Table 3.
Associations between estrogen receptor, progesterone receptor, family history of breast cancer, age at first breast cancer diagnosis, chemotherapy, radiotherapy, hormone replacement therapy, age at menopause, and parity and risk of CBC, stratified by high/low weighted PRS (239 SNPs) in Non-Hispanic White women
| Below median PRS | Above median PRS | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| CBCs No. (%) | UBCs No. (%) | RR (95%CI) | P | CBCs No. (%) | UBCs No. (%) | RR (95%CI) | P | PHeterogeneity | |
| ER status at first breast cancer | |||||||||
| Positive | 204 (54.9) | 430 (65.5) | Ref | 359 (70.1) | 458 (73.6) | Ref | |||
| Negative | 168 (45.1) | 227 (34.5) | 1.33 (0.95–1.86) | 0.09 | 153 (29.9) | 164 (26.4) | 1.11 (0.79–1.55) | 0.55 | 0.41 |
| PR status at first breast cancer | |||||||||
| Positive | 194 (54.2) | 408 (63.3) | Ref | 339 (68.6) | 440 (71.2) | Ref | |||
| Negative | 164 (45.8) | 237 (36.7) | 1.24 (0.88–1.74) | 0.22 | 153 (31.4) | 178 (28.8) | 1.21 (0.87–1.68) | 0.26 | 0.92 |
| Family history of breast cancer | |||||||||
| No | 284 (67.3) | 592 (79.8) | Ref | 384 (64.5) | 544 (75.1) | Ref | |||
| Yes | 138 (32.7) | 150 (20.2) | 1.67 (1.23–2.25) | 0.0009 | 211 (35.5) | 180 (24.9) | 1.66 (1.27–2.16) | 0.0002 | 1 |
| Age at first breast cancer diagnosis | |||||||||
| < 45 | 177 (41.9) | 295 (39.8) | Ref | 219 (36.8) | 284 (39.2) | Ref | |||
| ≥ 45 | 245 (58.1) | 447 (60.2) | 0.66 (0.28–1.55) | 0.34 | 376 (63.2) | 440 (60.8) | 0.66 (0.28–1.53) | 0.33 | 0.96 |
| Chemotherapy | |||||||||
| No | 167 (39.6) | 300 (40.4) | Ref | 284 (47.7) | 292 (40.3) | Ref | |||
| Yes | 255 (60.4) | 442 (59.6) | 0.90 (0.67–1.22) | 0.51 | 311 (52.3) | 432 (59.7) | 0.61 (0.46–0.81) | 0.0005 | 0.04 |
| Radiotherapya | |||||||||
| No | 172 (40.8) | 182 (37.2) | Ref | 239 (40.2) | 153 (37.3) | Ref | |||
| Yes | 250 (59.2) | 559 (62.8) | 1.05 (0.80–1.38) | 0.71 | 356 (59.8) | 571 (62.7) | 0.95 (0.74–1.22) | 0.67 | 0.59 |
| HRT at first breast cancer diagnosis | |||||||||
| No | 320 (76.4) | 571 (77.5) | Ref | 461 (78.3) | 579 (80.3) | Ref | |||
| Yes | 99 (23.6) | 166 (22.5) | 1.08 | 0.67 | 128 (21.7) | 142 (19.7) | 1.22 | 0.25 | 0.59 |
| (0.76–1.53) | (0.87–1.70) | ||||||||
| Age at menopauseb | |||||||||
| Postmenopausal 45+ | 106 (25.3) | 153 (20.8) | Ref | 145 (24.5) | 168 (23.4) | Ref | 0.46 | ||
| Postmenopausal < 45 | 82 (19.6) | 144 (19.5) | 0.86 | 0.49 | 103 (17.4) | 121 (16.8) | 1.10 | 0.63 | |
| (0.57–1.32) | (0.74–1.65) | ||||||||
| Premenopausal | 231 (55.1) | 440 (59.7) | 0.78 | 0.20 | 343 (58.1) | 430 (59.8) | 1.03 | 0.86 | |
| (0.54–1.13) | (0.73–1.46) | ||||||||
| Parity at first breast cancer diagnosis | |||||||||
| Parous | 329 (78.3) | 597 (80.6) | Ref | 449 (75.8) | 555 (77.0) | Ref | |||
| Nulliparous | 91 (21.7) | 144 (19.4) | 1.10 | 0.60 | 143 (24.2) | 166 (23.0) | 0.99 | 0.95 | 0.65 |
| (0.78–1.54) | (0.74–1.33) | ||||||||
Non-Hispanic White women only, WECARE I and WECARE II Studies combined
CBC, contralateral breast cancer; CI, confidence interval; ER, estrogen receptor; No., number; PR, progesterone receptor; PRS, polygenic risk score; RR, rate ratio; UBC, unilateral breast cancer; HRT, hormone replacement therapy
Adjusted for the top five principal components, log-weight offset term, age at first breast cancer diagnosis, age at menarche, age at menopause, number of full-term pregnancies, stage of first breast cancer, histology of first breast cancer, family history of breast cancer, chemotherapy, and hormone therapy
aControl proportions account for counter-matched sampling of the WECARE I Study and do not represent true distributions in this population
b1 year prior to breast cancer diagnosis to preclude treatment-induced menopause