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 For the first time in 32 years, the American Cancer Society (ACS) is changing the age at which it recommends women start getting regular mammograms. ACS now recommends women at an average risk for breast cancer begin regular mammograms at age 45—it had previously recommended women start at 40—and can transition to every other year at age 55. 
 
 The new recommendations, which offer a more personalized approach to who needs screening when, are the result of an ACS evidence review that was published Tuesday in the journal JAMA. 
 
 The new ACS guidelines advise that: 
 
 • Women 45-54 with an average risk of breast cancer should get annual mammograms • Women 55 years and up can switch to every other year, but should have the option to stick with annual screens if they choose • Women should have the option to begin annual screening at 40 
 
 The ACS says its guidelines were due for an update—the group’s most recent recommendations date back to 2003, when it recommended annual mammograms beginning at age 40. “In 2003 nobody talked about the balance of benefits and harms which is now a really a standard for guidelines,” says Dr. Richard Wender, the chief of cancer control at ACS. 
 
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 This may help clear up at least some of the confusion around when women should start screening, and how frequently they should go in once they start. In 2009, when the U.S. Preventive Services Task Force (USPSTF) said there was insufficient evidence to support the recommendation that women start screening at 40, USPSTF changed its official advice to biennial screening beginning at age 50 for most women. Earlier in 2015, its draft guidelines reinforced the 2009 recommendations. The ACS, meanwhile, continued to recommend a starting age of 40. 
 
 “What I can confidently state is that the simple [2003] guideline fueled confusion. It caused women and clinicians to choose, ‘Well, I either follow this guideline or I follow that guideline and I don’t understand why they are so different,'” says Wender. “We know that we have an obligation to make sure that clinicians are educated and the public has the right education and guidance, including more helpful decision making tools.” 
 
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 The new guidelines are a little more in line with those issued by the USPSTF. “There are many similarities,” the USPSTF said in a statement about the new ACS guidelines. “We both found that the benefit of mammography increases with age, with women in their 50s, 60s, and early 70s benefiting most from regular mammography screening.” 
 
 The new ACS guidelines are more granular than previous ones, with screening advice and frequency broken down by age. “The evidence simply no longer supports one-size-fits-all,” says Dr. Kevin Oeffinger, chair of the ACS breast cancer guideline panel and a family physician at Memorial Sloan Kettering Cancer Center. “In medicine we are moving closer and closer to bringing about a personalized approach.” 
 
 In a preemptive response to the new guidelines, the American College of Radiology, which represents doctors and groups that perform mammography, and Society of Breast Imaging, a proponent of early detection, said in a statement release to the media that they “continue to recommend that women get yearly mammograms starting at age 40.” 
 
 When asked whether, as a clinician, his own views on screening have changed through the years, Wender said yes. “It’s easy to say that any test that might result in a prevention of a death should be worthwhile, and why wouldn’t you do that for everyone?” he says. “I’ve come to appreciate two things over time. There just is no perfect screening test. And I really have come to embrace a balance of the benefits and drawbacks to screening.” 
 
 One of those drawbacks is false positives; over 10 years, a woman getting an annual mammogram has a 61% chance of getting such results. Another is the mounting data that mammograms do not save nearly as many lives as experts hoped they would, and can lead to aggressive treatment of early-stage cancers that may be unnecessary. 
 
 The ACS says it recommends all women become familiar with the potential benefits, limitations and harms that come with breast cancer screening. “I continue to impressed with the savviness of American women with regard to health issues,” says Oeffinger. “This is a topic women have spent much time thinking and reading about. We really emphasize the doctor-patient relationship and the opportunity for someone who really knows a patient to answer questions and help them understand the different information out there, and reach a decision together.” 
 
 Wender adds: “Although it’s tempting to impose our own values, patients—both men and women—want and are able to, with appropriate guidance, make a personal decision.” 
 
 Read more: Why Doctors Are Rethinking Breast-Cancer Treatment ||||| (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 way 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. 
 
 Several reports discuss the spontaneous regression of cancer, including breast cancer 
 
 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. ||||| Here are the American Cancer Society’s new recommendations for women at average risk: 
 
 Women should undergo regular screening mammography starting at age 45. 
 
 Women 45 to 54 years of age should be screened annually. 
 
 Women 55 years and older should transition to biennial screening or have the opportunity to continue screening annually. 
 
 Women should have the opportunity to begin annual screening between the ages of 40 and 44 years. 
 
 Women should continue screening mammography as long as their overall health is good and they have a life expectancy of 10 years or longer. 
 
 Clinical breast examination is not recommended for breast cancer screening among average-risk women at any age. 
 
 “The most important thing about our new guidelines is to validate that screening mammography is the most effective thing a woman can do to reduce her chances of dying of breast cancer,” the cancer society’s Dr. Richard Wender told NBC News. 
 
 “A woman should make a personal decision as whether she should start screening before age 45 but we clearly recommend that by age 45 all women should start regular screening every year.” 
 
