Table 1.
Characteristics of the patients a
| Variables | Number of patients (%) |
|---|---|
| All |
9,415 (100) |
| Age at surgery, yr |
|
| <35 |
309 (3.3) |
| 35 to 50 |
3,809 (40.5) |
| 51 to 65 |
3,637 (38.6) |
| >65 |
1,660 (17.6) |
| Menopausal status |
|
| Premenopausal |
4,278 (45.4) |
| Postmenopausal |
5,137 (54.6) |
| Histological tumor subtype |
|
| Ductal |
7,114 (75.6) |
| Lobular |
1,150 (12.2) |
| Mixed |
397 (4.2) |
| Other |
754 (8.0) |
| pT |
|
| pT1 |
6,601 (70.1) |
| pT2 |
2,514 (26.7) |
| pT3/4 |
300 (3.2) |
| pN |
|
| pNx |
309 (3.3) |
| pN0 |
5,201 (55.2) |
| pN+ |
3,905 (41.5) |
| Tumor grade |
|
| G1 |
2,160 (22.9) |
| G2 |
4,930 (52.4) |
| G3 |
2,007 (21.3) |
| NA |
318 (3.4) |
| ER positivity |
|
| ≥20% |
9,228 (98.0) |
| <20% |
187 (2.0) |
| PgR positivity |
|
| ≥20% |
6,758 (71.8) |
| <20% |
2,657 (28.2) |
| Ki-67 level |
|
| <14% |
3,169 (33.7) |
| 14% to 19% |
2,276 (24.2) |
| ≥20% |
3,970 (42.2) |
| PVI |
|
| Absent |
7,039 (74.8) |
| Present |
2,376 (25.2) |
| Surgery |
|
| Quadrantectomy |
7,777 (82.6) |
| Mastectomy |
1,638 (17.4) |
| Radiotherapy |
|
| No |
1,416 (15.0) |
| Yes |
7,999 (85.0) |
| Chemotherapy |
|
| No |
6,386 (67.8) |
| Yes |
3,029 (32.2) |
| Competing riskb |
|
| No events |
7,149 (75.9) |
| Locoregional relapse |
592 (6.3) |
| Distant metastasis |
852 (9.0) |
| Other | 822 (8.7) |
aER, Estrogen receptor; NA, Not applicable; PgR, Progesterone receptor; pN, Pathologic node stage; pT, Pathologic tumor stage; PVI, Peritumoral vascular invasion. bDuring a median follow-up time, estimated in nonevents, of 8.1 years (IQR = 6.1 to 10.2 years).