Women with dense breasts may need annual mammograms

(Reuters Health) - While most older women might not need breast cancer screening with mammography more often than every three years, some women with dense breasts may need mammograms every year, U.S. research suggests. Among women aged 50 to 74, those without a high risk for breast cancer or dense breast tissue didn’t have an increase in breast cancer deaths if they went for mammography every three years instead of every two years.

But with dense breasts and a higher risk for these tumors, yearly mammograms were associated with fewer breast cancer deaths than screening every other year, researchers report in the Annals of Internal Medicine. “Women at low risk and low breast density will experience more harms with little added benefit with annual and biennial screening compared to triennial screening, whereas women with dense breasts and high breast cancer risk may have added benefit from annual compared to biennial mammography,” lead study author Amy Trentham-Dietz of the University of Wisconsin-Madison said by email. Doctors are conflicted about when and how often to recommend routine screening mammograms for women who don’t have lumps or discomfort in their breasts. Even though these exams can save lives, they can sometimes subject women to unnecessary and painful treatments that don’t find tumors or lower their risk of dying from cancer.

Last year, the American Cancer Society shifted its guidelines to encourage women to start annual screenings at 45 instead of 40 and to cut back to every other year once they turn 55. The U.S. Preventive Services Task Force recommends mammograms every other year for women ages 50 to 74. Worldwide, breast cancer is the most common malignancy in women. About one in nine women will eventually develop it, and the risk increases with age and when a woman’s mother, sister or daughter has been diagnosed with the disease. Typically, if there is a suspicious area on a mammogram, women get additional imaging to rule out cancer, followed by a biopsy if more information is still needed to determine if the suspect cells are malignant.

When the extra tests don’t find cancer, the mammogram result is considered a “false positive.” For the current study, researchers estimated the odds of false positive mammograms, biopsies that didn’t find cancer and deaths averted based on age, cancer risk factors and breast density. Compared with screening every two years, getting mammograms every three years could reduce false positives, biopsies and over-diagnosis without much effect on the number of cancer deaths averted for the majority of women – the ones with average cancer risk and lower breast density.

When women had a high risk of breast cancer, however, annual screening was better regardless of breast density, noted Dr. Christine Berg of Johns Hopkins University School of Medicine in Baltimore, who wrote an accompanying editorial. However, “breast cancers are also more difficult to detect in dense breasts,” Berg added by email. “Therefore annual mammograms allow for comparison of subtle changes.” The way women know if they have dense breasts is to get a mammogram - and density can change over time, noted Dr. Pamela DiPiro of the Dana Farber Cancer Institute in Boston. “Annual mammography is a patient's best chance of detecting breast cancer early, with the known caveat that additional imaging, ultrasound or even a benign biopsy may be recommended,” DiPiro, who wasn’t involved in the study, said by email.

Still, the take-home message for women is complicated, said Dr. Kathryn Evers, director of mammography at Fox Chase Cancer Center in Philadelphia. “There are numerous risk factors for breast cancer and women have different levels of comfort with the risks and benefits involved,” Evers, who wasn’t involved in the study, said by email. “The fact that there are so many different recommendations regarding when and how often women should be screened points out that there are no definitive answers – women should talk to their doctors about what regimen will be best for them, taking all of these factors into account,” Evers added.

Gene Tests Up Among Young Breast Cancer Patients

Amy Norton

A growing number of young women with breast cancer are being tested for the BRCA gene mutations that substantially raise the risks of breast and ovarian tumors, a new study shows.

Researchers found that of nearly 900 women who developed breast cancer at age 40 or younger, most had undergone BRCA testing within a year of their diagnosis.


And the percentage went up over time: By 2013, 95 percent had been tested, according to findings published online Feb. 11 in JAMA Oncology.

Experts called the results good news, since BRCA testing has long been recommended for women diagnosed with breast cancer before the age of 50.

"This is great, it's heartening," said Dr. Jeffrey Weitzel, director of clinical cancer genetics at City of Hope, in Duarte, Calif.

But, he added, women in the study were largely white, well-educated and had health insurance -- and it's unlikely that disadvantaged U.S. women would show the same high rate of BRCA testing.

"We need to keep working on extending the reach of genetic testing," said Weitzel, who co-wrote an editorial published with the study.

Media coverage following actress Angelina Jolie's disclosure that she carried the BRCA1 mutation has improved awareness about the testing and cancer preventive surgeries, previous research has suggested.

