Change of mammographic density predicts the risk of contralateral breast cancer - a case-control study

Breast Cancer Research

Table 4 Odds ratio of CBC in relation to changes in mammographic density after first breast cancer

Post-diagnostic change of density
Percent density	N	OR*	95% CI	OR**	95% CI
Absolute decrease ≥10%	96	0.49	0.28 to 0.85	0.45	0.24 to 0.84
Stable (<10% decrease to <10% increase)	243	1.00	Ref.	1.00	Ref.
Absolute increase ≥10%	17	0.74	0.23 to 2.40	0.83	0.24 to 2.87
P -value for trend***		0.04		0.04
Area density	N	OR*	95% CI	OR**	95% CI
Absolute decrease ≥10 cm ²	108	0.67	0.38 to 1.16	0.54	0.30 to 0.99
Stable (<10 cm ² decrease to <10 cm ² increase)	197	1.00	Ref.	1.00	Ref.
Absolute increase ≥10 cm ²	33	0.79	0.35 to 1.78	0.71	0.30 to 1.69
P -value for trend***		0.35		0.13

* Adjusted through matching for age at diagnosis, calendar period of diagnosis, adjuvant therapy and follow-up time.
** Adjusted through matching for age at diagnosis, calendar period of diagnosis, adjuvant therapy and follow-up time, and additionally in the analyses for percent density and non-dense area at first diagnosis.
*** Trend test is based on the ordered categories of change of percent density and dense area, respectively
Patients with <10% or >90% percent mammographic density at baseline (N = 66), or those with <10 cm² or >70 cm² dense area (N = 84), were excluded, since they cannot possibly undergo changes in percent mammographic density, or dense area, of the defined magnitude A similar strategy has previously been used by others when studying changes in mammographic density [5].

ISSN: 1465-542X