Breast cancer detection using single-reading of breast tomosynthesis (3D-mammography) compared to double-reading of 2D-mammography: Evidence from a population-based trial.

BACKGROUND: Most population breast cancer (BC) screening programs use double-reading of 2D-mammography. We recently reported the screening with tomosynthesis or standard mammography-2 (STORM-2) trial, showing that double-read tomosynthesis (pseudo-3D-mammography) detected more BC than double-read 2D-mammography. In this study, we compare screen-detection measures for single-reading of 3D-mammography with those for double-reading of 2D-mammography, to inform screening practice. METHODS: This is a secondary analysis based on STORM-2 which prospectively compared 3D-mammography and 2D-mammography in sequential screen-readings. Asymptomatic women ≥49 years who attended population-based screening (Trento, 2013-2015) were recruited. Participants recalled at any screen-read from parallel double-reading arms underwent further testing and/or biopsy. Single-reading of 3D-mammography, integrated with acquired or synthetized 2D-mammograms, was compared to double-reading of 2D-mammograhy alone for screen-detection measures: number of detected BCs, cancer detection rate (CDR), number and percentage of false-positive recall (FPR). Paired binary data were compared using McNemar's test. RESULTS: Screening detected 90, including 74 invasive, BCs in 85 of 9672 participants. CDRs for single-reading using integrated 2D/3D-mammography (8.2 per 1000 screens; 95% CI 6.5-10.2) or 2D synthetic/3D-mammography (8.4 per 1000 screens; 95% CI: 6.7-10.4) were significantly higher than CDR for double-reading of 2D-mammography (6.3 per 1000 screens; 95% CI: 4.8-8.1), P<0.001 both comparisons. FPR% for single-read 2D/3D-mammography (2.60%; 95% CI: 2.29-2.94), or single-read 2D synthetic/3D-mammography (2.76%; 95% CI: 2.45-3.11), were significantly lower than FPR% for double-read 2D-mammography (3.42%; 95% CI: 3.07-3.80), P<0.001 and P=0.002 respectively. CONCLUSIONS: Single-reading of 3D-mammography (integrated 2D/3D or 2Dsynthetic/3D) detected more BC, and had lower FPR, compared to current practice of double-reading 2D-mammography alone - these findings have implications for population BC screening programs.

Breast cancer screening with tomosynthesis (3D mammography) with acquired or synthetic 2D mammography compared with 2D mammography alone (STORM-2): a population-based prospective study.

BACKGROUND: Breast tomosynthesis (pseudo-3D mammography) improves breast cancer detection when added to 2D mammography. In this study, we examined whether integrating 3D mammography with either standard 2D mammography acquisitions or with synthetic 2D images (reconstructed from 3D mammography) would detect more cases of breast cancer than 2D mammography alone, to potentially reduce the radiation burden from the combination of 2D plus 3D acquisitions. METHODS: The Screening with Tomosynthesis Or standard Mammography-2 (STORM-2) study was a prospective population-based screening study comparing integrated 3D mammography (dual-acquisition 2D-3D mammography or 2D synthetic-3D mammography) with 2D mammography alone. Asymptomatic women aged 49 years or older who attended population-based screening in Trento, Italy were recruited for the study. All participants underwent digital mammography with 2D and 3D mammography acquisitions, with the use of software that allowed synthetic 2D mammographic images to be reconstructed from 3D acquisitions. Mammography screen-reading was done in two parallel double-readings conducted sequentially for 2D acquisitions followed by integrated acquisitions. Recall based on a positive mammography result was defined as recall at any screen read. Primary outcome measures were a comparison between integrated (2D-3D or 2D synthetic-3D) mammography and 2D mammography alone of the number of cases of screen-detected breast cancer, the cancer detection rate per 1000 screens, the incremental cancer detection rate, and the number and percentage of false-positive recalls. FINDINGS: Between May 31, 2013, and May 29, 2015, 10 255 women were invited to participate, of whom 9672 agreed to participate and were screened. In these 9672 participants (median age 58 years [IQR 53-63]), screening detected 90 cases of breast cancer, including 74 invasive breast cancers, in 85 women (five women had bilateral breast cancer). To account for these bilateral cancers in cancer detection rate estimates, the number of screens used for analysis was 9677. Both 2D-3D mammography (cancer detection rate 8·5 per 1000 screens [82 cancers detected in 9677 screens]; 95% CI 6·7-10·5) and 2D synthetic-3D mammography (8·8 per 1000 [85 in 9677]; 7·0-10·8) had significantly higher rates of breast cancer detection than 2D mammography alone (6·3 per 1000 [61 in 9677], 4·8-8·1; p<0·0001 for both comparisons). The cancer detection rate did not differ significantly between 2D-3D mammography and 2D synthetic-3D mammography (p=0·58). Compared with 2D mammography alone, the incremental cancer detection rate from 2D-3D mammography was 2·2 per 1000 screens (95% CI 1·2-3·3) and that from 2D synthetic-3D mammography was 2·5 per 1000 (1·4-3·8). Compared with the proportion of false-positive recalls from 2D mammography alone (328 of 9587 participants not found to have cancer at assessment) [3·42%; 95% CI 3·07-3·80]), false-positive recall was significantly higher for 2D-3D mammography (381 of 9587 [3·97%; 3·59-4·38], p=0·00063) and for 2D synthetic-3D mammography (427 of 9587 [4·45%; 4·05-4·89], p<0·0001). INTERPRETATION: Integration of 3D mammography (2D-3D or 2D synthetic-3D) detected more cases of breast cancer than 2D mammography alone, but increased the percentage of false-positive recalls in sequential screen-reading. These results should be considered in the context of the trade-off between benefits and harms inherent in population breast cancer screening, including that significantly increased breast cancer detection from integrating 3D mammography into screening has the potential to augment screening benefit and also possibly contribute to overdiagnosis. FUNDING: None.

