A new study suggests that having annual mammogram only detects but not decrease deaths from breast cancer.
Researchers from the University of Toronto's Dalla Lana School of Public Health led by epidemiologist Anthony Miller, an epidemiologist, found that religiously submitting oneself to annual mammogram does not guarantee survival from breast cancer.
They followed 89,835 Canadian women aged 40 to 59 and divided them into two groups: 50 percent underwent yearly physical breast examination while the other half had annual mammogram screening for five consecutive years.
After the 25-year monitoring period, they found that seven percent of those who had annual mammogram screening developed breast cancer. The same percentage was also observed to those who had physical breast examination. Furthermore, there was no difference on the death rate on both groups which were equally at one percent.
They also found out that 22 percent of the women who underwent annual mammogram were overdiagnosed, which means that one out of 424 women who were screened, received unnecessary cancer treatment.
The common knowledge about the importance of the use of mammogram as a diagnostic tool, on the other hand, was not addressed in the study.
Though the American College of Radiology was quick to denounce the study's findings, the researchers stood by their conclusions and challenged them to support their claim with factual data showing that mammograms prevented death from breast cancer.
"Modern treatment is so much more effective now that the lead time gained by mammography has little impact on the outcome," said Miller to LA Times.
Dr. H. Gilbert Welch, an epidemiologist and biostatistics professor at Dartmouth College's Geisel School of Medicine, said that the study offered the utmost-quality evidence about the commonness of overdiagnosis.
He told LA Times, "I think there's growing realization that all is not well with mammography. People in the cancer community and the cancer surgery community are aware of the problem of overdiagnosis. They're aware that mammography was oversold, that its benefits were exaggerated and its harms were kind of downplayed."
This study was published on Feb. 11 in the British Medical Journal.
