Breast cancers are the most common form of cancers found in women, the detection of breast cancer at an early stage appears likely to improve their prognosis. Self examination is an important factor in detection as is the use of mammographies.

The choice to undergo mammography screening for women is important, and requires that they do so with balanced information. In a dozen randomized trials, of approximately 400,000 women in total, have evaluated breast cancer screening by mammography in the general population. A majority of these tests are in fact modest level of evidence, for reasons of defective design or inaccuracy of their reports.

In terms of total mortality, a benefit of screening mammography in the general population has not been demonstrated, or if it has a positive or negative effect on total mortality figures. Taking into account the results of tests of good and poor quality, we can estimate that the effect is a relative decrease in mortality from 1% to a relative increase of 3%, after 13 years.

In terms of mortality from breast cancer, a benefit of screening with mammography in the general population is uncertain. In an optimistic assumption, it would invite between 700 and about 2,500 women to avoid death by breast cancer after 14 years. The screening with mammograms has not decreased the number of aggressive treatments, including ablations of a breast due to cancer.

The mammography screening in the general population detects a large number of breast cancers. However, about one third of cancers are diagnosed between two screening sessions. On the other hand, 30% to 50% of cancers detected are probably not very dangerous, because few localized and aggressive.

The most common side effects of screening mammography are discomfort and pain, which is slight and moderate during the examination, and anxiety caused by the detection of a suspicious anomaly which often proves ultimately not be a cancer, hence the term false positives (about 60% of anomalies detected are in fact “false positives”).

The cancer diagnoses of non-hazardous types are the cause of tests and unnecessary treatments, sometimes aggressive, which themselves have side effects. The repeated breast irradiation is the source of some cancers, although we are unfamiliar with the number, which led to deaths estimated at between 1 and 5 per 100 000 women screened regularly from age 50 and followed until the end of their lives.

The risks of false positives, treatment and excessive radiation-induced cancers are all higher than mammography screening that is begun early.

In total, in early 2006, in the general population of women aged less than 50 years, the risk-benefit balance screening of breast cancer on mammograms is unfavorable; beyond the age of 70, there is not available Data showing effectiveness.

Between 50 and 69 years, the benefits are hypothetical, in about 40,000 women, screening with mammography by regular methodical clinical examination did not provide any tangible benefit, and it is unclear whether this has a clinical screening effect on total mortality or breast cancer. If the decision is made to perform screening by mammogram despite the uncertainties and limitations of the method, the best conditions are generally those of organized screening, with control of its quality.