Featured Research

from universities, journals, and other organizations

Oral Contraceptives With Higher Levels Of Progestin Protect Against Ovarian Cancer, Study Suggests

Date:
January 2, 2002
Source:
Duke University Medical Center
Summary:
A new Duke University Medical Center study shows that oral contraceptives with higher levels of progestin seem to reduce a woman's risk of ovarian cancer. The study is featured in the January issue of the Journal of the National Cancer Institute.

A new Duke University Medical Center study shows that oral contraceptives with higher levels of progestin seem to reduce a woman's risk of ovarian cancer. The study is featured in the January issue of the Journal of the National Cancer Institute.

Oral contraceptives have long been associated with a decreased risk of ovarian cancers. Some studies show that three or more years of oral contraceptive use reduces the risk of developing epithelial ovarian cancer by 30-50 percent, and the decrease in risk grows with the duration of use.

While it has been commonly considered that this reduction in risk is based in limiting ovulation, the Duke study, led by Joellen Schildkraut of the Duke Comprehensive Cancer Center, indicates that the progestin levels in the oral contraceptives might be as important as ovulation reduction in the prevention of ovarian cancer.

Schildkraut and her colleagues studied 390 women with epithelial ovarian cancer and 2,865 control subjects. The women were between 20 and 54 years of age and had been identified from a study known as the Cancer and Steroid Hormone (CASH) study conducted from 1980 to 1982. The CASH study collected data on ovarian cancer rates and oral contraceptives use in women to characterize the protective effect of specific oral contraceptive formulations on ovarian cancer risk. In the original study, all formulations of oral contraceptives seemed to reduce ovarian cancer risk.

However, Schildkraut and her colleagues re-analyzed the data to determine whether higher estrogen or progestin levels in pill formulations might have more of a protective effect than formulations with lower levels of those hormones.

"If reduction in ovulation alone was the only protective effect of oral contraceptives, then we would find that all formulations had the same reduction in risk," Schildkraut said. "That's not what we found in this study."

Comparing oral contraceptives by estrogen and progestin potency, the researchers found that oral contraceptives with higher levels of progestin are associated with greater reduction of risk of ovarian cancer than those with lower progestin potency, regardless of estrogen content, duration of use and latency. The study also showed that women who took pills with higher progestin levels showed a significant reduction in risk, even when taken for a short period of time -- three to 18 months. The amount of estrogen in the pill did not seem to affect ovarian cancer risk, the scientists found. Non-users of oral contraceptives appeared to be at a greater risk of ovarian cancer than women who took oral contraceptive, regardless of formulation, they found.

The findings of the study by Schildkraut and her colleagues are supported by a study of the biological effects of progestin conducted at Duke that is also published in the January issue of Journal of the National Cancer Institute. The study in monkeys shows that the progestin component of oral contraceptives seems to be related to increased cell turnover in the ovarian epithelium, indicating that progestin might lower ovarian cancer risk by activating cancer-preventative molecular pathways in the ovary. In the study, 80 monkeys were randomly divided into four groups: one receiving an oral contraceptive with both estrogen and progestin, one receiving progestin alone, one receiving estrogen alone and one (the control group) receiving nothing. The two groups of monkeys given the pills containing progestin showed a striking and significant increase in cell death than the control group or the estrogen group. According to researchers, by increasing the cell death and turnover in the ovarian epithelium, there is more of a chance of eliminating damaged cells that can turn cancerous.

"We believe these two studies show that there are biological effects related to the progestin that are playing a role in the reduction in ovarian cancer risk associated with oral contraceptive use," Schildkraut said. "We hope that by identifying this pathway and its key mechanism, future ovarian cancer research will capitalize on information to achieve maximum protection against ovarian cancer, while minimizing side effects."

Schildkraut does caution that while pills that are higher in progestin are protective against ovarian cancer, they might increase risk of certain types of breast cancer. She said this consideration needs to be studied further, and that other agents, such as vitamin D, may be able to capitalize on this prevention pathway without increasing breast cancer risk.

The Duke study did have its limitations, cautioned Schildkraut. The researchers cited possible misclassifications of some of the pills and a lack of formulations and dosages for all oral contraceptives. Also, the women in the CASH study were young (44.1) compared to the average age (59) of women who develop ovarian cancer in the general population. Researchers said this makes it difficult to know whether these results would apply to menopausal women who develop ovarian cancer.

The Duke study was funded by the National Cancer Institute, the National Institutes of Health, Department of Health and Human Services and the Department of Defense.

According to the American Cancer Society, ovarian cancer is the sixth most common cancer among women, excluding non-melanoma skin cancers. Approximately 23,400 new cases of ovarian cancer were diagnosed in the United States in 2001. Approximately 13,900 women died of ovarian cancer in that same year. Ovarian cancer accounts for 4 percent of all cancers in women.


Story Source:

The above story is based on materials provided by Duke University Medical Center. Note: Materials may be edited for content and length.


Cite This Page:

Duke University Medical Center. "Oral Contraceptives With Higher Levels Of Progestin Protect Against Ovarian Cancer, Study Suggests." ScienceDaily. ScienceDaily, 2 January 2002. <www.sciencedaily.com/releases/2002/01/020102074449.htm>.
Duke University Medical Center. (2002, January 2). Oral Contraceptives With Higher Levels Of Progestin Protect Against Ovarian Cancer, Study Suggests. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2002/01/020102074449.htm
Duke University Medical Center. "Oral Contraceptives With Higher Levels Of Progestin Protect Against Ovarian Cancer, Study Suggests." ScienceDaily. www.sciencedaily.com/releases/2002/01/020102074449.htm (accessed July 23, 2014).

Share This




More Health & Medicine News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Idaho Boy Helps Brother With Disabilities Complete Triathlon

Idaho Boy Helps Brother With Disabilities Complete Triathlon

Newsy (July 23, 2014) An 8-year-old boy helped his younger brother, who has a rare genetic condition that's confined him to a wheelchair, finish a triathlon. Video provided by Newsy
Powered by NewsLook.com
Stone Fruit Listeria Scare Causes Sweeping Recall

Stone Fruit Listeria Scare Causes Sweeping Recall

Newsy (July 22, 2014) The Wawona Packing Company has issued a voluntary recall on the stone fruit it distributes due to a possible Listeria outbreak. Video provided by Newsy
Powered by NewsLook.com
Huge Schizophrenia Study Finds Dozens Of New Genetic Causes

Huge Schizophrenia Study Finds Dozens Of New Genetic Causes

Newsy (July 22, 2014) The 83 new genetic markers could open dozens of new avenues for schizophrenia treatment research. Video provided by Newsy
Powered by NewsLook.com
CDC Head Concerned About a Post-Antibiotic Era

CDC Head Concerned About a Post-Antibiotic Era

AP (July 22, 2014) Sounding alarms about the growing threat of antibiotic resistance, CDC Director Tom Frieden warned Tuesday if the global community does not confront the problem soon, the world will be living in a devastating post-antibiotic era. (July 22) Video provided by AP
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