Table. University of Colorado Young Women's Breast Cancer Cohort.
| Characteristic | No. (%) | P Value | |||
|---|---|---|---|---|---|
| Nulliparous (n = 217) | PPBC <5 y (n = 175) | PPBC 5 to <10 y (n = 153) | PPBC ≥10 y (n = 156) | ||
| Age at diagnosis, mean (SD), y | 36.9 (5.2) | 35.5 (5.1) | 38.5 (4.6) | 41.3 (3.2) | <.001a |
| Biological subtype | |||||
| Luminal A (ER+, PR+, Her2−) | 84 (38.7) | 74 (42.3) | 70 (45.8) | 61 (39.1) | .66b |
| Luminal B (ER+, PR±, Her2+) | 34 (15.7) | 22 (12.6) | 21 (13.7) | 21 (13.5) | |
| Her2+ (ER−, PR−) | 16 (7.4) | 15 (8.6) | 13 (8.5) | 11 (7.1) | |
| Triple negative (ER−, PR−, Her2−) | 32 (14.7) | 35 (20.0) | 17 (11.1) | 28 (17.9) | |
| Missing Her2 | 38 (17.5) | 20 (11.4) | 16 (10.5) | 27 (17.3) | |
| Missing ER or PR | 2 (0.9) | 2 (1.1) | 3 (2.0) | 0 | |
| Other | 11 (5.1) | 7 (4.0) | 13 (8.5) | 8 (5.1) | |
| Estrogen status | |||||
| ER+ | 142 (65.4) | 114 (65.1) | 104 (68.0) | 97 (62.2) | .78b |
| ER− | 62 (28.6) | 53 (30.3) | 40 (26.1) | 53 (34.0) | |
| Missing | 13 (5.6) | 8 (4.6) | 9 (5.9) | 6 (3.8) | |
| Histologic grade | |||||
| Grade I | 25 (11.5) | 11 (6.3) | 14 (9.2) | 22 (14.1) | .08b |
| Grade II | 70 (32.3) | 51 (29.1) | 55 (36.0) | 61 (39.1) | |
| Grade III | 104 (47.9) | 96 (54.9) | 73 (47.7) | 57 (36.5) | |
| Missing | 18 (8.3) | 17 (9.7) | 11 (7.2) | 16 (10.3) | |
| Tumor size | |||||
| DCIS | 0 | 1 (0.6)c | 0 | 0 | .42b |
| 0.1 to ≤2.0 cm | 110 (50.7) | 85 (48.6) | 63 (41.2) | 75 (48.1) | |
| >2.0 to ≤5.0 cm | 69 (31.8) | 57 (32.6) | 56 (36.6) | 54 (34.6) | |
| >5.0 cm | 17 (7.8) | 17 (9.7) | 19 (12.4) | 20 (12.8) | |
| Missing | 21 (9.7) | 15 (8.6) | 15 (9.8) | 7 (4.5) | |
| Stage | |||||
| I | 87 (40.1) | 46 (26.3) | 46 (30.1) | 52 (33.3) | .01b |
| II | 98 (45.2) | 91 (52.0) | 66 (43.1) | 64 (41.0) | |
| III | 32 (14.7) | 38 (21.7) | 41 (26.8) | 40 (25.6) | |
| Year of diagnosis | |||||
| 1980-1998 | 45 (20.7) | 30 (17.1) | 19 (12.4) | 50 (32.1) | <.001b |
| 1999-2004 | 62 (28.6) | 32 (18.3) | 48 (31.4) | 40 (25.6) | |
| 2005-2014 | 110 (50.7) | 113 (64.6) | 86 (56.2) | 66 (42.3) | |
| BMI, mean (SD) | 25.0 (6.9) | 26.1 (6.0) | 26.0 (6.0) | 26.7 (7.0) | .03a |
| Chemotherapy | |||||
| Yes | 136 (62.7) | 132 (75.4) | 100 (65.4) | 93 (59.6) | .02b |
| No | 38 (17.5) | 15 (8.6) | 25 (16.3) | 22 (14.1) | |
| Missing | 43 (19.8) | 28 (16.0) | 28 (18.3) | 41 (26.3) | |
| Radiotherapy | |||||
| Yes | 99 (45.6) | 76 (43.4) | 74 (48.4) | 57 (36.5) | .39b |
| No | 55 (25.3) | 45 (25.7) | 31 (20.3) | 41 (26.3) | |
| Missing | 63 (29.0) | 54 (30.9) | 48 (31.4) | 58 (37.2) | |
| Patients with metastasis | 22 (10.1) | 29 (16.6) | 28 (18.3) | 24 (15.4) | .09b |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); DCIS, ductal carcinoma in situ; ER, estrogen receptor; PPBC, postpartum breast cancer; PR, progesterone receptor; +, positive; −, negative; ±, positive or negative.
a
Kruskal-Wallis test.
b
χ2 Test.
c
Indicates that DCIS in breast and positive lymph nodes is stage II.