American Cancer Society says women should start mammograms at 45

Liz Szabo | USA TODAY

Show Caption Hide Caption Mammograms: start later, screen less often The American Cancer Society has released new breast cancer screening recommendations for women. USA TODAY’s Liz Szabo and Shannon Rae Green discuss the news.

Six years ago, the American Cancer Society lashed out against a federal task force that suggested most women could wait to get a mammogram until age 50, instead of age 40, the age that other groups recommended to begin breast cancer screening. Delaying mammograms, the cancer society said, would lead to the death of more women.

Now, in a move that reflects changing attitudes about cancer screening, the American Cancer Society is itself recommending fewer mammograms.

In guidelines released Tuesday, the society said that women at average risk of breast cancer should begin annual mammograms at age 45 – five years later than it had previously recommended. The society said it reached this conclusion after carefully weighing both the benefits and harms of mammograms for younger women, whose risk of breast cancer is much lower than that of older women.

By age 55, women can transition to being screened every other year. That's because breast cancers tend to grow more slowly after menopause, making it safe for women to be checked less often, according to the guidelines, published online Tuesday in JAMA, formerly the Journal of the American Medical Association.

In another major change, the society said doctors no longer need to perform breast exams during women's checkups, since these exams have not been shown to save lives.

These are big changes for the American Cancer Society — the USA's largest cancer charity and perhaps the best-known advocate for screening. As recently as 1992, the American Cancer Society recommended women get a "baseline" mammogram at age 35 to 39, so that doctors would have an image for comparison to their later screening results.

The new guidelines reflect the growing recognition that mammograms can do harm, as well as good, said Richard Wender, chief cancer control officer at the American Cancer Society.

"The biggest evolution has been not in the American Cancer Society, but in the science of cancer screening and the evolution of health care in general," Wender said.

The society now promotes a mammogram schedule adapted to the biology of breast cancer and a woman's changing risk as she ages, Wender said. The society picked age 45 as the start date for screening because that's when a woman's risk of breast cancer begins to spike. Before that, a woman is more likely to be hurt than helped by mammograms, which can produce "false positive" results that may lead women to undergo unnecessary follow-up tests, including invasive biopsies.

A less common, but far more serious, problem caused by mammograms is "overdiagnosis," which occurs when screening tests detect slow-growing cancers that may never to threaten a woman's life. Because doctors can't tell which breast tumors are essentially harmless, they end up treating all of them. That can lead women to undergo surgery, radiation or other treatments they don't need. Although studies have estimated that up to half of breast cancers don't need to be treated, the cancer society now says that the true number is between 1% to 10%. The cancer society estimates that nearly 232,000 women will be diagnosed with breast cancer in 2015 and more than 40,000 will die from it.

The cancer society's last update on mammograms, published in 2003, barely mentioned overdiagnosis, finding "little to no evidence" for it.

"We're moving to an era where people are recognizing the limitations of screening tests," said Nancy Keating, a primary care physician at Brigham and Women's Hospital in Boston, who co-wrote an accompanying editorial in JAMA. "For many years, we convinced everybody, including doctors, that mammograms are the best tests and everyone has to have one. But now we're acknowledging that the benefits are modest and the harms are real."

The recommendations are only for women at average risk of breast cancer, rather than those with a family history, genetic mutations or other factors that put them at higher risk. Women under age 45 who feel strongly about mammograms can continue to get them, as can women over 55 who want to be screened every year, Wender said. The cancer society is planning to publish screening guidelines for women at high risk of breast cancer in the future.

That part of the guidelines also reflects a growing trend in medicine: helping patients make informed decisions, rather than dictating to them, Wender said.

Some medical groups still urge earlier mammograms. The American College of Radiology and Society for Breast Imaging, whose members interpret mammograms, continue to recommend women get annual mammograms beginning at 40.

"If you want to save the most lives, that's the recommendation that will do it," said physician Debra Monticciolo, chair of the American College of Radiology's breast imaging commission.

These conflicting recommendations — with different medical groups recommending that screening start at 40, 45 or 50 — could "add to the confusion" about mammograms, said Fran Visco, president of the National Breast Cancer Coalition.

Both men and women have heard changing messages in recent years, as doctors increasingly take a "less is more" approach to tests.

Three years ago, the American Cancer Society recommended that cervical cancer screenings — once a staple of a woman's annual checkup — could be safely done every three to five years. The U.S. Preventive Services Task Force — the advisory panel whose 2009 mammogram advice caused such a stir — has said that men can skip prostate cancer screening entirely. And a campaign called Choosing Wisely — whose members include dozens of medical specialty groups -- has highlighted hundreds of tests and procedures that can cause harm when used inappropriately.

Most women overestimate how much mammograms actually help, said Lisa Schwartz, a professor of medicine at the Dartmouth Institute for Health Policy and Clinical Practice in New Hampshire. Mammograms reduce the risk of dying from breast cancer by as little as 15% to as much as 40%, depending on which studies people consider.

That means that 85% of women in their 40s and 50s who die of breast cancer would have died whether or not they were screened, said Keating, a professor at Harvard Medical School.

The cancer society once cast screening as a black-and-white choice between life and death, Schwartz said. In the 1980s, the American Cancer Society ran ads telling women, "If you haven't had a mammogram, you need more than your breasts examined."

The message, Schwartz said, "was that you're an irresponsible person if you don't get screened." Three decades after those ads appeared, many doctors still convey that message and many women still believe it, Schwartz said.

Those kinds of messages are outdated, Wender said.

In the future, the American Cancer Society will never tell women that "a choice to do more or less screening is anything less than an expression of a woman's personal beliefs and values."

MAMMOGRAMS RISKS AND BENEFITS

Although mammograms can save lives, their benefits are much more modest than many women assume. They also carry risks.

Results if 10,000 women get annual mammograms from ages 40 to 49:

Lives saved due to mammograms

Women treated unnecessarily

Number of ...