Featured Research

from universities, journals, and other organizations

Unsuccessful fertility drug users have reduced breast cancer risk, study suggests

Date:
July 6, 2012
Source:
Journal of the National Cancer Institute
Summary:
Women using fertility drugs who did not conceive a 10-plus week pregnancy were at a statistically significant reduced risk of breast cancer compared to nonusers; however, women using the drugs who conceived a 10-plus week pregnancy had a statistically significant increased risk of breast cancer compared to unsuccessfully treated women, but a comparable risk to nonusers, according to a new study.

Women using fertility drugs who did not conceive a 10-plus week pregnancy were at a statistically significant reduced risk of breast cancer compared to nonusers; however, women using the drugs who conceived a 10-plus week pregnancy had a statistically significant increased risk of breast cancer compared to unsuccessfully treated women, but a comparable risk to nonusers, according to a study published July 6 in the Journal of The National Cancer Institute.

Ovulation-stimulating fertility drugs temporarily elevate estrogen levels in women, and estrogen is known to play an important role in breast cancer. While some studies report increased breast cancer risk following infertility treatment, other analyses have been inconclusive.

In order to determine the risk of young-onset breast cancer after use of ovulation-stimulating fertility drugs, Chunyuan Fei, Ph.D., at the National Institute of Environmental Health Sciences (NIEHS), and colleagues, conducted a sister-matched case-control study, in part funded by Susan Komen for the Cure, called the Two Sister Study (which was developed from the Sister Study), which looked at women diagnosed with breast cancer under the age of 50 years and their breast cancer-free control sisters, who were studied between September 2008-December 2010. They looked specifically at fertility-drug exposure according to whether or not it had resulted in a pregnancy lasting at least 10 weeks.

The researchers found that women who had used fertility drugs showed a non-statistically significantly reduced risk of breast cancer compared to women who did not use fertility drugs and women who used fertility drugs and did not conceive a 10-plus week pregnancy were at a statistically significantly lowered risk of breast cancer compared to nonusers. Women who had used fertility drugs and conceived a 10-plus week pregnancy did, however, have a statistically significantly increased risk of breast cancer compared to women who had been unsuccessfully treated. "Our data suggest that exposure to a stimulated pregnancy is enough to undo the reduction in risk associated with a history of exposure to ovulation-stimulating drugs," the authors write. They believe the exposure to the fertility drugs potentially raises risk by modifying pregnancy-related remodeling of breast tissue. However, successfully treated women had a comparable level of breast cancer risk to non-users.

The authors note a few limitations of the study, including the reliance on self-reported fertility drug usage, and lack of data on specific diagnosis for infertility.

In an accompanying editorial, Louise A. Brinton, Ph.D., of the Division of Cancer Epidemiology and Genetics at the National Cancer Institute, feels that the findings of the study are hard to understand in the context of previous studies with results ranging from a lowered risk to a higher risk to no relationship between the drugs and the risk of early onset of breast cancer. Brinton explains that the reduced overall risk associated with drug usage may be related to the fact that one of the drugs, clomiphene, is a selective estrogen receptor modulator (SERM) similar to tamoxifen, an established chemo-preventative. On the other hand, increased risk seen in successfully treated women may be related to the increased exposure to ovarian hormones, as well as "the dual effect of pregnancy on breast cancer risk, namely a short-term transient increase that dissipates with time and eventually leads to a long-term risk reduction," Brinton writes. Another complicating factor in interpreting the study's results is its focus on women who developed breast cancer before age 50, which is more often associated with genetic factors than breast cancers diagnosed at a later age.

Brinton concludes that additional research is needed to understand these associations. "Because of such complexities, results from individual investigations must be cautiously interpreted and weighed against the considerable benefits associated with fertility drug usage, including a high probability of carrying pregnancies to term, which can lead to substantial long-term reductions in breast cancer risks."


Story Source:

The above story is based on materials provided by Journal of the National Cancer Institute. Note: Materials may be edited for content and length.


Journal Reference:

  1. Louise A. Brinton. Breast Cancer Risk After Use of Fertility Drugs: Stimulating New Controversy. Journal of The National Cancer Institute, July 6, 2012 DOI: 10.1093/jnci/djs275

Cite This Page:

Journal of the National Cancer Institute. "Unsuccessful fertility drug users have reduced breast cancer risk, study suggests." ScienceDaily. ScienceDaily, 6 July 2012. <www.sciencedaily.com/releases/2012/07/120706234743.htm>.
Journal of the National Cancer Institute. (2012, July 6). Unsuccessful fertility drug users have reduced breast cancer risk, study suggests. ScienceDaily. Retrieved August 23, 2014 from www.sciencedaily.com/releases/2012/07/120706234743.htm
Journal of the National Cancer Institute. "Unsuccessful fertility drug users have reduced breast cancer risk, study suggests." ScienceDaily. www.sciencedaily.com/releases/2012/07/120706234743.htm (accessed August 23, 2014).

Share This




More Health & Medicine News

Saturday, August 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Newsy (Aug. 21, 2014) An experimental drug used to treat Marburg virus in rhesus monkeys could give new insight into a similar treatment for Ebola. Video provided by Newsy
Powered by NewsLook.com
Two US Ebola Patients Leave Hospital Free of the Disease

Two US Ebola Patients Leave Hospital Free of the Disease

AFP (Aug. 21, 2014) Two American missionaries who were sickened with Ebola while working in Liberia and were treated with an experimental drug are doing better and have left the hospital, doctors say on August 21, 2014. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
Cadavers, a Teen, and a Medical School Dream

Cadavers, a Teen, and a Medical School Dream

AP (Aug. 21, 2014) Contains graphic content. He's only 17. But Johntrell Bowles has wanted to be a doctor from a young age, despite the odds against him. He was recently the youngest participant in a cadaver program at the Indiana University NW medical school. (Aug. 21) Video provided by AP
Powered by NewsLook.com
American Ebola Patients Released: What Cured Them?

American Ebola Patients Released: What Cured Them?

Newsy (Aug. 21, 2014) It's unclear whether the American Ebola patients' recoveries can be attributed to an experimental drug or early detection and good medical care. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins