Table 1.
Risk factors by study site.
| Risk Factors | MGH | NWH | UPenn |
|---|---|---|---|
| N = 58,706 | N = 39,189 | N = 24,661 | |
| N (%) | |||
| Age, mean +/− SD | 52.57 +/− 9.55 | 51.37 +/− 8.82 | 55.6 +/− 9.29 |
| Age | |||
| 40–44 years | 15,723 (26.78) | 10,796 (27.55) | 3966 (16.08) |
| 45–49 years | 9811 (16.71) | 8380 (21.38) | 3851 (15.62) |
| 50–54 years | 9246 (15.75) | 6976 (17.80) | 4154 (16.84) |
| 55–59 years | 8862 (15.10) | 5245 (13.38) | 4226 (17.14) |
| 60–64 years | 7047 (12.00) | 3845 (9.81) | 3787 (15.36) |
| 65–69 years | 4724 (8.05) | 2400 (6.12) | 2857 (11.59) |
| 70–74 years | 3293 (5.61) | 1547 (3.95) | 1820 (7.38) |
| Race/Ethnicity | |||
| White | 48,072 (81.89) | 35,394 (90.32) | 11,312 (45.87) |
| Black or African American | 3266 (5.56) | 630 (1.61) | 11,279 (45.74) |
| Hispanic | 3177 (5.41) | 392 (1.00) | 560 (2.27) |
| Asian | 3027 (5.16) | 1545 (3.94) | 920 (3.73) |
| Other/Unknown | 1164 (1.98) | 1228 (3.13) | 590 (2.39) |
| Age at menarche | |||
| 7 to 11 years | 10,216 (17.40) | 5895 (15.04) | 4653 (18.87) |
| 12 to 13 years | 29,764 (50.70) | 22,502 (57.42) | 13,190 (53.49) |
| ≤14 years | 15,529 (26.45) | 10,643 (27.16) | 4445 (18.02) |
| Missing | 3197 (5.45) | 149 (0.38) | 2373 (9.62) |
| Age at first birth | |||
| Nulliparous | 15,673 (26.70) | 7297 (18.62) | 5794 (23.49) |
| <20 years | 5721 (9.75) | 1671 (4.26) | 4731 (19.18) |
| 20–24 years | 11,652 (19.85) | 5979 (15.26) | 5001 (20.28) |
| 25–29 years | 11,349 (19.33) | 9923 (25.32) | 4671 (18.94) |
| ≤30 | 12,217 (20.81) | 14,124 (36.04) | 3895 (15.79) |
| Missing | 2094 (3.57) | 195 (0.50) | 569 (2.31) |
| Breast density | |||
| Almost entirely fat | 4342 (7.40) | 755 (1.93) | 2359 (9.57) |
| Scattered fibroglandular tissue | 23,145 (39.43) | 9608 (24.52) | 12,216 (49.54) |
| Heterogeneously dense | 27,112 (46.18) | 22,898 (58.43) | 9162 (37.15) |
| Extremely dense | 4107 (7.0) | 5928 (15.13) | 924 (3.75) |
| Menopausal | |||
| Pre-or peri-menopausal | 24,645 (41.98) | 19,235 (49.08) | 11,971 (48.54) |
| Post-menopausal | 34061 (58.02) | 19,954 (50.92) | 12,690 (51.46) |
| BMI, mean (SD) | 27.21 (6.39) | 26.2 (5.80) | 29.46 (7.40) |
| Prior Breast Biopsy | |||
| None | 57,807 (98.47) | 32,788 (83.67) | 19,764 (80.14) |
| One | 541 (0.92) | 4656 (11.88) | 4259 (17.27) |
| Two or more | 358 (0.61) | 1745 (4.45) | 638 (2.59) |
| Prior atypical hyperplasia/benign breast findings 1 | 849 (1.45) | 204 (0.52) | 91 (0.37) |
| No. of first-degree relatives with breast cancer (%) | |||
| None | 51,037 (86.94) | 32,666 (83.36) | 20,756 (84.17) |
| One | 7093 (12.08) | 5865 (14.97) | 3500 (14.19) |
| Two or more | 576 (0.98) | 658 (1.68) | 405 (1.64) |
| No. of second-degree relatives with breast cancer (%) | |||
| None | 51,285 (87.36) | 28,052 (71.58) | 21,893 (88.78) |
| One | 5818 (9.91) | 7764 (19.81) | 2169 (8.80) |
| Two or more | 1603 (2.73) | 3373 (8.61) | 599 (2.43) |
| No. of first or second degree relatives with ovarian cancer (%) | |||
| None | 58,646 (99.90) | 39,152 (99.91) | 23,644 (95.88) |
| One | 58 (0.10) | 7 (0.02) | 919 (3.73) |
| Two or more | 2 (0.00) | 30 (0.08) | 98 (0.40) |
| 5-year invasive cancer subtype, N (%) |
|||
| ER/PR+HER2− | 619 (57.31) | 379 (56.48) | 318 (55.99) |
| ER/PR+HER2+ | 77 (7.13) | 55 (8.20%) | 30 (5.28) |
| ERPR−HER2+ | 29 (2.69) | 15 (2.24) | 18 (3.17) |
| ERPR−HER2− | 58 (5.37) | 36 (5.37) | 38 (6.69) |
| Invasive cancer, missing subtype | 21 (1.94) | 27 (4.02) | 14 (2.46) |
1 At MGH, patients reported if they’d ever had benign tissue removed from the breast. At both MGH and NWH, we also included pathology report data on atypical hyperplasia, LCIS, or lobular neoplasia. At UPenn, patients self-reported prior atypical hyperplasia.