A STUDY evaluating the impact of breast cancer screening has shown that the benefits of regular mammograms extend well beyond reduced mortality. According to data presented at the American Society of Breast Surgeons (ASBrS) 2018 Annual Meeting, women with breast cancer who underwent regular mammograms were diagnosed with earlier-stage disease and were significantly less likely to require aggressive treatment compared to those who delayed or never underwent screening.¹ 

Of the more than 1,000 breast patients retrospectively analyzed, those who had a mammogram within 24 months of diagnosis had smaller tumors and were less likely to get a mastectomy, chemotherapy, or axillary node dissection compared to those who did not. Moreover, researchers noted that the benefits of screening were even more pronounced in patients 40 to 49 years old, compared to those who never had a mammogram. 

Distinct Study Objectives 

“THIS STUDY is notable because research on the impact of screening mammography typically focuses on its relationship to breast cancer mortality, not tumor stage and the therapies required,” said Elisa Port, MD, FACS, Chief of Breast Surgery and Director of the Dubin Breast Center at Mount Sinai Hospital, New York. “Although regular mammograms unquestionably have been demonstrated to reduce mortality, this study shows 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.” 

Elisa Port, MD, FACS

As Dr. Port reported at a press briefing in advance of the ASBrS meeting, although screening mammography has been shown to significantly reduce breast cancer mortality across many different age groups, compliance remains suboptimal. Recent data show that 60% to 70% of women who are qualified actually undergo screening mammography. 

“One of the main issues is that controversy persists regarding the value of mammography, and guidelines vary regarding the age to start and the frequency with which to undergo mammography,” Dr. Port explained. “Studies focusing only on reduction in mortality from screening mammography do not take into account other potential benefits of early detection such as the minimization of medical and surgical treatment patients need or receive to optimize survival rates.” 

For this study, Dr. Port and colleagues retrospectively reviewed patients with breast cancer who were treated at Mount Sinai Hospital between September 2008 and May 2016 and who were at least 40 years old at the time of diagnosis. Patients were divided into 2 groups: those who underwent screening within 24 months of diagnosis and those who underwent screening 25 or more months prior to diagnosis, including those who had never had a mammogram. 

The researchers used logistic regression to assess the association between the two groups and clinical factors including receipt of chemotherapy, nodal status, tumor size, and receipt of mastectomy or axillary dissection. Subgroup analysis was then performed based on age at diagnosis. 

More Than a Survival Advantage 

IN TOTAL, 1,125 breast cancer patients were treated during this period. Of these patients, 819 (73%) had screening within 24 months of diagnosis, whereas 306 (27%) had screening 25 months or more before diagnosis, including 65 (6%) who had never had a mammogram, Dr. Port reported. 

Overall, patients with a 25-month or more interval between diagnosis and prior screening were significantly more likely to receive chemotherapy (odds ratio [OR] = 1.51, P = .004), undergo mastectomy (OR = 1.32, P = .047), and require axillary dissection (OR = 1.66, P = .005) than patients who underwent screening within 24 months of diagnosis. 

Among patients who underwent upfront surgery (93%), those receiving more recent mammograms had significantly smaller tumors than those who had screening 25 months or more from diagnosis. In contrast, the subgroup of patients never screened had the largest mean tumor size. 

When stratified by age, patients 40 to 49 years old who never had a mammogram presented with later-stage disease and required more involved treatments. On the other hand, those who underwent mammograms were much less likely to have large tumors. 

“Among those who were never screened, there was upstaging by virtue of a larger tumor size,” said Dr. Port. “These patients were more likely to have positive nodes, undergo mastectomy, require axillary dissection, and require chemotherapy compared to those screened within 24 months.” 

According to Dr. Port, these findings are significant because the age at which to begin screening has become a focus of controversy. Under current American Cancer Society guidelines, screening mammography is considered optional for women aged 40 to 44, and by U.S. Preventive Services Task Force guidelines, screening is classified as optional for those aged 40 to 49. 

“Based on these results, decision-making with one’s physician regarding the use of screening mammography should not only take into account survival advantage and false-positive results, but other endpoints including the potential for less aggressive treatment,” Dr. Port concluded. ■

DISCLOSURE: Dr. Port reported no conflicts of interest. 

REFERENCE 

1. Ahn S, Wooster M, Valente C, et al: Impact of screening mammography on treatment in women diagnosed with breast cancer. 2018 American Society of Breast Surgeons Annual Meeting. Abstract 403820. Presented May 4, 2018.