According to a recent article published in The Journal of the American Medical Association, women whose breast cancer is detected through screening mammography have a reduced risk of distant spread of cancer, compared to women whose breast cancer was detected outside of screening mammography.
Breast cancer claims the lives of approximately 40,000 women annually in the United States alone. Cure rates for cancers that are detected and treated early are high with the use of standard treatment. However, cure rates are reduced dramatically in women whose breast cancer is detected and treated once it has spread to distant sites in the body. Therefore, efforts on screening for early breast cancer have become widespread with the use of mammography, so cancer may be detected and treated when it is most curable. Controversy over the effects of mammography on overall survival as well as resource utilization has existed among some practitioners; however, evidence continues to mount that indicates screening mammography is a useful tool in reducing overall deaths due to breast cancer.
Researchers from Finland recently conducted a clinical study that evaluated data from nearly 2,000 women who had been diagnosed with breast cancer in 1991 or 1992. The study included women who had their cancer detected by screening mammography, as well as women whose cancer was detected outside of screening mammography. The researchers evaluated several biological and clinical variables among the participants, and determined potential relationships between these variables and outcomes. At an average of 9.5 years follow-up, detection of cancer through screening mammography was a variable that was associated with a reduced risk of cancer recurrences to distant sites in the body, as well as an improved survival at 10 years. Survival rates without distant spread of cancer at 10 years for women who had their cancer detected through mammography, compared to those whose cancer was detected outside of mammography were 92% vs. 85% for those with cancer size <11mm, 88% vs. 76% for those with cancer size 11-20 mm, 86% vs. 63% for those with a cancer size of 21-30 mm, and 68% vs. 50% for those with a cancer size >30 mm.
The researchers concluded that patients whose cancer is detected by screening mammography have a significantly improved rate of survival without distant spread of cancer at 10 years, compared to women whose cancer was detected outside of screening mammography. These results add to a growing body of evidence that long-term outcomes for women diagnosed with breast cancer are improved with screening mammography. Women who are 40 years of age or older, or are at a high risk of developing breast cancer may wish to speak with their physician about their individual risks and benefits of screening mammography.
Reference: Joensuu H, Lehtimäki T, Holli K, et al. Risk for Distant Recurrence of Breast Cancer Detected by Mammography Screening or Other Methods. The Journal of the American Medical Association. 2004; 292: 1064-1073.