Cancer Risk Not Equal in Both Breasts

A double mastectomy might not be called for in many cases 

In a finding that could change how physicians identify candidates for a double mastectomy, new research has found the risk of breast cancer varies dramatically from one breast to the other.

Researchers studied 252 women with a type of breast lesion called atypical lobular hyperplasia, which is believed to be a precursor to cancer.

Fifty of the women, or 20 percent, developed breast cancer. Of those, 34 cancers, or 68 percent, occurred in the same region of the same breast where the lesions were found earlier.

Many physicians believe atypical lobular hyperplasia in one breast means a much higher rate of breast cancer developing in either breast, says Dr. David L. Page, lead study author and a professor of pathology and preventive medicine at Vanderbilt University School of Medicine in Nashville.

For that reason, physicians often recommend that women undergo a double mastectomy, or removal of both breasts, to prevent breast cancer down the line.

"We've been guided by the belief that this type of lesion is a marker for increased risk anywhere in either breast," Page says. "We decided 30 years ago we were going to do a double mastectomy—all or nothing—but that approach is not totally supported by the facts."

The study appears in a recent issue of The Lancet.

In an accompanying commentary, Dr. Sunil Lakhani of the Institute of Cancer Research and Royal Marsden Hospital in London says the study provides "evidence to counteract the myth that the risk of invasive carcinoma after a diagnosis of lobular in situ neoplasia is equal in both breasts."

Dr. Jay Brooks, chief of oncology and hematology at the Ochsner Clinic Foundation in Baton Rouge, La., says the study raises interesting questions about the best course of action when dealing with these lesions.

No Definitive Statements To Be Made At This Time

"It's a very provocative finding, and that's good," Brooks says. "But it's still a relatively small number of patients to make a definitive statement about it."

Furthermore, Brooks adds, not every woman developed breast cancer in the same breast. According to the study, 12 women, or 24 percent, developed breast cancer in the other breast. In 2 percent, the side was unknown.

Until recently, physicians looked for two major types of precancerous breast lesions, Page says.

One is ductal carcinoma in situ, which previous research has shown means a high risk of developing cancer in that location of the breast, Page says.

The second is lobular carcinoma in situ, which physicians believed meant a high risk of developing breast cancer anywhere in either breast, he says. But this assumption was based on the faulty interpretation of data, he says.

Atypical lobular hyperplasia is sometimes called lobular carcinoma in situ. In fact, the two are distinct types of lesions and should not be lumped together, Page says.

Both are benign breast diseases. But atypical lobular hyperplasia lesions tend to be smaller, he says.

Women with lobular carcinoma in situ may have an increased risk of breast cancer in both breasts. And therefore, a double mastectomy may be what is called for.

But atypical lobular hyperplasia may be something "in between" the ductal and lobular carcinomas in situ. Women with atypical lobular hyperplasia have an increased risk of developing breast cancer—if not in the precise location of the lesions, in the same region of the same breast, Page says.

There May Be No Need For a Double Mastectomy

That means there may be no need for a double mastectomy as a preventive measure, he says. Instead, a single mastectomy, or even a partial mastectomy, may be all that is necessary.

A partial (segmental) mastectomy involves the removal of the breast cancer and a larger portion of the normal breast tissue around the breast cancer (the areas removed during the surgery are shaded in green).

Surgeons are still working on developing a more effective method, Page adds. "There's going to be a lot of controversy here ... I think it should change medical practice."

Although there are no precise statistics, about 2 percent to 4 percent of women who get biopsies are diagnosed with atypical lobular hyperplasia. Those at highest risk are premenopausal women between the ages of 40 and 60, he says.

Brooks says there is more to consider than just the type of lesion a woman has when recommending for or against a mastectomy. Her family history of breast and ovarian cancer, her genetic risk, and her emotional state play a role.

Some women insist on the mastectomy because they are so fearful of cancer, he says.

Using the chemotherapy drug tamoxifen is also a means of reducing breast cancer risk in women prone to it, he says.

"What this study is showing is that breast cancer is a disease that in many cases starts off with precancerous lesions that we can use as a marker and do something about it," Brooks says.

Always consult your physician for more information.

New Breast Cancer Gene Discovered 

Researchers hope it will lead to earlier detection and improved treatment 

A new breast cancer gene discovered by scientists at the National Institutes of Health (NIH) may help researchers diagnose the disease in its early stages and treat it more effectively.

The new gene, found in breast cancer cells and in normal salivary glands, is named BASE (Breast Cancer And Salivary Gland Expression), says Kristi A. Egland, a postdoctoral fellow at the NIH and lead author of the report, published in a recent issue of the Proceedings of the National Academy of Sciences.

"We have identified the RNA and the gene that encodes the protein for BASE," says senior author Dr. Ira Pastan, of the NIH's Laboratory of Molecular Biology. "The next step is to make an antibody to detect the protein. That is what Kristi is working on now."

The hope is that an antibody can be developed that could detect the protein in the bloodstream. If so, that could prove to be a way to detect breast cancer in the early stages. Researchers also hope to make a vaccine to kill these cells that make the unique protein, Pastan says.

"Everyone has this gene," Pastan explains. However, the protein made by the gene is secreted only by breast cancer and salivary gland cells. "In 30 or 40 percent of breast cancers [as shown in their laboratory studies], the gene is active and appears to make a protein that is secreted," Pastan says.

The discovery adds to a body of literature about genes and breast cancer. For several years, scientists have known that about 5 percent to 10 percent of breast cancer cases are thought to be caused by inherited genetic mutations in two breast cancer genes, BRCA1 and BRCA2.

The genes code for proteins that have tumor suppressor capabilities, but in women who have mutations in these genes, the protein is abnormal and does not suppress the tumors. A blood test can detect these mutations.

Always consult your physician for more information.