Table S1.
Summary of characteristics distribution in BCS or mastectomy underwent postoperative radiotherapy before and after PSM
| Characteristics | BCS n=379 | Mastectomy n=397 | P-value | BCS n=196 | Mastectomy n=196 | P-value | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| N | % | N | % | N | % | N | % | |||
| Before PSM | After PSM | |||||||||
| Age (years) | 0.315 | 1.000 | ||||||||
| ≤40 | 93 | 24.5 | 110 | 27.7 | 47 | 24.0 | 47 | 24.0 | ||
| >40 | 286 | 75.5 | 287 | 72.3 | 149 | 76.0 | 149 | 76.0 | ||
| Primary tumor site | 0.001 | 1.000 | ||||||||
| OQ | 287 | 75.7 | 271 | 68.3 | 153 | 78.1 | 153 | 78.1 | ||
| IQ/CQ | 84 | 22.2 | 96 | 24.2 | 40 | 20.4 | 40 | 20.4 | ||
| Unknown | 8 | 2.1 | 30 | 7.5 | 3 | 1.5 | 3 | 1.5 | ||
| Menopausal status | 0.057 | 1.000 | ||||||||
| Premenopausal/perimenopause | 239 | 63.1 | 276 | 69.5 | 138 | 70.4 | 138 | 70.4 | ||
| Postmenopausal | 140 | 36.9 | 121 | 30.5 | 58 | 29.6 | 58 | 29.6 | ||
| Tumor size | 0.000 | 1.000 | ||||||||
| ≤3 cm | 348 | 91.8 | 300 | 83.5 | 243 | 88.7 | 243 | 88.7 | ||
| >3 cm | 31 | 8.2 | 97 | 16.5 | 31 | 11.3 | 31 | 11.3 | ||
| Number of positive axillary LNs | 0.000 | 1.000 | ||||||||
| 1–2 | 328 | 86.5 | 297 | 74.8 | 170 | 86.7 | 170 | 86.7 | ||
| 3 | 51 | 13.5 | 100 | 25.2 | 26 | 13.3 | 26 | 13.3 | ||
| Histological grade | 0.568 | 1.000 | ||||||||
| I/II | 226 | 59.6 | 222 | 55.9 | 119 | 60.7 | 119 | 60.7 | ||
| III | 145 | 38.3 | 165 | 41.6 | 75 | 38.3 | 75 | 38.3 | ||
| Unknown | 8 | 2.1 | 10 | 2.5 | 2 | 2.9 | 2 | 2.9 | ||
| Lymphovascular invasion status | 0.433 | 1.000 | ||||||||
| No | 231 | 60.9 | 231 | 58.2 | 166 | 60.6 | 166 | 60.6 | ||
| Yes | 148 | 39.1 | 166 | 41.8 | 108 | 39.4 | 108 | 39.4 | ||
| Molecular subtype | 0.000 | 1.000 | ||||||||
| Luminal A | 118 | 31.1 | 73 | 18.4 | 52 | 26.5 | 52 | 26.5 | ||
| Luminal B/Her-2 - | 154 | 40.6 | 143 | 36.0 | 82 | 41.8 | 82 | 41.8 | ||
| Luminal B/Her-2+ | 66 | 17.4 | 82 | 20.7 | 38 | 19.4 | 38 | 19.4 | ||
| Her-2 enriched | 12 | 3.2 | 39 | 9.8 | 5 | 2.6 | 5 | 2.6 | ||
| TNBC | 29 | 7.7 | 60 | 15.1 | 19 | 9.7 | 19 | 9.7 | ||
Note: P-values were calculated using chi-square test.
Abbreviations: BCS, breast conserving surgery; PSM, propensity score match; OQ, outer quadrant; IQ, inner quadrant; CQ, central quadrant; LN, lymph node; LVI, lymphovascular invasion; Her-2, human epidermal growth factor receptor-2; TNBC, triple-negative breast cancer.