Oral contraceptives and the risk of endometrial cancer

The relationship between the use of combbination oral contraceptives (OCs) and the risk of endometrial cancer was assessed in a case-control study conducted in the Swiss Canton of Vaud between 1 January 1988 and 31 July 1990. Subjects included 122 women aged 75 or less with histologically confirmed endometrial cancer, and 309 control women in hospital for acute conditions unrelated to OC use. Overall, 14 percent of cases and 27 percent of controls had ever used OCs, corresponding to a multivariate relative risk (RR) of 0.5 (95 percent confidence interval [CI]: 0.3. 0.8). The risk of endometrial cancer was found to be related inversely to duration of OC use: RR=1.0 for less than two years of OC use; 0.5 for two to five years; and 0.3 (95 percent CI: 0.1, 0.7) for more than five years. The protection appeared greater within 20 years since last use, and the RR rose to 0.8 after 20 or more years since last use; numbers are too small, however, for reliable inference from these subanalyses. No significant interaction or modifying effect was observed with other major factors related to endometrial cancer, including parity, body mass index, estrogen replacement therapy, and cigarette smoking. While this study provides further evidence for the protective effect of OCs against risk of endometrial cancer, the relationship requires continued evaluation to assess the long-term implications and public health impact of OC use.This work was supported in part by the Swiss National Science Foundation Grant No. 3.866-0.88.     

Pooled analysis of 3 European case-control studies of epithelial ovarian cancer: III. Oral contraceptive use

The relationship between use of oral contraceptives (OCs) and other contraceptive methods and the risk of ovarian cancer was examined in a combined analysis of 3 hospital-based case-control studies conducted in Italy, the United Kingdom, and Greece, for a total of 971 ovarian cancer cases and 2,258 controls under age 65. Compared with never-users, the combined multivariate relative risk (RR) for ever-users was 0.6 (95% confidence interval, CI = 0.4-0.8) and the estimates were consistent in the 3 datasets. The protection was also similar across strata of age and parity. Considering various measures of OC use, available in the Italian and British datasets only, the protection conveyed on ovarian cancer risk increased with the duration of use and persisted in the medium-long period: the RR in women reporting their last OC use greater than or equal to 15 years prior to diagnosis was 0.5 (95% CI = 0.2-1.0). The risks in ever-users were appreciably lower in those women who reported their first OC use before 25 years of age (RR = 0.3 for first use before age 25, 0.8 for first use at age 25-34 and 0.7 at 35 years or after). Such findings emerged similarly from Italian and British data. This combined analysis, besides offering further quantitative estimates of the protective effects of OCs on ovarian cancer risk in European populations, provides useful insights into the time pattern of the relationship between OC use and ovarian carcinogenesis, suggesting that the protection persists for 15 years or more after cessation of use and may be larger for use at younger age.     

A case-control study of breast cancer and hormonal contraception in Costa Rica

By 1981, 11% of married women in Costa Rica ages 20-49 years had used depot-medroxyprogesterone acetate (DMPA) and 58% had used oral contraceptives (OCs). Since 1977, the Costa Rican Ministry of Health has maintained a nationwide cancer registry. These circumstances provided an opportunity for a population-based, case-control study of DMPA, OCs, and breast cancer in Costa Rica. Cases were 171 women ages 25-58 years with breast cancer diagnosed between 1982 and 1984; controls were 826 women randomly chosen during a nationwide household survey. Cases and controls were interviewed with the use of a standard questionnaire covering their reproductive and contraceptive histories. Logistic regression methods were used to adjust for confounding factors. While few cases or controls had ever used DMPA, DMPA users had an elevated relative risk (RR) estimate of breast cancer of 2.6 (95% confidence limits = 1.4-4.7) compared with never users. However, no dose-response relationship was found; even the group of women who had used DMPA for less than 1 year had an elevated RR estimate (RR = 2.3; 95% confidence limits = 1.0-5.1). In contrast, OC users had no elevation in RR compared with never users (RR = 1.2; 95% confidence limits = 0.8-1.8). The results of the DMPA analysis are inconclusive. Before decisions are made on whether to continue providing this effective contraceptive method, other ongoing studies will need to confirm of refute these findings.     

Oral contraceptives and breast cancer in northern Italy. Final report from a case-control study.

