Table 2. Cox proportional hazards model for disease-free survival.
| Variables | Young group | Old group | ||
|---|---|---|---|---|
| HR(95%CI) | P | HR(95%CI) | P | |
| N1-3 | 0.578 (0.350-0.953) | 0.032 | 0.271 (0.167-0.440) | <0.001 |
| Primary tumor size >5cm | 0.272 (0.136-0.545) | <0.001 | 0.359 (0.157-0.822) | 0.015 |
| Lymphovascular invasion | 0.502 (0.299-0.842) | 0.009 | 0.788 (0.433-1.434) | 0.436 |
| ER/PgR positive | 0.400 (0.149-1.078) | 0.070 | 0.720 (0.270-1.923) | 0.512 |
| HER2 positive | 0.637 (0.253-1.602) | 0.338 | 1.299 (0.628-2.683) | 0.480 |
| Adjuvant chemotherapy | 1.085 (0.374-3.144) | 0.881 | 0.939 (0.587-1.504) | 0.795 |
| Adjuvant radiotherapy | 1.621(0.986-2.666) | 0.057 | 0.985 (0.608-1.594) | 0.950 |
| Endocrine therapy | 4.021(1.378-11.729) | 0.011 | 2.530 (1.337-4.786) | 0.004 |
| ER/PgR+ and HER2- | 1.731(0.578-5.182) | 0.326 | 0.634 (0.239-1.681) | 0.360 |
Abbreviations: HR: hazard ratio; CI: confidential interval; ER: estrogen receptor; PgR: progesterone receptor; HER2: human epidermal growth factor receptor 2.