Women who took part in their past two consecutive mammography examinations had a significantly reduced risk of breast cancer mortality, a study found.
“While there is ample evidence that breast cancer mortality is reduced in those who attend screening, these results demonstrate that repeated attendance confers greater protection than attendance at a single screen,” said lead study author Professor Stephen Duffy, of Queen Mary University of London, in a press release. “We need to ensure that the screening experience is as stress-free as possible, so that people will come back.”
The researchers examined data on Swedish women eligible for mammography in nine counties between 1992 and 2016. These data were linked with registry and regional cancer center data pertaining to breast cancer diagnosis, cause, and date of death. Women were classified by which screening(s) they attended: intermittent participants (most recent screening examination prior to diagnosis only), lapsed participants (penultimate screening examination only), serial participants (both examinations), and serial nonparticipants (neither examination).
Final analysis included data on 549,091 women with an average age of 58.9 ± 6.7 years. There were 392,135 serial participants, 41,746 intermittent participants, 30,945 lapsed participants, and 84,265 serial nonparticipants.
Serial participants’ breast cancer mortality risk was half that of serial nonparticipants (relative risk [RR], 0.51; 95% confidence interval [CI], 0.48-0.55; P<0.001), as was their risk of breast cancer mortality within 10 years of diagnosis (RR, 0.50; 95% CI, 0.46-0.55; P<0.001). Lapsed and intermittent participants also had a lower mortality risk than that of serial nonparticipants, but the difference was not as significant, and serial participants had much lower risks of both outcomes compared to lapsed and intermittent participants.
The study was published in Radiology.
“This comprehensive study is the result of a long-term cooperative effort of the physicians and other professional staff in nine Swedish counties, all of whom were trained in the Falun School,” said Professor Laszlo Tabar, principal investigator of the study, of Falun Central Hospital. “The analysis of the massive dataset was masterfully handled by the statisticians of the Swedish Organized Service Screening Evaluation Group. This work adds additional evidence confirming the value of early detection of breast cancer through regular attendance at mammography screening, helping women and their physicians make informed decisions.”