To assess the relation between oral contraceptive (OC) use and breast cancer, we analysed data from a case-control study conducted in Northern Italy between 1983 and 1991 on 2,309 cases below age 60 and 1,928 controls admitted to hospital for acute diseases unrelated to OC use and to any of the known or potential risk factors for breast cancer. OC use was reported by 16% of cases and 14% of controls. The multivariate relative risk (RR) for ever vs never use of combination OC was 1.2 (95% confidence interval (CI) 1.0-1.4). However, there was no trend in risk with duration. The RR was elevated for very short use, but declined to 0.8 (95% CI = 0.5-1.0) for five or more years'' use. No noteworthy relationship was found for other major measures of OC use, although RR estimates were above unity for women who had stopped use less than 5 years before (RR = 1.5, 95% CI = 1.1-2.0), started use less than 10 years before (RR = 1.3, 95% CI = 1.0-1.9), started when 25 or more years old (RR = 1.4, 95% CI = 1.1-1.7), or after first birth (RR = 1.2, 95% CI = 1.0-1.5). No interaction was observed between OC use and family history of breast cancer, parity and age at first birth. A separate analysis of 373 cases and 456 control below age 40 showed no association with ever use (RR = 0.9, 95% CI = 0.6-1.2).     

Impact of teenage oral contraceptive use in a population-based series of early-onset breast cancer cases who have undergone BRCA mutation testing

Oral contraceptive (OC) use in young women has been associated with an increased risk of breast cancer. This matched case-control study aims to elucidate the combined effects of OC use and genetic factors in a population-based series of BRCA1/2 mutation-tested early-onset breast cancers. A first invasive breast cancer was diagnosed in 259 women aged 40 years between 1990 and 1995 in the South Swedish Health Care Region. A total of 245 women were included in this study. Information on family history of cancer, reproductive factors, smoking and OC use was obtained from questionnaires or patient charts. Three age-matched controls per case were chosen from a prospective South Swedish cohort. Ever OC use and current OC use were not associated with breast cancer. Cases were more likely to have used OCs before age 20 years (adjusted odds ratio (OR) 2.10 (95% CI 1.32-3.33)) and before their first child (adjusted OR 1.63 (95% CI 1.02-2.62)). When stratified by age, the effect of early OC use was limited to women diagnosed prior to age 36 years (OR 1.53 (1.17-1.99) per year of OC use prior to age 20 years). The risks were similar for low-dose and high-dose OCs. The probability of being a BRCA1/2 mutation carrier was three times higher among cases who started OC use prior to age 20 years compared with cases who started at age 20 years or older or who had never used OCs. However, the duration of OC use was similar among cases with and without BRCA1/2 mutations. No association was seen with a first-degree family history of breast cancer. Each year of OC use prior to age 20 years conferred a significantly increased risk for early-onset breast cancer, while there was no risk associated with use after age 20 years.     

Hormone replacement therapy and breast cancer in former users of oral contraceptives--The Norwegian Women and Cancer study

Combined estrogen-progestin menopausal therapy (HRT) and combined estrogen-progestin contraceptives (OC) both increase breast cancer risk during current use and a few years after. We investigated risk of breast cancer in women who were users of HRT dependant on former history of OC use in a large, national population-based cohort study, the Norwegian Women and Cancer study (NOWAC). Exposure information was collected through postal questionnaires. Based on follow-up of 30,118 postmenopausal women by linkage to national registers of cancer, deaths, and emigration we revealed 540 incident breast cancer cases between 1996 and 2004. Compared to never users of either drugs current use of HRT gave a significant (p = 0.002) higher risk of breast cancer in former OC users, RR = 2.45 (95% CI 1.92-3.12), than among never users of OCs, RR = 1.67 (1.32-2.12). Relative risk of current use of HRT was similar for estrogen only and combinations with progestin added in ever users of OCs. The increased risk of breast cancer in current HRT users with a history of former OC use could have potential great impact on postmenopausal breast cancer risk as the proportion of postmenopausal women with former OC use will continue to increase.     

