Mammography does not reduce breast cancer mortality?

Difficult decision

Tatiana Shcheglova, Copper News

In British society, and not only, there has been a debate for a long time around the justification of mandatory mass screening of the female population for breast cancer. Some experts doubt both the effectiveness of this method for early detection of the disease, and the balance between the benefits it brings – saved lives – and the potential harm to health that can lead to errors in diagnosis, as well as regular exposure to X-rays, which can have a mutagenic effect. The latest study by scientists from Oxford may tip the scales towards the "mammo-skeptics" and make many British women even more carefully weigh all the pros and cons before going for the procedure.

For a quarter of a century, since 1988, the National Health Service (NHS) has been operating in the UK to detect breast cancer in women aged 50 to 64 years. British women from this age group are regularly strongly reminded by their family doctors of the need to have a mammogram. However, all these years, the controversy surrounding this program has not subsided in the country, which has become especially acute in the last few years.

So, in the fall of 2011, Susan Bewley, professor of obstetrics and gynecology at King's College London, wrote an open letter to the chief British oncologist, Sir Mike Richards, in which she announced her decision to refuse regular examinations, despite a family history of breast cancer, in connection with with a high percentage of overdiagnosis and accused the NHS of hiding the whole truth about mammography.

In response, Richards promised to promote independent research on the benefits and harms of mass screening. These independent studies, the results of which became known a year later, in the fall of 2012, showed that regular examinations reduced breast cancer mortality by 20 percent in their participants, saving about 1,300-1,400 lives annually.

However, another statistic was also revealed – about 4 thousand British women annually undergo absolutely unnecessary treatment, including mastectomy, radiation and chemotherapy, according to the results of mammographic examination. These are the severe, often life–destroying consequences of the very overdiagnosis that Beuley spoke about - the changes in breast tissues detected during mammography were so insignificant and the prognosis of their malignant degeneration and rapid growth was so small that, without an examination, they would not have brought women any harm in their entire lives.

After learning about this twofold statistic – for every life saved, there are three destroyed ones – Richards ordered a review of the rules for conducting a mass screening program, abolishing the obligation to participate in it and leaving women to decide for themselves, weighing all the pros and cons, whether they should be examined or not.

Meanwhile, the results of a large–scale analysis conducted by Oxford University specialists have also called into question the first part of the 2012 studies - the positive impact of mass mammographic examinations on the mortality rate from breast cancer. As part of their work published in the June issue of the Journal of the Royal Society of Medicine (Breast cancer mortality trends in England and the assessment of the effectiveness of mammography screening: population-based study), the authors studied mortality statistics in the Oxford region from 1979 to 2009, as well as mortality data from breast cancer across the UK in all age groups from 1971 to 2009, that is, for almost forty years. The Oxford region was chosen because only in it, unlike the rest of the country, all possible causes of death are indicated on the death certificate. Scientists paid special attention to the situation with mortality from breast cancer before and after 1988.

Contrary to expectations, the greatest decrease in mortality rates was found not in the age group of 50-64 years, but among women younger than 40 years who do not undergo regular examinations. Thus, in the period from 1988 to 2001 in this age group there was a decrease in the mortality rate by two percent, and in the period from 2001 to 2009 – by five percent. But the mortality of women aged 50-64 years, as the authors note, routine testing for breast cancer, in comparison with the younger group, had practically no effect – in the first of the time periods, their indicator fell by only 1.2 percent, and in the second – by three percent.

Statistics indicate, the authors conclude, that although in each individual case the examination may be beneficial, at the population level, the effect of mass screening for breast cancer, which was expected to significantly reduce mortality from this disease, is not observed, and the overall decrease in this indicator is associated with a qualitative improvement in therapy methods. In short, the decision to participate in the program or refuse it has become even more difficult for British women than before.

Portal "Eternal youth" http://vechnayamolodost.ru13.06.2013