Table 1. Characteristics of study participants.
| Characteristics | Overall (n = 11,452) | Stable (n = 8,786) | 1 SD elevated* (n = 2,666) | p-value | ||
|---|---|---|---|---|---|---|
| Age (yr) | 49.3 ± 9.8 | 49.3 ± 9.7 | 49.5 ± 10.1 | 0.59 | ||
| Pathologic T stage | ||||||
| In situ | 28 (0.2) | 21 (0.2) | 7 (0.3) | |||
| T1 | 6,997 (61.1) | 5,472 (62.3) | 1,525 (57.2) | |||
| T2 | 3,945 (34.5) | 2,954 (33.6) | 991 (37.2) | |||
| T3 | 445 (3.9) | 310 (3.5) | 135 (5.1) | |||
| T4 | 13 (0.1) | 6 (0.1) | 7 (0.3) | |||
| Unknown | 24 (0.2) | 23 (0.3) | 1 (0.0) | |||
| Pathologic N stage | < 0.01 | |||||
| N0 | 7,286 (63.6) | 5,823 (66.3) | 1,463 (54.9) | |||
| N1 | 2,980 (26) | 2,155 (24.5) | 825 (30.9) | |||
| N2 | 747 (6.5) | 514 (5.9) | 233 (8.7) | |||
| N3 | 410 (3.6) | 271 (3.1) | 139 (5.2) | |||
| Unknown | 29 (0.3) | 23 (0.3) | 6 (0.2) | |||
| Subtype | < 0.01 | |||||
| Luminal A (ER or PR+/HER2−) | 7,504 (65.5) | 5,815 (66.2) | 1,689 (63.4) | |||
| Luminal B (ER or PR+/HER2+) | 1,209 (10.6) | 929 (10.6) | 280 (10.5) | |||
| HER2+ (ER and PR−/HER2+) | 1,070 (9.3) | 815 (9.3) | 255 (9.6) | |||
| TNBC (ER and PR−/HER2−) | 1,432 (12.5) | 1,040 (11.8) | 392 (14.7) | |||
| Unknown | 237 (2.1) | 187 (2.1) | 50 (1.9) | |||
| Treatment | ||||||
| Chemotherapy | < 0.01 | |||||
| No | 4,020 (35.1) | 3,373 (38.4) | 647 (24.3) | |||
| Yes | 7,373 (64.4) | 5,359 (61) | 2,014 (75.5) | |||
| Unknown | 59 (0.5) | 54 (0.6) | 5 (0.2) | |||
| Radiation therapy | < 0.01 | |||||
| No | 2,858 (25.0) | 2,259 (25.7) | 599 (22.5) | |||
| Yes | 8,505 (74.3) | 6,447 (73.4) | 2,058 (77.2) | |||
| Unknown | 89 (0.8) | 80 (0.9) | 9 (0.3) | |||
| Hormone therapy | < 0.01 | |||||
| No | 2,518 (22.0) | 1,879 (21.4) | 639 (24.0) | |||
| Yes | 8,831 (77.1) | 6,815 (77.6) | 2,016 (75.6) | |||
| Unknown | 103 (0.9) | 92 (1.0) | 11 (0.4) | |||
| Baseline CA15-3 (U/mL) | 10.0 (4.5) | 9.6 (4.3) | 11.4 (5.0) | < 0.01 | ||
Values are presented as mean ± standard deviation or number (%).
SD = standard deviation; ER = estrogen receptor; PR = progesterone receptor; HER2 = human epidermal growth factor 2; CA15-3 = cancer antigen 15-3; TNBC = triple negative breast cancer.
*Elevated ≥ 1 SD of baseline CA15-3 (4.5).