A Swedish trial that followed patients for nearly three decades (29 years) revealed that those who were screened had 30 percent fewer breast cancer deaths than those who were not screened. What the researchers also found was that the longer the screening process, the better the results. In fact, researchers say the majority of the mortality benefit occurs more than 10 years after starting screening. Many critics have said that the benefits of mammograms is overblown, but this trial showed that many of the results needed longer monitoring before the results would be revealed. In studying women for just 10 years, for example, it may be in year 12 or 15 that the screening may have caught the cancer. The trial followed 133,000 women ages 40 to 74, living in two Swedish counties.
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