Cancer and Steroid Hormone Study of the Centers for Disease Control and the National Institute of Child Health and Human Development. Oral-contraceptive use and the risk of breast cancer

Some Further Consideration on the Role of Oral Contraceptives in Breast Carcinogenesis

Available evidence concerning oral contraceptives and their potential interaction with reproductive history on breast cancer risk Is reviewed. The relative risks in 15 out of 15 studies were above unity among younger women (i.e., below age 35 and perhaps up to 45) for long-term oral contraceptive use, although apparent heterogeneities emerged in the risk estimates. The overall evidence is reassuring in subsequent age groups, whereas the modifying effects or interactions between oral contraceptives, reproductive factors and breast cancer risk are still largely undefined. Thus we suggest that, besides chance and bias, the apparent discrepancies between various studies should be considered within the framework of the complex time- and age-effects of hormone-related risk factors on breast carcinogenesis.

Using the Lorenz Curve to Characterize Risk Predictiveness and Etiologic Heterogeneity

The Lorenz curve is a graphical tool that is used widely in econometrics. It represents the spread of a probability distribution, and its traditional use has been to characterize population distributions of wealth or income, or more specifically, inequalities in wealth or income. However, its utility in public health research has not been broadly established. The purpose of this article is to explain its special usefulness for characterizing the population distribution of disease risks, and in particular for identifying the precise disease burden that can be predicted to occur in segments of the population that are known to have especially high (or low) risks, a feature that is important for evaluating the yield of screening or other disease prevention initiatives. We demonstrate that, although the Lorenz curve represents the distribution of predicted risks in a population at risk for the disease, in fact it can be estimated from a case-control study conducted in the population without the need for information on absolute risks. We explore two different estimation strategies and compare their statistical properties using simulations. The Lorenz curve is a statistical tool that deserves wider use in public health research.

Identifying Etiologically Distinct Sub-Types of Cancer: A Demonstration Project Involving Breast Cancer

With the advent of increasingly detailed molecular portraits of tumor specimens, much attention has been directed toward identifying clinically distinct subtypes of cancer. Subtyping of tumors can also be accomplished with the goal of identifying distinct etiologies. We demonstrate the use of new methodologies to identify genes that distinguish etiologically heterogeneous subtypes of breast cancer using data from the case-control Cancer and Steroid Hormone Study. Tumor specimens were evaluated using a breast cancer expression panel of 196 genes. Using a statistical measure that distinguishes the degree of etiologic heterogeneity in tumor subtypes, each gene is ranked on the basis of its ability to distinguish etiologically distinct subtypes. This is accomplished independently using case-control comparisons and by examining the concordance odds ratios in double primaries. The estrogen receptor gene, and others in this pathway with expression levels that correlated strongly with estrogen receptor levels, demonstrate high degrees of etiologic heterogeneity in both methods. Our results are consistent with a growing literature that confirms the distinct etiologies of breast cancers classified on the basis of estrogen receptor expression levels. This proof-of-principle project demonstrates the viability of new strategies to identify genomic features that distinguish subtypes of cancer from an etiologic perspective.

Genomic investigation of etiologic heterogeneity: methodologic challenges

Background

The etiologic heterogeneity of cancer has traditionally been investigated by comparing risk factor frequencies within candidate sub-types, defined for example by histology or by distinct tumor markers of interest. Increasingly tumors are being profiled for molecular features much more extensively. This greatly expands the opportunities for defining distinct sub-types. In this article we describe an exploratory analysis of the etiologic heterogeneity of clear cell kidney cancer. Data are available on the primary known risk factors for kidney cancer, while the tumors are characterized on a genome-wide basis using expression, methylation, copy number and mutational profiles.

Methods

We use a novel clustering strategy to identify sub-types. This is accomplished independently for the expression, methylation and copy number profiles. The goals are to identify tumor sub-types that are etiologically distinct, to identify the risk factors that define specific sub-types, and to endeavor to characterize the key genes that appear to represent the principal features of the distinct sub-types.

Results

The analysis reveals strong evidence that gender represents an important factor that distinguishes disease sub-types. The sub-types defined using expression data and methylation data demonstrate considerable congruence and are also clearly correlated with mutations in important cancer genes. These sub-types are also strongly correlated with survival. The complexity of the data presents many analytical challenges including, prominently, the risk of false discovery.

Conclusions

Genomic profiling of tumors offers the opportunity to identify etiologically distinct sub-types, paving the way for a more refined understanding of cancer etiology.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2288-14-138) contains supplementary material, which is available to authorized users.

Oral contraceptives and breast cancer risk overall and by molecular subtype among young women

BACKGROUND

Evidence suggests that recent oral contraceptive (OC) use is associated with a small increased breast cancer risk; yet risks associated with contemporary OC preparations and by molecular subtype are not well characterized.

