Table 2

Change in mammographic features after treatment with tamoxifen or placebo

Percentage of women changing to a parenchymal pattern of lower radiologic densityMean reduction in the estimated percentage of the breast showing radiological densities
Tamoxifen % (na)Placebo % (n)PbTamoxifen Mean ± SD (n)Placebo Mean ± SD (n)Pb
All women44.4 (36)15.2 (33)0.010−9.4 ± 12.0 (36)−3.6 ± 5.3 (33)0.010c
Age at baseline (yr)
<5066.7 (21)18.8 (16)0.007−12.1 ± 11.0 (21)−3.6 ± 4.5 (16)0.003c
≥5013.3 (15)11.8 (17)1−5.7 ± 12.6 (15)−3.5 ± 6.2 (17)0.540d
Duration of treatment (yr)
1.0–3.438.5 (13)6.7 (15)0.069−6.9 ± 11.1 (13)−3.3 ± 3.5 (15)0.282c
3.5–5.047.8 (23)22.2 (18)0.114−10.9 ± 12.4 (23)−3.8 ± 6.6 (18)0.024c
  • a Total number of women in category.

  • b Fisher’s exact test. All Ps are two-sided.

  • c t test with unequal variances.

  • d t test with equal variances.