Regular mammograms significantly reduce risk for breast cancer death

Key takeaways:

• The risk for breast cancer death was 66% to 72% lower among women who attended all screenings vs. those who did not attend any screening.
• Physicians should stress the importance of regular screenings.

Women who regularly attended their mammogram screenings before a breast cancer diagnosis had up to a 72% reduced risk for death compared with those who attended none, according to a recent study.

“Ideally, when women receive a notice that they are due for their regular mammogram, they are able to attend as close to the recommended interval, ie, annually or biennially. However, sometimes women miss their appointment, and may not return to regular screening until the next exam,” Robert A. Smith, PhD, director of the American Cancer Society Center for Cancer Screening, told Healio. “In some instances, women miss several scheduled examinations.”

Thus, “we have been exploring the effect of missing one and more than one mammography examination on their risk of dying from breast cancer,” Smith, whose study was presented at the annual meeting of the Radiological Society of North America, said.

The researchers analyzed data on 37,079 patients with breast cancer who were invited to undergo screening mammograms between 1992 and 2016. They tracked the patients’ participation in five or fewer of the most recent screening invitations before diagnosis.

Overall, 4,564 breast cancer deaths occurred during the study.

Depending on the number of screening invitations, 58% to 73% of patients participated in all scheduled screening exams and 73% to 96% participated in at least one scheduled screening exam. The survival rates ranged from 82.7% to 86.9% among those who participated in all their exams vs. 59.1% to 77.6% among those who participated in no screening exams.

In an analysis of women who had five prior screening invitations, the risk for breast cancer death was 72% lower among those who participated in all five screenings compared with those who attended none (HR = 0.28; 95% CI, 0.25-0.33). Smith and colleagues reported that there was a risk reduction of 66% (HR = 0.34; 95% CI 0.26-0.43) even after a “conservative adjustment” for possible self-selection factors.

“We were surprised that the results showed such a strong protective effect of regular attendance at all scheduled mammography examinations,” Smith said. “It does stand to reason if a woman has breast cancer and misses one or more examinations, then her breast cancer will continue to grow until she experiences symptoms, and it is more likely to be advanced.”

Smith explained that physicians often stress the importance of receiving a mammogram screening but not the importance of regular screenings.

“Most women do not have breast cancer, or detectable breast cancer at the time of their screening mammograms,” he said. “If it is not convenient to keep the appointment, women may end up postponing their next exam to some future date that is months later, and may find they cannot attend that appointment either.”

Ultimately, “primary care physicians need to stress that keeping mammography appointments is essential because a woman may have an early breast cancer that will be detected,” Smith said.

“Our findings are also a reminder that imaging facilities should prioritize getting a woman who missed her examination back on the schedule as soon as possible,” he added. “The screening intervals are set to ensure the greatest possibility to detect breast cancer early.”

References:

• Regular screening mammograms significantly reduce breast cancer deaths. https://www.eurekalert.org/news-releases/1008945. Published Nov. 30, 2023. Accessed Nov. 30, 2023.
• Smith R, et al. Beneficial effect of repeated participation in breast cancer screening on survival. Presented at: Radiology Conference & Annual Meeting; Nov. 26-30, 2023; Chicago.