(Reuters Health) - The likelihood that U.S. women with early-stage cancer in one breast will have both breasts removed varies depending on where they live, a new study shows.
For example, between 2010 and 2012, among women ages 20 to 44 with cancer in one breast, about 15 percent had both breasts removed in the District of Columbia, compared to about 49 percent in South Dakota.
"The variation is very striking," said senior author Ahmedin Jemal, of the American Cancer Society in Atlanta.
When women have breast cancer in one breast, having both breasts removed usually isn't helpful, experts say. Last year the American Society of Breast Surgeons issued a statement to discourage women with one-sided, or unilateral, breast cancer who don't have a genetic or family risk for the disease from undergoing a double, or contralateral, mastectomy.
Still, Jemal and his colleagues point out in JAMA Surgery, past research has found an increase in contralateral mastectomies among women with early stage cancer in one breast.
For women at average risk and cancer in one breast, "taking off the other breast doesn’t significantly reduce the risk of a cancer on the other side, because their risk wasn’t that high to begin with," said Dr. Laurie Kirstein, a breast surgical oncologist at Memorial Sloan Kettering Cancer Center in New York City who wasn't involved in the new study.
To examine trends across states, the researchers analyzed data collected between 2004 and 2012 from more than 1.2 million women with early stage cancer in one breast.
Across the country, the proportion of such women ages 20 to 44 who opted for contralateral mastectomy rose from about 11 percent to about 33 percent. Over the same period, the proportion of similar women age 45 and older who had both breasts removed rose from about 4 percent to about 10 percent.
Rates of contralateral mastectomy varied by state but were consistently highest in women ages 20 to 44.
During the last two years of the study, more than 40 percent of women in that age range who lived in South Dakota, Iowa, Colorado, Missouri, Nebraska, Tennessee, Maine and Montana chose to have both breasts removed. That was true for less than 25 percent of such women who lived in New Hampshire, Delaware, New Jersey, Louisiana, Idaho, Alaska, South Carolina, Nevada, Massachusetts, Wyoming, Hawaii and the District of Columbia.
The researchers also looked at the proportion of women undergoing reconstructive surgery after having both breasts removed. They found that while the highest rates of double breast removals were generally clustered in the Midwest, the highest rates of breast reconstruction afterward were generally clustered in the Northeast.
Jemal told Reuters Health that the study can't explain why so many women are opting for contralateral mastectomies, but the rate in the U.S. is higher than in other countries.
For example, only 2 percent to 3 percent of women in the UK with cancer in one breast have the other breast removed, too, compared to 13.5 percent in the U.S.
The researchers didn't have information on how many of the women in the study were at higher risk for breast cancer because it runs in their family or because they had been treated in the past with radiation therapy to the chest.
Kirstein told Reuters Health that for women with a genetic predisposition to breast cancer, "the bilateral mastectomy is seen as a risk reducing procedure."
She said some women who aren't at higher risk still choose to have the cancer-free breast removed even after learning about the risks and benefits.
The variation in rates by state may be explained by healthcare access, income and what women suggest to each other about treatments, she told Reuters Health.
Doctors need to have detailed conversations with women about their treatment options, said Jemal.
"First, the surgeons have to have this discussion with the patient," he said. "Second, patients have to take time to make a decision. They don’t want to make the decision right away, because anxiety is very high right after diagnosis."
Kirstein said she asks patients to think of how they'll feel about their decision in 10 years.
"We support whatever the patients want to do, but we want them to understand what they’re doing," she said.