cell-of-origin of high-grade serous carcinoma, acquiring TP53 mutation, evolving to tubal precursor lesions, including "p53 signature" and serous tubal intraepithelial carcinoma, and metastasizing to the ovary as clinically evident ovarian cancer. The etiological mechanisms associated with known epidemiological risk factors, i.e., ovulation and retrograde menstruation, have also been suggested. Mutagens and transforming growth factors, such as reactive oxygen species and insulin-like growth factor axis proteins, as well as the apoptosis-rescuing protein hemoglobin are abundantly present in the ovulatory follicular fluid and peritoneum fluid, which bathes the fimbrial epithelium, and induces malignant transformation after repeated exposure. In accordance with the proposed cleansing effect of progesterone from studies on oral contraceptive use or term pregnancy, a recent study indicated that the p53-null tubal epithelial cells are selectively cleared by progesterone depending on its progesterone receptor. In this report, by analyzing different time effects of oral contraceptive use or pregnancy in the prevention of ovarian cancer and by aligning them with the carcinogenic and cleansing clearance concepts of ovulation and progesterone, as well as the fact of progressive loss of progesterone receptor during tubal transformation, we deduced the natural history of ovarian high-grade serous carcinoma. The natural history begins at the first ovulation and spans for more than 30 years, taking 10 years from the normal tubal epithelium to the "p53 signature" status, another 15 years to progesterone receptor negative serous tubal intraepithelial carcinoma, and a final 5+ years to high-grade serous carcinoma. The estimated natural history may help understand the pathogenesis of high-grade serous carcinoma and defines the window for early detection and chemoprevention.

Age at last birth and risk of developing epithelial ovarian cancer: a meta-analysis

Background: Many epidemiologic studies have explored the association between age at last birth (ALB) and the risk of epithelial ovarian cancer, but the results remain controversial. Methods: A literature search was performed in PubMed, Web of Science, China National Knowledge Infrastructure (CNKI) and WanFang Med Online for relevant articles published up to April 2019. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated using a random-effect model. Dose-response relationship was assessed by restricted cubic spline model. Results: Thirteen articles with 19,959 cases and 2,451,071 participants were included in our meta-analysis, and we found that ALB was negatively associated with epithelial ovarian cancer. The pooled RR (95% CI) of epithelial ovarian cancer for the highest versus the lowest stratification of ALB was 0.77 (0.65-0.91). Furthermore, significantly negative associations were shown in case-control studies (RR: 0.73; 95% CI: 0.60-0.88), studies conducted in North America (RR: 0.71; 95% CI: 0.60-0.84), studies with adjustment for parity (RR: 0.76; 95%CI: 0.63-0.93), studies with adjustment for tubal ligation (RR: 0.74; 95% CI: 0.58-0.94), in the subgroup analysis. In dose-response analysis, the risk of epithelial ovarian cancer decreased nonlinearly with the increase of ALB, and the negative results become significant when ALB was 22.5 years old. Conclusion: This meta-analysis suggested that ALB was negatively associated with the risk of epithelial ovarian cancer. The risk of epithelial ovarian cancer decreased gradually with the ALB for women.

Appraising the role of previously reported risk factors in epithelial ovarian cancer risk: A Mendelian randomization analysis

BACKGROUND

Various risk factors have been associated with epithelial ovarian cancer risk in observational epidemiological studies. However, the causal nature of the risk factors reported, and thus their suitability as effective intervention targets, is unclear given the susceptibility of conventional observational designs to residual confounding and reverse causation. Mendelian randomization (MR) uses genetic variants as proxies for risk factors to strengthen causal inference in observational studies. We used MR to evaluate the association of 12 previously reported risk factors (reproductive, anthropometric, clinical, lifestyle, and molecular factors) with risk of invasive epithelial ovarian cancer, invasive epithelial ovarian cancer histotypes, and low malignant potential tumours.

METHODS AND FINDINGS

Genetic instruments to proxy 12 risk factors were constructed by identifying single nucleotide polymorphisms (SNPs) that were robustly (P < 5 × 10-8) and independently associated with each respective risk factor in previously reported genome-wide association studies. These risk factors included genetic liability to 3 factors (endometriosis, polycystic ovary syndrome, type 2 diabetes) scaled to reflect a 50% higher odds liability to disease. We obtained summary statistics for the association of these SNPs with risk of overall and histotype-specific invasive epithelial ovarian cancer (22,406 cases; 40,941 controls) and low malignant potential tumours (3,103 cases; 40,941 controls) from the Ovarian Cancer Association Consortium (OCAC). The OCAC dataset comprises 63 genotyping project/case-control sets with participants of European ancestry recruited from 14 countries (US, Australia, Belarus, Germany, Belgium, Denmark, Finland, Norway, Canada, Poland, UK, Spain, Netherlands, and Sweden). SNPs were combined into multi-allelic inverse-variance-weighted fixed or random effects models to generate effect estimates and 95% confidence intervals (CIs). Three complementary sensitivity analyses were performed to examine violations of MR assumptions: MR-Egger regression and weighted median and mode estimators. A Bonferroni-corrected P value threshold was used to establish strong evidence (P < 0.0042) and suggestive evidence (0.0042 < P < 0.05) for associations. In MR analyses, there was strong or suggestive evidence that 2 of the 12 risk factors were associated with invasive epithelial ovarian cancer and 8 of the 12 were associated with 1 or more invasive epithelial ovarian cancer histotypes. There was strong evidence that genetic liability to endometriosis was associated with an increased risk of invasive epithelial ovarian cancer (odds ratio [OR] per 50% higher odds liability: 1.10, 95% CI 1.06-1.15; P = 6.94 × 10-7) and suggestive evidence that lifetime smoking exposure was associated with an increased risk of invasive epithelial ovarian cancer (OR per unit increase in smoking score: 1.36, 95% CI 1.04-1.78; P = 0.02). In analyses examining histotypes and low malignant potential tumours, the strongest associations found were between height and clear cell carcinoma (OR per SD increase: 1.36, 95% CI 1.15-1.61; P = 0.0003); age at natural menopause and endometrioid carcinoma (OR per year later onset: 1.09, 95% CI 1.02-1.16; P = 0.007); and genetic liability to polycystic ovary syndrome and endometrioid carcinoma (OR per 50% higher odds liability: 0.89, 95% CI 0.82-0.96; P = 0.002). There was little evidence for an association of genetic liability to type 2 diabetes, parity, or circulating levels of 25-hydroxyvitamin D and sex hormone binding globulin with ovarian cancer or its subtypes. The primary limitations of this analysis include the modest statistical power for analyses of risk factors in relation to some less common ovarian cancer histotypes (low grade serous, mucinous, and clear cell carcinomas), the inability to directly examine the association of some ovarian cancer risk factors that did not have robust genetic variants available to serve as proxies (e.g., oral contraceptive use, hormone replacement therapy), and the assumption of linear relationships between risk factors and ovarian cancer risk.