METHODS

We conducted a population-based case-control study of invasive breast cancer among women ages 20 to 44 residing in the Seattle-Puget Sound area from 2004 to 2010 (985 cases and 882 controls). We collected information on contraceptive use and participant characteristics via an in-person interview. Multivariable-adjusted logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Lifetime duration of OC use for ≥ 15 years was associated with an increased breast cancer risk (OR, 1.5; 95% CI, 1.1-2.2). Current OC use (within 1 year of reference date) for ≥ 5 years was associated with an increased risk (OR, 1.6; 95% CI, 1.1-2.5) and there were no statistically significant differences in risk by OC preparation. Risk magnitudes were generally greater among women ages 20 to 39, and for estrogen receptor-negative (ER(-)) and triple-negative breast cancer (current use for ≥ 5 years among ages 20-39: ER(-) OR, 3.5; 95% CI, 1.3-9.0; triple-negative OR, 3.7; 95% CI, 1.2-11.8), although differences between groups were not statistically significant.

CONCLUSIONS

Long-term use of contemporary OCs and current use for ≥ 5 years was associated with an increased breast cancer risk among women ages 20 to 44. Risk may be greater among younger women and for ER(-) and triple-negative breast cancer, but these findings require confirmation.

IMPACT

Continued surveillance and pooled analyses of OC use and breast cancer risk by molecular subtype are needed as OC preparations evolve.

A conceptual and methodological framework for investigating etiologic heterogeneity

Cancer has traditionally been studied using the disease site of origin as the organizing framework. However, recent advances in molecular genetics have begun to challenge this taxonomy, as detailed molecular profiling of tumors has led to discoveries of subsets of tumors that have profiles that possess distinct clinical and biological characteristics. This is increasingly leading to research that seeks to investigate whether these subtypes of tumors have distinct etiologies. However, research in this field has been opportunistic and anecdotal, typically involving the comparison of distributions of individual risk factors between tumors classified on the basis of candidate tumor characteristics. The purpose of this article is to place this area of investigation within a more general conceptual and analytic framework, with a view to providing more efficient and practical strategies for designing and analyzing epidemiologic studies to investigate etiologic heterogeneity. We propose a formal definition of etiologic heterogeneity and show how classifications of tumor subtypes with larger etiologic heterogeneities inevitably possess greater disease risk predictability overall. We outline analytic strategies for estimating the degree of etiologic heterogeneity among a set of subtypes and for choosing subtypes that optimize the heterogeneity, and we discuss technical challenges that require further methodologic research. We illustrate the ideas by using a pooled case-control study of breast cancer classified by expression patterns of genes known to define distinct tumor subtypes.

Lipid profile of women using oral contraceptive pills

Oral contraceptives (OCs) are the most popular type of birth control pills. The study was designed to examine the biochemical changes which occur due to the use of oral contraceptive pills (OCs). The study was based on the questionnaire for having the information of any reproductive history fasting, age, health, nature of menstrual cycle, bleeding, disease etc and blood profiling for biochemical analysis of the women includes high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), total cholesterol (TC) and triglycerides (TG). Lipid profiling was carried out by using a commercially available diagnostic test kits. SPSS was used to analyze the data. The results showed statistically significant differences among users of OCs compared to non-users. Total cholesterol (242.92 +/- 2.842 mg dL(-1)), HDL-C (58.65 +/- 1.098 mg dL(-1)), LDL-C (115.84 +/- 1.266 mg dL(-1)) and triglycerides (105.56 +/- 2.341 mg dL(-1)) were significantly higher compared to the non-users (Total cholesterol 218.49 +/- 1.762, HDL-C 48.17 +/- 0.543, LDL-C 100.321 +/- 0.951 and triglycerides 83.77 +/- 2.299 mg dL(-1)). The result suggests that OCs increase the level of high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), total cholesterol (TC) and triglycerides (TG).

Oral contraceptive formulation and risk of breast cancer

BACKGROUND

While evidence on the association between oral contraceptive (OC) use and breast cancer generally suggests little or no increased risk, the question of whether breast cancer risk varies by OC formulation remains controversial. Few studies have examined this issue because large samples and extensive OC histories are required.

STUDY DESIGN

We used data from a multicenter, population-based, case-control investigation. Women aged 35-64 years were interviewed. To explore the association between OC formulation and breast cancer risk, we used conditional logistic regression to derive adjusted odds ratios, and we used likelihood ratio tests for heterogeneity to assess whether breast cancer risk varied by OC formulation. Key OC exposure variables were ever use, current or former use, duration of use and time since last use. To strengthen inferences about specific formulations, we restricted most analyses to the 2282 women with breast cancer and the 2424 women without breast cancer who reported no OC use or exclusive use of one OC.