Jolie had both of her breasts removed in 2013 after learning she has the BRCA mutation. And, in 2015, she had her ovaries and fallopian tubes removed due to the significantly increased risk of ovarian cancer that stems from having the BRCA1 mutation. But, the authors of the new study note that the rise in gene testing among patients in this study largely predated Jolie's disclosure.

Inherited mutations in the BRCA1 and BRCA2 genes account for 5 to 10 percent of all breast cancers, and about 15 percent of all ovarian cancers, according to the U.S. National Cancer Institute.

Since the mutations raise the risk of early cancer, women who develop either disease at a young age have a relatively higher chance of harboring the flawed genes.

So BRCA testing is recommended for women diagnosed with breast cancer before age 50. That's, in part, to help guide their treatment decisions, explained Dr. Ann Partridge, the senior researcher on the new study, and an oncologist at Dana-Farber Cancer Institute, in Boston.

Women who carry the mutations have a high risk of developing a second cancer in the other breast, so some may want to opt for a double-mastectomy as a preventive measure. (Experts also advise women with BRCA mutations to have their ovaries removed by age 40, since there is no screening test for ovarian cancer, or any way to prevent it.)

BRCA testing also gives families information, Partridge explained. "On one hand, it could give them some peace of mind if the test is negative," she said. If it's positive, then certain family members may want to be tested, too, she added.

For the current study, Partridge and her colleagues surveyed 897 women who'd been diagnosed with breast cancer at age 40 or younger, at some point between 2006 and 2013. All were treated at one of 11 hospitals in Massachusetts, Colorado and Minnesota.

Of women diagnosed in 2006, 77 percent said they'd received BRCA testing. That went up to 95 percent among women diagnosed in 2013, the study reported.

Overall, about 12 percent of women who were tested had a BRCA mutation. And most of those women -- 86 percent -- decided to have a double-mastectomy, the study showed.

But half of the women who tested negative for a BRCA mutation also had a double-mastectomy, the researchers found.

That's concerning, both Partridge and Weitzel said. Women without the gene mutations have a low risk of developing a second cancer in the other breast, and there's no evidence that a double-mastectomy improves their long-term survival.

"We don't want to be doing procedures that aren't medically indicated," Partridge said.

It's not clear why so many women with negative test results opted for a double-mastectomy -- but it's also not surprising, Partridge noted, since it's consistent with past studies.

"Some women may do it for peace of mind," Partridge said, "or because they do believe it will improve their survival, even though there's no evidence."

At a time of high anxiety, she said, some women may not fully process the risk/benefit information they're hearing.

According to Weitzel, BRCA testing should ideally include genetic counseling, to help ensure that women understand their results.

But in reality, that counseling does not always happen, he said.

Under the Affordable Care Act, also known as Obamacare, BRCA testing is a covered preventive service for women at high risk of having a mutation. And, Weitzel said, Medicaid is now paying for testing, though the coverage varies by state.

There's still work to be done to improve "underserved" women's access to BRCA testing and counseling, Weitzel said -- including women in lower-income countries.

Task Force Issues New Breast Cancer Screening Recommendations

Cari Nierenberg

Women who have an average risk of breast cancer should have mammograms every two years from ages 50 to 74, according to the latest recommendations released today by the U.S. Preventive Services Task Force (USPSTF).

Women in this 50-to-74 age group are the most likely to benefit from regular breast cancer screenings, suggested the USPSTF, a 17-person, government-appointed panel of medical experts that makes recommendations on the effectiveness of preventive health services.

Average-risk women in their 40s also may benefit from getting mammograms, but their overall likelihood of seeing a benefit is smaller, and the potential for harm is larger than for average-risk women age 50 and older, according to the USPSTF's recommendations, published online today (Jan. 11) in the journal Annals of Internal Medicine.

These latest USPSTF guidelines are basically the same as those the panel released in 2009. But since that time, there has been greater agreement among the guidelines of several major groups of experts, such as the American Cancer Society, the American College of Physicians and the American Academy of Family Physicians, said Dr. Albert Siu, chair of the task force and a professor of geriatrics and palliative medicine at the Icahn School of Medicine at Mount Sinai in New York City. [6 Things Women Can Do to Lower Breast Cancer Risk]

These groups have independently concluded that mammography is effective and that its benefits increase particularly in women age 50 and over, Siu told Live Science.

