According to a recent article published in the Journal of the National Cancer Institute, it appears that screening mammography within a community may not improve survival in breast cancer patients. However, several previous clinical trials have indicated the contrary by showing that screening mammography does in fact improve survival in breast cancer patients. Women should not change their screening schedules based solely on the results of this particular analysis.
Breast cancer is diagnosed in approximately 250,000 women annually in the United States alone. Cure rates following standard therapy for breast cancer are high if the cancer is found and treated early; however, long-term survival for patients with advanced breast cancer is dismal. Therefore, screening for early detection and treatment of breast cancer has been under heavy scrutiny in order to improve survival in patients with breast cancer. Several previous clinical trials directly comparing women who have undergone screening mammography to those who do not undergo screening have indicated that screening mammography detects breast cancer earlier and improves overall survival in breast cancer patients. On the other hand, not all studies have produced the same conclusion. It is currently recommended that women who are forty years or older undergo regular screening with mammography.
Researchers from the University of Washington recently evaluated data to further evaluate the impact of screening mammography on long-term outcomes in patients with breast cancer. The study included 1,351 women who had died of breast cancer between 1983 and 1998 and the same number of women who had not had breast cancer. The researchers sought to determine if women without breast cancer had undergone more screening for breast cancer than women with breast cancer. Researchers reported that breast screening was not associated with an overall significant reduction in breast cancer deaths. For women at high risk of breast cancer, there was a reduction of death, but there were no differences between various subgroups of women with different risks for developing breast cancer.
The authors of the study concluded that breast cancer screening in the 1980s and 1990s was associated with, at most, a modest reduction in breast cancer deaths. Their list of possible reasons for these findings includes: chance due to relatively small numbers in this study, women with cancer may have sought screening, short follow-up and lack of information about risk of breast cancer. They also suggest that improvements in the treatment of breast cancer could have affected outcome. In addition, women are more aware of small breast masses than they were when large randomized trials of screening were carried out. They also suggest that that screening is possibly less effective in community settings than in the setting of randomized trials. However, despite these findings, the authors did not suggest the abandonment of screening for early breast cancer. Women should speak with their physician regarding their individual risks and benefits of undergoing screening mammography.
Reference: Elmore JG, Reisch LM, Barton MB , et al. Efficacy of breast cancer screening in the community according to risk level. Journal of the National Cancer Institute. 2005;97:1035-1043.