NEW YORK (CNN) -- Breast cancer prevention is mostly aimed at surveillance -- such as mammograms and self-examinations -- and in some cases drugs, such as tamoxifen.

But for women at a particularly high risk for developing breast cancer, there's a surgical option called prophylactic mastectomy -- the complete removal of healthy breast tissue to prevent the disease from occurring in the first place.

Medical research into the effectiveness of breast removal has been unclear. Now, a new study published in this week's New England Journal of Medicine says breast removal may be an effective option, though not a 100 percent guarantee, for women at high risk of developing breast cancer.

"We see that there has been a 90 percent or greater reduction in the likelihood of developing breast cancer in this group," said the study's leader, Dr. Lynn Hartmann of the Mayo Clinic in Rochester, Minnesota. "Similarly, deaths from breast cancer were reduced to a significant extent in these high-risk women."

The decision to have a healthy breast removed to avoid cancer is a difficult one and may seem extreme. But for some women, the fear of developing breast cancer is overwhelming, and mastectomy is the only option that will put their minds at ease.

"These patients always tell me that every time they go for a mammogram, for a week of two before they're very, very anxious. And until they get the results of a mammogram, they're terrified," said Dr. Stephen Colen of New York University.

With advances in breast reconstruction, the surgery is not as disfiguring as many people may think. Still, some doctors believe that the removal of healthy breast tissue is too extreme.

"If a woman has only a 50 percent chance of getting breast cancer ... she can reduce that considerably with tamoxifen," said Dr. William Wood of Emory University in Atlanta. "If she's followed well, the likelihood is that if she gets breast cancer, it can be found and treated very successfully."

The researchers who conducted this latest study emphasized that they are not recommending prophylactic mastectomy for all high-risk patients. But they said it is important that women be completely informed as they make the difficult decision between their fear of cancer and their perception of body image and femininity.

Hartmann and her colleagues examined the medical records of 639 women, 214 of whom were considered at high risk for breast cancer and 425 who faced a moderate risk. All of the women had their breasts removed between 1960 and 1993. Researchers also studied 403 sisters of the study participants.

The high-risk women came from families with several cases of breast cancer, while the moderate-risk women had a less-striking family history of the disease.

Hartmann found that three of the women in the high-risk group, or 1.4 percent, developed breast cancer after their operations, compared with 39 percent of their sisters who chose not to have their breasts removed.

Overall, seven of the 639 women developed breast cancer following surgery.

Hartmann said there had been worries about the effectiveness of mastectomies because no surgery can remove every breast cancer cell and breast tissue is known to extend to the collar bone, armpit and elsewhere.

In a Journal editorial accompanying the study, Dr. Andrea Eisen and Dr. Barbara Weber of the University of Pennsylvania said the findings "can only be viewed as good news for women who are considering this option."

But Eisen and Weber pointed out that while preventative mastectomies may have prevented 18 deaths in the test group, the results also indicate that 621 women "who probably would have survived" underwent a disfiguring and potentially psychologically damaging operation anyway.

Medical Correspondent Dr. Steve Salvatore andReuters contributed to this report.