CONCLUSIONS

Our comprehensive examination of possible aetiological drivers of ovarian carcinogenesis using germline genetic variants to proxy risk factors supports a role for few of these factors in invasive epithelial ovarian cancer overall and suggests distinct aetiologies across histotypes. The identification of novel risk factors remains an important priority for the prevention of epithelial ovarian cancer.

The Chemoprevention of Ovarian Cancer: the Need and the Options

PURPOSE OF REVIEW

Ovarian cancer (OvCa) is the most lethal of all gynecological cancers, with a 5-year survival around 46%, mainly due to limitations in early diagnosis and treatment. Consequently, the chemoprevention of OvCa emerges as an important option to control this dismal disease. Here, we discuss the role of risk assessment in the design of chemoprevention strategies for OvCa, describe candidate agents, and assess future directions in this field.

RECENT FINDINGS

OvCa chemoprevention represents an opportunity for all women, especially those at high risk such as carriers of BRCA1 or BRCA2 mutations. The use of oral contraceptives confers substantial protection against OvCa including women at high risk, which increases with longer use. Despite strong evidence for their efficacy, safety concerns and the magnitude of the requisite interventional clinical trials seem to have precluded definitive studies of oral contraceptives for this application. Several other classes of drugs, including non-steroidal anti-inflammatory drugs, retinoids, angiopreventive agents, poly(ADP-ribose) polymerase inhibitors, and tyrosine kinase inhibitors have shown promise for OvCa chemoprevention.

SUMMARY

Currently, no agent is proven by interventional trials to possess chemopreventive properties against OvCa. The key opportunities in the chemoprevention of OvCa include the development of surrogate biomarkers for OvCa, the molecular definition of OvCa risk that will help select those who may benefit the most from chemoprevention, the identification of additional agents likely driven by understanding the molecular pathogenesis of OvCa, and the development of dedicated resources and support mechanisms for OvCa. Overall, there is significant optimism for the future of OvCa chemoprevention.

Cancer Mortality in Italy, 1970–2002

Aims and background

To update previous work on Italian cancer mortality.

Methods

WHO data were used to calculate death rates for 30 cancer sites for 2002. Trends were analyzed with joinpoint regression over the 1970–2002 period.

Results

Total cancer deaths for 2002 in Italy were 163,070 (93,398 men, 69,672 women). Male cancer mortality rose until 1988 and since then has had a 1.4% yearly fall. The first cause of cancer death in males was lung cancer, accounting for 28% of deaths. The decrease in mortality from male lung cancer came about the end of the 1980's (estimated annual percentage change, EAPC, −1.26 from 1989 to 1993 and −2.32 thereafter) and was the main reason for the favorable trends in total male cancer mortality, reflecting the change in smoking prevalence in Italian males. Female total cancer mortality trends have also been favorable, with an overall yearly drop of 1.1% since 1992. The most frequent causes of cancer deaths in females were breast and colorectal cancers, accounting for 16% and 14% of cancer deaths, and both showed declining trends (EAPC, −1.80 since 1992 and −1.51 from 1993 for breast and colorectal cancers, respectively). Female lung cancer has been on the rise (EAPC, 0.82 since 1987) for the last decades due to the rise in cigarette smoking since the 1970's in Italian females.

Discussion

Mortality from the most common cancers in Italy showed a favorable trend over recent years, the maintenance and potential improvement of which would require a strategy focusing on the control of tobacco and alcohol consumption, nutrition and diet. Early diagnosis for selected neoplasms can also have a relevant impact, together with advancements in treatments.

Management Options after Prophylactic Surgeries in Women with BRCA Mutations: A Review

Background

Although breast cancer is relatively common, only about 5% of cases are due to inheritance of highly penetrant cancer susceptibility genes. The majority of these are caused by mutations in the BRCA1 and BRCA2 genes, which are also associated with an increased risk of ovarian cancer. Increased surveillance, chemoprevention, and prophylactic surgeries are standard options for the effective medical management of mutation carriers. However, optimal management of female carriers who choose to undergo prophylactic surgeries is still poorly understood.

Methods

The authors provide an overview of the current literature regarding medical management options for women carriers of BRCA1 and BRCA2 gene mutations and the implications for those individuals who have chosen to undergo prophylactic surgeries.

Results

BRCA mutation carriers who opt for prophylactic surgeries are still at risk for development of malignancy, and appropriate monitoring is warranted.

Conclusions

There are limited data on the appropriate medical management for BRCA mutation carriers after prophylactic surgeries. However, a management plan can be extrapolated from the general management recommendations for surveillance and other risk-reducing strategies in BRCA-positive individuals.

