Featured Research

from universities, journals, and other organizations

Study Confirms Breast Cancer Risk In Continuous Combined Hormone Therapy Risk Begins To Return To Normal After Women Stop Taking Hormones

Date:
December 3, 2002
Source:
NIH/National Heart, Lung, And Blood Institute
Summary:
Researchers confirmed that a daily, combined dose of estrogen and progestin increases breast cancer risk in post menopausal women, but added that this risk begins to return to normal about six months after women stop taking the hormones.

Researchers confirmed that a daily, combined dose of estrogen and progestin increases breast cancer risk in post menopausal women, but added that this risk begins to return to normal about six months after women stop taking the hormones.

The analysis was part of the National Institute of Child Health and Human Development (NICHD) Women's Contraceptive and Reproductive Experiences Study and appears in the December, 2002 Obstetrics & Gynecology. The majority of the study's funding was provided by the NICHD. The Centers for Disease Control and Prevention in Atlanta contributed additional staff and computer support for the study. The National Cancer Institute also provided additional funding.

"It is reassuring that breast cancer risk begins to return to normal six months after women stop combined dose estrogen-progestin therapy," said Duane Alexander, M.D., Director of the NICHD. "Women, in consultation with their physicians, need to make the most informed decision possible. The study authors have provided them with one more piece of important information."

The NIH Women's Health Initiative (WHI) trial was the first large clinical trial to assess the risks and benefits of continuous combined hormone therapy. Last July, researchers stopped the WHI trial because the risk of breast cancer and heart disease from combined hormone replacement therapy outweighed its potential benefits.

In this form of therapy, women take a combination of the hormones estrogen and progestin. Essentially, the hormone estrogen relieves such symptoms of menopause as hot flashes, night sweats, sleeplessness, and vaginal dryness. When taken alone, however, estrogen also increases a woman's risk for cancer of the uterine lining, or endometrium. Combining estrogen with progestin virtually eliminates the risk of endometrial cancer.

"In planning the NICHD study, we sought to learn as much as we could about the risks associated with the various kinds of hormone therapy," said Robert Spirtas, DrPH, Chief of NICHD's Contraception and Reproductive Health Branch and senior author of the study. "At the time, little information existed on whether combined hormone therapy posed the same risks as estrogen therapy alone."

In the WHI trial, women used continuous combined hormone therapy and researchers monitored their health during the course of the study. When it became clear that the women were developing breast cancer at higher than normal rates, the researchers stopped the trial. Because the study was stopped only recently, the WHI researchers cannot tell yet whether the women in the study face any increased risk of breast cancer now that they stop taking the hormones.

In contrast, researchers for the NICHD study began by questioning women who had been diagnosed with breast cancer about their hormone use and other potential risk factors for breast cancer. These women were then compared to a similar group of women who had not developed breast cancer.

"Our data suggest a positive association between continuous combined HRT and breast cancer risk among current, longer term users," the study authors concluded. "Progestin administered in an uninterrupted regimen may be a contributing factor."

The current study enrolled women who had been diagnosed with breast cancer between July 1, 1994 and April 30, 1998 at treatment centers in Atlanta, Detroit, Los Angeles, Philadelphia, and Seattle. A total of 3823 postmenopausal white and black women were analyzed for the study. In all, the medical histories of 1870 women who had developed breast cancer were compared to the histories of 1953 women who did not have breast cancer.

The researchers found that women on continuous combined therapy for 5 years or more were 1.54 times more likely to developing breast cancer than other women their age not on this form of therapy. The risk of breast cancer increased the longer the women used this form of therapy. However, six months after the women discontinued the combined therapy, their risk of breast cancer began to return to normal. This held true for women who took the hormones for 5 years or longer before stopping, as well as for women who took the hormones for only about 6 months.

"The NICHD study also included former users, and our data indicate that the increased risk associated with use of continuous combined hormone therapy began returning to normal about 6 months after the women stopped using them," Dr. Spirtas said.

The analysis also found that an alternate form of hormone therapy, which involves taking the hormones separately, on different days of the month, may not increase breast cancer risk in this group of women. The alternate form of therapy, sequential estrogen-progestin therapy, includes a number of regimens in which patients take the hormone progestin only for 5 to 14 days per month. Earlier studies have indicated, however, that sequential estrogen-progestin therapy may increase the risk for cancer of the uterine lining, or endometrium. The increase in endometrial cancer from sequential estrogen-progestin therapy is thought to be less than the risk from taking estrogen alone.

Estrogen alone may be prescribed to women whose uterus has been surgically removed, as these women no longer have a risk of endometrial cancer. The NICHD study did not find any additional risk of breast cancer in women who took estrogen alone. A recent study by the NCI found, however, that women taking estrogen alone may be at increased risk for cancer of the ovary. (The NCI's release on this study is available at http://newscenter.cancer.gov/pressreleases/Laceyovarian.html.)

A separate WHI study of estrogen alone in women who had a hysterectomy before joining the WHI hormone program continues unchanged because, at this point, researchers are uncertain of the balance of risks and benefits of estrogen.

The NICHD is part of the National Institutes of Health (NIH), the biomedical research arm of the federal government. NIH is part of the U.S. Department of Health and Human Services. NICHD sponsors research on development, before and after birth; maternal, child, and family health; reproductive biology and population issues; and medical rehabilitation. NICHD publications, as well as information about the Institute, are available from the NICHD Web site, http://www.nichd.nih.gov, or from the NICHD Clearinghouse, 1-800-370-2943; e-mail NICHDClearinghouse@mail.nih.gov.


Story Source:

The above story is based on materials provided by NIH/National Heart, Lung, And Blood Institute. Note: Materials may be edited for content and length.


Cite This Page:

NIH/National Heart, Lung, And Blood Institute. "Study Confirms Breast Cancer Risk In Continuous Combined Hormone Therapy Risk Begins To Return To Normal After Women Stop Taking Hormones." ScienceDaily. ScienceDaily, 3 December 2002. <www.sciencedaily.com/releases/2002/12/021203075254.htm>.
NIH/National Heart, Lung, And Blood Institute. (2002, December 3). Study Confirms Breast Cancer Risk In Continuous Combined Hormone Therapy Risk Begins To Return To Normal After Women Stop Taking Hormones. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2002/12/021203075254.htm
NIH/National Heart, Lung, And Blood Institute. "Study Confirms Breast Cancer Risk In Continuous Combined Hormone Therapy Risk Begins To Return To Normal After Women Stop Taking Hormones." ScienceDaily. www.sciencedaily.com/releases/2002/12/021203075254.htm (accessed August 29, 2014).

Share This




More Health & Medicine News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

3 Things To Know About The Ebola Outbreak's Progression

3 Things To Know About The Ebola Outbreak's Progression

Newsy (Aug. 29, 2014) Here are three things you need to know about the deadly Ebola outbreak's progression this week. Video provided by Newsy
Powered by NewsLook.com
Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Who Could Be Burnt by WHO's E-Cigs Move?

Who Could Be Burnt by WHO's E-Cigs Move?

Reuters - Business Video Online (Aug. 28, 2014) The World Health Organisation has called for the regulation of electronic cigarettes as both tobacco and medical products. Ciara Lee looks at the impact of the move on the tobacco industry. Video provided by Reuters
Powered by NewsLook.com
CDC Director On Ebola Outbreak: 'It's Worse Than I Feared'

CDC Director On Ebola Outbreak: 'It's Worse Than I Feared'

Newsy (Aug. 28, 2014) CDC director Tom Frieden says the Ebola outbreak is even worse than he feared. But he also said there's still hope to contain it. 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