14 February 2017

About the dangers of false positive results

False positive mammography results lead to refusal of repeated examinations

Anna Stavina, XX2 century

To make a mammogram, the breast is "flattened" in a special vice.
This is not the most pleasant and not the most reliable diagnostic procedure,
but there is no alternative to it yet.

Regular mammography is currently the only way to detect breast cancer early. However, it also happens that patients are informed about a "suspicious" mammogram, and subsequent tests show that the alarm was false. According to a new study, women who find themselves in such a situation tend to postpone the next mammogram or even refuse to perform the procedure regularly.

The study was based on the analysis of medical data of 261767 Chicago residents. The results of the work were published in Cancer Epidemiology, Biomarkers and Prevention (Dabbous et al., Impact of a False-Positive Screening Mammogram on Secondary Screening Behavior and Stage at Breast Cancer Diagnosis).

It turned out that women who were recommended to undergo mammography once a year, after receiving false positive results, postponed the procedure for an average of 13 months. That is, in fact, the next examination was carried out after two years, and not after one. Those who had negative results were usually only 3-6 months late.

This schedule change, in turn, could affect the patient's chances of survival if the tumor subsequently did appear. The probability that cancer will be diagnosed at a late stage in women from the second group averaged 0.3%. And for those who have already experienced a "false alarm", the risk of late detection of the tumor was slightly increased – it was 0.4%.

Some patients stopped visiting the clinic altogether after receiving false positive results. However, it is not known whether this is due to the fact that they decided to abandon the procedure – or began to undergo it somewhere else.

"This is a very fine line," says the study's lead author Firas Dabbous from the James and Helen Russell Institute for Research and Innovation. – We understand that it is necessary to detect tumors, if there are any. But at the same time, we would like to protect patients from an abundance of false positive results and unnecessary subsequent diagnosis."

The question of how often women should undergo mammography is still the subject of active debate in the professional community. Erroneous positive results cause understandable anxiety in patients. In addition, to refute the diagnosis, women have to undergo expensive and sometimes painful procedures, including a biopsy. It turns out that the harm from the examination may outweigh the possible benefits."

"The authors of the work found significant delays in mammograms," says Robert Smith, vice president of the American Cancer Society. – If their observations can be reproduced in other studies, it will mean that women who have received false positive mammography results need to pay additional attention. For example, such patients can be sent several messages reminding them of the need to undergo an examination."

The features of mammography as a screening method are such that the frequency of false positive results is about 10%. A biopsy is required in 7-17% of cases. At the same time, patients who still had a biopsy with a negative result are 19% more likely to refuse subsequent mammograms compared to those who did not need a biopsy.

However, with all the disadvantages of mammography, there are no more advanced methods of early detection of breast cancer at the disposal of doctors yet. Therefore, experts do not recommend giving up mammography and taking it as regularly as possible.

Portal "Eternal youth" http://vechnayamolodost.ru  14.02.2017

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