A follow-up from the United States indicate that more invasive cancers found during screening mammography since called tomosynthesis introduced. In addition, the technique seems to lead to fewer false positives.
The results, published in a new study in the journal JAMA, based on analysis of over 450 000 mammograms.
About 40 percent of those made with tomosynthesis, where x-ray images of the breast are taken from different angles, which in turn provides three-dimensional images of the breast tissue.
When the researchers compared data before and after tomosynthesis implemented at 13 hospitals studied in the United States notes that the 1.2 additional cases of invasive cancers found per 1,000 women screened. This corresponds to a relative increase of 29 percent.
Invasive cancer means that the tumor is growing into nearby tissues. The presence of less dangerous tumors called ductal carcinoma in situ, however, was unchanged.
After tomosynthesis introduced, the researchers also to 16 fewer women per 1000 screening occasions were called back for further investigation, a relative reduction of 15 percent.
The researchers stress, however, a number of limitations in the study, that it was not randomized.
The results say nothing about the clinical outcome, such as whether more women are saved from dying of breast cancer, or if tomosynthesis leads to increased so-called overdiagnosis, ie, detection of tumors that had not made themselves known if the woman had not been screened.
The radiation dose tomosynthesis is approximately twice that of conventional mammography.
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