--- title: Routine Mammograms for Younger Women: Yea or Nay? description: In women's ongoing dilemma over when to start routine mammogram screening for breast cancer, a large new, longitudinal study may add a wrinkle. 7141143 canonical: https://time.com/archive/7141143/routine-mammograms-for-women-yea-or-nay/ author: TIME Staff article:opinion: false article:content_tier: free article:published_time: 2011-06-30T19:16:55.000Z article:modified_time: 2026-03-16T10:56:57.770Z article:section: Health og:title: Routine Mammograms for Younger Women: Yea or Nay? og:description: In women's ongoing dilemma over when to start routine mammogram screening for breast cancer, a large new, longitudinal study may add a wrinkle. 7141143 og:url: https://time.com/archive/7141143/routine-mammograms-for-women-yea-or-nay/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt4ecdcf644f8a7865/698a946bcabb1d92bde5a6d0/307_healthland_mammogram_0701.jpg?branch=production&width=640&quality=75&auto=webp&crop=16:9 og:image:width: 1200 og:image:height: 675 og:image:alt: 307_healthland_mammogram_0701 og:type: article twitter:card: summary_large_image twitter:title: Routine Mammograms for Younger Women: Yea or Nay? twitter:description: In women's ongoing dilemma over when to start routine mammogram screening for breast cancer, a large new, longitudinal study may add a wrinkle. 7141143 twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt4ecdcf644f8a7865/698a946bcabb1d92bde5a6d0/307_healthland_mammogram_0701.jpg?branch=production&width=640&quality=75&auto=webp&crop=16:9 ---  * [Health](/section/health/) # Does a New Mammogram Study Affect Screening Guidelines? by [TIME Staff](https://time.com/author/time-staff/) Jun 30, 2011 7:16 PM UTC  Getty Images by [TIME Staff](https://time.com/author/time-staff/) Jun 30, 2011 7:16 PM UTC In women’s ongoing dilemma over when to start routine mammogram screening for breast cancer, a large new, longitudinal study may add a wrinkle.more The Swedish Two-County Trial, which began in the late 1970s, followed 133,000 women who were divided into two groups: half were invited to have routine mammograms for seven years and the other half received “usual care,” which did not include mammograms. After 29 years of follow-up, the study’s authors found that routine screening was associated with a 30% lower risk of death from breast cancer. The data suggested that one death was prevented for every 1,300 mammograms; put another way, one breast-cancer death would be prevented by screening 300 women every two to three years for 10 years. **MORE:** [Why Mammograms Are Less Effective Among Breast Cancer Survivors](http://healthland.time.com/2011/02/24/why-mammograms-are-less-effective-among-breast-cancer-survivors/) In the study, women aged 40 to 49 in the screening group received a mammogram every two years; those aged 50 to 74 were screened about every three years. The findings suggest that mammograms can save lives. Of course, that fact was never in question. In 2009, when the United States Preventive Services Task Force (USPSTF) reversed its longstanding guidelines and began recommending routine breast-cancer screening for women starting at age 50, instead of age 40\. The issue was not that mammograms didn’t save lives. Rather, it was that before age 50, the task force found, the risks and potential harms of routine screening outweighed its potential benefits. Mammograms can result in false-positive results, which can further lead to unnecessary tests and invasive procedures like biopsies. False positives also lead to tremendous anxiety. What’s more, mammograms often pick up cancers that are so slow-growing, they would never even have been noticed in a woman’s lifetime. And often by the time they catch deadly fast-growing cancers, the tumors have already spread to other parts of the body and become incurable. In November 2009, the USPSTF recommended that most women (those without gene mutations that are associated with breast cancer or close relatives with the disease) begin getting mammograms every two years starting at age 50\. At the time, the New York _Times_ [reported](http://www.nytimes.com/2009/11/17/health/17cancer.html): --- > “” --- Many American women who had begun getting yearly mammograms starting at age 40 — as per the task force’s previous recommendations from 2002 — were dismayed by the new rules. And other national groups including the National Cancer Institute and the American Cancer Society held firm to their previous guidelines despite the USPSTF’s about-face. Both organizations still recommend routine screening every one or two years for women age 40 and older. **MORE:** [MRI May Detect More Cases of Recurrent Breast Cancer](http://healthland.time.com/2010/11/30/study-mri-may-detect-more-cases-of-recurrent-breast-cancer/) But while mammograms catch many cancers, they miss up to 20% of them, according to the National Cancer Institute. And some 6% to 8% of mammograms may result in false positives. “It’s not a perfect examination by any means but we have quite an accumulation of data that shows mammography is associated with a reduced risk of dying from breast cancer and the opportunity to be treated less aggressively,” Robert A. Smith, director of cancer screening at the American Cancer Society, [told](http://thechart.blogs.cnn.com/2011/06/28/study-confirms-mammography-reduces-risk-of-breast-cancer-death/) CNN. It’s worth noting that the Swedish study’s findings did not separate out women by age, so they don’t shed any light on the risk-benefit ratio of screening for women in their 40s versus women in their 50s or 60s. They also don’t much impact the USPSTF’s 2009 recommendations. **MORE:** [Can Breast Milk Predict Cancer Risk?](http://healthland.time.com/2011/04/04/can-breast-milk-predict-cancer-risk/) As with many complicated health issues, it remains largely up to individual women and their doctors to decide when to begin screening. ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/archive/7141143/routine-mammograms-for-women-yea-or-nay/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/archive/7141143/routine-mammograms-for-women-yea-or-nay/"},"headline":"Does a New Mammogram Study Affect Screening Guidelines?","datePublished":"2011-06-30T19:16:55.000Z","dateModified":"2026-03-16T10:56:57.770Z","description":"In women's ongoing dilemma over when to start routine mammogram screening for breast cancer, a large new, longitudinal study may add a wrinkle. 7141143","url":"https://time.com/archive/7141143/routine-mammograms-for-women-yea-or-nay/","keywords":[],"thumbnailUrl":"https://static.time.com/v3/assets/bltea6093859af6183b/blt4ecdcf644f8a7865/698a946bcabb1d92bde5a6d0/307_healthland_mammogram_0701.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","author":[{"@type":"Person","name":"TIME Staff","url":"https://time.com/author/time-staff/"}],"articleSection":"Health","image":[{"@type":"ImageObject","url":"https://static.time.com/v3/assets/bltea6093859af6183b/blt4ecdcf644f8a7865/698a946bcabb1d92bde5a6d0/307_healthland_mammogram_0701.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","width":1200,"height":675,"headline":"307_healthland_mammogram_0701","caption":"","creditText":"Getty Images","representativeOfPage":true}],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/section/health/","name":"Health"}},{"@type":"ListItem","position":2,"item":{"@id":"https://time.com/archive/7141143/routine-mammograms-for-women-yea-or-nay/","name":"Does a New Mammogram Study Affect Screening Guidelines?"}}]}] ```