Table 3.
Tumor and surgical characteristics for 423 cases with breast cancer or carcinoma in situ undergoing BCS in two hospitals
| Variable | Cases treated in high-volume hospital (n = 322) | Cases treated in low-volume hospital (n = 101) | p value |
|---|---|---|---|
| Age at time of surgery, median (IQR), years | 57 (51–65) | 59 (53–69) | 0.01 |
| BMI, mean±SD, kg/m2 | 24.8±3.6 | 25.7±5.0 | 0.06 |
| Smoker, yes, n (%) | 44 (13.7) | 13 (12.9) | 0.84 |
| Cup size, n (%) | 0.73 | ||
| A–B | 94 (29.2) | 29 (28.7) | |
| C–D | 159 (49.4) | 48 (47.5) | |
| E–I | 67 (20.8) | 16 (15.8) | |
| Missing | 2 (0.6) | 8 (7.9) | |
| Tumor localization, n (%) | 0.56 | ||
| Upper inner quadrant | 51 (15.8) | 16 (15.8) | |
| Lower inner quadrant | 32 (9.9) | 12 (11.9) | |
| Upper outer quadrant | 141 (43.8) | 44 (43.6) | |
| Lower outer quadrant | 58 (18.0) | 14 (13.9) | |
| Central | 34 (10.6) | 10 (9.9) | |
| Overlapping | 6 (1.9) | 5 (5.0) | |
| Histological finding, n (%) | 0.06 | ||
| DCIS | 48 (14.9) | 21 (20.8) | |
| IDC | 185 (57.5) | 42 (41.6) | |
| IDLC | 51 (15.8) | 17 (16.8) | |
| ILC | 22 (6.8) | 12 (11.9) | |
| Othera | 16 (4.3) | 9 (6.2) | |
| cT categoryb, n (%) | 0.01 | ||
| 1a–c | 174 (54) | 50 (49.5) | |
| 2 | 94 (29.2) | 24 (23.7) | |
| 3–4 | 4 (1.2) | 3 (3.0) | |
| is | 50 (15.5) | 24 (23.8) | |
| cN status, n (%) | 0.62 | ||
| Positive | 31 (9.6) | 6 (5.9) | |
| Negative | 291 (90.4) | 95 (94.1) | |
| Neo-adjuvant therapy, n (%) | 89 (27.6) | 20 (19.8) | 0.12 |
| MRI before surgery, n (%) | 242 (75.2) | 63 (62.4) | 0.04 |
| Maximal radiological diameter of disease, median (IQR), mm | 16 (10–24) | 12 (0–57) | 0.00 |
| Radiological underestimation of tumor size, median (IQR), mm | 4 (2–11) | 7 (3–15) | 0.04 |
| Maximal pathological lumpectomy diameter, median IQR), mm | 53 (45–65) | 70 (53–85) | 0.00 |
| Postoperative maximal pathological tumor size, median (IQR), mm | 16 (9–24) | 18 (10–31) | 0.13 |
| Focally positive margins, n (%) | 33 (10.2) | 7 (6.9) | 0.32 |
| Non-radical resection (positive margins)c, n (%) | 19 (5.9) | 15 (14.9) | 0.00 |
| Positive margins: DCIS, n (%) | 4 (21.1) | 1 (6.7) | |
| Positive margins: invasive tumor, n (%) | 15 (78.9) | 14 (93.3) | |
| Presence of DCIS component in resection, n (%) | 208 (64.3) | 53 (52.5) | 0.02 |
BCS, breast-conserving surgery; IQR, interquartile range; BMI, body mass index; SD, standard deviation; IDC, invasive ductal carcinoma; IDLC, invasive ductolobular carcinoma; ILC, invasive lobular carcinoma; DCIS, ductal carcinoma in situ; cT, clinical primary tumor size; cN, clinical lymph node status; MRI, magnetic resonance imaging.
aLobular carcinoma in situ, mucinous carcinoma, metaplastic carcinoma, papillary carcinoma, and tubular carcinoma.
bTNM classification following the American Joint Committee on Cancer Eighth Edition Cancer Staging.
cResection was considered incomplete if the margins were more than focally positive. Focally positive margins were considered as negative margins.