Combined oral contraceptive use before the first birth and epithelial ovarian cancer risk

Background:

Combined oral contraceptive (COC) use reduces epithelial ovarian cancer (EOC) risk. However, little is known about risk with COC use before the first full-term pregnancy (FFTP).

Methods:

This Canadian population-based case–control study (2001–2012) included 854 invasive cases/2139 controls aged ⩾40 years who were parous and had information on COC use. We estimated odds ratios (aORs) and 95% confidence intervals (CI) adjusted for study site, age, parity, breastfeeding, age at FFTP, familial breast/ovarian cancer, tubal ligation, and body mass.

Results:

Among parous women, per year of COC use exclusively before the FFTP was associated with a 9% risk reduction (95% CI=0.86–0.96). Results were similar for high-grade serous and endometrioid/clear cell EOC. In contrast, per year of use exclusively after the FFTP was not associated with risk (aOR=0.98, 95% CI=0.95–1.02).

Conclusions:

Combined oral contraceptive use before the FFTP may provide a risk reduction that remains for many years, informing possible prevention strategies.

Prior oral contraceptive use in ovarian cancer patients: assessing associations with overall and progression-free survival

Background

Prior studies have described a reduced risk of developing ovarian cancer with the use of oral contraceptives. In this context, we decided to examine if oral contraceptive use prior to a diagnosis of ovarian cancer is associated with better overall and progression-free survival.

Methods

This retrospective cohort study included ovarian cancer patients who were seen at the Mayo Clinic in Rochester, Minnesota from 2000 through 2013. Patients completed a risk factor questionnaire about previous oral contraceptive use, and clinical data were extracted from the electronic medical record.

Results

A total of 1398 ovarian cancer patients responded to questions on oral contraceptive use; 571 reported no prior use with all others having responded affirmatively to oral contraceptive use. Univariate analyses found that oral contraceptive use (for example, ever versus never) was associated with better overall survival (hazard ratio (HR) 0.73 (95 % confidence interval (CI): 0.62, 0.86); p = 0.0002) and better progression-free survival (HR 0.71 (95 % CI: 0.61, 0.83); p < 0.0001). In multivariate analyses, contraceptive use continued to yield a favorable, statistically significant association with progression-free survival, but such was not the case with overall survival.

Conclusions

This study suggests that previous oral contraceptive use is associated with improved progression-free survival in patients diagnosed with ovarian cancer.

Contraceptive methods and ovarian cancer risk among Chinese women: A report from the Shanghai Women's Health Study

Oral contraceptive use is associated with reduced ovarian cancer risk; however, associations with other contraceptive methods, such as intrauterine device (IUD) and tubal ligation, are less clear. Women in China differ from western women in regard to mechanisms and duration of use of contraception. This study was undertaken to evaluate associations between contraceptive methods and ovarian cancer risk using data from the prospective Shanghai Women's Health Study. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated by Cox proportional hazards regression. A total of 174 epithelial ovarian cancer cases were found to occur among 70,259 women who were followed-up for a total of 888,258 person-years. The majority of women had ever used any contraception (77.0%), including IUD (55.6%), oral contraceptive (20.4%), tubal ligation (14.7%) or contraceptive shots (2.6%). Ever use of any contraception was associated with a nonsignificant reduction in ovarian cancer risk (HR: 0.86, 95% CI: 0.60-1.24). Longer duration of IUD use was associated with lower ovarian cancer risk (p-value for trend = 0.04). Compared with never users, women with durations of IUD use longer than the median (20 years) were 38% less likely to develop ovarian cancer (HR: 0.62, 95% CI: 0.40-0.97). Based on the high prevalence and long duration of IUD use among Chinese women, we estimate a preventive fraction of 9.3%, corresponding to approximately 16 ovarian cancer cases. High prevalence of long-term IUD use may, therefore, contribute to the low incidence of ovarian cancer observed in China.

Evaluation of the effectiveness of testicular cancer and testicular self-examination training for patient care personnel: intervention study

Testicular cancer (TC) is the most common malignancy among men aged 15-35 years. Testicular self-examination (TSE) is an important tool for preventing late-stage TC diagnoses. This study aimed to assess health beliefs and knowledge related to TC and TSE and the effectiveness of TC and TSE training for patient care staff in a hospital. This was a prospective, randomized, controlled intervention study. The study included 96 patient care staff divided into two groups of 48 participants each: Group I, the interactive education group, and Group II, the pamphlet education group. The results demonstrated that TSE practice and TC knowledge significantly increased in both Group I and Group II. Significant differences were observed between the groups pre and post education. TSE and TC knowledge levels were higher for participants in Group I than those in Group II. There was a significant difference in the performance of TSEs between groups: the rates were 83.3% in Group I and 54.2% in Group II. Perceived confidence and perceived barriers increased significantly for both groups. Interactive education sessions should be used to train men at risk for TC to perform TSEs.

Oral contraceptives and risk of ovarian cancer and breast cancer among high-risk women: a systematic review and meta-analysis

PURPOSE

To estimate the risks of ovarian cancer and breast cancer associated with oral contraceptive (OC) use among women at elevated risk owing to mutations in BRCA1/2 or a strong family history.

METHODS

We searched PubMed, Embase, the Cochrane Database of Systematic Reviews, and ClinicalTrials.gov for studies published 2000 to 2012 that evaluated associations between OC use and breast or ovarian cancer among women who are carriers of a BRCA1/2 mutation or have a family history of breast or ovarian cancer.

RESULTS

From 6,476 unique citations, we identified six studies examining ovarian cancer risk in BRCA1/2 mutation carriers and eight studies examining breast cancer risk in BRCA1/2 mutation carriers. For BRCA1/2 mutation carriers combined, meta-analysis showed an inverse association between OC use and ovarian cancer (odds ratio [OR], 0.58; 95% CI, 0.46 to 0.73) and a nonstatistically significant association with breast cancer (OR, 1.21; 95% CI, 0.93 to 1.58). Findings were similar when examining BRCA1 and BRCA2 mutation carriers separately. Data were inadequate to perform meta-analyses examining duration or timing of use. For women with a family history of ovarian or breast cancer, we identified four studies examining risk for ovarian cancer and three for breast cancer, but differences between studies precluded combining the data for meta-analyses, and no overall pattern could be discerned.

