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Table 4 Breast cancer risk according to MRI percent dense volume and Cumulus and visual assessment percent dense area (Medial-Lateral Oblique view), by BRCA1/BRCA2 genetic status

From: Assessing the usefulness of a novel MRI-based breast density estimation algorithm in a cohort of women at high genetic risk of breast cancer: the UK MARIBS study

  No. women No. cancers No. pyears IRR (95% CI) P-value (adjusted age) IRR (95% CI) P-value (adjusted age, BMI & parity)
BRCA1 Carriers
MRI % dense volume 117 21 687 1.84 (0.77, 4.38) 0.17 1.02 (0.26, 4.05) 0.98
Cumulus MLO % dense area 94 16 579 2.72 (0.99, 7.48) 0.053 1.24 (0.35, 4.37) 0.74
VA MLO % dense area 94 16 579 4.03 (1.40, 11.6) 0.010 3.39 (0.94, 12.2) 0.062
BRCA2 Carriers
MRI % dense volume 69 18 385 2.06 (0.78, 5.45) 0.15 3.10 (0.77, 12.4) 0.11
Cumulus MLO % dense area 71 15 418 1.66 (0.60, 4.60) 0.33 10.4 (1.58, 68.0) 0.015
VA MLO % dense area 71 15 418 1.75 (0.62, 4.90) 0.29 3.70 (0.64, 21.2) 0.14
Non-carriers
MRI % dense volume 361 14 2,532 4.49 (1.16, 17.3) 0.030 2.54 (0.56, 11.6) 0.23
Cumulus MLO % dense area 332 7 2,367 1.13 (0.25, 5.17) 0.87 0.24 (0.04, 1.45) 0.12
VA MLO % dense area 327 7 2,336 1.45 (0.32, 6.66) 0.63 0.43 (0.08, 2.41) 0.34
  1. The non-carrier group includes those who tested negative for a known BRCA1/2 family mutation as well as those in whom no mutation was
  2. detected after a BRCA1/2 mutation screen, because of small numbers.
  3. Pyears = number of person-years in study and follow-up period
  4. IRR = incidence rate ratio for the upper two quartiles relative to the lower two quartiles (the trend test was not attempted due to the small numbers). CI = confidence intervals.