Oral contraceptives, menopausal hormone therapy use and risk of B-cell non-Hodgkin lymphoma in the California Teachers Study

We examined oral contraceptive (OC) and menopausal hormonal therapy (MHT) use in relation to risk of B-cell non-Hodgkin lymphoma (NHL). Women under age 85 years participating in the California Teachers Study with no history of hematopoietic cancer were followed from 1995 through 2007. A total of 516 of 114,131 women eligible for OC use analysis and 402 of 54,758 postmenopausal women eligible for MHT use analysis developed B-cell NHL. Multivariable adjusted and age stratified Cox proportional hazards models were fit to estimate relative risks (RRs) and 95% confidence intervals (95% CI). Ever versus never OC use was marginally associated with lower B-cell NHL risk, particularly among women first using OCs before age 25 years (RR=0.72, 95% CI=0.51-0.99); yet, no duration-response effect was observed. No association was observed for ever versus never MHT use among postmenopausal women (RR=1.05, 95% CI=0.83-1.33) overall or by formulation (estrogen alone, ET, or estrogen plus progestin, EPT). Among women with no MHT use, having bilateral oophorectomy plus hysterectomy was associated with greater B-cell NHL risk than having natural menopause (RR=3.15, 95% CI=1.62-6.13). Bilateral oophorectomy plus hysterectomy was not associated with risk among women who used ET or EPT. These results indicate that exogenous hormone use does not strongly influence B-cell NHL risk.     

A prospective study of oral contraceptive use and risk of breast cancer (Nurses' Health Study, United States)

Results of previous epidemiologic studies have provided reassurance that there is little, if any, increase in risk of breast cancer with oral contraceptive (OC) use in general. However, in several studies, an increased risk of breast cancer has been observed in two subgroups, young women who used OCs for extended durations and in women who used OCs prior to a first-term pregnancy. We evaluated these relationships using data from the ongoing Nurses' Health Study cohort (United States). We documented 3,383 cases of breast cancer from 1976 to 1992 among 1.6 million person-years of follow-up. We observed no overall relationship between duration of OC use and breast cancer risk, even among women who reported using OCs for 10 or more years (multivariate relative risk [RR]=1.11, 95 percent confidence interval [CI]=0.94-1.32). Among women less than 45 years of age, the multivariate RR for using OCs for 10 or more years was 1.07 (CI=0.70-1.65) compared with never-users. The risk associated with five or more years of OC use prior to a first full-term pregnancy compared with never-use was 0.96 (CI=0.65-1.43). Among women less than 45 years of age, we observed no evidence of an increased risk with OC use before a first full-term pregnancy (use for five or more years: RR=0.57, CI=0.24-1.31). Because of the age distribution of our cohort, we were unable to evaluate these relationships among women less than 40 years of age. Our study provides considerable evidence that long-term past OC use, either overall or prior to a first full-term pregnancy, does not result in any appreciable increase in breast cancer risk in women over 40 years of age.     

Female hormone utilisation and risk of hepatocellular carcinoma.

The relationship between female hormone use and primary liver cancer was analysed using data from a case-control study conducted between 1984 and 1992 in Milan on 82 female incident cases with histologically or serologically confirmed hepatocellular carcinoma and 368 controls admitted to hospital for acute non-neoplastic, non-hormone-related diseases. An elevated relative risk (RR) or primary liver cancer was observed in oral contraceptive (OC) users (RR 2.6, for ever versus never users, 95% confidence interval, CI 1.0-7.0). The RR was directly related to duration of use (RR 1.5 for < or = 5 years and 3.9 for > 5 years) and persisted for longer than 10 years after stopping use (RR 4.3%, 95% CI 1.0-18.2). The RR were below unity, although not significantly, for women ever using oestrogen replacement therapy (RR 0.2, 95% CI 0.03-1.5) and female hormones for indications other than contraception and menopausal therapy (RR 0.4, 95% CI 0.1-1.5). The long-lasting, association between risk of hepatocellular carcinoma and OC use has potential implications on a public health scale, since primary liver cancer is a relatively rare disease among young women, but much more common at older ages. This study provides limited but reassuring evidence on the possible relationship between oestrogen replacement treatment and subsequent risk of hepatocellular carcinoma.     

Oral contraceptive use and the risk of ovarian cancer: An Italian case-control study

The association between oral contraceptive (OC) use and the risk of ovarian cancer was analysed in a case-control study, conducted between 1985 and 1989 on 505 epithelial ovarian cancer cases under 60 years of age, and 1375 controls in hospitals for a spectrum of acute conditions, not gynaecological, hormonal or neoplastic, apparently unrelated to OC use. 41 (8.1%) women with epithelial ovarian cancer and 192 (14.0%) controls reported OC use. The multivariate relative risk (RR) for ever use was 0.7 (95% confidence interval (CI) = 0.5–1.0). The risk decreased with duration of use: compared with never users the multivariate RRs were 0.9 and 0.5 respectively for less than 2 years and 2 years or more users (X²₁ trend = 6.17, P = 0.01). The risk of ovarian cancer decreased with recency and latency of use: the estimated RR were 0.5 and 0.9 in women reporting last OC use less than 10 or 10 years or more from the diagnosis of the disease, and 0.6 and 0.8 in those reporting first OC use less than 10 or 15 or more years before. The protective effect of OC was consistent in separate strata of selected covariates, including parity and other major known or suspected risk factors for ovarian cancer. There was some indication that the protection declines with advancing age, but the risk estimates were similar in premenopause and postmenopause.     