CONCLUSION

Our analyses suggest that associations between ever use of OCs and ovarian and breast cancer among women who are BRCA1 or BRCA2 mutation carriers are similar to those reported for the general population.

Oral contraceptive pills as primary prevention for ovarian cancer: a systematic review and meta-analysis

OBJECTIVE

To estimate the overall reduction in ovarian cancer risk associated with the use of oral contraceptive pills (OCPs) and whether reduction in risk is affected by specifics of OCP use, such as formulation or duration of use.

DATA SOURCES

We searched PubMed, Embase, the Cochrane Database of Systematic Reviews, and ClinicalTrials.gov for studies published from January 1990 to June 2012, with primary analysis of studies published since January 2000.

METHODS OF STUDY SELECTION

We reviewed 6,476 citations. We included English-language controlled studies with human participants reporting a quantitative association between exposure to OCPs (in which the explicit or implicit indication for OCP use was prevention of pregnancy or ovarian cancer) compared with no use of OCPs. Two investigators independently reviewed the title and abstract and full-text of articles for inclusion or exclusion decision; discordant decisions were resolved by team review and consensus.

TABULATION, INTEGRATION, AND RESULTS

Fifty-five studies met inclusion criteria. A random-effects meta-analysis of 24 case-control and cohort studies showed significant reduction in ovarian cancer incidence in ever-users compared with never-users (odds ratio 0.73, 95% confidence interval 0.66-0.81). There was a significant duration-response relationship, with reduction in incidence of more than 50% among women using OCPs for 10 or more years. The lifetime reduction in ovarian cancer attributable to the use of OCPs is approximately 0.54% for a number-needed-to-treat of approximately 185 for a use period of 5 years.

CONCLUSION

Significant duration-dependent reductions in ovarian cancer incidence in the general population are associated with OCP use.

Reproductive factors for ovarian cancer in southern Chinese women

Objective

To investigate the association between reproductive factors and the risk of ovarian cancer among southern Chinese women.

Methods

A hospital-based case-control study was undertaken in Guangzhou, Guangdong Province, between 2006 and 2008. A structured questionnaire was used to obtain information on parity, oral contraceptive use and other reproductive factors in a sample of 500 incident ovarian cancer patients and 500 controls (mean age, 59 years). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using unconditional logistic regression models.

Results

High parity was inversely associated with ovarian cancer, with an adjusted OR 0.43 (95% CI, 0.30 to 0.62) for women who had given birth to 3 or more children compared to women who had given no more than one birth. Ever use of oral contraceptives was also protective against ovarian cancer; adjusted OR 0.56 (95% CI, 0.40 to 0.78). No association was found for hormone replacement therapy, menopausal status, hysterectomy and family history of ovarian and/or breast cancer.

Conclusion

High parity and oral contraceptive use are associated with a lower risk of ovarian cancer in southern Chinese women.

Ovarian cancer risk is reduced by prolonged lactation: a case-control study in southern China

BACKGROUND

Ovarian cancer is an important neoplasm that is difficult to diagnose and treat; therefore, prevention is the preferable strategy. Growing evidence indicates a protective effect of breastfeeding on ovarian cancer risk.

OBJECTIVE

The objective was to investigate the association between lactation and the risk of ovarian cancer among southern Chinese women.

DESIGN

A case-control study was undertaken in Guangzhou, Guangdong Province, between August 2006 and July 2008. A validated and reliable questionnaire was used to obtain information on the months of lactation and number of children breastfed in a sample of 493 incident ovarian cancer patients and 472 hospital-based controls (mean age: 59 y). Logistic regression analyses were performed to assess the association between breastfeeding and the risk of ovarian cancer.

RESULTS

Significant inverse dose-response relations were found for both duration of lactation and the number of children breastfed. The adjusted ORs were 0.09 (95% CI: 0.04, 0.19) for women with ≥31 mo of total lactation and those with ≤10 mo of lactation and 0.38 (95% CI: 0.27, 0.55) for women with ≥3 children breastfed compared with those with one child breastfed.

CONCLUSION

Prolonged lactation is associated with a lower risk of ovarian cancer in parous Chinese women.

Reproductive factors in relation to ovarian cancer: a case-control study in Northern Vietnam

BACKGROUND

Ovarian cancer, one of the most common cancers in women and the most serious gynecologic cancer, is known to be influenced by reproductive factors, but these factors have not previously been examined in Vietnamese women.

STUDY DESIGN

We analyzed 262 ovarian cancer patients recruited from 27 hospitals in 12 provinces and Ha Noi City from April 2001 to May 2006, plus 755 controls matched by age and residential address.

RESULTS

The risk of ovarian cancer was significantly lower in parous women than nulliparous women. Use of an intrauterine contraceptive device was also associated with a reduced risk. In contrast, induced abortion, late menopause and years of ovulation were significantly associated with an increased risk of cancer.

CONCLUSIONS

Parity and intrauterine device use were associated with a reduced risk of ovarian cancer in Vietnamese women, whereas induced abortion, late menopause and years of ovulation were associated with an increased risk.