All of the groups recognize that there is a role for starting mammograms in women in their 40s and support the idea of a personal, informed choice for women in this age group, he said.

"The decision to start mammogram screening before age 50 should be an individual one" for average-risk women, the new guidelines state.

In other words, women ages 40 to 49 should consider starting breast cancer screenings, but their doctors should inform them about the potential benefits and possible harms of the screening test so that they can weigh both sides in making their decision.

After reviewing the newest scientific evidence on mammograms, the task force found that the number of deaths from breast cancer that the screening test can prevent in average-risk women under 50 is smaller than that in older women, and that the number of false-positive results and unnecessary biopsies is larger.

A false positive is a result that suggests a woman may have cancer but additional testing and procedures later show that she does not. False-positive findings can be stressful and provoke anxiety, and they may lead to the possibility of overdiagnosis and overtreatment.

Still, the task force supports the decision of women who want to start screening in their 40s, and the new guidelines note that the risk of problems from screening may increase decrease as women move from their early 40s to their late 40s, Siu said.

Weighing risks and benefits

Various organizations that make breast cancer recommendations have come to relatively similar conclusions in the areas where the science is fairly black and white, Siu said.

Where the groups diverge is in their different interpretations of the gray areas, where studies have not been done, or the areas for which the groups weigh the benefits and risks differently, he said.

For example, one gray area is whether average-risk women in the 45-to-55 age group should start mammograms and, if so, how frequently they should get them, he noted.

Unlike the USPSTF recommendations to start mammograms at age 50 and rescreen every two years, the American Cancer Society advises women to begin mammograms at age 45 and to have them yearly until age 54. Then, at age 55, women should get mammograms every two years, according to the group's latest recommendations, released in 2015.

Recommendations from other groups, such as the American College of Obstetricians and Gynecologists and the National Comprehensive Cancer Network (a worldwide alliance of cancer centers), call for yearly mammograms in average-risk women age 40 and older.

The differing recommendations about when and how often to get mammograms can leave women feeling confused, but ultimately, the decision all boils down to personal choice and consideration of the benefits and risks, Siu said.

The majority of American women fall into the average-risk breast cancer category, Siu said. Women are considered to have average risk if they do not show symptoms of breast cancer, such as a breast lump or high-risk breast lesion, have never had breast cancer, do not have a known genetic mutation for breast cancer, such as a BRCA1 or BRCA2 gene mutation, and did not receive chest radiation at an early age.

The average-risk group also includes women age 40 and over who have breast cancer in their family, such as a mother, sister, aunt or daughter who was diagnosed with the disease, but did not have a genetic mutation for it.

New to the USPSTF guidelines this year was the group's evaluation of the effectiveness of three-dimensional mammography, as well as an evaluation of the effectiveness of adjunctive treatment for dense breasts with MRI, ultrasound or 3D mammograms, Siu said. The task force made no recommendations in these two areas because they found insufficient evidence to determine the balance of benefits and harms. [6 Foods That May Affect Breast Cancer Risk]

The task force also said that there was insufficient evidence to recommend that average-risk women age 75 and over continue getting mammograms.

Mammography is an effective but imperfect tool, Siu said. Over the past decade, science has begun to recognize that there are potential harms from cancer screening, including overdiagnosis, or the detection and treatment of cancer in people who would have never been bothered by the disease in their lifetimes, he explained.

There is increased recognition that overdiagnosis does exist, and it may be on the order of one in five women diagnosed with breast cancer over approximately 10 years, Siu said.

Even knowing this chance for overdiagnosis, the task force recognizes that many women, especially women under 50, may choose to get screened more often, but they should be aware and informed of the risks, he said.

Breast Cancer Rates for Blacks Catch Up to Whites

by MAGGIE FOX

Black women have long been more likely to die of breast cancer than white women, but this frightening statistic was once tempered a bit because black women were less likely than whites to get breast cancer in the first place.

No more. A new report from the American Cancer Society finds black women are just as likely to get breast cancer as their white neighbors, and they are 42 percent more likely to die of it.

"From 1989 to 2012, breast cancer death rates have decreased by 36 percent; and, as a result, 249,000 U.S. breast cancer deaths have been averted during this time period," the American Cancer Society's Carol DeSantis and colleagues write in their report.

