Studies show that tomosynthesis identifies more breast cancers than mammography

Digital breast tomosynthesis identifies more breast cancers than conventional digital mammography, according to two studies presented at the last European Radiology Congress (ECR 2017). In addition, the rates of recall between the two modalities are comparable, according to the researchers.

Both studies examined the use of digital tomosynthesis in a screening setting. In one, researchers found digital tomosynthesis identifying 80% more cancers than digital mammography. In the other, the researchers found that the breast cancer detection rate was about 50% higher for women surveyed with digital tomosynthesis compared with women screened for digital mammography.

In an age where the question remains whether digital tomosynthesis is ready to replace digital mammography for breast cancer screening, evidence continues to grow in favor of the former.

Italian study

In the first study, researchers from the city of Reggio Emilia in northern Italy analyzed data from more than 19,000 women who were randomized to receive digital mammography or digital mammography plus digital tomosynthesis from March 2014 to March 2016. Each patient had a double screening test only once, according to researcher Dr. Valentina Lotti of Arcispedale Santa Maria Nuovain Reggio Emilia.

Women aged 45 to 70 years were randomized into random groups. The digital mammography group included 9,782 women, while the digital tomosynthesis plus digital mammography group included 9,623 women.

Digital mammography detected 45 cancers (six in situ) and digital mammography plus digital tomosynthesis detected 79 cancers (14 in situ).

The overall relative detection rate was 1.8, while the relative detection rate for cancer in situ was 2.4. The researchers found no difference in breast density. However, digital tomosynthesis showed great improvement for smaller tumors (10 mm to 20 mm), with a relative detection rate of 2.6.

“In our randomized trial, 80% more cancers were identified in the study group compared to the control group. This detection is similar to in situ, invasive, pT1 [small] cancers, and dense, fat breasts, ”said Lotti.

Norwegian study

In the following study, Dr. Tone Hovda and colleagues at Drammen Hospital in Drammen, Norway, compared the rate of recall and breast cancer detection rate after one year of screening with synthetic images and digital tomosynthesis against digital mammography in the Norwegian breast cancer screening program. They found that the rate of cancer detected by screening increased by 50% in the digital tomosynthesis group.

A total of 18,172 women aged 50-69 years living in Oslo were screened with digital tomosynthesis in 2014, while a control group of 30,883 women were screened with digital mammography.

Tabela - Tomossínte x MamografiaThe findings indicate that the rate of recall did not differ in the comparison between digital tomosynthesis and digital mammography, most likely due to a rate of recall already low in Norway.

However, the positive predictive value (PPV) of withdrawals and biopsy was higher for the experimental group than for the control group.

“It implies that the number of false positives in the recalls reduced for the tomosynthesis group, and this is an important benefit for both women and society as it reduces the burden of recalls unnecessary, ”said Dr. Hovda.

“Due to the increased rate of breast cancer detected by nearly 50% screening for those surveyed with synthetic 2D and digital tomosynthesis compared to those examined with regular 2D digital mammography and false positive reduction, digital tomosynthesis is the superior modality. ”He observed.

Concerns about the dose of radiation added from digital tomosynthesis due to the need for 2D acquisition were addressed by the use of synthesized 2D mammography, in which the 2D image is derived from digital tomosynthesis data.

Other objections to digital tomosynthesis as a tracking tool include increased reading time, increased data loading, overdiagnosis problems, and what extra cancers will be diagnosed. "All of these issues need further investigation," concluded Dr. Hovda.


Source: AuntMinnie.com


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Written by

Thiago Braga

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