 For the new recommendations, published in the Journal of the American Medical Association, a team of experts studied all the research they could find on the risks and benefits of mammograms. 
 
 They found that regular mammograms in women aged 40 to 69 did reduce the number of breast cancer deaths. 
 
 This evidence outweighs the occasional study that finds otherwise — such as a large 2014 Canadian study that cast doubt on whether mammograms actually reduce the risk of dying from breast cancer, and a 2012 study published in the New England Journal of Medicine that found that as many as a third of cancers detected through routine mammograms may not be life-threatening. 
 
 The researchers said at the time that 1 million women may have been overdiagnosed, which means they were needlessly treated, not to mention emotionally distressed. 
 
 At least one study has showed that many women suffer intense anguish after they get called for a follow-up mammogram when a radiologist has spotted something suspicious. 
 
 One of the new studies used to revise the recommendations found that when women are diagnosed with breast cancer before menopause, the tumors often tend to be more dangerous and fast-growing. Women who are past menopause tend to have slower-growing tumors and thus it's safer to screen them every other year, the team at University of California Davis reported in the Journal of the American Medical Association. 
 
 Dr. Therese Bevers of MD Anderson Cancer Center, who helps set breast cancer screening guidelines for the National Comprehensive Cancer Network, doesn’t think the new advice is going to clear up the confusion. 
 
 “This is one more set of recommendations that will be confusing to women and their primary care providers,” Bevers said. “Women are going to have questions and their providers may not know how to address them.” 
 
 Breast cancer is a leading killer of U.S. women. Every year, it's diagnosed in 200,000 women and a few men, and kills around 40,000. 
 
 Mammograms are an annual ritual for millions of American women, considered so important that federal law mandates that most health insurance plans pay for them without charging the patient anything. The X-rays can detect tiny tumors long before they are big enough to be felt. 
 
 “The USPSTF’s draft recommendations and the new ACS guidelines both recognize that a mammogram is a good test, but not a perfect one." 
 
 And research clearly shows that treating a tumor early makes for easier, less invasive surgery and can save lives. 
 
 The guidelines are for women of average risk. Women whose mothers, sisters or other close relatives had breast cancer, or who know they have a genetic mutation that raises their own risk, should start sooner. 
 
 “Though the evidence shows that there are some benefits from mammography screening starting at age 40, those benefits more clearly outweigh the harms from age 45 onward," said Dr. Elizabeth Fontham, dean of the School of Public Health at Louisiana State University and the chair of the group that developed the guidelines. 
 
 "Still, some women will choose to begin screening between age 40 and 44, both because they are concerned about their risk of breast cancer, either in general or because they are at higher risk, and are less concerned about the chances of experiencing a false positive findings. Those women should have the opportunity to start screening at 40 if they choose.” 
 
 The USPSTF issued a statement saying the new American Cancer Society guidelines are closer to its own. 
 
 “Importantly, both identify strategies that help women, together with their doctors, identify and treat this serious disease. We both found that the benefit of mammography increases with age, with women in their 50s, 60s, and early 70s benefiting most from regular mammography screening,” the group said. 
 
 “The USPSTF’s draft recommendations and the new ACS guidelines both recognize that a mammogram is a good test, but not a perfect one, and that there are health benefits to beginning mammography screening for women in their 40s.” 
 
 The American College of Obstetricians and Gynecologists is sticking to its guidelines. 
 
 “ACOG maintains its current advice that women starting at age 40 continue mammography screening every one to two years and recommends a clinical breast exam," the group said. 
 
 What’s most important, all groups agree, is for a woman to talk about her risk with her doctor, and decide what she’s most comfortable doing. 
 
 Breast cancer risk can be genetic but most cases of breast cancer are in women who had no known family history of the disease.
– For years, guidelines regarding mammograms have been, well, all over the place. The US Preventive Services Task Force recommends women get a mammogram every two years starting at age 50. Since 2003, the American Cancer Society has recommended annual mammograms starting at age 40. The society's first mammogram guideline revisions in more than a decade are only complicating matters. A breakdown, per NBC News and CNN: Women with an average risk of breast cancer should have a mammogram every year from age 45 to 54. If a woman wants one sooner, she should be able to start at age 40, as long as she understands false positives are more common at this age. Women over 55 years can continue annual screenings or choose to have a mammogram every two years since breast cancers develop more slowly in post-menopausal women. This is part of what an ACS doctor calls "a personalized approach," per Time. Keep up with annual or biennial screenings while you remain in good health and have a life expectancy of at least 10 years. Average-risk women can opt out of routine breast checks altogether. Why fewer checks? The society's chief medical officer tells CNN that mammograms aren't always beneficial, and the stress of the procedures, plus misdiagnoses, actually cause harm. If a woman "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,'" he says. Critics, however, say the new guidelines are dangerous since experts only examined whether screening saved a woman's life, rather than led to an early diagnosis. Confused? This won't help: The American College of Radiology and the Society of Breast Imaging "continue to recommend that women get yearly mammograms starting at age 40," according to a release.