"Widening racial disparities in breast cancer mortality are likely to continue, at least in the short term, in view of the increasing trends in breast cancer incidence rates in black women," DeSantis's team writes in CA: A Cancer Journal for Clinicians.

"Although the overall breast cancer incidence rate is slightly lower in black women than in white women, the breast cancer death rate is 42 percent higher in blacks than in whites."

A combination of factors is likely to blame. Black women are often diagnosed when their breast cancer is at a later stage; they are more likely to be obese and to have other conditions, such as diabetes; they're more likely to get aggressive and hard-to-treat tumors; they're less likely to have access to good health care; and they're less likely to be offered, and to accept, the best treatment options.

Several studies offer clues — there may be genetic differences, there may be disparities in getting medical care, and black women may simply avoid doctors more. A 2013 study found black women were often sicker to start with, suffering other conditions besides breast cancer.

"Black women are also disproportionately diagnosed with triple-negative breast cancers," DeSantis's group wrote. This type of tumor is very difficult to treat.

According to the National Cancer Institute, 25 in every 100,000 white women die of breast cancer. Nearly 34 in every 100,000 African-American women die of breast cancer. Just 16 out 100,000 Hispanic and American Indian women die of breast cancer.

This week's study finds similar patterns. Hispanic women may have lower breast cancer rates, DeSantis and colleagues said, because they have children at younger ages and have more children than women from other ethnic groups. Having children younger protects from breast cancer, as does breastfeeding those children.

"About 12 percent of women in the U.S. (or 1 in 8) will be diagnosed with breast cancer in their lifetime," the researchers wrote.

"This lifetime risk represents an average of the risks of different women, rather than the risk of any one woman. Lifetime risk includes the possibility that women will die from other causes before being diagnosed with breast cancer and is often misinterpreted to apply only to women who live to very old ages."

What can women do?

"The World Cancer Research Fund International estimates that one third of breast cancers could be prevented through healthy behaviors, including maintaining a healthy body weight, engaging in regular physical activity, and not drinking alcohol," the researchers noted.

"There is growing evidence that high levels of fruit and vegetable consumption may reduce the risk of hormone-receptor-negative breast cancer." That's the kind that cannot be treated with the most common hormone-based drugs, including tamoxifen and Herceptin.

New breast cancer guidelines: screen later, less often

(CNN) In a move sure to befuddle women -- and anger some breast cancer survivors -- the American Cancer Society has issued new guidelines saying less screening for breast cancer is better than more.

The venerated cancer organization says women should start getting mammograms at 45 instead of 40, and that everyone can skip the routine manual breast checks by doctors.

An exhaustive review of the medical literature shows these measures just aren't very effective, according to the group. "The chance that you're going to find a cancer and save a life is actually very small," said Dr. Otis Brawley, the society's chief medical officer.

Now three key groups -- the American College of Obstetricians and Gynecologists, the American Cancer Society, and the U.S. Preventive Services Task Force -- recommend different ages for starting regular mammograms: 40, 45 and 50 respectively.

While mammograms save lives, they can also cause harm, and each group does a different job of balancing the pros and cons.

Earlier testing is not necessarily better

The problem with mammograms is that they have a relatively high false positive rate, which means women sometimes have to undergo painful and time-consuming tests only to find out they never had cancer in the first place.

The chances of false positives are especially high for women under 45, as they have denser breasts and tumors are harder to spot on an image. "If she starts screening at age 40, she increases the risk that she'll need a breast cancer biopsy that turns out with the doctor saying 'You don't have cancer, so sorry we put you through all this,'" Brawley said.

He said he knows women who've had false positives year after year. "False positives are a huge deal," he said. "These women are so frightened and inconvenienced they swear off mammography for the rest of their lives."

Six years ago, the federal government's Preventive Services Task Force caused a furor when it declared that women in their 40s didn't need to get routine mammograms. Younger women whose breast cancers were caught by mammograms angrily responded that they would have been dead if they'd followed that guideline.

They said they'd gladly risk a false positive, with all the inconvenient and sometimes painful followup, for the chance of finding a cancer.

Learning from that experience, the American Cancer Society has sought to soften its message, emphasizing that women in their early 40s should still be able to get mammograms if they want them, as long as they understand the risks.

There's the risk of a false positive, plus the risk that a mammogram could catch a very small breast cancer that will go away on its own, or never progress to the point that it hurts a woman. In other words, a mammogram could catch a tumor that isn't really worth catching.