Role of epigenomics in ovarian and endometrial cancers

Ovarian cancer is the most lethal gynecologic malignancy and while constituting only 3% of all female cancers, it causes 14,600 deaths in the USA annually. Endometrial cancer, the most diagnosed and second-most fatal gynecologic cancer, afflicts over 40,000 US women annually, causing an estimated 7780 deaths in 2009. In both advanced ovarian and endometrial carcinomas, the majority of initially therapy-responsive tumors eventually evolve to a fully drug-resistant phenotype. In addition to genetic mutations, epigenetic anomalies are frequent in both gynecologic malignancies, including aberrant DNA methylation, atypical histone modifications and dysregulated expression of distinct microRNAs, resulting in altered gene-expression patterns favoring cell survival. In this article, we summarize the most recent hypotheses regarding the role of epigenetics in ovarian and endometrial cancers, including a possible role in tumor 'stemness' and also evaluate the possible therapeutic benefits of reversal of these oncogenic chromatin aberrations.

Reproductive and hormonal factors in association with ovarian cancer in the Netherlands cohort study

Parity, oral contraceptive use, and hysterectomy are known to protect against ovarian cancer, whereas the effect of other reproductive factors remains unclear. The authors investigated the association between several reproductive and hormonal factors and the risk of epithelial invasive ovarian cancer among postmenopausal women participating in the Netherlands Cohort Study on Diet and Cancer. Information on reproductive history and exogenous hormone use was obtained through a self-administered questionnaire at baseline in 1986. After 16.3 years of follow-up, 375 cases and 2,331 subcohort members were available for case-cohort analysis. Ovarian cancer risk was reduced for parous women, with increasing parity, and for hysterectomized women. Moreover, the authors found evidence that oral contraceptive use is protective against ovarian cancer, even when initiated at an older age. In addition, a reduced risk was observed for each year reduction in age at natural menopause and per year reduction in total menstrual life span. A small increased risk was observed with prolonged time to pregnancy, but no difference was found between ever-married nulliparous women and never-married nulliparous women. Moreover, no associations were observed for age at first birth, age at menarche, age at first and last use of oral contraceptives, and use of hormone replacement therapy.

Effects of oral contraceptives or a gonadotropin-releasing hormone agonist on ovarian carcinogenesis in genetically engineered mice

Although epidemiologic evidence for the ability of combined oral contraception (OC) to reduce the risk of ovarian cancer (OvCa) is convincing, the biological mechanisms underlying this effect are largely unknown. We conducted the present study to determine if OC also influences ovarian carcinogenesis in a genetic mouse model and, if so, to investigate the mechanism underlying the protective effect. LSL-K-ras(G12D/+)Pten(loxP/loxP) mice were treated with ethinyl estradiol plus norethindrone, contraceptive hormones commonly used in combined OC, or norethindrone alone, or a gonadotropin-releasing hormone agonist. The combined OC had a 29% reduction in mean total tumor weight compared with placebo (epithelial tumor weight, -80%). Norethindrone alone reduced mean total tumor weight by 42% (epithelial tumor weight, -46%), and the gonadotropin-releasing hormone agonist increased mean total tumor weight by 71% (epithelial tumor weight, +150%). Large variations in tumor size affected the P values for these changes, which were not statistically significant. Nonetheless, the OC reductions are consistent with the epidemiologic data indicating a protective effect of OC. Matrix metalloproteinase-2 activity was decreased in association with OC, indicating that OC may affect ovarian carcinogenesis by decreasing proteolytic activity, an important early event in the pathogenesis of OvCa. In contrast, OC increased invasion in a K-ras/Pten OvCa cell line established from the mouse tumors, suggesting that OC hormones, particularly estrogen, may have a detrimental effect after the disease process is under way. Our study results support further investigation of OC effects and mechanisms for OvCa prevention.

The fallopian tube: primary site of most pelvic high-grade serous carcinomas

Epithelial ovarian cancer is the most common cause of mortality from gynecologic malignancy, and most of epithelial cancers are of serous type. The site of origin of pelvic high-grade serous carcinoma has been the subject of debate for 60 years. This paper reviews the evidence that pelvic serous carcinoma originates from the fallopian tube mucosa and puts forward a theory that inflammation in the tube, caused by menstrual cytokines or infection, is critical to the genesis of these tumors. Other risk factors for pelvic serous carcinoma will be reviewed, including oral contraceptive use, parity, infertility, and tubal ligation.Studies were identified for this review by searching the English language literature in the MEDLINE database between the years 1995 and 2007 using the following keywords: fallopian tube neoplasia, ovarian serous adenocarcinoma, pregnancy, oral contraceptive, infertility, pelvic inflammatory disease, cytokines, menstruation, and tubal ligation, followed by an extensive review of bibliographies from articles found through the search.The clinical implications of this theory are discussed, and a change in surgical practice is recommended, with salpingectomy at the time of simple hysterectomy. This theory also has implications for the development of new methods of screening for pelvic serous carcinomas, as there are no screening methods that are currently available to find this form of cancer in an early stage. Inflammatory markers could be detected in the vagina from the fallopian tube indicating possible chronic inflammation and a risk factor for mutagenesis leading to serous carcinoma.

Genetic counseling and testing for common hereditary breast cancer syndromes: a paper from the 2007 William Beaumont hospital symposium on molecular pathology

Throughout the past 15 years, the identification of several genes associated with hereditary breast cancer has fueled the growth of clinical genetic counseling and testing services. In addition, increased knowledge of the genetic and molecular pathways of the known hereditary breast cancer genes, as well as an increased understanding of the impact of testing on individuals has added to the ability to identify, manage, and provide psychosocial support for mutation carriers. This review provides an overview of the clinical features, cancer risks, causative genes, and management for hereditary breast and ovarian cancer syndrome, Cowden syndrome, and Li-Fraumeni syndrome. This article summarizes the genetic counseling process and genetic test result interpretation, including a review of the key elements involved in the provision of risk assessment and informed consent, as well as a review of the risks, benefits, and limitations of cancer susceptibility genetic testing.

Cost-effectiveness analysis of prevention strategies for gynecologic cancers in Lynch syndrome

BACKGROUND

Women with Lynch syndrome (hereditary nonpolyposis colorectal cancer) have an increased lifetime risk for endometrial and ovarian cancer. Screening and prophylactic surgery have been recommended as prevention strategies. In this study, the authors estimated the net health benefits and cost-effectiveness of these strategies in a Markov decision-analytic model.

