Table 3.
Baseline demographic, tumor, and treatment characteristics, by duration of concomitant medication use (never, fewer than six months, six or more months).
| Concomitant CYP2D6 inhibitor use among TAM users (N=960) | |||
|---|---|---|---|
| Never use (N=644) | Use <6 mos. (N=88) | Use 6+ mos. (N=228) | |
| Patient characteristics | n (%) | n (%) | n (%) |
| Age at diagnosis, years | |||
| 45–54 | 137 (21.3) | 17 (19.3) | 52 (22.8) |
| 55–69 | 289 (44.9) | 37 (42.1) | 86 (42.9) |
| 70–79 | 218 (33.9) | 34 (38.6) | 90 (39.5) |
| Year of diagnosis | |||
| 1993–1995 | 227 (35.3) | 20 (22.7) | 63 (27.6) |
| 1996–1997 | 184 (28.6) | 33 (37.5) | 87 (38.2) |
| 1998–1999 | 233 (36.2) | 35 (39.8) | 78 (34.2) |
| BMI prior to diagnosis | |||
| <25 kg/m2 | 329 (51.4) | 42 (47.7) | 110 (48.3) |
| 25–29.99 kg/m2 | 199 (31.1) | 27 (30.7) | 64 (28.1) |
| 30+ kg/m2 | 112 (17.5) | 19 (21.6) | 54 (23.7) |
| White | 619 (96.1) | 84 (95.5) | 222 (97.4) |
| Menopausal status at diagnosis | |||
| Premenopausal | 66 (10.3) | 6 (6.8) | 28 (12.3) |
| Perimenopausal | 32 (5.0) | 6 (6.8) | 17 (7.5) |
| Postmenopausal | 546 (84.8) | 76 (86.4) | 183 (80.3) |
| Tumor and treatment characteristics | |||
| Tumor stage at diagnosis | |||
| Local | 441 (68.5) | 54 (61.4) | 143 (62.7) |
| Regional | 203 (31.5) | 34 (38.6) | 85 (37.3) |
| Grade at diagnosis | |||
| Well differentiated | 102 (17.7) | 14 (18.2) | 35 (16.6) |
| Moderately differentiated | 261 (45.4) | 35 (45.5) | 94 (44.6) |
| Poorly differentiated | 179 (31.1) | 23 (29.9) | 70 (33.2) |
| Undifferentiated | 33 (5.7) | 5 (6.5) | 12 (5.7) |
| Primary radiation treatment | 444 (69.2) | 61 (69.3) | 155 (68.0) |
| Primary chemotherapy | 193 (30.1) | 28 (31.8) | 79 (34.8) |
| Median TAM duration (IQR), mos. | 57 (31–61) | 54.5 (35.5–61) | 59 (36–61) |
Abbreviations: BMI=body mass index, Mos.=months, IQR=interquartile range, TAM=tamoxifen.