RESULTS

Thirty-eight formulations were reported by the 2674 women who used one OC; most OC formulations were used by only a few women. We conducted multivariable analyses on the 10 formulations that were each used by at least 50 women and conducted supplemental analyses on selected formulations of interest based on recent research. Breast cancer risk did not vary significantly by OC formulation, and no formulation was associated with a significantly increased breast cancer risk.

CONCLUSIONS

These results add to the small body of literature on the relationship between OC formulation and breast cancer. Our data are reassuring in that, among women 35-64 years of age, we found no evidence that specific OC formulations increase breast cancer risk.

Contraception for cancer survivors

Women who have survived cancer may need guidance in choosing a method of contraception. This paper reviews the evidence supporting the safety and efficacy of available methods of contraception for cancer survivors and concludes that the Copper T380A intrauterine device (IUD), a highly effective, reversible, long-acting, hormone-free method should be considered a first-line contraceptive option for women with a history of a hormonally mediated cancer. However, the levonorgestrel-containing IUD may be preferable for women being treated with tamoxifen and women who have survived non-hormonally mediated cancers. Women with IUDs can undergo all forms of imaging, including computed tomography and magnetic resonance imaging.

Cancer registry databases: an overview of techniques of statistical analysis and impact on cancer epidemiology

Cancer registries provide systematically collected information on cancer incidence, prevalence, mortality, and survival of different cancers. Aggregated and de-identified patient-level information on cancer is available for analysis from individual cancer registries, nationally from the Surveillance, Epidemiology, and End Results program, the Centers for Diseases Control and Prevention, the North American Association of Central Cancer Registries; and internationally from the International Association of Cancer Registries. Over the past few decades, the type and extent of cancer-related information captured by different cancer registries have been greatly expanded by linkage with other population-based information sources, such as the census data and the Centers for Medicare and Medicaid Services claims data. In addition, sophisticated statistical analytical techniques have been developed that have greatly expanded the traditional purview of cancer registries focused on descriptive epidemiology and disease quantification to a much broader analytical horizon ranging from study of cancer etiology; rare cancers in specific demographic groups; interaction of environmental and genetic factors in causation of cancer; impact of co-morbidities, race, geographic, socioeconomic, and provider-related factors on access, diagnosis, and treatment; outcomes and end results of cancer treatment; and cancer control initiatives to diverse areas of cancer care disparity, public health policy, public health education, and importantly, cost-effectiveness of cancer care. Thus, it is not surprising that cancer registries have increasingly become indispensable parts of local, national, and international cancer control programs, and it is certain that cancer registries will continue to be extraordinary resources of information for clinicians, researchers, scientists, policy makers, and the public in our fight against cancer.

Age-related crossover in breast cancer incidence rates between black and white ethnic groups

BACKGROUND

Although breast cancer incidence is higher in black women than in white women among women younger than 40 years, the reverse is true among those aged 40 years or older. This crossover in incidence rates between black and white ethnic groups has been well described, has not been completely understood, and has been viewed as an artifact.

METHODS

To quantify this incidence rate crossover, we examined data for 440 653 women with invasive breast cancer from the National Cancer Institute's Surveillance, Epidemiology, and End Results database from January 1, 1975, through December 31, 2004. Data on invasive female breast cancers were stratified by race, age at diagnosis, year of diagnosis, and tumor characteristics. Standard descriptive analyses were supplemented with Poisson regression models, age-period-cohort models, and two-component mixture models. All statistical tests were two-sided.

RESULTS

We observed qualitative (ie, crossing or reversing) interactions between age and race. That is, age-specific incidence rates overall (expressed as number of breast cancers per 100 000 woman-years) were higher among black women (15.5) than among white women (13.1) younger than 40 years (difference = 2.4, 95% confidence interval [CI] = 2.4 to 2.4), and then, age-specific rates crossed with rates higher among white women (281.3) than among black women (239.5) aged 40 years or older (difference = 41.8, 95% CI = 41.7 to 41.9). The black-to-white incidence rate crossover was observed for all tumor characteristics assessed, although the crossover occurred at earlier ages of diagnosis for low-risk tumor characteristics than for high-risk tumor characteristics. The incidence rate crossover between ethnic groups was robust (ie, reliable and reproducible) to adjustment for calendar period and birth cohort effects in age-period-cohort models (P < .001 for difference by race).

CONCLUSION

Although this ecologic study cannot determine the individual-level factors responsible for the racial crossover in vital rates, it confirms that the age-related crossover in breast cancer incidence rates between black and white ethnic groups is a robust age-specific effect that is independent of period and cohort effects.

Efficacy of estriol in inhibiting epithelial proliferation in mammary fibroadenoma: randomized clinical trial

CONTEXT AND OBJECTIVE

Mammary fibroadenoma is a disease that affects a large number of women of reproductive age. The aim of this study was to evaluate the proliferative activity of mammary fibroadenoma through expression of Ki-67 and c-myc antigens, following administration of oral contraceptive with or without estriol.