METHODS

Five strategies were compared for a hypothetical cohort of women with Lynch syndrome: 1) no prevention ('reference'); 2) prophylactic surgery (hysterectomy and bilateral salpingo-oophorectomy) at age 30 years; 3) prophylactic surgery at age 40 years; 4) annual screening with endometrial biopsy, transvaginal ultrasound, and CA 125 from age 30 years; and 5) annual screening from age 30 years until prophylactic surgery at age 40 years (combined strategy). Net health benefit was measured in quality-adjusted life years (QALYs), and the primary outcome measured was the incremental cost-effectiveness ratio (ICER). Baseline and transition probabilities were obtained from published literature, and costs were from the U.S. Department of Health and Human Services and Agency for Health Care Quality and Research. Sensitivity analyses were performed for uncertainty around various parameters.

RESULTS

The combined strategy provided the highest net health benefit (18.98 QALYs) but had an ICER of $194,650 per QALY relative to the next best strategy (prophylactic surgery at age 40 years). Prophylactic surgery at age 30 years and annual screening were dominated by alternate strategies.

CONCLUSIONS

Annual screening followed by prophylactic surgery at age 40 years was the most effective gynecologic cancer prevention strategy, but the incremental benefit over prophylactic surgery alone was attained at substantial cost. The ICER would become favorable by improving the effectiveness and reducing the costs of screening in this population.

Ovarian cancer hormonal and environmental risk effect

To understand the influence of hormonal and environmental factors on the risk of ovarian cancer, it is important to remember the established risk factors and postulated mechanisms that lead to the development of ovarian cancer. Several risk factors have been identified as increasing the risk of epithelial ovarian cancer, including low pariety, infertility, early age of menarche, and late age of menopause. This article discusses the different hypotheses and focuses on hormonal and environmental risk factors, as well the chemoprevention of epithelial ovarian cancer.

Cancer mortality in the European Union, 1970-2003, with a joinpoint analysis

BACKGROUND

Cancer mortality peaked in the European Union (EU) in the late 1980s and declined thereafter.

MATERIALS AND METHODS

We analyzed EU cancer mortality data provided by the World Health Organization in 1970-2003, using join point analysis.

RESULTS

Overall, cancer mortality levelled off in men since 1988 and declined in 1993-2003 (annual percent change, APC = -1.3%). In women, a steady decline has been observed since the early 1970s. The decline in male cancer mortality has been driven by lung cancer, which levelled off since the late 1980s and declined thereafter (APC = 2.7% in 1997-2003). Recent decreases were also observed for other tobacco-related cancers, as oral cavity/pharynx, esophagus, larynx and bladder, as well as for colorectal (APC = -0.9% in 1992-2003) and prostate cancers (APC = -1.0% in 1994-2003). In women, breast cancer mortality levelled off since the early 1990s and declined thereafter (APC = -1.0% in 1998-2003). Female mortality declined through the period 1970-2003 for colorectal and uterine cancer, while it increased over the last three decades for lung cancer (APC = 4.6% in 2001-2003). In both sexes, mortality declined in 1970-2003 for stomach cancer and for a few cancers amenable to treatment.

CONCLUSION

This update analysis of the mortality from cancer in the EU shows favorable patterns over recent years in both sexes.

Gonadotropins and ovarian cancer

Ovarian epithelial cancer (OEC) accounts for 90% of all ovarian cancers and is the leading cause of death from gynecological cancers in North America and Europe. Despite its clinical significance, the factors that regulate the development and progression of ovarian cancer are among the least understood of all major human malignancies. The two gonadotropins, FSH and LH, are key regulators of ovarian cell functions, and the potential role of gonadotropins in the pathogenesis of ovarian cancer is suggested. Ovarian carcinomas have been found to express specific receptors for gonadotropins. The presence of gonadotropins in ovarian tumor fluid suggests the importance of these factors in the transformation and progression of ovarian cancers as well as being prognostic indicators. Functionally, there is evidence showing a direct action of gonadotropins on ovarian tumor cell growth. This review summarizes the key findings and recent advances in our understanding of these peptide hormones in ovarian cancer development and progression and their role in potential future cancer therapy. We will first discuss the supporting evidence and controversies in the "gonadotropin theory" and the use of animal models for exploring the involvement of gonadotropins in the etiology of ovarian cancer. The role of gonadotropins in regulating the proliferation, survival, and metastasis of OEC is next summarized. Relevant data from ovarian surface epithelium, which is widely believed to be the precursor of OEC, are also described. Finally, we will discuss the clinical applications of gonadotropins in ovarian cancer and the recent progress in drug development.

Ovarian cancer risk in relation to medical visits, pelvic examinations and type of health care provider

BACKGROUND

Whether the current recommendations for ovarian cancer prevention and screening (annual history and physical examination) are effective has not been evaluated. We examined the relation between health care use and the risk of ovarian cancer.

METHODS

Using a case-control study design, we recorded the frequency of medical visits and pelvic examinations and the type of health care provider visited during a 5-year period from interviews with women with and without ovarian cancer between between July 1998 and July 2003. We used multivariable logistic regression analysis to calculate the adjusted odds ratio of ovarian cancer associated with the frequency of medical visits and pelvic examinations and the type of health care provider. In addition, we stratified cases and controls by menopausal status and cancer histologic subtype and grade.

RESULTS

A total of 668 cases and 721 age-matched controls agreed to participate in the study. We observed an increased risk of ovarian cancer among women who, during the 5-year study period, did not have a medical visit (odds ratio [OR] 2.8, 95% confidence interval [CI] 1.5-5.0) or pelvic examination (OR 3.9, 95% CI 2.2-6.9) or who had no regular health care provider (OR 2.7, 95% CI 1.3-5.7). This increase in risk was most pronounced among women who were postmenopausal (no medical visit, OR 7.7, 95% CI 2.6-23.0; no pelvic examination, OR 3.3, 95% CI 1.7-6.0; no health care provider, OR 12.5, 95% CI 2.7-57.5).

