Regular screening mammograms reduce risk of breast cancer mortality

Having a mammogram for 2 consecutive years before a breast cancer diagnosis conferred a significant reduction in mortality compared to skipping one or both screens, according to the results of the prospective study published in Radiology.

The risk reduction decreased for women who missed even one of the previous two exams, the researchers said.

“Our previous work has shown an advantage of participation in screening when defined as participation in the most recent screen only. We therefore wanted to know the value of regular screening versus irregular screening. ” Stephen W. Duffy, BSc, MSc, CStat, researcher at the Center for Cancer Prevention and professor of cancer screening at Queen Mary University in London, told Healio. “The screen that can save a life is the screen that detects cancer at an early stage. There is clearly a greater likelihood that his life will be saved if one attends the regularly scheduled screens. “

Stephen W. Duffy

Duffy and colleagues gathered data on 549,091 women (mean age, 58.9 years) included in Swedish national registries between 1992 and 2016 to estimate the effect of successive mammography screening examinations on breast cancer mortality.

The researchers calculated incidence-based mortality based on whether the women had both screens (serial participants; n = 392,135), only the most recent screening prior to diagnosis (intermittent participants; n = 41,746), only the penultimate screening before diagnosis (non-dependent participants; n = 30,945) or no screening (serial non-participants; n = 84,265).

The researchers used Poisson regression analysis to assess incidence-based breast cancer death rates. They also assessed the incidence of fatal breast cancers within 10 years.

The results showed that compared to serial non-participants, serial participants had a 49% lower risk of breast cancer mortality (RR = 0.51; 95% CI, 0.48-0.55 ) and a 50% lower risk of death from breast cancer within 10 years of diagnosis. (RR = 0.5; 95% CI, 0.46-0.55).

Serial participation was also associated with a significant reduction in breast cancer mortality compared to intermittent participation (RR = 0.77; 95% CI 0.69-0.86) and lapsed participation ( RR = 0.7; 95% CI 0.61-0.8).

Researchers observed smaller reductions in breast cancer mortality associated with intermittent (RR = 0.67; 95% CI, 0.59-0.76) and lapsed (RR = 0.72; 05%, 0.63-0.83) compared to the serial non-participation.

It should be noted that the researchers observed no significant difference in mortality between intermittent participants and participants who lost their jobs (RR = 0.92; 95% CI 0.78 to 1.08).

“Our study reinforces the principle that early detection continues to confer risk reduction [for] dying [of] breast cancer, even in the age of effective adjuvant systemic treatments, ”said Duffy. “We have also shown that this benefit can be maximized by serial participation in screening. This implies that the screening experience should be made as safe, acceptable and positive as possible so that women who are screened come back the next time. “

Future research should examine these results in more detail to determine to what extent the added benefit of serial attendance is driven by the change in stage of detection of screening or interval cancers, added Duffy.

“If someone attends regular screening, it can add a limitation on the extent to which a tumor can grow in the interval between screens,” he said. “It would also be helpful to look at disease stage and survival based on time since last screening and demographics, such as age. This could inform the frequency of screening for different populations in the future. “

For more information:

Stephen W. Duffy, BSc, MSc, CStat, can be reached at Queen Mary University of London, Mile End Road, London E1 4NS; email: [email protected].