But since doctors can't reliably discern the harmful from the harmless cancers, they treat them all. This means some women are getting potentially harmful treatments, such as radiation, chemotherapy and surgery, when their tumor would never have caused a problem, Brawley says.

A Canadian study looked at 44,925 women who were screened for breast cancer, and 106 of them fell into this category and were treated for breast cancer "unnecessarily," according to a review in the New England Journal of Medicine.

New guidelines have their critics

While agreeing with the American Cancer Society that mammograms aren't perfect, some advocates for women criticized the group's new guidelines. First, they said the society looked mostly at studies of film mammography, which in the United States has almost been entirely replaced by digital mammography.

Digital mammograms generate clearer images and do a better job of finding cancer and have a lower false positive rate.

"It's like standard versus HD TV," said Dr. Therese Bevers, the chair of the National Comprehensive Cancer Network's guidelines panel for breast cancer screening and diagnosis, and the medical director of the Cancer Prevention Center at the MD Anderson Cancer Center.

Second, critics said the cancer society looked only at whether screening saved a woman's life, and not at whether screening caught a cancer early, so the woman could avoid the most drastic treatments, such as chemotherapy or mastectomy.

"The American Cancer Society made the value judgment that screening is only worth it if improves survival," said Dr. Marisa Weiss, a breast cancer survivor and president of Breastcancer.org. "There's an arrogance to that. Let women decide what's meaningful to them."

Insurance companies also decide

The new guidelines also state that women over age 55 can choose to get a mammogram every other year, since breast cancers in post-menopausal women tend to develop more slowly.

To a great extent it will be insurance companies that decide at what age women get mammograms. In 2009, they typically continued to pay for mammograms starting at age 40 even though the government's task for force recommended mammograms starting at age 50.

But it's not clear what they'll do now that the American Cancer Society has also raised the age for mammograms.

"(Insurance) plans will certainly take these updated recommendations into account when evaluating their coverage policies," Clare Krusing, a spokeswoman for America's Health Insurance Plans, wrote to CNN in an email.

The new guidelines are meant for women at average risk of breast cancer. The society says women with a family history or who carry a gene that predisposes them to breast cancer may need to start screening earlier and more frequently.

As for the recommendation to discontinue routine manual breast exams by doctors, many advocates for women with breast cancer agree there's a lack of good evidence that they save lives, but some said they saw no reason to get rid of them.

"It's a free and added way of knowing whether or not a lump is there," said Leigh Hurst, founder of the Feel Your Boobies Foundation.

In the end, with so many different opinions on preventing breast cancer, experts are worried women will throw up their hands.

"Our biggest concern is that this will create a lot of potential havoc in the day-to-day practice of caring for women," said Dr. Christopher Zahn, the vice president of practice activities for ACOG.

Black Women More Likely to Get Wrong Breast Cancer Care, Study Confirms

by MAGGIE FOX

Black women are much more likely to get the wrong treatment for breast cancer, be diagnosed later and have bigger tumors than white women, researchers reported Tuesday.

It's the largest study yet to look at the disparities in breast cancer treatment in the U.S., and it confirms what many other studies have found — that African-American women are prone to a nastier type of breast cancer, and that they don't get the same standard of care as white women.

Native American women also appear to be at higher risk of more aggressive cancer, the study found — and they also tend to get poor care.

"We found that there is a consistent pattern of late diagnosis and not receiving recommended treatment for some racial and ethnic groups across all breast cancer subtypes," said Lu Chen of the at Fred Hutchinson Cancer Research Center in Seattle, who led the study.

Her team looked at data on more than 100,000 American women listed in a National Cancer Institute cancer registry.

"Women in several racial/ethnic groups are more likely to be diagnosed with more advanced stage breast cancer," they wrote in their report, published in the journal Cancer Epidemiology, Biomarkers and Prevention.

"African-American and American Indian/Alaska Native women in particular had the highest risk of being diagnosed with stage IV triple-negative breast cancer," they added. Black women had a 40 percent to 70 percent higher risk of having stage IV cancer - which has spread through the body and which can no longer be eradicated -than whites.

Native American women where nearly four times as likely to have stage IV triple-negative cancer, a particularly hard-to-treat type.

And black and Hispanic women were 30 percent to 40 percent more likely than whites to get the wrong treatment for their cancer type, the team found. There are several subtypes of cancer and now there are tailored therapies for certain types.

