An ongoing debate about when and how often women should undergo screening mammograms is intensifying in medical circles.

A new study and an editorial published online March 15 in JAMA Internal Medicine are adding new fuel to the fight.

The research suggests many U.S. screening centers are testing women earlier and more often than necessary, and an accompanying editorial warns that “recommendations from breast cancer centers for frequent screening mammography in younger women may do more harm than good.”

That prompted a rapid response from the American College of Radiology (ACR) and Society of Breast Imaging, which called both pieces misleading. The groups added that the writers ignored racial and regional disparities.

So, when should a woman start having mammograms and how often should she go? As the latest debate suggests, it all depends on who you ask.

“We should engage in shared decision making with our patients, to discuss the pros and cons of breast cancer screening,” said study author Dr. Jennifer Marti, a breast surgeon at Weill Cornell Medical Center in New York City. “Women should decide if beginning screening at age 45 to 50 or earlier, at age 40, is best for them.”

Marti noted that the U.S. Preventive Services Task Force (USPSTF) supports beginning screening mammograms at age 50 and then every two years to 74. The USPSTF says earlier screening should be based on an individual evaluation of risks and benefits. That’s in line with most breast cancer screening around the world.

Which age to start?

For the new study, the researchers looked at 487 U.S. centers that provide recommendations on screening mammography.

Of 431 centers that recommended a starting age, 87% advise women to begin screening at age 40; 8% recommended starting at age 45; and nearly 5% at age 50, the study found.

Of 429 centers that also recommended how often women should get checked, about eight in 10 suggested yearly screening.

The researchers wrote that USPSTF and American Cancer Society recommendations reflect data pointing to the potential harms of earlier screening. Those include false-positive findings, and unnecessary biopsies, surgeries and other therapies for benign or slow-growing tumors.

The study pointed out, however, that best screening practices may differ for high-risk groups, such as Ashkenazi Jewish and Black women.

“The public advice provided by high-volume breast centers in the U.S. suggests that these centers may prioritize factors not reflected in the data, such as patient and physician preferences, recommendations from specialty societies, concerns about litigation or possible financial considerations,” the study authors concluded.

Dr. Anand Habib of the University of California, San Francisco, co-wrote the accompanying editorial.

Over a decade, the editorial noted, false-positive rates for annual screening were 61% compared to 42% for screening every other year. The risk of biopsy from false positives was 7% for annual mammography and 4.8% for the biennial screening.

‘Downsides’ need discussion

Marti said she had noticed anecdotally that many doctors encourage earlier screenings.

“Patients and physicians tend to overestimate the benefit of cancer screening,” she said. “For breast cancer, the benefits are smaller than we tend to think, and we often don’t talk with our patient about the downsides of screening mammography.” Experts note that false positive results on a mammogram can lead to unnecessary biopsies and lots of worry for women.

In its written response, the ACR called the assertion that financial incentives were driving local screening recommendations “outrageous and insulting.”

The group noted that some groups — the ACR, Society of Breast Imaging, and American Society of Breast Surgeons — do currently recommend annual mammograms starting at 40. The American College of Obstetricians and Gynecologists also recommends mammograms every one to two years starting at age 40.

The statement said moving away from annual screening starting at age 40 would result in more breast cancer deaths, as many as 10,000 in the United States each year. It said the study overstated harms, could result in denied insurance coverage taking away women’s choices, and that it disproportionately affected Black and rural women.

Minorities more affected

Dr. Dana Smetherman, head of the ACR Commission on Breast Imaging, said, “The most lives are saved by starting at age 40 and having annual screening mammograms. I think that the differences come in with how you weigh the harms, what they call the harms or the risks, really, of screening mammograms.”

The study data don’t include technology that can reduce the number of patient recalls, Smetherman said.

“Another thing that is becoming more important and more recognized is the disproportionate negative effect that delaying until 50 and not doing mammograms annually has on minority populations,” she added.

Since 1990, deaths due to breast cancer have dropped about 40% for white women in the United States, compared to about 26% for Black women, Smetherman said. And 23% of breast cancers in Black women develop before age 50, compared to 16% in white women.

“I think this is something that we’re all becoming more aware of and are starting to consider more when we look at guidelines and ages to start,” she said.

The American Cancer Society recommends annual screening between 45 and 55 years, then every one to two years, as women choose.

Robert Smith, senior vice president of cancer screening for the American Cancer Society, noted that the USPSTF’s own models find a greater benefit to annual screening. But he said the task force is concerned about the consequences of false positives, and some of those numbers are cited in the study.

It’s a fair point that the recall rate for mammograms is too high, Smith said. He suggested having specialized radiologists, rather than generalists, interpret breast images as a way to improve accuracy.

Smith noted that surveys of primary care providers find most recommend screening in the 40s because their patients want it.

“Women do seem to place a higher value on detecting breast cancer early than any anxiety or harms associated with the workup of an abnormal mammogram,” Smith said.

More information

The U.S. Centers for Disease Control and Prevention has more on breast cancer screening.

SOURCES: Jennifer Marti, MD, surgeon, divisions of breast and endocrine surgery, Weill Cornell Medicine, New York City; Dana Smetherman, MD, breast radiologist, and chair, radiology department, Ochsner Medical Center, New Orleans, and chair, American College of Radiology Commission on Breast Imaging; Robert Smith, PhD, senior vice president, cancer screening, American Cancer Society, Atlanta; JAMA Internal Medicine, March 15, 2021, online

Source: HealthDay