INTERPRETATION

Although the exact mechanism underlying the association between medical visits, pelvic examinations and type of health care provider and ovarian cancer is unknown, women should be encouraged to maintain regular medical care.

Risk of cancer development in relation to oral contraception

Combined oral contraceptives (COCs) are among the most widely used effective and reversible means of family planning. Their beneficial effects are well documented, but many questions are still raised concerning a possible association between the use of COCs and the development of cancer. The authors provide a broad and up-to-date review of the literature regarding the relation between COC use and carcinogenesis in different organs. Studies have not unequivocally confirmed that such a relation exists with regard to breast cancer. Much research focused on the influence COC use could have on the incidence of cervical cancer; most of it was analyzed by J. Smith and co-workers. These authors confirmed the existence of a weak relation between COC use and the development of cervical carcinoma, especially in women using COCs for longer periods. Ovarian carcinoma has the worst prognosis of all cancers of reproductive organs in women. The risk of developing ovarian cancer in women using COCs is at least 40% smaller than in other women; the degree of protection given by COCs is directly proportional to the duration of use of this form of contraception. Reliable scientific data prove convincingly that the risk of endometrial cancer is smaller in women who used COCs than in women who never took them.

Oral contraceptives and ovarian cancer: an update, 1998-2004

Over the last two decades, ovarian cancer incidence and mortality for younger generations have been declining in most developed countries, and the decline has been greatest in countries where oral contraceptive (OC) use had spread earlier. The overall estimated protection from cohort and case-control studies is approximately 30% for ever OC users, and increases with duration of use by approximately 5% per year of use to about 50% for long-term (> or =10 years) users. The favourable effect of OC against ovarian cancer risk persists for at least 20 years after OC use has ceased, and it is not confined to any particular type of OC formulation. The reduced risk among OC users is observed in women without or with family history or genetic predisposition to ovarian cancer, and for most histological types of epithelial ovarian cancer, although the pattern of risk is less consistent for mucinous than for other types. The protection of OC on ovarian cancer risk, also in view of its long-term persistence, corresponds to the avoidance of 3000-5000 ovarian cancers (and 2000-3000 deaths) per year in Europe, and a similar figure in North America.

Gonadotropin-induced superovulation drives ovarian surface epithelia proliferation in CD1 mice

The ovarian surface epithelium (OSE) is a monolayer of cells that surround the ovary and accommodate repeated tear and repair in response to ovulation. OSE cells are thought to be the progenitors of 90% of ovarian cancers. Currently, the total amount of proliferation of the OSE has not been reported in response to one ovulatory event. In this study, proliferation of the OSE was quantified in response to superovulation induced by ip injection of pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) in immature 27-d-old CD1 mice using bromodeoxyuridine (BrdU). BrdU incorporation into the OSE cells was measured from the time of hCG injection for a total cumulative label of 12 h. BrdU incorporation was also measured from the time of PMSG injection for a total label of 60 h to correlate proliferation with specific gonadotropin stimulation. The OSE proliferation was significantly higher in superovulated animals compared with control mice at all time points. Proliferation was also analyzed in discrete anatomical sections and indicated that OSE covering antral follicles and corpora lutea proliferated more rapidly than OSE distal to follicular growth. Finally, apoptosis was assessed in response to ovulation, and virtually no cell death within the OSE was detected. These data demonstrate that the OSE, especially near antral follicles and corpora lutea, proliferates significantly in response to the gonadotropins PMSG and hCG. Therefore, ovarian surface cell division in response to ovulation could contribute to ovarian cancer by proliferation-induced DNA mutations and transformed cell progression.

Recreational physical activity and sedentary behavior in relation to ovarian cancer risk in a large cohort of US women

Factors that influence circulating sex hormones, such as physical activity, have been proposed to influence ovarian cancer risk; however, results from previous epidemiologic studies have been inconsistent. The authors examined the association among physical activity, sedentary behavior, and ovarian cancer risk in the American Cancer Society Cancer Prevention Study II Nutrition Cohort, a prospective study of cancer incidence and mortality, using information obtained at baseline in 1992. From 1992 to 2001, 314 incident ovarian cancer cases were identified among 59,695 postmenopausal women who were cancer free at enrollment. Cox proportional hazards modeling was used to compute hazard rate ratios while adjusting for potential confounders. No overall association was observed between measures of past physical activity or with recreational physical activity at baseline and risk of ovarian cancer in this study (for the highest category of physical activity compared with none: hazard rate ratio = 0.73, 95% confidence interval: 0.40, 1.34). However, a prolonged duration of sedentary behavior was associated with an increased risk (for > or = 6 vs. < 3 hours per day: hazard rate ratio = 1.55, 95% confidence interval: 1.08, 2.22; p(trend) = 0.01). Results from this study suggest that high levels of sedentary behavior may increase the risk of ovarian cancer, but they do not support a major impact of light and moderate physical activity on ovarian cancer risk.

Prevention of ovarian cancer

Ovarian cancer is the leading cause of death from gynaecological malignancy. The incidence is high in the Western world. The incidence of ovarian cancer is reduced by pregnancy, lactation, the oral contraceptive pill and tubal ligation. Lifestyle factors are important in the aetiology of ovarian cancer and current evidence suggests the risk can be reduced by eating a diet rich in fruit and vegetables, taking regular exercise, avoiding smoking, avoiding being overweight and avoiding long-term use of hormonal replacement therapy (HRT). Familial ovarian cancer is responsible for about 10% of ovarian cancer cases. Strategies available to high-risk women include screening (covered elsewhere) and prophylactic salpingo-oophorectomy. The precise role of chemoprevention for high-risk women in the form of the oral contraceptive pill is unclear.

