Table 4.
Predictive impact of mammographic density reduction (MDR) on recurrence-free survival
| Variable | Hazard ratio | 95% Confidence interval | P-value |
|---|---|---|---|
| Age, yr (continuous) | 0.99 | 0.96, 1.02 | 0.393 |
| MDR | |||
| ≥ 10% (reference) | 1.00 | 0.101 | |
| 5-10% | 1.33 | 0.67, 2.65 | 0.413 |
| 0-5% | 1.92 | 1.01, 3.64 | 0.048 |
| < 0% (increased) | 2.26 | 1.10, 4.64 | 0.027 |
| Size, cm (continuous) | 1.19 | 1.05, 1.35 | 0.006 |
| Lymph node positive | 2.02 | 1.20, 3.40 | 0.008 |
| High histologic grade | 1.29 | 0.78, 2.16 | 0.323 |
| Chemotherapy | 0.79 | 0.39, 1.60 | 0.520 |
| Ki-67 ≥ 10% | 1.77 | 1.05, 3.00 | 0.033 |
Cox proportional hazard regression model for recurrence-free survival. Risk of recurrence was analyzed using the group with the greatest reduction (MDR ≥ 10%) as the reference. MDR: absolute mammographic density reduction (pre-treatment - post-treatment).