Table 3.
Joint effects of reproductive factors on breast cancer PFS
| Variables | Progression (%) | HR (95% CI)a | ||
|---|---|---|---|---|
| Age at first birth (y) | Intervals between first and second birth (y) | |||
| <23 | ≤5 | 71 (16.8) | 1.00 (reference) | |
| >5 | 11 (12.8) | 0.89 (0.46, 1.75) | ||
| ≥23 | ≤5 | 133 (18.1) | 1.00 (reference) | |
| >5 | 25 (12.6) | 0.52 (0.31, 0.89) | ||
| P for interaction | 0.351 | |||
| Age at first birth (y) | Intervals between first birth and diagnosis (y) | |||
| <23 | <10 | 5 (26.3) | 3.07 (1.00, 9.44) | |
| 10~19 | 20 (16.7) | 1.00 (reference) | ||
| ≥20 | 77 (15.7) | 1.33 (0.39, 4.55) | ||
| ≥23 | <10 | 54 (18.1) | 1.54 (0.96, 2.45) | |
| 10~19 | 88 (12.9) | 1.00 (reference) | ||
| ≥20 | 165 (15.3) | 1.29 (0.89, 1.86) | ||
| P for interaction | 0.205b/0.846c | |||
| Age at first birth (y) | Intervals between last birth and diagnosis (y) | |||
| <23 | <10 | 10 (16.4) | 1.21 (0.50, 2.94) | |
| 10~19 | 15 (18.5) | 1.00 (reference) | ||
| ≥20 | 65 (16.1) | 1.90 (0.47, 7.66) | ||
| ≥23 | <10 | 78 (17.7) | 1.40 (0.89, 2.21) | |
| 10~19 | 65 (12.2) | 1.00 (reference) | ||
| ≥20 | 138 (14.7) | 1.28 (0.86, 1.92) | ||
| P for interaction | 0.616b/0.599c | |||
Abbreviations: HR, hazard ratio; PFS, progression‐free survival.
a
Adjusted for age at diagnosis, education, menopausal status, clinical stage, ER status, HER2 status.
b
Between age at first birth and intervals between birth and diagnosis (<10 y vs 10~19 y).
c
Between age at first birth and intervals between birth and diagnosis (>20 y vs 10~19 y); Bold character indicates statistically significant result.