TABLE 1.
Distribution of clinical and tumor characteristics by early discontinuation versus completion of tamoxifen therapy among 4,503 premenopausal women with ER-positive breast cancer in a population-based cohort of premenopausal women diagnosed with first primary breast cancer, ProBe CaRe study (2002–2011).
| Patient and tumor characteristics | Early Discontinuation | Complete Therapy |
|---|---|---|
| N (%) | N (%) | |
| Total | 1001 (22) | 3502 (78) |
| Mean follow-up (sd) | 6.6 (2.8) | 7.6 (2.4) |
| Recurrence | ||
| Yes | 202 (20) | 388 (11) |
| No | 799 (80) | 3144 (89) |
| Switched from Tamoxifen to AI | ||
| TAM to AI | 306 (30) | 1502 (42) |
| TAM only | 705 (70) | 2087 (58) |
| Age at diagnosis | ||
| <35 | 64 (6.4) | 146 (4.2) |
| 35–39 | 108 (11) | 366 (10) |
| 40–44 | 228 (23) | 877 (25) |
| 45–49 | 360 (36) | 1276 (36) |
| 50+ | 241 (24) | 837 (24) |
| Stage at diagnosis | ||
| Stage I | 277 (28) | 885 (25) |
| Stage II | 506 (51) | 1935 (55) |
| Stage III | 214 (21) | 664 (19) |
| Tumor Diameter | ||
| < 2cm | 514 (51) | 1834 (52) |
| 2 to <5cm | 436 (44) | 1488 (42) |
| ≥ 5cm | 49 (4.9) | 180 (5.1) |
| Number of metastatic lymph nodes | ||
| 0 | 392 (39) | 1280 (37) |
| 1 | 235 (24) | 903 (26) |
| 2 | 114 (11) | 455 (13) |
| 3+ | 258 (26) | 854 (24) |
| Histologic grade | ||
| I | 199 (21) | 742 (21) |
| II | 536 (57) | 1815 (57) |
| III | 204 (22) | 708 (22) |
| Unknown | 62 | 237 |
| HER2 status | ||
| HER2− | 591 (81) | 2243 (83) |
| HER2+ | 141 (19) | 455 (17) |
| Unknown/Not measured | 269 | 804 |
| Type of primary surgery | ||
| Mastectomy | 436 (44) | 1549 (44) |
| Lumpectomy | 565 (56) | 1953 (56) |
| Chemotherapy | ||
| Yes | 858 (86) | 3219 (92) |
| No | 143 (14) | 283 (8.1) |
| Radiation therapy | ||
| Yes | 491 (49) | 1928 (55) |
| No | 514 (51) | 1574 (45) |
| Anti-HER2 therapy | ||
| Yes | 82 (8.2) | 383 (11) |
| No | 919 (92) | 3119 (89) |
| Charlson Comorbidity Score | ||
| 1+ | 111 (11) | 292 (8.4) |
| 0 | 890 (89) | 3210 (92) |
| Comorbidities during treatment | ||
| 1+ | 95 (9.5) | 349 (10) |
| 0 | 906 (91) | 3153 (90) |
| Statin Use | ||
| Yes | 69 (6.9) | 185 (5.6) |
| No | 932 (93) | 3317 (95) |
| Medication Initiation during treatment | ||
| Yes | 610 (61) | 2029 (58) |
| No | 391 (39) | 1473 (42) |
| Socioeconomic Factors | ||
| Household Income | ||
| 3rd tertile | 281 (28) | 1223 (35) |
| 2nd tertile | 297 (30) | 1206 (34) |
| 1st tertile | 418 (42) | 1068 (31) |
| Marital Status | ||
| Married | 637 (64) | 2406 (69) |
| Single | 364 (36) | 1096 (31) |
| Education | ||
| Higher Education | 345 (35) | 1408 (41) |
| College | 426 (43) | 1408 (41) |
| High School | 219 (22) | 659 (19) |
Abbreviations: AI=aromatase inhibitors; HER2= human epidermal growth factor receptor 2; TAM=tamoxifen