Contrast-enhanced mammography for the assessment of screening recalls: a two-centre study

Abstract

Objectives: To evaluate the potential of contrast-enhanced mammography (CEM) for reducing the biopsy rate of screening recalls.

Methods: Recalled women were prospectively enrolled to undergo CEM alongside standard assessment (SA) through additional views, tomosynthesis, and/or ultrasound. Exclusion criteria were symptoms, implants, allergy to contrast agents, renal failure, and pregnancy. SA and CEM were independently evaluated by one of six radiologists, who recommended biopsy or 2-year follow-up. Biopsy rates according to SA or recombined CEM (rCEM) were compared with the McNemar's test. Diagnostic performance was calculated considering lesions with available final histopathology.

Results: Between January 2019 and July 2021, 220 women were enrolled, 207 of them (median age 56.6 years) with 225 suspicious findings analysed. Three of 207 patients (1.4%) developed mild self-limiting adverse reactions to iodinated contrast agent. Overall, 135/225 findings were referred for biopsy, 90/225 by both SA and rCEM, 41/225 by SA alone and 4/225 by rCEM alone (2/4 being one DCIS and one invasive carcinoma). The rCEM biopsy rate (94/225, 41.8%, 95% CI 35.5-48.3%) was 16.4% lower (p < 0.001) than the SA biopsy rate (131/225, 58.2%, 95% CI 51.7-64.5%). Considering the 124/135 biopsies with final histopathology (44 benign, 80 malignant), rCEM showed a 93.8% sensitivity (95% CI 86.2-97.3%) and a 65.9% specificity (95% CI 51.1-78.1%), all 5 false negatives being ductal carcinoma in situ detectable as suspicious calcifications on low-energy images.

Conclusions: Compared to SA, the rCEM-based work-up would have avoided biopsy for 37/225 (16.4%) suspicious findings. Including low-energy images in interpretation provided optimal overall CEM sensitivity.

Key points: • The work-up of suspicious findings detected at mammographic breast cancer screening still leads to a high rate of unnecessary biopsies, involving between 2 and 6% of screened women. • In 207 recalled women with 225 suspicious findings, recombined images of contrast-enhanced mammography (CEM) showed a 93.8% sensitivity and a 65.9% specificity, all 5 false negatives being ductal carcinoma in situ detectable on low-energy images as suspicious calcifications. • CEM could represent an easily available one-stop shop option for the morphofunctional assessment of screening recalls, potentially reducing the biopsy rate by 16.4%.

Keywords: Biopsy, needle; Breast neoplasms; Ductal carcinoma in situ; Mammography, contrast-enhanced; Mass screening.

Fig. 1

Study phases and endpoint analyses

Fig. 2

True positive case at contrast-enhanced mammography. A 53-year-old woman was recalled for suspicious calcifications in the left breast. An ultrasound-guided core needle biopsy was performed, resulting in a diagnosis of grade 2 ductal carcinoma in situ. Low-energy images (panels A and C) show multiple groups of pleomorphic calcifications in the left upper-outer quadrant (white arrows in light blue rectangles). Recombined images (panels B and D, light blue rectangles) revealed an area of non-mass enhancement involving the whole upper-outer quadrant

Fig. 3

False positive case at contrast-enhanced mammography. A 69-year-old woman was recalled for a suspicious finding in the right breast, subsequently diagnosed as adenosis. Low-energy images (panels A and C) show a small opacity in the right upper-outer quadrant (light blue rectangles) with a correlated sub-centimetric enhancement focus on the recombined images (panels B and D, light blue rectangles)

Fig. 4

True negative case at contrast-enhanced mammography. A 58-year-old woman was recalled for a suspicious retroareolar irregular opacity in the right breast (panel A and C, light blue rectangles). An ultrasound-guided core needle biopsy was performed, leading to a diagnosis of apocrine metaplasia. The absence of enhancement foci on recombined images (panels B and D) would have oriented the referral to follow-up

Fig. 5

True negative case at contrast-enhanced mammography. A 49-year-old woman was recalled for a suspicious asymmetry in the upper quadrants of the left breast, not observable on the craniocaudal view (low-energy image, panel A) but definitely noticeable on the mediolateral oblique view (low-energy image, panel C, light blue rectangle). Standard assessment referred this finding to ultrasound-guided core needle biopsy, leading to a diagnosis of fibrosis. Conversely, the absence of enhancement in recombined images, both on the whole craniocaudal view (panel B) and in correspondence of the suspicious area on the mediolateral oblique view (panel D) would have oriented the work-up to a normal result with referral to re-screening at a 2-year interval

Fig. 6

False negative case at contrast-enhanced mammography. A 67-year-old woman was recalled for a suspicious group of pleomorphic calcifications in the in the upper quadrants of the right breast, subsequently diagnosed as a grade 2 ductal carcinoma in situ, clearly visible on low-energy contrast-enhanced mammography images (panels A and C, light blue rectangles) but not associated with any enhancement on recombined images (panels B and D)