The Case for Early Screening Mammography

Kristin Jenkins
May 08, 2018

In the United States, the continuing controversy over the best age to start screening mammography has put women younger than 50 years at significantly increased risk for delayed diagnosis, which leads to more extensive and costly treatment and affects quality of life as well as the bottom line.

This was the message from Elisa Port, MD, chief of breast surgery at Mount Sinai Hospital and director of the Dubin Breast Center, New York City, NY, who was speaking recently at the annual meeting of the American Society of Breast Surgeons (ASBrS).

"I worry that doing fewer mammograms now is being pennywise and pound foolish," Port said at a press conference held at the ASBrS meeting. "Not doing mammograms because of cost or fear of false-positives is a decision that is likely to blow up later when women face more extensive therapy, including surgery and chemotherapy."

Port said that her "personal recommendation for screening mammography would be for women to have it annually starting at age 40." She added that in women at high risk, "screening needs to start earlier."

At the meeting, Port and colleagues presented an analysis of data from a single-center retrospective study of more than 1000 women with breast cancer. It showed that across all age groups, screening mammography within 24 months of diagnosis was associated with smaller tumors overall and a lower likelihood of mastectomy, chemotherapy, or axillary node dissection compared with screening performed at an interval of 25 months or longer, or not at all.

However, in patients 40 to 49 years of age — for whom screening mammography remains optional — those who had never had a mammogram were diagnosed with a much larger tumor compared with those screened in the 24 months before diagnosis (23 mm vs 13 mm; P = .0417).

Younger unscreened women were also 2.5 times more likely than screened peers to have positive lymph nodes (odds ratio [OR], 4.52; P = .0035) and were also more likely to undergo mastectomy (OR, 3.44; P = .0068), axillary node dissection (OR, 4.64; P = .0002), and chemotherapy (OR, 2.52; P = .0287), the team reported.

"While regular mammograms unquestionably have been demonstrated to reduce mortality, this study shows that they also are associated with less complex treatment regimens, with less risk of undesirable side effects that can diminish a survivor's ongoing quality of life," said Port.

"Decision making regarding the use of screening mammography should not only take into account survival advantage but other endpoints, including potential for less aggressive treatment," she added.

In a press release issued by the ASBrS, Julie Margenthaler, MD, a breast surgeon at Washington University School of Medicine in St Louis, Missouri, confirmed that numerous studies showing the benefits of screening mammography have typically focused on a reduction in mortality.

"This is a large study that ties regular screening to hard data on the type of treatment required," said Margenthaler, who is also chair of the ASBrS Communications Committee. "Surprisingly, we continue to see conflicting data on the benefits of screening mammography for women less than 50 years of age," she noted.

Current Recommendations

The US Preventive Services Task Force (USPSTF) currently recommends that screening mammography be offered to women every 2 years from ages 50 to 74 years. Before age 50, screening mammography is recommended on a patient-by-patient basis, taking into account the "patient context... including the patient's values regarding specific benefits and harms."

The American Cancer Society recommends that all women begin yearly mammograms by age 45 and switch to mammograms every other year beginning at age 55. It also advises that "Women should have the choice to start screening with yearly mammograms as early as age 40 if they want to."

In 2015, the National Center for Health Statistics published findings on long-term health trends in the United States showing that only 65% of women older than age 40 had had a mammogram within the prior 2 years, noted Port.

Should Be 'Individualized Decision'

When approached for comment, Sarah Blair, MD, professor of surgery at the University of California San Diego, said this study is important but the issue of the optimal age at which to begin screening mammography needs to be examined by using a larger database.

She emphasized that breast cancer screening should be "an individualized decision," not just based on the USPSTF guidelines. Family history and other risk factors for breast cancer have to be considered, and good communication with the patient is essential.

However, Blair also noted that the incidence of breast cancer in women 40 to 49 years of age is about 15%. "If women who start screening mammography at age 40 are willing to accept a slightly higher false-positive rate, then this data provides more ammunition for screening mammography," she told Medscape Medical News. "This is push-back on the guidelines."

Most of the women Blair talks to say they would rather risk a false-positive result on screening mammography than face the prospect of morbidity associated with chemotherapy, including cognitive changes. "That's the one thing they hate," said Blair.

Details of the Analysis

For their observational study, Port and colleagues examined 1125 patients diagnosed with cancer between 2008 and 2016. Participants were divided into two groups. The first group consisted of 819 women (73%) who had undergone mammography within 24 months of diagnosis; and the second group was composed of 306 women (27%) who had delayed screening 25 months or longer before a diagnosis of breast cancer. This latter group included 65 women (6%) who had never had a mammogram.

The investigators looked at the association factors, such as whether the patient underwent chemotherapy, mastectomy, and/or axillary dissection. Node status and tumor size were stratified according to whether the patient had received upfront surgery (1045 patients; 93%) or neoadjuvant chemotherapy.

A subgroup analysis examined age at diagnosis: 40 to 49 years, 50 to 59 years, 60 to 69 years, and 70 years or older.

Overall, women screened at intervals of 25 months or longer were significantly more likely to receive chemotherapy (OR, 1.51; P = .0040), to undergo mastectomy (OR, 1.32; P = .0465), and to require axillary dissection (OR, 1.66; P = .0045) than patients who underwent screening in the 24 months before diagnosis.

Those with longer screening intervals also had larger tumors than those who underwent mammography every 2 years or less before diagnosis (mean, 14.5 mm vs 12.5 mm; P = .0225).

In the past decade, adherence to screening guidelines has plateaued, Port noted. Newer guidelines have moved away from recommending annual mammograms, citing risk for overtreatment and false-positive findings outweighing benefit in younger women.

Decision-making with physicians should take into account false-positive results as well as the potential for less aggressive treatment, she suggested.

"There are data to suggest that women are willing to tolerate more false-positive results if it reduces the risk of more aggressive treatment down the road, or death," Port said.

A false-positive result on screening mammography doesn't necessarily lead to biopsy or surgery, she pointed out. "Most false-positives are just a call-back for additional ultrasound screening. At that point the issue is resolved and can be put to rest."

The use of three-dimensional mammography has also reduced the number of call-backs, Port said.

"With earlier diagnosis, patients may decrease their likelihood of needing these treatments and their associated risks. In addition, more extensive therapies add significantly to costs to the healthcare system," she said.

Port and coauthors, Margenthaler, and Blair have disclosed no relevant financial relationships.

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Reviewed on 5/9/2018

SOURCE: Medscape, May 08, 2018. American Society of Breast Surgeons 2018 Annual Meeting. Presented May 4, 2018.

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