by Marthe Larsen,
Elsebeth Lynge, Christoph I. Lee, Kristina Lång, Solveig Hofvind
The Breast: VOLUME 69, P306-311, JUNE
2023 (Published: March 21, 2023)
Purpose
The European
Society on Breast Imaging has recommended supplemental magnetic resonance
imaging (MRI) every two to four years for women with mammographically dense
breasts. This may not be feasible in many screening programs. Also, the
European Commission Initiative on Breast Cancer suggests not implementing
screening with MRI. By analyzing interval cancers and time from screening to
diagnosis by density, we present alternative screening strategies for women
with dense breasts.
Methods
Our BreastScreen
Norway cohort included 508 536 screening examinations, including 3125
screen-detected and 945 interval breast cancers. Time from screening to
interval cancer was stratified by density measured by an automated software and
classified into Volpara Density Grades (VDGs) 1–4. Examinations with volumetric
density ≤3.4% were categorized as VDG1, 3.5%–7.4% as VDG2, 7.5%–15.4% as VDG3,
and ≥15.5% as VDG4. Interval cancer rates were also determined by continuous
density measures.
Results
Median time from
screening to interval cancer was 496 (IQR: 391–587) days for VDG1, 500 (IQR:
350–616) for VDG2, 482 (IQR: 309–595) for VDG3 and 427 (IQR: 266–577) for VDG4.
A total of 35.9% of the interval cancers among VDG4 were detected within the
first year of the biennial screening interval. For VDG2, 26.3% were detected
within the first year. The highest annual interval cancer rate (2.7 per 1000
examinations) was observed for VDG4 in the second year of the biennial
interval.
Conclusions
Annual screening of
women with extremely dense breasts may reduce the interval cancer rate and
increase program-wide sensitivity, especially in settings where supplemental
MRI screening is not feasible.
