Breast Cancer Screening Frequency Makes a Big Survival Difference

CHICAGO — Women who routinely showed up for their scheduled mammogram appointments had lower risk of dying of breast cancer after developing it than those who had delayed or skipped screening, a subanalysis of an observational study from Sweden showed.

Among 37,079 breast cancer patients, the more screening exams they attended prior to diagnosis, the lower the likelihood of breast cancer mortality after diagnosis, reported Robert Smith, PhD, of the American Cancer Society Center for Cancer Screening and Emory University School of Public Health in Atlanta.

Women who attended all five of their scheduled mammogram appointments during the study period had a 72% lower risk of mortality from breast cancer compared with patients who skipped all of these appointments (HR 0.28, 95% CI 0.25-0.33, P<0.0001), Smith told attendees at the Radiological Society of North America annual meeting.

Women who attended all their invited screening mammograms had a breast cancer-specific survival rate of over 80%, whereas the rate ranged from 59.1% to 77.6% for women who didn’t participate in any screenings. Even after conservative adjustment for potential self-selection factors, there was a highly significant 66% relative difference in the risk of breast cancer death.

“Most women will not develop breast cancer in their lifetimes,” Smith said. “For those who do, regular screening considerably improves the probability of survival.”

As to the mechanism of benefit, he suggested, “These findings show that as much as possible, adherence to regular mammography screening is the very best insurance a woman has against being diagnosed with an advanced breast cancer that could be life-threatening.”

He noted while the benefits of mammography screening have been well established in reducing breast cancer mortality, most U.S. women don’t get screened on a regular interval and many are screened only sporadically or not at all. And while multiple advertising campaigns express the need for mammograms, there is scant discussion of regularity.

“The importance of regular attendance in mammography screening should be clearly articulated in breast cancer screening messaging,” he argued.

Smith also suggested that the onus for keeping breast cancer screening appointments should not just fall on the patients, but on the clinicians as well. The researchers stressed that imaging facilities should prioritize getting patients in for screening at the earliest opportunity. “This is especially important when women have to cancel their appointments. Facilities should reschedule these screening mammograms for the next earliest available appointment,” Smith suggested.

The researchers obtained mammography screening history from oncology centers throughout Sweden for a period from 1992 to 2016. Using data from the Swedish Cause of Death Register, the researchers identified 4,564 breast cancer deaths among the patients included in the study. The researchers tracked all of the women’s participation in up to five of the most recent invitations for breast cancer screening prior to their cancer diagnosis.

In commenting on the study, Stamatia Destounis, MD, of Elizabeth Wende Breast Care in Rochester, New York, called the magnitude of reduction in the risk of dying “very significant” and noted that it reproduces and mimics results of multiple previous studies.

“Going to regular screening will improve your chances of surviving breast cancer, and you are bound to do better than someone who does not go to their screenings,” Destounis told MedPage Today.

In terms of study limitations, Smith acknowledged that “these results are for case survival, not population mortality, although results are consistent with recent findings of a greater mortality reduction for those who participated in both their most recent scheduled screens.”

The main analysis of their data had shown that women who attended both of their two screening mammograms prior to a breast cancer diagnosis had a 49% lower risk of breast cancer mortality and a 50% lower risk of death from breast cancer within 10 years of diagnosis compared with serial nonparticipants.

Please enable JavaScript to view the

comments powered by Disqus.