DESIGN AND SETTING

Placebo-controlled double-blind randomized clinical trial in the Mastology Sector of the Department of Gynecology, Universidade Federal de São Paulo.

METHODS

Thirty-three fibroadenoma patients were studied. Ten women (group 1) took an oral contraceptive constituted by levonorgestrel and ethinyl estradiol together with placebo manufactured in the same capsule for four consecutive cycles with a seven-day interval between them. The other 23 patients (group 2) took the same oral contraceptive together with estriol, which was put into the same capsule and used in the same way as among the group 1 patients. After four cycles, the nodules were surgically removed and sent for immunohistochemical analysis of Ki-67 and c-myc expression.

RESULTS

The Ki-67 and c-myc analysis did not reveal any significant differences between the study groups. The values were 9.16 and 10.54 for group 1 and 10.86 and 17.03 for group 2, respectively. There was a tendency towards higher expression of antigens in group 2.

CONCLUSION

Our results showed that there was no significant statistical difference in Ki-67 and c-myc expression between our study groups, but only a tendency towards higher expression among users of oral contraceptives containing estriol.

Oral Contraceptives and the Risk of Death From Breast Cancer

OBJECTIVE

To examine the relationship between the use of oral contraceptives and the risk of death from breast cancer.

METHODS

We used interview data from the Cancer and Steroid Hormone Study, linked to cancer registry data from the Surveillance, Epidemiology, and End Results Program, to examine the 15-year survival and prior use of oral contraceptives among 4,292 women aged 20 to 54 years when diagnosed with breast cancer from December 1, 1980, to December 31, 1982. Cox proportional hazard models were used to estimate the relative rate of death from breast cancer by oral contraceptive use.

RESULTS

Duration of oral contraceptive use, time since first use, age at first use, and use of specific pill formulations were not associated with survival. For time since last use, the risk of death from breast cancer decreased significantly with increasing time since last use of oral contraceptives, but a consistent gradient effect was not observed. Adjusted hazard ratios ranged from 0.86 to 1.41 and were 1.00 or less for all recency categories except during 13 to 24 months before diagnosis; none was statistically significant. Women who were currently using oral contraceptives had an adjusted hazard ratio of 0.90 (0.68, 1.19).

CONCLUSION

Overall, oral contraceptive use had neither a harmful nor a beneficial effect on breast cancer mortality. The differences between pill users and nonusers were slight, and the risk estimates were usually reduced with confidence limits that nearly always included 1.0.

Contraception in Canada: a review of method choices, characteristics, adherence and approaches to counselling

Contraception is a significant concern for Canadian women of child-bearing age, their partners and their health care providers. In this narrative review we provide information on current trends and recent changes in Canadians' choices of contraceptive methods. We review the characteristics of contraceptive methods available in Canada, with an emphasis on hormonal methods and newer options such as the transdermal contraceptive patch, the vaginal contraceptive ring and the levonorgestrel-releasing intrauterine system. We also discuss adherence to contraception as well as approaches to counselling to promote adherence and to reduce the risk of sexually transmitted infections in the context of contraception.

Oral contraceptive use as a risk factor for premenopausal breast cancer: a meta-analysis

OBJECTIVE

To perform a meta-analysis of case-control studies that addressed whether prior oral contraceptive (OC) use is associated with premenopausal breast cancer.

METHODS

We searched the MEDLINE and PubMed databases and bibliography reviews to identify case-control studies of OCs and premenopausal breast cancer published in or after 1980. Search terms used included breast neoplasms, oral contraceptives, contraceptive agents, and case-control studies. Studies reported in all languages were included. Thirty-four studies were identified that met inclusion criteria. Two reviewers extracted data from original research articles or additional data provided by study authors. We used the DerSimonian-Laird method to compute pooled odds ratios (ORs) and confidence intervals (CIs) and the Mantel-Haenszel test to assess association between OC use and cancer.

RESULTS

Use of OCs was associated with an increased risk of premenopausal breast cancer in general (OR, 1.19; 95% CI, 1.09-1.29) and across various patterns of OC use. Among studies that provided data on nulliparous and parous women separately, OC use was associated with breast cancer risk in both parous (OR, 1.29; 95% CI, 1.20-1.40) and nulliparous (OR, 1.24; 95% CI, 0.92-1.67) women. Longer duration of use did not substantially alter risk in nulliparous women (OR, 1.29; 95% CI, 0.85-1.96). Among parous women, the association was stronger when OCs were used before first full-term pregnancy (FFTP) (OR, 1.44; 95% CI, 1.28-1.62) than after FFTP (OR, 1.15; 95% CI, 1.06-1.26). The association between OC use and breast cancer risk was greatest for parous women who used OCs 4 or more years before FFTP (OR, 1.52; 95% CI, 1.26-1.82).