On the diagnostic accuracy of stereotactic vacuum-assisted biopsy of nonpalpable breast abnormalities. Results in a consecutive series of 769 procedures performed at the Trento Department of Breast Diagnosis.

AIMS AND BACKGROUND: To assess the diagnostic accuracy of stereotactic vacuum-assisted biopsy of nonpalpable breast lesions. METHODS AND STUDY DESIGN: 769 consecutive vacuum-assisted biopsy procedures were retrospectively reviewed. Positive predictive value for carcinoma (B5) at vacuum-assisted biopsy was assessed on the overall series and by age, lesion morphology and size, degree of suspicion and calendar period. The accuracy of vacuum-assisted biopsy was based on surgical histology or follow-up (no change at 12 months was assumed as negative). RESULTS: Lesions were depicted as isolated microcalcifications, opacity + microcalcifications, or opacity in 716 (93.1%), 28 (3.6%), or 25 (3.2%) cases, respectively. Vacuum-assisted biopsy was negative (B1 = 63; B2 = 319) in 382 (49.7%), borderline (B3) in 142 (18.5%), suspicious (B4) in 2 (0.3%), and positive (B5) in 243 (31.6%) cases (in situ = 185, 24.1%), invasive = 58 (7.5%)), respectively. Age (χ²df3 = 19.50; P <0.002), size (χ²df4 = 51.02; P = 10⁻6) and degree of suspicion (χ²df2 = 146.68; P = 10⁻6) were associated with a B5 outcome, no significant association was evident for morphology (χ²df2 = 0,47; P <0.78), whereas calendar period had a moderate but significant inverse association (χ²df2 = 6.12; P <0.04). The positive predictive value for surgically confirmed carcinoma (in situ or invasive) was 0% for B1, 0.7% for B2, 12.3% for B3, 100% for B4, 92.7% for in situ B5, and 94.6% for invasive B5. Conversion from in situ B5 to invasive was 12.3% and was insignificantly associated with size (χ²df2 = 0.95; P = 0.62) and histology grade (χ²df2 = 3.64; P = 0.16). Down-grading of vacuum-assisted biopsy lesions to a less severe histology occurred in 13 (7.2%) in situ and in 16 (28.6%) invasive carcinomas. B3 cases upgrading to more severe lesions was 0%, 4.5% or 16.0% in the presence of no, mild, or severe atypia. CONCLUSIONS: The study confirmed a good performance of vacuum-assisted biopsy, possibly influenced by the local scenario (e.g., radiologist's and pathologist's interobserver variability and sampling modality). Conflicting results with the literature may have local explanations rather than being due to inadequate performance.

Prospective study of breast tomosynthesis as a triage to assessment in screening.

There is limited evidence on the role of 3D mammography with tomosynthesis in breast screening, although early studies suggest that it may improve specificity. We prospectively evaluated the effect of integrating 3D mammography as a triage to assessment in 158 consecutive recalls to assessment (recalled in standard 2D-mammographic screening) in asymptomatic subjects. Radiologists provided 3D mammography-based opinion as to whether recall/assessment was warranted or unnecessary, and all subjects proceeded to assessment. 3D triage was positive (confirmed the need for assessment) in all 21 subjects with breast cancer (there were no false negatives), and would have avoided recall in 102 of 137 (74.4%) subjects with a negative/benign final outcome in whom 3D triage did not recommend recall. Proportion of true negative 3D triage (as a proxy for potential reduction in recalls) was slightly higher in dense than non-dense breasts, did not differ across age-groups, but was significantly associated with the type of lesion seen on imaging (being highest for distortions, asymmetric densities, and lesions with ill-defined margins). While the simulation design may have over-estimated the potential for 3D mammography triage to reduce recalls, this study clearly demonstrates its capability to improve breast screening specificity and to reduce recall rates. Future studies of 3D mammography should further assess its role as a recall-reducing strategy in screening practice and should include formal cost-analysis.