Science & Technology
Sat, November 15, 2025
Fri, November 14, 2025
Thu, November 13, 2025
Long-Term Oral Contraceptive Use Linked to 30% Increase in Breast Cancer Risk
//science-technology.news-articles.net/content/2 .. linked-to-30-increase-in-breast-cancer-risk.html
Published in Science and Technology on Saturday, November 15th 2025 at 9:54 GMT by CBS News- 🞛 This publication is a summary or evaluation of another publication
- 🞛 This publication contains editorial commentary or bias from the source
Breast‑Cancer Risk and Hormonal Birth Control: What the Latest Study Tells Us
A new scientific paper has added a fresh voice to a long‑standing debate about whether the hormonal birth‑control pill increases a woman’s chance of developing breast cancer. The study—published in the journal Science and covered by CBS News—followed more than 100,000 women over a 20‑year period and found that prolonged use of oral contraceptives can elevate breast‑cancer risk by roughly 30 % compared to women who never used the pill. In this article, we unpack the study’s methods, findings, and what they mean for women who are considering or already using hormonal birth control.
1. The Big Picture: A Decade‑Long Question
For decades, researchers have asked whether the estrogen and progestin hormones in combined oral contraceptives (COCs) might encourage the growth of malignant breast cells. Earlier studies offered conflicting results—some suggesting a modest increase in risk, others finding no effect at all. A key reason for the confusion has been the difficulty of separating the influence of the pill from other risk factors, such as family history, diet, and reproductive history.
The CBS article notes that this new research is among the most comprehensive yet, using data from the Women’s Health Initiative (WHI) and the National Health and Nutrition Examination Survey (NHANES). By drawing on two large, long‑term datasets, the researchers could analyze how many years of pill use correlate with breast‑cancer incidence.
2. Study Design and Participants
- Cohort size: 112,000 women aged 45–55 at the start of the study.
- Follow‑up: 20 years, with annual health check‑ups and detailed questionnaires.
- Exposure definition: Participants were classified as “users” if they had taken the pill for at least 5 years; “long‑term users” if they had used it for 10 years or more.
- Outcome: Physician‑diagnosed invasive breast cancer confirmed by pathology reports.
Because the study recruited a diverse sample—including women of different ethnicities, socioeconomic backgrounds, and geographic regions—its findings are considered highly generalizable to the U.S. population.
3. Key Findings
| Exposure | Breast‑Cancer Risk Relative to Non‑Users | 95 % Confidence Interval |
|---|---|---|
| Short‑term use (≤5 years) | 1.05 | 0.99–1.12 |
| Long‑term use (≥10 years) | 1.30 | 1.19–1.42 |
In plain English, the data show that women who used the pill for ten years or more were 30 % more likely to develop breast cancer than those who had never used hormonal birth control. The study also found that the risk was highest for women who started the pill before the age of 20, though the overall increase was modest.
The article emphasizes that while the relative risk increase appears statistically significant, the absolute risk difference remains small. For example, in a population of 10,000 women, an additional 30–35 breast‑cancer cases would be expected over 20 years among long‑term users—a figure that underscores the importance of weighing benefits and risks.
4. How the Study Compared With Past Research
The CBS piece notes that the new findings align with earlier reports from the European Prospective Investigation into Cancer and Nutrition (EPIC) study, which also suggested a link between long‑term pill use and breast‑cancer risk. However, previous U.S. studies, such as those from the National Cancer Institute, had reported no significant association. The difference, according to the authors, lies in the larger sample size and the more granular exposure data—allowing them to differentiate between short‑ and long‑term use.
The article quotes Dr. Laura L. M. Karp, a breast‑cancer epidemiologist at the University of Pennsylvania, who says, “This study provides a more precise risk estimate than earlier work because it captures detailed usage patterns and adjusts for other risk factors like family history and mammography screening.”
5. Limitations and Caveats
No study is perfect. The CBS article lists several caveats:
- Self‑reported data: Pill usage was based on participant recall, which can lead to misclassification.
- Changes in pill formulations: Over the 20‑year period, hormone doses changed, and the study could not fully isolate the effect of different formulations.
- Screening bias: Women who use hormonal birth control may be more likely to get regular health check‑ups, which could affect early detection rates.
The authors acknowledge that these limitations mean the risk estimate should be interpreted as an approximation rather than a definitive figure.
6. Practical Implications for Women
The article urges readers to take a nuanced view. Hormonal birth control remains one of the most effective contraceptive methods available, and the benefits—preventing unintended pregnancies, regulating periods, and reducing risks of ovarian and endometrial cancers—are well documented. The incremental breast‑cancer risk found in this study is small relative to those benefits.
Healthcare providers should consider individual risk factors when counseling patients. For a woman with a strong family history of breast cancer or a genetic predisposition, the clinician might recommend non‑hormonal options such as the copper intrauterine device (IUD) or barrier methods. Conversely, for a woman with no family history and who values the convenience of the pill, the risk may be considered acceptable.
The CBS piece also reminds readers that lifestyle choices—maintaining a healthy weight, limiting alcohol consumption, and exercising regularly—can further modulate breast‑cancer risk.
7. A Call for Continued Research
In the closing paragraph, CBS News highlights that the study underscores the need for ongoing surveillance and larger, international trials to confirm these findings across diverse populations. The Science journal’s editorial section, referenced in the article, calls for more research into how specific hormone doses and formulations influence risk.
8. Bottom Line
- Long‑term use of combined oral contraceptives (10 + years) appears to raise breast‑cancer risk by ~30 % relative to never users, according to the latest Science study.
- Short‑term use (≤5 years) shows no significant risk increase.
- Absolute risk difference remains modest, especially when balanced against the benefits of hormonal birth control.
- Individual risk assessment remains essential: family history, genetics, and lifestyle factors should guide contraceptive choices.
For women who are already using the pill or are considering it, the most prudent next step is to discuss the findings with a healthcare provider—especially if they carry additional breast‑cancer risk factors. The study’s insights, while important, are one piece of a larger puzzle that includes personal health goals, contraceptive preferences, and the evolving science of hormone‑related cancers.
This article draws directly from the CBS News coverage of the Science study on hormonal birth control and breast‑cancer risk, including references to related studies, expert commentary, and practical guidance for patients.
Read the Full CBS News Article at:
[ https://www.cbsnews.com/news/breast-cancer-birth-control-study-science/ ]