CONCLUSION

Use of OCs is associated with an increased risk of premenopausal breast cancer, especially with use before FFTP in parous women.

Hormonal contraception in adolescents: special considerations

With the rates of unintended pregnancies in teenagers remaining high, it is crucial to present adolescents with all of the contraceptive options available to them. While barrier methods, for example, male condoms, are easily accessible and do not have adverse effects, their use must be consistent and correct with each act of intercourse. Hormonal contraception affords much better efficacy in preventing pregnancy when used with full compliance. Oral contraceptives are a popular method of contraception among adolescents and offer many non-contraceptive benefits along with the prevention of pregnancy. They have very few significant adverse effects, which are outweighed by the significant morbidity associated with teenage pregnancies, and can be used by most adolescent females. However, their minor bothersome effects do contribute to the high discontinuation rates seen. In addition, many girls find it difficult to remember to take a pill every day, leading to higher failure rates in teenagers than in adult women. The advent of long-acting, progestogen (progestin)-only methods, such as injectables and implantables, has been generally accepted by adolescents and these methods have proven to be more efficacious by avoiding the need for daily compliance. However, progestogen-only methods cause irregular bleeding and amenorrhea, which is not acceptable to many teenagers. In addition, the most widely used implant was taken off the market a few years ago and newer forms are not yet widely accessible. Other novel methods are currently available, including the transdermal patch and the vaginal ring. Both are combinations of estrogen and progestogen and have similar efficacy and adverse effect profiles to oral contraceptives. Their use may be associated with greater compliance by adolescents because they also do not require adherence to a daily regimen. However, there may be some drawbacks with these newer methods, for example, visibility of the patch and difficulty with insertion of the vaginal ring. When regular contraceptive modalities fail, emergency contraception is available. Choices include combination oral contraceptives, progestogen-only pills, mifepristone, or placement of a copper-releasing intrauterine device. These methods can be very useful for preventing pregnancy in adolescents as long as adolescents are aware of their existence and have easy access to them.

The woman patient after WHI

An epidemic of fear and distrust has infected women (and physicians) after publication of the Women's Health Initiative (WHI). The overinflated negative data emerging from the oestroprogestinic arm of WHI have frightened women and gave rise to the most difficult emotions to cope with. Keywords such as cancer, death and hormones combined together, have potentiated an avoidant attitude towards hormonal therapy (HT) driven more emotionally than rationally. This negative aura has not been dissipated by the positive data from the oestrogen-only arm of WHI. This paper will discuss: women's different emotional reactions to and coping strategies for HT-related fear after WHI; the communication skills physicians should use in focusing on positive messages emerging from WHI; predictors of current HT use; the meaning of the higher use of HT in postmenopausal highly-educated women and women gynaecologists; the importance of increasing healthy life-styles as a taking of responsibility towards aging by every woman; shifting from passivity to active sharing of the decision making process with the caring physician; and the use of an individually tailored HT, when appropriate, as part of an active strategy in the pursuit of a longer health expectancy.

Prevention of Hormone-Related Cancers: Breast Cancer

Carcinogenesis in the breast is a hormonally dependent process. Evidence implicating estrogen as a key breast carcinogen comes from various lines of investigation. Traditional epidemiologic studies demonstrate associations between estrogen exposure, both exogenous and endogenous, and increased breast cancer risk. Ongoing genetic epidemiologic studies also show associations between specific polymorphisms in estrogen-metabolizing genes and risk, albeit inconsistently. The application of these findings to the treatment and, more recently, the prevention of breast cancer has led to the development of agents that either (1) inhibit estrogen action at the estrogen receptor (selective estrogen receptor modulators (SERMs]); or (2) inhibit estrogen-synthesizing enzymes, thereby abrogating synthesis of this hormone (aromatase inhibitors). Large phase III trials have evaluated the ability of such agents to reduce the incidence of breast cancer in women at increased risk of the disease. The National Surgical Adjuvant Breast and Bowel Project (NSABP) P-1: Breast Cancer Prevention Trial (BCPT) demonstrated the superiority of the SERM tamoxifen to placebo in reducing breast cancer risk, leading to the Food and Drug Administration approval of tamoxifen for risk reduction. The implementation of tamoxifen for this indication has not become widespread in clinical practice, however, for a variety of reasons that we discuss. Results from the NSABP Study of Tamoxifen and Raloxifene, which compares the risk-reducing efficacy as well as toxicity of these two SERMs in a similar high-risk population, will be available in the near future. Based on promising data involving reduction of contralateral breast cancer risk in adjuvant studies, several aromatase inhibitors, including letrozole, anastrozole, and exemestane, are being incorporated into trials evaluating their efficacy as preventive agents in women at increased risk.

