Tamoxifen has been shown to slow the growth of existing breast cancer and has been approved by the FDA for women who are at high risk of developing breast cancer.

Dr. Stanley Sides measured the size of a metastatic tumor nodule that has spread from the patient's breast to her lungs.

Anita Coomer of Whitewater was diagnosed with breast cancer in September 1995.

In October of that year, she underwent a modified radical mastectomy on the left side, and she started chemotherapy the next month.

She finished chemo in April 1996, and has remained cancer-free.

Tracie Anderson's story is similar. The Dexter woman was diagnosed with breast cancer in November 1996, and finished chemotherapy on Feb. 7, 1997.

Both Coomer, 50, and Anderson, 34, are taking Tamoxifen to help prevent the cancer from coming back. They will take the drug, one of the most widely used cancer-fighting medications, for five years.

Tamoxifen has made headlines recently because cancer specialists believe that, in addition to controlling the spread of malignant tissue in women who have cancer, it may also prevent breast cancer in women at high risk of developing the disease.

Tamoxifen attacks cancer cells by blocking estrogen receptors in malignant cells, preventing them from growing and dividing.

Another cancer drug now in the news is Herceptin, which helps slow the growth of advanced breast cancer.

Herceptin works by blocking development of HER2, a genetic protein that signals cell growth. In women whose HER2 levels are too high, cell growth goes out of control, spreading cancer.

Used in combination with traditional chemotherapy or Taxol, Herceptin doubles the chance that malignancies will shrink. In most patients studied, it stopped the growth of malignancies for about three months.

Earlier this month, the Federal Drug Administration formally recommended using Tamoxifen to prevent breast cancer and Herceptin to help slow the further spread of the disease.

Dr. Stanley Sides, a Cape Girardeau oncologist, said the majority of breast cancer patients won't benefit from Herceptin, because only 25 to 30 percent of women with breast cancer have the HER2 defect.

"It won't be of benefit in 70 to 75 percent of breast cancer patients," Sides said. "I'm trying not to let women feel like this is the magic bullet."

He is more enthusiastic about using Tamoxifen to prevent breast cancer.

A national study showed Tamoxifen decreased the risk of developing breast cancer in high-risk women by 45 percent, Sides said.

There are some risks associated with Tamoxifen use, including development of blood clots in the lungs and uterine cancer.

Sides said 1.3 of every 1,000 women who take Tamoxifen and who have intact uteruses develop uterine cancer, a rate he calls "very low."

"But because of that, Tamoxifen is described as a carcinogen. It has been a little controversial as to whether or not Tamoxifen should be approved for the prevention of breast cancer in high risk women, because newer drugs coming out seem not to have the tendency to cause cancer of the uterus," Sides said.

But with the information at hand, it seems to me to be entirely realistic to offer Tamoxifen to women at high risk on the basis of family history of multiple biopsies suggesting premalignant changes in the breast."

Coomer and Anderson have been following the news regarding using Tamoxifen to prevent breast cancer.

"I wish I'd known about it sooner," Anderson joked.

For Coomer, it means another advance in the battle against breast cancer.

"I think 10 years from now, if my daughter would get it, she probably wouldn't even have to have a mastectomy," she said.

Anderson had no family history of breast cancer. In Coomer's case, a paternal aunt was diagnosed with the disease.

But 80 percent of the women who develop breast cancer have no family history of the disease, experts say.

"It's just random," Sides said.

Some ethnic groups -- including Jewish women -- have a higher risk of developing the disease because of genetic predispositions, he said.

Drugs like Tamoxifen and Herceptin are good steps forward, Sides said. But they aren't cures.

"Right now, chemotherapy has been the gold standard in cancer treatment for over 20 years, despite all these new therapies. They're not hitting us a home run," he said.