Mammograms and Mortality: How Has the Evidence Evolved?

Randomized controlled trials of radiotherapy show that it increases lung and esophageal cancer mortality among women treated for early-stage breast cancer (Early Breast Cancer Trialists' Collaborative Group 2005). Latest Mortality Results across Trials Latest Mortality Results across Trials The meta-analysis by Nelson et al. (2016) that informs the US Preventive Services Task Force mammography guidelines primarily considers the relative risk of breast cancer mortality at the latest available date for each trial. In all age groups, the relative risk of breast cancer mortality is less than one, indicating that the ratio of the breast cancer mortality rate in intervention to control is less than one. As summarized in Table 2, the most recent mortality results from the Canadian National Breast Screening Study (Miller et al. 2014) show an imprecise increase in breast cancer mortality for women in their 40s and an imprecise decrease in breast cancer mortality for women in their 50s. Based on these results, it is not surprising that the literature, which focuses on breast cancer mortality as the primary outcome at various points in time, does not identify a compelling trend in breast cancer mortality as follow-up length increases. [Extracted from the article]