Reproductive history and mortality after breast cancer diagnosis

OBJECTIVE

To assess whether reproductive factors are associated with mortality after breast cancer diagnosis.

METHODS

We followed up 4,299 U.S. women enrolled between 1980 and 1982 at ages 20-54 years as incident breast cancer cases in a population-based, case-control study, the Cancer and Steroid Hormone Study. Vital status through 1997 for these cases was obtained by linking Cancer and Steroid Hormone Study data to Surveillance, Epidemiology, and End Results files. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for death associated with selected reproductive factors using proportional hazards models.

RESULTS

During a median follow-up of 14.5 years, 1,847 deaths occurred. Women aged 20-45 years whose last birth occurred 12 months or less (age-adjusted HR = 1.62, 95% CI 1.10-2.37) and 13-48 months before breast cancer diagnosis (age-adjusted HR = 1.35, 95% CI 1.05-1.75) were at an increased risk for death compared with nulliparous women. After adjusting for additional factors including tumor stage, women whose last birth occurred 12 months or less before diagnosis remained at an increased risk for death (HR = 1.51, 95% CI 1.02-2.23). Fifteen-year survival was 38%, 51%, and 60% among women aged 20-45 years whose last birth was 12 months or less, 13-48 months, and more than 48 months before diagnosis, respectively, compared with 65% among nulliparous women. Mortality risk was not associated with age at first birth, parity, or breastfeeding duration among women aged 20-45 years or among women aged 46-54 years.

CONCLUSION

A recent birth may be an adverse prognostic indicator among women diagnosed with breast cancer at ages 20-45 years.

Oral contraceptives and reproductive system cancer

Extensive research during the last 20 years has shown that oral contraceptives are safe. Several recent epidemiological studies have confirmed that combined oral contraceptives (COCs) provide substantial protection against endometrial and ovarian cancer, and this protection is long-lasting and may persist for 15 or more years after termination of OC use. In many studies COCs have been associated with an increased risk of cervical abnormalities and cervical cancer, but there might be alternative explanations for these epidemiological associations (COC users can start having sexual intercourse at an earlier age, they have more sexual partners, and they rarely use barrier methods of contraception), so OCs act as a promoter for HPV-induced carcinogenesis. Finally, women who are currently using COCs or have used them in the past 10 years are at a slightly increased risk of having breast cancer during the next 10 years, although the additional cancers diagnosed tend to be localized to the breast and they are less advanced clinically than the cancers diagnosed in those who have never used COCs.

Oral Contraceptives and the Risk of Ductal Breast Carcinoma in situ

Recent evidence suggests that oral contraceptive use is associated with little to no increased risk of invasive breast carcinoma. No study has examined the relationship between oral contraceptive use and the risk of non-invasive breast carcinoma, that is, breast carcinoma in situ.

OBJECTIVE

To define the role of oral contraceptive use in the development of breast carcinoma in situ.

METHODS

The data are 875 ductal carcinoma in situ (DCIS) cases diagnosed among residents of the state of Connecticut from September 15, 1994 to March 14, 1998 and between the age of 20 and 79 years as well as 999 control subjects. Controls are female Connecticut residents collected via random-digit-dial and frequency matched to the cases by 5-year age intervals. Telephone interviews were used to collect information on risk factors and cancer screening history. Logistic regression was used to provide maximum likelihood estimates of the odds ratios (OR) with 95% confidence intervals (95% CI).

RESULTS

The risk of being diagnosed with DCIS for women who had ever used oral contraceptives was not increased relative to women who had never used them (OR: 1.0, 95% CI: 0.8, 1.2). The risk did not significantly increase with duration of oral contraceptive use, nor with duration of high estrogen use, time since last use, progestin or estrogen type, or age at first use. Furthermore, the association between oral contraceptive use and DCIS risk did not vary by the presence of a family history of breast cancer or by menopausal status.

CONCLUSIONS

In these data, no evidence was found for an increased risk of ductal carcinoma in situ associated with the use of oral contraceptives.

