Three dimensional mammography reported to increase diagnostic accuracy

Robin Wulffson MD's picture
mammogram, screening, breast cancer, 3D, diagnosis, accuracy, tomosynthesis
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A new study has reported that three dimensional (3D) mammography, also known as tomosynthesis, significantly increases diagnostic accuracy, compared to standard digital mammography. In addition, it significantly reduces recall rates for non-cancer cases. Researchers affiliated with the Avon Comprehensive Breast Center, Massachusetts General Hospital (Boston, Massachusetts) published their findings online on November 20 in the journal Radiology.

In contrast to conventional mammography, which involves two X-ray images of each breast, tomosynthesis captures multiple images from different angles. These images are then used to make a 3D reconstruction of the breast. The researchers designed a study to compare radiologists’ diagnostic accuracy and recall rates for breast tomosynthesis combined with digital mammography versus digital mammography alone.

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The study group comprised 1,192 women from five medical facilities who presented for either screening mammography or pre-biopsy breast imaging. The women underwent same-day digital mammography and tomosynthesis imaging of both breasts in two views: mediolateral-oblique and craniocaudal. A mediolateral-oblique view is an angle that allows more of the breast tissue to be imaged (it covers the main area of a woman’s breast) as well as the tissue the armpit. It will show glandular as well as fatty tissue, and it covers a larger area than a craniocaudal view. A craniocaudal view will show as much as possible of the breast’s glandular tissue (ducts and lobes), the surrounding fatty tissue, and the outermost edge of the chest wall muscle. This view cannot capture much of the breast tissue that is in the armpit and upper chest.

The total radiation dose for the combined studies was less than 3 mGy, which is twice times that of digital mammography alone; however, that level is below the limit for a single mammogram set by the FDA. Two groups of radiologists who were experienced in mammogram interpretation but not tomosynthesis interpretation were trained by an experienced tomosynthesis reader to interpret the images. The researchers found that 997 women eligible for analysis: 780 presented for a screening mammogram and 217 presented for pre-biopsy imaging. The images of 312 (including 48 cases of biopsy-proven cancer) were assigned to the first group of radiologists and 310 (including 51 cases of biopsy-proven cancer) were assigned to the second group of radiologists. The radiologists first scored the digital mammograms alone and then scored the combined mammogram and tomosynthesis images. The accuracy of their interpretation was measured against the pathology results.
The investigators found that the diagnostic accuracy for combined tomosynthesis and digital mammography was superior to that of digital mammography alone. Compared to standard mammography, the accuracy of tomosynthesis was 7.2% better in study 1 and 6.8% better in study 2 was 6.8%. Furthermore, the recall rates for non-cancer cases for all readers significantly decreased with addition of tomosynthesis (range: 6%–67% improvement). Increased sensitivity was largest for invasive cancers (study 1: 15%; study 2: 22% in studies 1 and 2. The increased sensitivity was 3% for in situ cancers (cancers that had not spread beyond the breast) in both studies.

The authors concluded that the addition of tomosynthesis to digital mammography offers the dual benefit of significantly increased diagnostic accuracy and significantly reduced recall rates for non-cancer cases.

Reference: Radiology

See also:
New study reports screening mammograms have not reduced breast cancer deaths
Breast cancer drug reported to cause sexual dysfunction
Does ovary removal impact sexual function in older women?
Tips to revitalize sex life after 50 with traditional Chinese medicine
Hormone replacement therapy use in US continues to decline

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Comments

John Gofman, M.D., Ph.D. – a nuclear physicist and a medical doctor, and one of the leading experts in the world on the dangers of radiation – presents compelling evidence in his book, Radiation from Medical Procedures in the Pathogenesis of Cancer and Ischemic Heart Disease, that over 50 percent of the death-rate from cancer is in fact induced by x-rays. The routine practice of taking four films of each breast annually results in approximately 1 rad (radiation absorbed dose) exposure, which is about 1,000 times greater than that from a chest x-ray. Even the American Cancer Society lists high-dose radiation to the chest as a medium to high risk factor for developing cancer. Reducing exposure to medical radiation such as unnecessary mammograms would actually likely reduce mortality rates. The practice of screening mammography poses significant and cumulative risks of breast cancer, especially for premenopausal women. False positive diagnoses are as high as 89 percent, leading many women to be unnecessarily and harmfully treated by mastectomy, more radiation, or chemotherapy.
Yep - stay tuned coverage of that issue is forthcoming.