Table 1. Baseline patient characteristics.
| Characteristics | Serum 25(OH)D status after 5-yr adjuvant endocrine therapy | |||
|---|---|---|---|---|
| Deficient (n = 242) | Sufficient (n = 213) | p-value | ||
| Age (yr) | 50.480 ± 10.408 | 53.740 ± 9.842 | 0.001 | |
| < 50 | 145 (59.9) | 74 (34.7) | < 0.001 | |
| ≥ 50 | 97 (40.1) | 139 (65.3) | ||
| BMI | 24.31 ± 3.57 | 24.50 ± 3.71 | 0.580 | |
| Serum 25(OH)D level after 5-yr adjuvant endocrine therapy (ng/mL) | 13.610 ± 3.792 | 29.350 ± 8.959 | < 0.001 | |
| Adjuvant endocrine therapy | < 0.001 | |||
| Tamoxifen | 165 (68.2) | 87 (40.8) | ||
| Anastrozole | 48 (19.8) | 69 (32.4) | ||
| Letrozole | 29 (12.0) | 57 (26.8) | ||
| Histologic subtype | 0.481 | |||
| IDC | 210 (86.8) | 180 (84.5) | ||
| ILC | 8 (3.3) | 12 (5.6) | ||
| Othera | 24 (9.9) | 21 (9.9) | ||
| Surgery | 0.001 | |||
| BCS | 142 (58.7) | 156 (73.2) | ||
| MRM | 100 (41.3) | 57 (26.8) | ||
| Tumor size (cm) | 2.129 ± 1.365 | 1.915 ± 1.224 | 0.081 | |
| ≤ 2 | 143 (59.1) | 146 (68.5) | 0.102 | |
| > 2, ≤ 5 | 92 (38.0) | 61 (28.6) | ||
| > 5 | 7 (2.9) | 6 (2.8) | ||
| No. of axillary LN metastases | 1.150 ± 2.883 | 1.270 ± 2.990 | 0.677 | |
| 0 | 170 (70.2) | 147 (69.0) | 0.493 | |
| 1–3 | 48 (19.8) | 39 (18.3) | ||
| 4–9 | 16 (6.6) | 22 (10.3) | ||
| ≥ 10 | 8 (3.3) | 5 (2.3) | ||
| No. of retrieved axillary LNs | 14.600 ± 6.086 | 14.370 ± 6.239 | 0.687 | |
| Histologic grade | 0.814 | |||
| 1 | 103 (42.6) | 97 (45.5) | ||
| 2 | 99 (40.9) | 83 (39.0) | ||
| 3 | 40 (16.5) | 33 (15.5) | ||
| Lymphatic invasion | 0.949 | |||
| No | 188 (77.7) | 166 (77.9) | ||
| Yes | 54 (22.3) | 47 (22.1) | ||
| Vascular invasion | 0.717 | |||
| No | 235 (97.1) | 208 (97.7) | ||
| Yes | 7 (2.9) | 5 (2.3) | ||
| Progesterone receptor | 0.251 | |||
| Negative | 43 (17.8) | 47 (22.1) | ||
| Positive | 199 (82.2) | 166 (77.9) | ||
| HER2 | 0.389 | |||
| Negative | 205 (84.7) | 174 (81.7) | ||
| Positive | 37 (15.3) | 39 (18.3) | ||
| p53 | 0.849 | |||
| Negative | 196 (81.0) | 174 (81.7) | ||
| Positive | 46 (19.0) | 39 (18.3) | ||
| Ki-67 (%) | 0.887 | |||
| < 14 | 130 (53.7) | 113 (53.1) | ||
| ≥ 14 | 112 (46.3) | 100 (46.9) | ||
| Adjuvant radiotherapy | 0.001 | |||
| No | 83 (34.3) | 44 (20.7) | ||
| Yes | 159 (65.7) | 169 (79.3) | ||
| Adjuvant chemotherapy | 0.444 | |||
| No | 138 (57.0) | 129 (60.6) | ||
| Yes | 104 (43.0) | 84 (39.4) | ||
| Adjuvant trastuzumab use | 0.354 | |||
| No | 228 (94.2) | 196 (92.0) | ||
| Yes | 14 (5.8) | 17 (8.0) | ||
| Season of patient's blood sampling | 0.631 | |||
| Spring | 59 (24.4) | 55 (25.8) | ||
| Summer | 62 (25.6) | 56 (26.3) | ||
| Autumn | 60 (24.8) | 59 (27.7) | ||
| Winter | 61 (25.2) | 43 (20.2) | ||
| Follow up duration (mo) | 109.580 ± 28.921 | 100.560 ± 23.672 | < 0.001 | |
| Follow up duration (mo) (from 5 years after diagnosis) | 49.540 ± 28.920 | 40.530 ± 23.698 | < 0.001 | |
Data are presented as mean ± standard deviation or number (%)
BMI = body mass index; 25(OH)D = 25-hydroxyvitamin D; IDC = invasive ductal carcinoma; ILC = invasive lobular carcinoma; BCS = breast conserving surgery; MRM = modified radical mastectomy; LN = lymph node; HER2 = human epidermal growth factor receptor 2.
aCribriform, medullary, micropapillary, mucinous, papillary, tubular subtype.