Breast cancer and specific types of oral contraceptives: a large Norwegian cohort study

The aim of our study was to examine the risk of breast cancer according to specific types of estrogens and progestagens in oral contraceptives (OCs) based on the prospective Norwegian Women and Cancer study (NOWAC). Between 1991-97 women aged 30-70 years were drawn at random from the central person register and mailed an invitation and a questionnaire. Women (102,443) were enrolled with follow-up information collected throughout 1999 by linkage with national registries of cancer, mortality and emigration based on the unique national identification number. Among the 96,362 women included in the present analysis 851 invasive breast cancer were diagnosed. The adjusted risk of breast cancer increased with 25% for ever use of OCs and the risk increased with increasing duration of use (test for trend: p = 0.007). No association between time since last use and breast cancer risk was found after stratification on duration of use. Positive trend was still found for total duration of use among women who used OCs more than 5 years ago. Second generation of OCs had an increased risk with increasing duration of use. Classifying progestagens according to chemical groups, the relative risk increased significantly with increasing cumulative dose of levonorgestrel progestagen. It was difficult to conclude for the other groups due to lack of power. In a multivariate analysis the cumulative dose for all progestagen groups were non-significant, although we observed a significant increased risk with increasing milligram-months of estrogen exposure (p = 0.002). In conclusion, the increased risk of breast cancer related with OC formulations could be due mostly to estrogen component.

Hormonal manipulations and breast cancer

Breast cancer is the most common cancer among women and the leading cause of death in women, 40 to 55 years of age. The lifetime odds of developing breast cancer are apparently up to 1 in 8 women in North America and 1 in 12 in Western Europe. According to the American Cancer Society, some 200,000 women (and 1,500 men) will be diagnosed with breast cancer this year. Although the incidence of breast cancer in women has been rising since the mid-1940s, the mortality has dropped modestly over the past decade, probably due to earlier and improved diagnosis and treatment. Evidence from both epidemiological and experimental studies points to an important role of reproductive variables in the development and promotion of human breast neoplasia. Hormonal manipulations, in the form of contraceptives, hormone replacement therapy, or antiestrogens, affect the incidence and course of breast cancer and may be useful in prevention and treatment of the tumor. In this review we summarize the current status of the use of hormones and antihormones in regard to breast cancer and outline possible areas of additional development and investigation.

TARGET AUDIENCE

Obstetricians and Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader will be able to summarize the effects of estrogen and progestogens on the breast and to list the effects of other hormonal modulators on the breast.

Androgens and mammary growth and neoplasia

OBJECTIVE

Evaluation of current clinical, experimental, genetic, and epidemiological data pertaining to the role of androgens in mammary growth and neoplasia.

DESIGN

Literature review.

SETTING

National Institutes of Health.

SUBJECT(S)

Recent, basic, clinical, and epidemiological studies.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Effects of androgens on mammary epithelial proliferation and/or breast cancer incidence.

RESULT(S)

Experimental data derived from rodents and cell lines provide conflicting results that appear be strain- and cell line-dependent. Epidemiologic studies have significant methodological limitations and provide inconclusive results. The study of molecular defects involving androgenic pathways in breast cancer is in its infancy. Clinical and nonhuman primate studies, however, suggest that androgens inhibit mammary epithelial proliferation and breast growth and that conventional estrogen treatment suppresses endogenous androgens.

CONCLUSION(S)

Abundant clinical evidence suggests that androgens normally inhibit mammary epithelial proliferation and breast growth. Suppression of androgens by conventional estrogen treatment may thus enhance estrogenic breast stimulation and possibly breast cancer risk. Clinical trials to evaluate the impact of combined estrogen and androgen hormone replacement regimens on mammary gland homeostasis are needed to address this issue.

Evaluating the safety of medicines, with particular reference to contraception

Toxicological studies and clinical trials cannot be expected to predict all important adverse effects of medicines and contraceptives. Post-marketing surveillance is essentially an epidemiological task that involves detecting associations between drugs and events. The first alerts about drug safety problems have often come from case reports, but epidemiological studies are needed to confirm adverse (or beneficial) effects and to provide quantitative information. This article illustrates methodological principles by considering three examples from the field of contraceptive safety: oral contraceptives and breast cancer, intrauterine contraception and pelvic inflammatory disease, and newer oral contraceptives and venous thromboembolism. Key issues that emerge include bias and confounding, the place of subgroup analyses, random error, and the use of computerized databases. In research on contraceptive and drug safety, conclusions usually need to be based on careful assessment of multiple observational studies.

Comparison of a traditional questionnaire with an icon/calendar-based questionnaire to assess occupational history

BACKGROUND

Self-reported work histories are an essential tool for estimating exposure in many occupational epidemiologic studies. However, the transience of some occupations such as farm work can hamper recall, resulting in inaccurate reporting. To address this problem, we have developed an icon/calendar-based questionnaire. This study compares work histories collected via this questionnaire to those collected via a traditional questionnaire.

METHODS

Eighty-nine farmworkers and non-farmworkers were interviewed twice, 8-10 months apart, about their lifetime employment. In the first interview, subjects were asked to recount their entire work history, starting from the interview date and moving backwards in time ("traditional questionnaire"). In the second interview, subjects were first asked about important life events, which were recorded with icons on a calendar. They were then asked to recount their work history, which was recorded, job-by-job, on the calendar with icons ("icon-calendar questionnaire").

