By

Michelle Castillo /

CBS News/ March 18, 2013, 5:57 PM

Mammograms for women ages 50 to 74 may not be needed every year

A new study shows that women between the ages of 50 to 74 that get mammography screenings every two years may be at no more risk for advanced-stage breast cancer and at a lower risk for false positives, than those who get tested annually.

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False positives on a mammogram may lead to unnecessary biopsies or treatments.

"You really decrease you chance of harm if you screen every two years," lead researcher Karla Kerlikowske, a primary care physician and professor of medicine at the University of California, San Francisco, said to Bloomberg Businessweek. "The fear was that if you do it every two years versus every year, you are going to have a really big tumor when you are diagnosed. The reality is these tumors just don't grow that rapidly."

The results, which were published on March 18 in JAMA Internal Medicine, follow the 2009 recommendation by the U.S. Preventive Services Task Force that advocated for biennial mammography for women in this age group instead of the previous suggestion of getting screened every one to two years.

However, the study authors pointed out that the original recommendations only looked at age as a factor for influencing breast cancer risk. This new study factored in age, breast density and postmenopausal use of hormone therapy (HT).

About 211,731 women received a breast cancer diagnosis in the U.S. in 2009 -- the latest year for which statistics were available -- and 40,676 will die each year from the disease, according to the Centers for Disease Control and Prevention. It is the most common cancer among women in the U.S. and one of the leading causes of cancer death among women of all races and Hispanic women.

The researchers looked at data from 11,474 women with breast cancer and 922,624 women without breast cancer who underwent screenings at U.S. facilities involved in the long-running Breast Cancer Surveillance Consortium (BCSC) from January 1994 to December 2008.

Women who went every two years for a screening were not associated with an increased risk of advance stage breast cancers or large tumors, even if the woman had dense breasts or used hormone replacement therapies, when compared with women who were screened every year.

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For women who were between the ages of 40 to 49, those with extremely dense breasts were 1.89 times more likely to be found with advance-stage cancers and 2.39 times more likely to have large tumors when they were screened every other year versus annually.

"This study is not about whether you should start screening at 40 or 50, but if you are going to be screened, does it matter if you do it every year or every two years," Kerlikowske said. "If you're in that younger group, with dense breasts, it probably does matter."

Women ages 50 to 74 were less likely to receive a false-positive diagnosis if they were screened every two years. For women who had mammographies every two and three years, they had a 30.7 and 21.9 percent respective risk of false positives than women who got screened each year (about 50 to 60 percent regardless of age, according to Susan G. Komen for the Cure).

But, women in the younger age group with extremely dense breasts had a 65.5 percent chance of a false positive if they were screened biennially, and women who used hormone therapy who had dense breasts regardless of age were at a 65.8 percent chance of a false positive.

Unlike the U.S. task force, the American Cancer Society recommends annual mammogram screening starting at age forty.

"I don't think any one study ought to change everything,"said Dr. Otis Brawley, chief medical officer of the American Cancer Society, to Reuters.

Brawley said he did not expect changes in official screening policies for professional organizations, but he did think doctors were moving towards a more personalized approach when it came to screening for breast cancer.

"This is one of several studies that are all pointing in the same direction over the last several years," he said.

© 2013 CBS Interactive Inc. All Rights Reserved.
10 Comments Add a Comment
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marychgo says:
As with MANY health issues, you need to know YOUR OWN MEDICAL HISTORY. A woman with close relatives who've had breast cancer, especially if they were young when they were diagnosed, should probably get a mammogram every year, no matter WHAT the general guidelines say! The aunt and uncle in MY family who had breast cancer were from the side of the family I DON'T take after, and were diagnosed quite late (he in his 60s, she in her 80s). I probably had four or five mammograms between age 40 and age 65...and NO positives, saving myself a few dollars and some radiation exposure. But when (back when I was 25!) I developed a dozen lumps under my arms, I was in my doctor's office within 36 hours, and was THRILLED to learn I was simply allergic to the aluminum in my anti-perspirant! (Yes, Virginia, Walgreens and CVS still sell those old-fashioned plain old deodorants!)
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hdc77494 says:
Turns out a LOT of the tests and procedures now "free" under Obamacare are equally worthless, but we all get to pay increased premiums because our government has decided we can't be trusted to choose our own coverage...
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auburnannie replies:
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A lot of those tests and procedures that are now free are life-savng for millions of people who could not have afforded them in the past due to a lack of health insurance.
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GoThermography says:
There is an alternative. Use Thermography. Go to www.Meditherm.com and click on the "Locations" to find a location near you. They are the only Thermography company that uses a Class 1 Medical device and have M.D.'s write the report. No Radiation, No Compression, Screens the area up to the shoulders and under the arms, both areas not screened by Mammograms.
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erasmus111 says:
Has it ever entered anyone's brain that maybe they might get breast cancer BECAUSE they are having these mammograms every year??

Like, years down the road you get breast cancer and you think "OMG, it found the breast cancer. It saved my life!" But just maybe having the radiation and having your breasts SQUISHED every year is what caused it!

Radiation NEVER leaves the body, and with all the other things you get radiation from, it just keeps on accumulating.
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sha457 says:
SOUNDS LIKE Obamas DEATH PANEL ON THE GO
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skeezix06 replies:
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Sounds more like the republicans to me.
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skeezix06 says:
Well, if it's not suitable for younger women as reported a while back and if it's not suitable for older women, just when IS it considered suitable? Never? We take our chances and hope we don't die?
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hdc77494 replies:
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The real issue is that by the time it actually shows up on a scan, survivability drops precipitously, and we actually don't have reliable early detection for breast cancer...
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PourpaixPourpaix says:
Well, something rings oddly true that if you don't give doctors the opportunity to examine you, they won't get you all screwed up.
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