Kahlenborn, C., Modugno, F., Potter, D. M., & Severs, W. B. (2006). Oral contraceptive use as a risk factor for premenopausal breast cancer: a meta-analysis. Mayo Clinic proceedings, 81(10), 1290-1302. https://doi.org/10.4065/81.10.1290
Kahlenborn C, Modugno F, Potter DM, Severs WB. Oral contraceptive use as a risk factor for premenopausal breast cancer: a meta-analysis. Mayo Clin Proc. 2006;81(10):1290-1302. doi:10.4065/81.10.1290
Kahlenborn, Chris, et al. "Oral contraceptive use as a risk factor for premenopausal breast cancer: a meta-analysis." Mayo Clinic proceedings, vol. 81, no. 10, 2006, pp. 1290-1302.
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The Polycarp Research Institute, Enola, PA, USA01mkye871
Penn State Milton S. Hershey Medical Center01h22ap11
Linked to ROR, the Research Organization Registry
Abstract
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.
Babic A et al., 2020·JAMA oncology·Free full text on PubMed Central
Breastfeeding has been associated with a reduced risk of epithelial ovarian cancer in multiple studies, but others showed no association. Whether risk reduction extends beyond that provided by pregnancy alone or differs by histotype is unclear. Furthermore, the observed associations between duration and timing of breastfeeding with ovarian cancer risk have been inconsistent. To determine the association between breastfeeding (ie, ever/never, duration, timing) and ovarian cancer risk overall and by histotype. DESIGN, SETTING, A pooled analysis of parous women with ovarian cancer and controls from 13 case-control studies participating in the Ovarian Cancer Association Consortium was performed. Odds ratios (ORs) and 95% CIs of the overall association were calculated using multivariable logistic regression and polytomous logistic regression for histotype-specific associations. All data were collected from individual sites from November 1989 to December 2009, and analysis took place from September 2017 to July 2019. Data on breastfeeding history, including duration per child breastfed, age at first and last breastfeeding, and years since last breastfeeding were collected by questionnaire or interview and was harmonized across studies. Diagnosis of epithelial ovarian cancer. A total of 9973 women with ovarian cancer (mean [SD] age, 57.4 [11.1] years) and 13 843 controls (mean [SD] age, 56.4 [11.7] years) were included. Breastfeeding was associated with a 24% lower risk of invasive ovarian cancer (odds ratio [OR], 0.76; 95% CI, 0.71-0.80). Independent of parity, ever having breastfed was associated with reduction in risk of all invasive ovarian cancers, particularly high-grade serous and endometrioid cancers. For a single breastfeeding episode, mean breastfeeding duration of 1 to 3 months was associated with 18% lower risk (OR, 0.82; 95% CI, 0.76-0.88), and breastfeeding for 12 or more months was associated with a 34% lower risk (OR, 0.66; 95% CI, 0.58-0.75). More recent breastfeeding was associated with a reduction in risk (OR, 0.56; 95% CI, 0.47-0.66 for <10 years) that persisted for decades (OR, 0.83; 95% CI, 0.77-0.90 for ≥30 years; P for trend = .02). Breastfeeding is associated with a significant decrease in risk of ovarian cancer overall and for the high-grade serous subtype, the most lethal type of ovarian cancer. The findings suggest that breastfeeding is a potentially modifiable factor that may lower risk of ovarian cancer independent of pregnancy alone.
Kahlenborn C et al., 2015·Linacre Q·Free full text on PubMed Central
There has been much debate regarding levonorgestrel emergency contraception's (LNG-EC's) method of action since 1999 when the Food and Drug Administration first approved its use. Proponents of LNG-EC have argued that they have moral certitude that LNG-EC works via a non-abortifacient mechanism of action, and claim that all the major scientific and medical data consistently support this hypothesis. However, newer medical data serve to undermine the consistency of the non-abortifacient hypothesis and instead support the hypothesis that preovulatory administration of LNG-EC has significant potential to work via abortion. The implications of the newer data have important ramifications for medical personnel, patients, and both Catholic and non-Catholic emergency room protocols. In the future, technology such as the use of early pregnancy factor may have the potential to quantify how frequently preovulatory LNG-EC works via abortion. Lay How Plan B (levonorgestrel emergency contraception) works has been vigorously debated ever since the Food and Drug Administration approved it in 1999. Many doctors and researchers claim that it has either no-or at most-an extremely small chance of working via abortion. However, the latest scientific and medical evidence now demonstrates that levonorgestrel emergency contraception theoretically works via abortion quite often. The implications of the newer data have important ramifications for medical personnel, patients, and both Catholic and non-Catholic emergency room rape protocols.
