Breast cancer 'can be prevented'

VXtreme Video Coverage of Dr. Fisher's press conference Part 1 | Part 2

Study: All ages of at-risk women helped by breast cancer drug

April 6, 1998
Web posted at: 3:27 p.m. EDT (1927 GMT)

PHILADELPHIA (CNN) -- "This is the first time in history that we have evidence that breast cancer can not only be treated, but can be prevented."

Longtime breast cancer researcher Dr. Bernard Fisher made that victorious declaration during a news conference Monday to announce that the breast cancer drug tamoxifen has been found to reduce breast cancer cases by 45 percent in women considered at high risk for the disease.

Fisher, who worked in the National Cancer Institute's breast cancer prevention trials with the drug tamoxifen, said he could remember a time in the last 20 years when searching for a way to prevent breast cancer would have been considered "entirely fanciful." Eventually, he said, that quest became recognized as something that scientists could do and "needed to do."

Fisher

His group's study, whose findings were described in detail at Monday's conference, showed that women at increased risk for developing breast cancer may be able to cut that risk nearly in half by taking tamoxifen, a drug now used to treat the disease.

Women considered at risk include those older than 60, those with a family history of breast cancer and those with precancerous tissue in their breasts.

Tamoxifen works by interfering with the interaction of breast cancer cells and estrogen, a hormone involved in the division and growth of cancerous cells.

Women at risk for breast cancer: Family history Advanced age Precancerous breast tissue Source: American Cancer Society

Risks linked to tamoxifen: Cancer in uterus Blood clots in the lungs Source: American Cancer Society

Breast cancer statistics: It is estimated there will be 180,300 new cases diagnosed this year There will be an estimated 43,900 deaths from breast cancer this year Source: American Cancer Society

"(Tamoxifen) attaches to the receptor in the cells that 'sees' estrogen and prevents the cell from 'seeing' estrogen. So it can actually stop the growth of breast cells and of breast cancer cells," said Dr. Larry Norton of Memorial Sloan Kettering Cancer Center in New York.

Side effects issue unresolved

However, tamoxifen has potential side effects, including an increased risk of uterine cancer and blood clots traveling from the legs to the lungs. A key question for researchers, and women taking tamoxifen, will be whether those risks are worth the benefit.

Dr. Leslie Ford, another researcher in the study, said the highest risks appear to be among women over 50, with younger groups seeing fewer to no more cases of uterine cancer and blood clots appearing in younger women taking tamoxifen than in the placebo groups.

But some women's health advocates are urging caution.

Zuckerman

"The long-term risks really, I believe are not known," said Diana Zuckerman of the National Women's Health Network. "We do know that women who have taken tamoxifen for breast cancer, women who have actually had breast cancer and then taken this drug, that five years of tamoxifen is a good thing and more than five years seems to be a bad thing.

"When you are talking about prevention, and usually prevention means taking a drug for the rest of your life, that becomes a real concern. Because if they can only take it for five years then you have to worry about what is going to happen later on."

Study involved 13,000 women

The cancer institute's study involved 13,338 women in the United States and Canada, making it one of the largest cancer prevention studies ever. Some women were given tamoxifen, others placebos.

For those given tamoxifen over a five-year period, one in 236 developed breast cancer. The expected breast cancer rate was one in 130 women. There were significant reductions in the occurrence of both invasive and non-invasive breast cancers in every age group, from 35-45 to the over-60 group.

The institute has already notified the participants of the results, which were considered so promising that women who were given placebos are being offered tamoxifen. All of the study participants will be monitored for the next two years.

Medical Correspondent Dr. Steve Salvatore contributed to this report.

CNN In-Depth Health:

• Breast Cancer
• Women's Health

Related stories:

• Study: Drug cuts breast cancer rate for women at risk - April 5, 1998
• New evidence links breast cancer to electromagnetic fields - March 24, 1998
• Study: U.S. cancer rates declining - March 13, 1998
• New test may help predict recurrence of breast cancer - December 31, 1997
• Chemotherapy, tamoxifen improve breast cancer survival - November 18, 1997

Related sites:

Note: Pages will open in a new browser window

• National Cancer Institute (NCI)
  • Press release: Breast Cancer prevention trial shows major benefit, some risk
  • NCI's CancerNet Cancer Information
  • Questions and Answers About Tamoxifen
• Philadelphia Online - The Inquirer and The Daily News
  • Health Philadelphia
  • Women's History Month: Breast Cancer
• Zeneca Pharmaceuticals
• American Cancer Society
• BreastCancerInfo.Com
  • Tamoxifen

External sites are not endorsed by CNN Interactive.

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	further reading on Tamoxifen and Breast Cancer

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