Table 1.
Patient and tumour characteristics according to type of operation
| Standard BCS (n = 3720) | Simple OPS (n = 243) | Complex OPS (n = 215) | P ¶ | |
|---|---|---|---|---|
| Patient age (years) * | 63 (23–91) | 59 (29–85) | 58 (30–81) | <0.001# |
| <41 | 149 (4.0) | 20 (8.2) | 20 (9.3) | |
| 41–50 | 620 (16.7) | 46 (18.9) | 43 (20.0) | |
| 51–65 | 1447 (38.9) | 111 (45.7) | 101 (47.0) | |
| >65 | 1504 (40.4) | 66 (27.2) | 51 (23.7) | |
| Invasive tumour size (mm) * † | 16 (1–80) | 18 (7–100) | 21 (2–86) | <0.001# |
| Tumour category‡ | <0.001 | |||
| T1 | 2686 (72.2) | 148 (60.9) | 93 (43.3) | |
| T2 | 1002 (26.9) | 89 (36.6) | 109 (50.7) | |
| T3 | 32 (0.9) | 6 (2.5) | 13 (6.0) | |
| Node category‡ | <0.001 | |||
| N0 | 2772 (74.6) | 159 (65.4) | 136 (63.3) | |
| N+ | 942 (25.4) | 84 (34.7) | 79 (36.7) | |
| Missing | 6 | 0 | 0 | |
| Histological subtype | 0.830 | |||
| Ductal | 2961 (79.9) | 200 (82.6) | 171 (80.3) | |
| Lobular | 399 (10.8) | 24 (9.9) | 24 (11.3) | |
| Other | 347 (9.4) | 18 (7.4) | 18 (8.5) | |
| Missing | 13 | 1 | 2 | |
| Nottingham histological grade | 0.062 | |||
| 1 | 688 (19.4) | 27 (12.9) | 29 (16.7) | |
| 2 | 1825 (51.6) | 117 (56.0) | 83 (47.7) | |
| 3 | 1025 (29.0) | 65 (31.1) | 62 (35.6) | |
| Missing | 182 | 34 | 41 | |
| Tumour multifocality | <0.001 | |||
| Yes | 274 (7.4) | 30 (12.7) | 28 (13.5) | |
| No | 3425 (92.6) | 207 (87.3) | 180 (86.5) | |
| Missing | 21 | 6 | 7 | |
| ER status§ | 0.018 | |||
| Positive | 3261 (87.9) | 203 (83.9) | 176 (82.6) | |
| Negative | 448 (12.1) | 39 (16.1) | 37 (17.4) | |
| Missing | 11 | 1 | 2 | |
| PR status§ | 0.319 | |||
| Positive | 2642 (71.3) | 165 (68.2) | 144 (67.6) | |
| Negative | 1063 (28.7) | 77 (31.8) | 69 (32.4) | |
| Missing | 15 | 1 | 2 | |
| HER2 amplification§ | 0.001 | |||
| Yes | 389 (10.7) | 43 (17.8) | 32 (15.4) | |
| No | 3246 (89.3) | 198 (82.2) | 176 (84.6) | |
| Missing | 85 | 2 | 7 | |
| Ki67 * § | 20 (1–97) | 27 (1–90) | 30 (1–100) | <0.001# |
| Tumour surrogate subtype | 0.003 | |||
| ER/PR+ HER2− | 2925 (80.5) | 175 (72.6) | 151 (72.9) | |
| ER/PR+ HER2+ | 285 (7.8) | 29 (12.0) | 21 (10.1) | |
| ER/PR− HER2+ | 104 (2.9) | 14 (5.8) | 11 (5.3) | |
| ER/PR− HER2− | 318 (8.8) | 23 (9.5) | 24 (11.6) | |
| Missing | 88 | 2 | 8 | |
| Radiotherapy field | <0.001 | |||
| Breast only | 3106 (83.7) | 185 (76.4) | 159 (74.0) | |
| Breast and regional lymph nodes | 604 (16.3) | 57 (23.6) | 56 (26.0) | |
| Missing | 10 | 1 | 0 | |
| Radiation dose and fractionation | 0.025 | |||
| Hypofractionation | 1640 (44.5) | 95 (39.3) | 90 (42.3) | |
| Standard fractionation | 1332 (36.2) | 88 (36.4) | 69 (32.4) | |
| Hypofractionation + boost | 345 (9.4) | 28 (11.6) | 18 (8.5) | |
| Standard fractionation + boost | 366 (9.9) | 31 (12.8) | 36 (16.9) | |
| Missing | 37 | 1 | 2 | |
| Endocrine treatment | 0.022 | |||
| Yes | 3265 (88.2) | 203 (84.2) | 179 (83.3) | |
| No | 435 (11.8) | 38 (15.8) | 36 (16.7) | |
| Missing | 20 | 2 | 0 | |
| Chemotherapy | <0.001 | |||
| Yes | 1599 (43.5) | 140 (58.3) | 141 (65.9) | |
| No | 2076 (56.5) | 100 (41.7) | 73 (34.1) | |
| Missing | 45 | 3 | 1 | |
| Neoadjuvant chemotherapy | ||||
| Yes | 168 (4.5) | 32 (13.2) | 41 (19.1) | <0.001 |
| No | 3552 (95.5) | 211 (86.8) | 174 (80.9) | |
| Anti-HER2 targeted therapy | <0.001 | |||
| Yes | 360 (9.7) | 40 (16.6) | 34 (15.8) | |
| No | 3340 (90.3) | 201 (83.4) | 181 (84.2) | |
| Missing | 20 | 2 | 0 | |
| Smallest peripheral margin (mm) * | 9 (0.1–62) | 7 (0.1–55) | 10 (0.1–45) | 0.002# |
Values in parentheses are percentages unless indicated otherwise; *values are median (range). Each tumour represents one case. Percentages may not sum to 100.0 due to rounding. †Based on histopathological assessment of specimen; neoadjuvant cases excluded. ‡Pretreatment clinical stage for neoadjuvant cases and histopathological tumour size for primary surgery. §Values derived from pretreatment core needle biopsy in neoadjuvant cases and from histopathological assessment of specimen in primary surgery. BCS, breast-conserving surgery; OPS, oncoplastic breast-conserving surgery; ER, oestrogen receptor; PR, progesterone receptor; HER2, human epidermal growth factor receptor 2. ¶χ2 or Fisher’s exact test, except #Kruskal–Wallis test.