Use of oral contraceptives and breast cancer risk: The Norwegian-Swedish Women's Lifestyle and Health Cohort Study.

Current use of oral contraceptives (OCs) has been reported to increase breast cancer risk slightly. In 1991/1992, a prospective cohort study specifically designed to examine the role of hormonal contraceptives in relation to breast cancer was conducted in Norway and Sweden. This study was entitled Women's Lifestyle and Health. Of 196,000 invited women aged 30-49 years, 106,844 women answered a 4-page questionnaire. Altogether, 103,027 women providing information on contraceptive use were included in the analysis presented here, and 1,008 primary invasive breast cancers were diagnosed throughout 1999 (end of follow-up). Proportional hazard regression was used to calculate relative risks (RRs) with adjustment for age and other possible confounders. An increased breast cancer risk was observed among women who were current/recent users of OCs of any type at the start of follow-up [RR, 1.6; 96% confidence interval (CI), 1.2-2.1]. Current/recent use (i.e., use in the year preceding cohort enrolment) of combined OCs (RR, 1.5; 95% CI, 1.0-2.0) and progestin-only pills (RR, 1.6; 95% CI, 1.0-2.4) entailed similar levels of increased risk. An increased risk of borderline significance was found among short-term (i.e., less than 13 months) users before age 20 years (RR, 1.3; 95% CI, 1.0-1.7) and before first full-term pregnancy (RR, 1.4; 95% CI, 1.0-1.8). Long-term users of OCs were at a higher risk of breast cancer than never users (test for trend, P = 0.005). Current/recent use of OCs is associated with an increased breast cancer risk. Use of combined OCs and progestin-only pills seem to increase the risk at the same level.     

Oral contraceptive use and mammographic patterns.

High-risk mammographic patterns represent an increased risk of contracting breast cancer and may be used as a surrogate endpoint for the disease. We examined the relationship between oral contraceptive (OC) use and mammographic patterns among 3218 Norwegian women, aged 40-56 years. Information on ever OC use, duration, and age of first OC use and other epidemiological data were obtained through questionnaires. The mammograms were categorized into five groups. Patterns I-III were combined into a low-risk group and patterns IV and V into a high-risk group. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression and adjusted for age, menopausal status, parity, age at first birth, and body mass index. Women who reported ever having used OCs were 20% more likely (OR 1.27, 95% CI 1.0-1.6) to have high-risk mammographic patterns compared with those reporting never having used OCs. There was no dose response between different measures of OC use and high-risk patterns. Among nulliparous women, ever OC users were four times more likely (OR 4.65, 95% CI 2.1-10.3) to have high-risk patterns compared with never users. Our findings suggest that, especially among nulliparous women, ever OC use may exert its effect on breast cancer risk through changes in breast tissue, which can be observed on a mammogram.     

Oral contraceptive and IUD use and endometrial cancer: a population-based case-control study in Shanghai, China

Oral contraceptive (OC) and intrauterine device (IUD) use have been shown to be protective factors for endometrial cancer in several epidemiological studies; however, few studies have been conducted in Chinese populations. We evaluated the association between OC and IUD use and endometrial cancer risk in a population-based case-control study among Chinese women in Shanghai, China. The study included 1,204 newly diagnosed endometrial cancer cases and 1,212 age frequency-matched healthy controls. Logistic regression models were used to estimate adjusted odds ratios (OR) and their 95% confidence intervals (95% CI). In our study population, 18.5% cases and 24.9% controls reported having ever used OCs with an OR of 0.75 (95% CI, 0.60-0.93), after adjusting for known risk or protective factors for endometrial cancer. The risk of endometrial cancer decreased with long-term use of OCs with the OR for more than 72 months of use being 0.50 (95% CI, 0.30-0.85). The effect of OC use remained 25 or more years after cessation of use; the associated OR was 0.57 (95% CI = 0.42-0.78) as compared to nonusers. Similarly, fewer cases than controls had ever used IUD, with the multivariable adjusted OR being 0.53 (95% CI = 0.43-0.65). A reduction in risk was observed regardless the duration of use or age at first and last use. These results suggest that OC and IUD use may confer long-term protection against endometrial cancer.     