To assess the possibility of a postfertilization effect in regard to the most common types of hormonal emergency contraception (EC) used in the US and to explore the ethical impact of this possibility. DATA A MEDLINE search (1966-November 2001) was done to identify all pertinent English-language journal articles. A review of reference sections of the major review articles was performed to identify additional articles. Search terms included emergency contraception, postcoital contraception, postfertilization effect, Yuzpe regimen, levonorgestrel, mechanism of action, Plan B. The 2 most common types of hormonal EC used in the US are the Yuzpe regimen (high-dose ethinyl estradiol with high-dose levonorgestrel) and Plan B (high-dose levonorgestrel alone). Although both methods sometimes stop ovulation, they may also act by reducing the probability of implantation, due to their adverse effect on the endometrium (a postfertilization effect). The available evidence for a postfertilization effect is moderately strong, whether hormonal EC is used in the preovulatory, ovulatory, or postovulatory phase of the menstrual cycle. Based on the present theoretical and empirical evidence, both the Yuzpe regimen and Plan B likely act at times by causing a postfertilization effect, regardless of when in the menstrual cycle they are used. These findings have potential implications in such areas as informed consent, emergency department protocols, and conscience clauses.
Zhu H et al., 2012·Eur J Contracept Reprod Health Care
It has been suggested that taking oral contraceptives (OCs) may increase breast cancer incidence. However, data in this regard are inconsistent. We performed this meta-analysis to estimate the association between OC use and breast cancer risk. Prospective cohort studies on OC use and breast cancer risk were identified by searching databases from the period 1960 to 2012. Results from individual studies were synthetically combined using STATA 11 software. A total of 13 prospective cohort studies were included in our meta-analysis, involving 11,722 cases and 859,894 participants. The combined relative risk (RR) of breast cancer for evercompared with never-OC users was 1.08 (95% confidence interval [CI]: 0.99-1.17). Dose-response analysis based on five eligible studies showed that every ten-years' increment of OC use was associated with a significant 14% (95% CI: 1.05-1.23) rise in breast cancer risk. Little evidence of publication bias was found. This meta-analysis provides evidence of a non-significant increase in breast cancer risk associated with ever OC use, but the risk for long-term OC users is significantly greater. However, the latter finding is based on only a limited number of studies.
Fitzpatrick D et al., 2023·PLoS medicine·Free full text on PubMed Central
Current or recent use of combined oral contraceptives (containing oestrogen+progestagen) has been associated with a small increase in breast cancer risk. Progestagen-only contraceptive use is increasing, but information on associated risks is limited. We aimed to assess breast cancer risk associated with current or recent use of different types of hormonal contraceptives in premenopausal women, with particular emphasis on progestagen-only preparations. Hormonal contraceptive prescriptions recorded prospectively in a UK primary care database (Clinical Practice Research Datalink [CPRD]) were compared in a nested case-control study for 9,498 women aged <50 years with incident invasive breast cancer diagnosed in 1996 to 2017, and for 18,171 closely matched controls. On average, 7.3 (standard deviation [SD] 4.6) years of clinical records were available for each case and their matched controls prior to the date of diagnosis. Conditional logistic regression yielded odds ratios (ORs) and 95% confidence intervals (CIs) of breast cancer by the hormonal contraceptive type last prescribed, controlled for age, GP practice, body mass index, number of recorded births, time since last birth, and alcohol intake. MEDLINE and Embase were searched for observational studies published between 01 January 1995 and 01 November 2022 that reported on the association between current or recent progestagen-only contraceptive use and breast cancer risk in premenopausal women. Fixed effects meta-analyses combined the CPRD results with previously published results from 12 observational studies for progestagen-only preparations. Overall, 44% (4,195/9,498) of women with breast cancer and 39% (7,092/18,171) of matched controls had a hormonal contraceptive prescription an average of 3.1 (SD 3.7) years before breast cancer diagnosis (or equivalent date for controls). About half the prescriptions were for progestagen-only preparations. Breast cancer ORs were similarly and significantly raised if the last hormonal contraceptive prescription was for oral combined, oral progestagen-only, injected progestagen, or progestagen-releasing intrauterine devices (IUDs): ORs = 1.23 (95% CI [1.14 to 1.32]; p < 0.001), 1.26 (95% CI [1.16 to 1.37]; p < 0.001), 1.25 (95% CI [1.07 to 1.45]; p = 0.004), and 1.32 (95% CI [1.17 to 1.49]; p < 0.001), respectively. Our meta-analyses yielded significantly raised relative risks (RRs) for current or recent use of progestagen-only contraceptives: oral = 1.29 (95% CI [1.21 to 1.37]; heterogeneity χ25 = 6.7; p = 0.2), injected = 1.18 (95% CI [1.07 to 1.30]; heterogeneity χ28 = 22.5; p = 0.004), implanted = 1.28 (95% CI [1.08 to 1.51]; heterogeneity χ23 = 7.3; p = 0.06), and IUDs = 1.21 (95% CI [1.14 to 1.28]; heterogeneity χ24 = 7.9; p = 0.1). When the CPRD results were combined with those from previous published findings (which included women from a wider age range), the resulting 15-year absolute excess risk associated with 5 years use of oral combined or progestagen-only contraceptives in high-income countries was estimated at: 8 per 100,000 users from age 16 to 20 years and 265 per 100,000 users from age 35 to 39 years. The main limitation of the study design was that, due to the nature of the CPRD data and most other prescription databases, information on contraceptive use was recorded during a defined period only, with information before entry into the database generally being unavailable. This means that although our findings provide evidence about the short-term associations between hormonal contraceptives and breast cancer risk, they do not provide information regarding longer-term associations, or the impact of total duration of contraceptive use on breast cancer risk. This study provides important new evidence that current or recent use of progestagen-only contraceptives is associated with a slight increase in breast cancer risk, which does not appear to vary by mode of delivery, and is similar in magnitude to that associated with combined hormonal contraceptives. Given that the underlying risk of breast cancer increases with advancing age, the absolute excess risk associated with use of either type of oral contraceptive is estimated to be smaller in women who use it at younger rather than at older ages. Such risks need be balanced against the benefits of using contraceptives during the childbearing years.
Asthana S et al., 2020·Eur J Obstet Gynecol Reprod Biol
Role of Oral Contraceptive (OC) as a risk factor for cervical cancer remained controversial and unclear. To evaluate risk of cervical cancer in OC users and non-users through a comprehensive systematic review. Search Strategy: Literature search conducted in databases from January 1990 till August 2019 using various search terms. Selection Criteria: Primary research studies that evaluated and assessed the association of OC use with cervical cancer with study design of case control or cohort types published in English language. Data Collection and Analysis: PRISMA guided review was done by two independent researchers. Effect size estimated by pooled Odds ratio with 95 % Confidence Interval (CI) in random effect models on OC pill use for the risk of cervical cancer. Review included 19 studies. Overall risk of invasive cancer on OC use was found to be significant with unknown status of HPV OR (95 % CI) as 1.51 (1.35, 1.68) and for unknown HPV as 1.66 (1.24, 2.21). Adenocarcinoma, squamous cell carcinoma and carcinoma in situ had significant association with OR (95 % CI) of 1.77 (1.4, 2.24), 1.29 (1.18, 1.42) and 1.7 (1.18, 2.44) respectively. OC pills use had a definite associated risk for developing cervical cancer specially for Adenocarcinoma and longer duration of OC pills use.
Beaber EF et al., 2014·Cancer Epidemiol Biomarkers Prev·Free full text on PubMed Central
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. 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). 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. 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. Continued surveillance and pooled analyses of OC use and breast cancer risk by molecular subtype are needed as OC preparations evolve.
General Gynecology › Breast Health › Breast Cancer Risk · Contraception › Oral Contraceptives › Cancer Risk
Francesmary Modugno, Chris Kahlenborn, Douglas M Potter, Walter B Severs
F Modugno, Christine Kahlenborn, Christopher Kahlenborn, C Kahlenborn, Doug Potter, D Potter, W Severs
PMID 17036554 17036554 DOI 10.4065/81.10.1290 10.4065/81.10.1290 Kahlenborn et al. 2006, Kahlenborn 2006
Cite this article
Kahlenborn, C., Modugno, F., Potter, D. M., & Severs, W. B. (2006). Oral contraceptive use as a risk factor for premenopausal breast cancer: a meta-analysis. Mayo Clinic proceedings, 81(10), 1290-1302. https://doi.org/10.4065/81.10.1290
Kahlenborn C, Modugno F, Potter DM, Severs WB. Oral contraceptive use as a risk factor for premenopausal breast cancer: a meta-analysis. Mayo Clin Proc. 2006;81(10):1290-1302. doi:10.4065/81.10.1290
Kahlenborn, Chris, et al. "Oral contraceptive use as a risk factor for premenopausal breast cancer: a meta-analysis." Mayo Clinic proceedings, vol. 81, no. 10, 2006, pp. 1290-1302.