Trends in cancer mortality in Switzerland, 1980-2001

Trends in cancer mortality in Switzerland were analysed over the period 1980-2001, on the basis of the World Health Organization database. Appropriately developed correction factors were utilized for the period before 1995, to allow for spurious trends introduced by the change between the 8th and the 10th revisions of the ICD. Steady declines in cancer mortality were observed, particularly from the mid-1980s onwards. Over the last decade, the fall in overall age-standardized (world standard) cancer mortality was 11.1% in men (from 158.1 in 1990-1991 to 140.6/100,000 in 2000-2001) and 7.6% in women (from 91.6 to 84.7/100,000), and the decline was larger in truncated rates from 35 to 64 years (-18.0 and -9.7%). In men, all major tobacco and alcohol neoplasms have declined until the late 1990s but have levelled off over the last few years, reflecting recent trends in alcohol and tobacco consumption. The fall in male lung cancer mortality was 20% over the last decade (from 42.9 to 34.3/100,000). In contrast, lung cancer mortality in women has steadily increased by 38% between 1981 and 1991 and by 47% between 1991 and 2001, to reach 10.7/100,000 at all ages and 18.3 at age 35 to 64, due to increased prevalence of smoking in subsequent generations of Swiss women. Other sites showing substantial declines include stomach and colorectum in both sexes, (cervix) uteri and breast in women. Likewise, prostate cancer showed modest favourable trends after 1995. Steady declines were observed for leukaemias, Hodgkin's disease and testicular cancer, namely, the neoplasms most influenced by therapeutic improvements, while trends in lymphomas and myeloma showed no clear pattern.

Cancer risk among patients with multiple sclerosis: a population-based register study

Cancer occurrence in patients with multiple sclerosis (MS) has been little studied, but associations with brain tumours, breast cancer, Hodgkin lymphoma and nasopharyngeal carcinoma have been suggested. We took advantage of population-based registers of MS and cancer to assess the risk of cancer following diagnosis of MS. Patients registered in the Danish Multiple Sclerosis Register were linked with the Danish Cancer Register to obtain information on cancer occurrence. The ratio of the observed to the number of expected cancers based on population-based incidence rates, i.e., the standardised incidence ratio (SIR), served as measure of the relative cancer risk. A database comprising all Danish women born after April 1, 1935, with information on all live-born children, was used in the analyses of breast cancer to adjust for reproductive factors. Overall 1,037 cancers were observed in 11,817 MS patients during 153,875 person-years of follow-up vs. an expected number of 1,098 (SIR = 0.94 [95% confidence interval CI: (0.89-1.00)]. The risk of brain tumours and Hodgkin lymphoma was not increased. A 16% overall reduced cancer risk in men with MS was explained by reduced numbers of cancers of the digestive, respiratory and genital organs. Though the overall cancer risk was not increased [SIR = 1.01(0.94-1.09), n = 676], female MS patients had an increased risk of breast cancer [SIR = 1.21 (1.05-1.39), n = 193]. Adjusting for parity and age at first child delivery did not change this risk estimate materially. In general MS patients are not at increased risk of cancer. Women with MS, however, seem to have a small excess risk of breast cancer, which cannot be attributed to reduced parity or delayed first child birth.

[Update on contraception]

Since the introduction of hormonal contraceptives in the 1960s, great advances have been achieved in contraception. Biological effects of sexual steroids as well as risks and benefits of oral contraception are better estimated. After the development of a new hormone-containing intra-uterine system, new hormone delivery systems offer women safe and effective contraceptive options. These new options that combine high efficacy and ease of use should allow better acceptance and compliance than daily pill ingestion and should then reduce the high rate of unintended pregnancies terminated by elective abortion. Transdermal contraceptive system and vaginal ring offer a promising innovative approach in pregnancy prevention. Subdermal implants give women the choice of a highly effective contraceptive system in spite of significant side effects. New hormonal delivery systems such as injectables are under development. Hysteroscopic tubal sterilization is now also available and is a very effective procedure. This wide variety of new contraceptive methods offers a marked improvement from previous medications for users by providing better efficacy and tolerability.

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.

The conventional nonsteroidal anti-inflammatory drug sulindac sulfide arrests ovarian cancer cell growth via the expression of NAG-1/MIC-1/GDF-15

Although the chemopreventive and antitumorigenic activities of nonsteroidal anti-inflammatory drug (NSAID) against colorectal cancer are well established, the molecular mechanisms responsible for these properties in ovarian cancer have not been elucidated. Therefore, there is an urgent need to develop mechanism-based approaches for the management of ovarian cancer. To this end, the effect of several NSAIDs on ovarian cancer cells was investigated as assessed by the induction of NAG-1/MIC-1/GDF-15, a proapoptotic gene belonging to the transforming growth factor-beta superfamily. Sulindac sulfide was the most significant NSAID activated gene 1 (NAG-1) inducer and its expression was inversely associated with cell viability as determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay. This growth suppression by sulindac sulfide was recovered by transfection of NAG-1 small interfering RNA. These results indicate that NAG-1 is one of the genes responsible for growth suppression by sulindac sulfide. Furthermore, we observed down-regulation of p21 WAF1/CIP1 by introduction of NAG-1 small interfering RNA into sulindac sulfide-treated cells. In addition, to elucidate other potential molecular mechanisms involved in sulindac sulfide treatment of ovarian cancer cells, we did a membrane-based microarray experiment. We found that cyclin D1, MMP-1, PI3KR1, and uPA were down-regulated by sulindac sulfide. In conclusion, a novel molecular mechanism is proposed to explain the experimental results and provide a rationale for the chemopreventive activity of NSAIDs in ovarian cancer.