It's long been known that black women are far more likely to die of their breast cancer than white women. Studies have offered all sorts of clues — there may begenetic differences, there may be disparities in getting medical care, black women may get inferior treatment, and black women may simply avoid doctors more.

A 2013 study found black women were often sicker to start with, suffering other conditions besides breast cancer.

According to the National Cancer Institute, 25 in every 100,000 white women die of breast cancer. Nearly 34 in every 100,000 black women die of breast cancer. Just 16 out 100,000 Hispanic and American Indian women die of breast cancer. 

Test Tells Breast Cancer Patients Who Can Safely Skip Chemo

by MARILYNN MARCHIONE, THE ASSOCIATED PRESS

Many women with early-stage breast cancer can skip chemotherapy without hurting their odds of beating the disease — good news from a major study that shows the value of a gene-activity test to gauge each patient's risk.

The test accurately identified a group of women whose cancers are so likely to respond to hormone-blocking drugs that adding chemo would do little if any good while exposing them to side effects and other health risks. In the study, women who skipped chemo based on the test had less than a 1 percent chance of cancer recurring far away, such as the liver or lungs, within the next five years.

"You can't do better than that," said the study leader, Dr. Joseph Sparano of Montefiore Medical Center in New York.

An independent expert, Dr. Clifford Hudis of New York's Memorial Sloan Kettering Cancer Center, agreed.

"There is really no chance that chemotherapy could make that number better," he said. Using the gene test "lets us focus our chemotherapy more on the higher-risk patients who do benefit" and spare others the ordeal.

The study was sponsored by the National Cancer Institute. Results were published online Monday by the New England Journal of Medicine and discussed at the European Cancer Congress in Vienna.

The study involved the most common type of breast cancer — early stage, without spread to lymph nodes; hormone-positive, meaning the tumor's growth is fueled by estrogen or progesterone; and not the type that the drug Herceptin targets. Each year, more than 100,000 women in the United States alone are diagnosed with this.

The usual treatment is surgery followed by years of a hormone-blocking drug. But many women also are urged to have chemo, to help kill any stray cancer cells that may have spread beyond the breast and could seed a new cancer later. Doctors know that most of these women don't need chemo but there are no great ways to tell who can safely skip it.

A California company, Genomic Health Inc., has sold a test called Oncotype DX since 2004 to help gauge this risk. The test measures the activity of genes that control cell growth, and others that indicate a likely response to hormone therapy treatment.

Past studies have looked at how women classified as low, intermediate or high risk by the test have fared. The new study is the first to assign women treatments based on their scores and track recurrence rates.

Of the 10,253 women in the study, 16 percent were classified as low risk, 67 percent as intermediate and 17 percent as high risk for recurrence by the test. The high-risk group was given chemotherapy and hormone-blocking drugs. Women in the middle group were randomly assigned to get hormone therapy alone or to add chemo. Results on these groups are not yet ready — the study is continuing.

But independent monitors recommended the results on the low-risk group be released, because it was clear that adding chemo would not improve their fate.

After five years, about 99 percent had not relapsed, and 98 percent were alive. About 94 percent were free of any invasive cancer, including new cancers at other sites or in the opposite breast.

"These patients who had low risk scores by Oncotype did extraordinarily well at five years," said Dr. Hope Rugo, a breast cancer specialist at the University of California, San Francisco, with no role in the study. "There is no chance that for these patients, that chemotherapy would have any benefit."

Dr. Karen Beckerman, a New York City obstetrician diagnosed with breast cancer in 2011, said she was advised to have chemo but feared complications. A doctor suggested the gene test and she scored very low for recurrence risk.

"I was convinced that there was no indication for chemotherapy. I was thrilled not to have to have it," and has been fine since then, she said.

Mary Lou Smith, a breast cancer survivor and advocate who helped design the trial for ECOG, the Eastern Cooperative Oncology Group, which ran it, said she thought women "would be thrilled" to skip chemo.

"Patients love the idea of a test" to help reduce uncertainty about treatment, she said. "I've had chemotherapy. It's not pretty."

The test costs $4,175, which Medicare and many insurers cover. Others besides Oncotype DX also are on the market, and Hudis said he hopes the new study will encourage more, to compete on price and accuracy.

"The future is bright" for gene tests to more precisely guide treatment, he said.