A case-control study of the possible association between oral contraceptives and malignant melanoma.

In a case-control study, we investigated 169 women aged 15-49 years with malignant melanoma notified to the Oxford and South Western cancer registries during the years 1971-1976, together with 507 matched controls. Data about medical, reproductive, drug and smoking histories were obtained both by reviewing general practitioner (GP) records and from the women themselves by postal questionnaires. There was no significant evidence of any overall increase in the risk of melanoma in oral contraceptive (OC) users (data from GP records-ever use vs never use, relative risk (RR) 1.34, 95% confidence limits 0.92-1.96; corresponding data from postal questionnaires-RR 1.13, limits 0.73-1.75). However, although not significant, the risk estimated from data in the postal questionnaires was higher in women who had used OCs for 5 years or more (use greater than or equal to 5 years vs never use, RR 1.57, limits 0.83-3.03). Previously demonstrated risk factors for melanoma, such as fair skin, blond or red hair and Celtic origin were found to be commoner in the cases than in the controls. Data from the Oxford/Family Planning Association contraceptive study were also examined. Unexpectedly there was a strong suggestion of a negative association between OC use and melanoma risk, but the analysis was based on only 12 women with the disease.     

Early oral contraceptive use and breast cancer among premenopausal women: final report from a study in southern Sweden

In southern Sweden during the 1960s, women began to use oral contraceptives (OCs) extensively at a young age. This case-control study investigates the relationship between the use of OCs and breast cancer development in women in southern Sweden diagnosed in the early 1980s. The risk for breast cancer after OC use among premenopausal women was modeled, after adjustment was made for age, age at menarche, and age at first full-term pregnancy or parity. Both the duration of OC use before 25 years of age and commencement of OC use at a young age were associated with a significant increase in the risk of breast cancer as well as a significant trend. The duration of OC use before the first full-term pregnancy was associated with an increased risk of breast cancer, but it did not show a significant trend. The total duration of OC use was weakly, but not significantly, associated with breast cancer development. The odds ratio for women starting OC use before 20 years of age was 5.8 [95% confidence interval (CI), 2.6-12.8]; for women using OCs for greater than 5 years before age 25, it was 5.3 (95% CI, 2.1-13.2); and for women using OCs for greater than or equal to 8 years before first full-term pregnancy, it was 2.0 (95% CI, 0.8-4.7). In multivariate analyses including the different measurements of OC use, only starting age of OC use was significantly associated with breast cancer. The exposure-response relationship between duration of OC use and risk of breast cancer depended on the age at first use of OCs. Given a fixed duration of OC use, the risk increased with younger starting age of OC use. The findings point to the importance of the early reproductive years as risk determinants for breast cancer after OC use.     

Oral contraceptive use and risk of breast cancer in older women (New Zealand)

the effect of oral contraceptive (OC) use at older ages on the risk of breast cancer was examined in a national population-based case-control study conducted in New Zealand. A total of 891 women aged 25 to 54 years with a first diagnosis of breast cancer, and 1,864 control subjects, randomly selected from the electoral rolls, were interviewed. The relative risk (RR) of breast cancer for women aged 45 to 54 years at diagnosis who had ever used OCs was 1.0 (95 percent confidence interval [CI]=0.77–1.3). There was no significant increase in risk of breast cancer among recent users of OCs of any age. Analyses according to age at first and last use among women aged 40 years and older at diagnosis showed no group with an elevated risk of breast cancer. Women who had used OCs for 10 years or longer after age 40 had an apparent increase in risk (RR=2.7, CI=0.97–7.5), but the trend in risk with duration of use was not significant. These findings suggest that OC use in older women does not affect their risk of breast cancer appreciably, but it is not possible to rule out a modest increase in risk with such use.This research was supported by grants from the Medical Research Council of New Zealand and from the Special Programme of Research, Development, and Research Training in Human Reproduction, World Health Organization.     

