In the German TOSYMA trial reported in The Lancet Oncology, Heindel et al found that screening with digital breast tomosynthesis plus synthesized mammography was superior in detecting invasive breast cancer vs standard digital mammography.
As stated by the investigators, “Two-dimensional (2D) full-field digital mammography is the current standard of breast cancer screening. Digital breast tomosynthesis generates pseudo–three-dimensional datasets of the breast from which synthesized 2D mammograms can be reconstructed. This innovative approach reduces the likelihood of overlapping breast tissues that can conceal features of malignancy.”
Study Details
The multicenter open-label trial enrolled women aged 50 to 69 years who had been invited to participate in a population-wide, quality-controlled mammography screening program. A total of 99,689 women were randomly assigned between July 2018 and December 2020 to receive digital breast tomosynthesis plus synthesized 2D mammography (n = 49,804) or digital mammography (n = 49,830). The primary endpoints were the detection rate of invasive breast cancer and invasive interval cancer rate at 24 months; analysis was performed in the modified full-analysis set, consisting of all randomly assigned participants who underwent either type of screening examination. Interval cancer rates are to be reported in the follow-up study.
The results from this study indicate that the detection rate for invasive breast cancer was significantly higher with digital breast tomosynthesis plus [synthesized] 2D mammography than digital mammography alone.— Heindel et al
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Key Findings
Among women with evaluable primary endpoint data, invasive breast cancers were detected in 354 of 49,715 women (detection rate = 7.1 cases per 1,000 women screened) in the digital breast tomosynthesis plus synthesized 2D group vs 240 of 49,762 women (detection rate = 4.8 cases per 1,000 women screened) in the digital mammography group (odds ratio [OR] = 1.48, 95% confidence interval [CI] = 1.25–1.75, P < .0001).
Detection rates of pT1 tumors (≤ 20 mm in largest dimension) were 5.1 vs 3.0 per 1,000 women screened (OR = 1.73, 95% CI = 1.41–2.13). Detection rates of ductal carcinoma in situ were 1.2 vs 1.3 per 1,000 women screened (OR = 0.94, 95% CI = 0.65–1.35). Recall rates were 4.9% vs 5.1% (OR = 0.98, 95% CI = 0.92–1.03).
A total of 23 device deficiencies in the digital breast tomosynthesis plus synthesized 2D group vs 5 in the digital mammography group were reported. No serious adverse events were reported.
The investigators concluded, “The results from this study indicate that the detection rate for invasive breast cancer was significantly higher with digital breast tomosynthesis plus [synthesized] 2D mammography than digital mammography alone. Evaluation of interval cancer rates in the follow-up study will further help to investigate incremental long-term benefits of digital breast tomosynthesis screening.”
Walter Heindel, MD, of the University of Münster and University Hospital Münster, is the corresponding author for The Lancet Oncology article.
Disclosure: The study was funded by the German Research Foundation. For full disclosures of the study authors, visit thelancet.com.
