Table 1 Study population characteristics by tumor AR expression
Characteristic | AR positivea (n = 2475) | AR negativea (n = 546) | P valueb |
|---|---|---|---|
Treatment assignment, % | – | ||
Tamoxifen | 21 | 21 | |
Letrozole | 22 | 18 | |
Tamoxifen ➔ Letrozole | 21 | 21 | |
Letrozole ➔ Tamoxifen | 21 | 20 | |
Tamoxifen (2-arm period) | 7 | 12 | |
Letrozole (2-arm period) | 8 | 10 | |
Received chemotherapy, % | 29 | 32 | 0.21 |
Local therapy, % | < 0.001 | ||
Breast conserving surgery with radiation therapy | 64 | 55 | |
Breast conserving surgery without radiation therapy | 4 | 5 | |
Mastectomy with radiation therapy | 12 | 18 | |
Mastectomy without radiation therapy | 20 | 22 | |
Age at randomization, mean (SD) | 62 (8) | 62 (8) | 0.10 |
Tumor size, % | < 0.001 | ||
≤ 2 cm | 67 | 54 | |
> 2–< 5 cm | 29 | 41 | |
≥ 5 cm | 3 | 4 | |
Missing | 1 | 1 | |
Number of lymph nodes positive, % | 0.15 | ||
0 | 63 | 58 | |
1–3 | 26 | 30 | |
4–9 | 7 | 8 | |
10+ | 3 | 3 | |
Not evaluable | 1 | 1 | |
Tumor grade, % | < 0.001 | ||
1 | 22 | 14 | |
2 | 57 | 50 | |
3 | 21 | 36 | |
Missing | 0 | 1 | |
ER expression (%), median (25th–75th percentile) | 95 (90–99) | 90 (75–95) | < 0.001 |
PR expression (%), median (25th–75th percentile) | 70 (20–90) | 50 (5–84) | < 0.001 |
Missing, n | 21 | 8 | |
Ki67 expression (%), median (25th–75th percentile) | 12 (6–18) | 12 (6–20) | 0.07 |
Missing, n | 59 | 31 | |
HER2 expression, % | 0.04 | ||
Positive | 5 | 8 | |
Negative | 95 | 92 | |
Missing | 0 | 0 | |