Large bowel cancer in women in relation to reproductive and hormonal factors: a case-control study

A community-based case-control study of the effect of reproductive factors on risk of large bowel cancer in Australia is described. The study involved 155 cases (99 colon cancer, 56 rectal cancer) and 311 controls who were interviewed with regard to pregnancies and their outcomes, lactation, menstrual history, and oral contraceptive (OC) use. Increasing parity was associated with a decreasing risk of colon cancer; para 0, relative risk (RR)=1; para 1-2, RR=0.9, 95% confidence interval (CI)=0.4-1.8; para greater than or equal to 3, RR=0.4, 95% CI=0.2-0.8; later age at first live birth (AFLB) was associated with increasing risk (AFLB less than or equal to 21 yr, RR=1; 22-25 yr, RR=2.3, 95% CI=1.0-5.5; greater than or equal to 26 yr, RR=2.7, 95% CI=1.2-6.2). These effects were independent of each other. Parity appeared to exert its predominant effect on risk of cancer of the right colon. OC use was more common among controls than cases (RR=0.5; 95% CI=0.3-1.2 for ever vs. never users) and showed a dose-response effect in multiple logistic analysis. The pattern of point-estimate RR for rectal cancer was largely congruent with those for colon cancer but was not significantly different from 1.0.     

Endometrial and ovarian cancer and oral contraceptives--findings in a large cohort study.

Many case-control studies have shown that oral contraceptives protect against endometrial cancer and epithelial ovarian cancer, but little information is available from cohort studies. The findings from the Oxford Family Planning Association contraceptive study are reported here; the relative risks for ever users of oral contraceptives in comparison with never users were 0.1 (95% confidence interval 0.0-0.7) for endometrial cancer and 0.4 (95% confidence interval 0.2-0.8) for ovarian cancer. There was a strong negative relationship between duration of oral contraceptive use and ovarian cancer risk. Thus, in comparison with never users of oral contraceptives, the relative risk for users of up to 48 months'' duration was 1.0 (95% confidence interval 0.4-2.5), while the relative risk for users of 97 months'' duration or more was only 0.3 (95% confidence interval 0.1-0.7).     

Use of oral contraceptives and risk of breast cancer in young women

Many studies have shown that oral contraceptive (OC) use increases a young woman's risk of breast cancer, although some studies suggest that the risk may be limited to recent use. The objective of this study was to determine what particular aspects of OC use could be important for breast cancer development at an early age in the cohort of women who had the opportunity to use OCs all of their reproductive life. The cases were first diagnosed with breast cancer at age 40 or younger between 1983 and 1988, and identified by the Los Angeles County Cancer Surveillance Program. Control subjects were individually matched to participating cases on birth date (within 36 months), race (white), parity (nulliparous versus parous), and neighborhood of residence. Detailed OC histories were obtained during in-person interviews with subjects. In general the risk estimates were small, and not statistically significant. Compared to no use, having used OCs for 12 years or more was associated with a modest non-significant elevated breast cancer risk with an odds ratio (OR) of 1.4 (95% confidence interval (CI)=0.8–2.4). Long-term (12 years or more) users of high-dose estrogen pills had a non-significant 60% higher breast cancer risk than never users (CI=0.9–3.2). Early use was associated with slightly higher ORs among young women (age 35), and among parous women. Recent use was associated with somewhat higher ORs among parous women and women above age 36. Analyses by stage, body weight, and family history yielded similar results. This study is consistent with a modest effect of early OC use on breast cancer risk in young women.     

Oral contraceptives and survival in breast cancer patients aged 20 to 54 years.

Recent oral contraceptive (OC) use is associated with modestly higher breast cancer incidence among younger women, but its impact on survival is unclear. This study examined the relationship between OC use before breast cancer diagnosis and survival. A population-based sample of 1,264 women aged 20 to 54 years with a first primary invasive breast cancer during 1990 to 1992 were followed up for 8 to 10 years. OC and covariate data were obtained by interviews conducted shortly after diagnosis and from medial records. All-cause mortality was ascertained through the National Death Index (n = 292 deaths). Age- and income-adjusted hazard ratios (HR) and 95% confidence intervals (95% CI) were estimated by Cox regression methods. All-cause mortality was not associated with ever use of OCs or duration of use. Compared with nonusers, mortality estimates were elevated among women who were using OCs at diagnosis or stopped use in the previous year (HR, 1.57; 95% CI, 0.95-2.61). The HR for use of high-dose estrogen pills within 5 years before diagnosis was double that of nonusers (HR, 2.39; 95% CI, 1.29-4.41) or, if the most recent pill included the progestin levonorgestrel, compared with nonusers (HR, 2.01; 95% CI, 1.03-3.91). Because subgroup estimates were based on small numbers of OC users, these results should be cautiously interpreted. Overall, most aspects of OC use did not seem to influence survival, although there is limited evidence that OC use just before diagnosis, particularly use of some pill types, may negatively impact survival in breast cancer patients aged 20 to 54 years.