What good does mammogram screening for breast cancer actually do? According to one major new study, not a lot. Mammograms are seeing the cancers that will never develop-and the discovery nonetheless triggers courses of chemotherapy and radiotherapy-but miss the life-threatening ones.
And the researchers also question the received wisdom that catching the cancer early makes all the difference. The researchers from Aarhus University in Denmark say they are seeing the same numbers of aggressive, late-stage breast cancer as before, suggesting that mammography isn't saving lives.
Their findings-which go against current public health policy-are based on data from 1.8 million Norwegian women aged 20 years and older, and cases of breast cancers that developed between 1987 and 2000.
Since mass screening was introduced in Norway, the researchers say that the rate of discovery of early-stage cancers in women aged between 50 and 69 had almost doubled. The cancers were dormant, however, and the women would have died with the cancer, but not from it, they say.
However, there had been no change in the numbers of advanced and life-threatening cancers, which suggests that mammograms were not picking them up.
Lead researcher Henrik Stovring doubts whether mammography is saving lives. "If that was the case, there should be an increase (in the discovery) of the early stages, and an almost equally-sized decline in the later stages as well, but this we did not find."
(Source: European Journal of Public Health, March 2014, doi: 10.1093/eurpub/cku015)