RESULTS

Number of jobs and amount of work time accounted for since first employment were significantly greater using the icon-calendar questionnaire than the traditional questionnaire, the disparity increasing with time from the date of interview. The ratio of number of jobs in the traditional questionnaire to number of jobs in the icon-calendar questionnaire decreased from 100.0% in the most recent time period to 0.0% in the earliest time period. While the percentage of time explained by employment remained relatively constant across time periods in the icon-calendar questionnaire, ranging from 86.3 to 98.9%, it rapidly decreased with time in the traditional questionnaire, from 77.9% in the most recent time period to 0.0% in the earliest time period.

CONCLUSIONS

The icon-calendar questionnaire was more effective than the traditional questionnaire for obtaining complex work histories during interviews, producing a more complete picture of a person's work history.

Oral contraceptive pills: considerations for the adolescent patient

Combined oral contraceptive pills (OCPs) are the most commonly prescribed method of birth control for adolescents. This article presents an overview of OCP pharmacology and summarizes the different types of OCPs. The initial patient evaluation and subsequent care are described, with a focus on management plans specific to adolescents. Emergency contraception, an alternative use of OCPs, is described as well. A thorough knowledge of OCPs and an appreciation of adolescent-specific management plans will enhance nurse practitioners' skills in preventing pregnancy in their adolescent patients.

The "boom and bust phenomenon": the hopes, dreams, and broken promises of the contraceptive revolution

The "boom and bust phenomenon" is a pattern that has emerged in the development, introduction, and delivery of a number of significant new contraceptive products in the United States. When a new contraceptive product is introduced with great promise and publicity, it usually experiences a "boom" during which sales, demand, and expectations are high. This boom is often followed by a "bust" phase during which a product does not live up to expectations, initial excitement falls off, and a drop in sales and use ensues. The boom and bust phenomenon goes to the heart of what some have referred to as the failed promise of the contraception revolution by creating obstacles to significant expansion of contraceptive choice in the United States. Case studies of oral contraceptives, intrauterine devices, and Norplant(R) are used to illustrate the boom and bust phenomenon and the effect it has had in shaping the direction of advances in contraceptive technology.

Prescribing and managing oral contraceptive pills and emergency contraception for adolescents

Combination OCPs are safe and effective ways to prevent unintended adolescent pregnancy if they are used properly. Numerous noncontraceptive benefits of OCPs can bolster continued combination OCP use. Progestin-only OCPs are an option, particularly for young women with medical contraindications to taking estrogens; however, because of their lower efficacy, progestin-only pills are not the first choice for oral contraception for adolescents. Health care providers can give young women a second chance to prevent unintended pregnancy by improving their access to emergency contraception through educating and counseling about emergency contraception at all office visits, by prescribing emergency contraceptive pills in advance, or by prescribing emergency contraceptive pills over the telephone.

Testing for Hereditary Risk of Ovarian Cancer

BACKGROUND: Approximately one out of every 10 ovarian cancers is caused by inherited mutations in identified genes. The characterization of hereditary ovarian cancer as an autosomal dominant disorder of specific gene mutations is more specific and useful than descriptive clinical syndromes such as "Lynch II," "site-specific ovarian cancer," or "breast-ovarian cancer." METHODS: The author reviewed recent studies of the biology, epidemiology, and medical management of hereditary ovarian cancer risk. RESULTS: Most hereditary ovarian cancer is attributable to two genes, BRCA1 and BRCA2, with other genes accounting for a smaller fraction. Women who inherit a mutation in any of these genes are far more likely than the general population to develop an epithelial malignancy of the ovary. Appropriate evaluation of family history can identify women most likely to have hereditary cancer risk, and genetic testing can definitively identify women with germline mutations that place them and their family at increased risk of ovarian cancer. CONCLUSIONS: Hereditary risk assessment, including genetic testing, can enhance medical management when used appropriately and should be accompanied by patient education and counseling.

Physiologic effects of steroid hormones and postmenopausal hormone replacement on the female breast and breast cancer risk

Most data demonstrate that breast cancer is hormonally influenced. For the woman with no history of breast cancer, the benefits of HRT may outweigh the risks. Although it remains the standard of care to discourage hormone use in patients who have had breast cancer, future studies may result in a change of this standard. There needs to be more research into these complex hormonal interactions so that we will have a better understanding of the true risks and benefits when we attempt to advise our patients regarding the best treatment regimens for them.

Seasonal trends in the self-detection of breast cancer: indications from the Cancer and Steroid Hormone (CASH) study

Of 2895 women who self-detected an incident breast cancer that required surgery, peaks in month of detection occurred in spring and late autumn (p = 0.012). For the subset of cases for whom receptor status was available, there was a highly significant seasonal variation in detection only for those with ER-negative tumors. Further investigations into seasonality and breast cancer detection may be warranted.