Breast density change as a predictive surrogate for response to adjuvant endocrine therapy in hormone receptor positive breast cancer

Table 2 Distribution of mammographic density before and after treatment and change in mammographic density

Variable	Mean (range)	Number	%
PreMD, %*	35.77 ± 13.94 (5.42-82.18)
< 10%		26	2.4
10% - 25%		223	20.9
25% - 50%		641	60.2
≥ 50%		175	16.4
PostMD, %	29.84 ± 12.12 (3.90-72.31)
< 10%		35	3.3
10% - 25%		364	34.2
25% - 50%		611	57.4
≥ 50%		55	5.2
MDR, %	5.92 ± 7.08 (-17.2-36.9)
< 5%		505	47.4
≥ 5%		560	52.6
< 0% (increased)		190	17.8
0%-5%		314	29.5
5%-10%		276	25.9
≥ 10%		285	26.8
MDRR, %
< 15%		486	45.6
≥ 15%		579	54.4
< 0% (increased)		190	17.8
0%-10%		198	18.6
10%-25%		356	33.4
≥ 25%		321	30.1

Mammographic density reduction (MDR) and MDR ratio (MDRR) ((preMD - postMD) × 100/preMD) were initially evaluated as continuous variables then as dichotomized, quartered variables. Patients were divided into two groups (MDR < 5%, 5% ≤ MDR), and four groups (MDR ≥ 10%, 5% ≤ MDR < 10%, 0 ≤ MDR < 5%, and MDR < 0% (increased MD)). PreMD: initial preoperative mammographic density; PostMD: density of follow up mammography after 8 to 20 months of hormone therapy.

ISSN: 1465-542X