Invasive interval breast cancer rates after digital breast tomosynthesis plus synthesised mammography versus digital mammography screening (TOSYMA): 24-month follow-up of the multicentre, open-label, randomised, controlled, superiority trial.
Stefanie Weigel, Hans-Werner Hense, Veronika Weyer-Elberich et al.
✦ AI-curated · Sources linked
In 30 seconds
TOSYMA-2 was the 24-month follow-up of a multicentre, open-label, randomised superiority trial at 17 German screening sites. It compared digital breast tomosynthesis plus synthesised two-dimensional mammography with digital mammography in women aged 50–70 years whose initial screening was negative. Invasive interval cancer rates were 14·2 versus 18·6 cases per 10 000 women, respectively (adjusted OR 0·76 [95% CI 0·55-1·06]; p=0·11). The primary outcome did not reach statistical significance, although the 12-month rate was lower with tomosynthesis plus synthesised mammography.
Key findings
- Over 24 months, invasive interval cancers occurred in 70 of 49 299 women in the tomosynthesis plus s2D group and 92 of 49 456 in the digital mammography group.
- The invasive interval cancer rates were 14·2 versus 18·6 cases per 10 000 women; adjusted OR 0·76 [95% CI 0·55-1·06]; p=0·11.
- At 12 months, rates were 4·5 versus 6·3 cases per 10 000 women; OR 0·71 [95% CI 0·52-0·97].
Why it matters
Interval cancers are diagnosed after a negative screening result, so their frequency is a relevant measure of screening performance. This large randomised comparison suggests a possible reduction with tomosynthesis plus synthesised mammography, but the nonsignificant primary result means the 24-month evidence does not establish that advantage. The 12-month finding provides supportive, but secondary, evidence.
What to keep in mind
The primary outcome did not reach statistical significance; the 12-month result was a prespecified secondary outcome.