Table 1. Characteristics of the study population matched by age at surgery.
| Characteristics | BRCA mutation with RRBSO (n=329) | BO without BRCA mutation (n=3,290) | p-value* | Intact ovaries without BRCA mutation (n=3,290) | p-value* | |
|---|---|---|---|---|---|---|
| Age (yr) | 0.940 | 0.937 | ||||
| Mean±SD | 42.4±4.8 | 42.5±4.8 | 42.5±4.8 | |||
| Min–Max | 26.7–49.9 | 26.0–49.9 | 26.2–49.9 | |||
| Age category | 1.000 | 1.000 | ||||
| <35 | 23 (7.0%) | 230 (7.0%) | 230 (7.0%) | |||
| 35–39 | 81 (24.6%) | 810 (24.6%) | 810 (24.6%) | |||
| 40–44 | 103 (31.3%) | 1,030 (31.3%) | 1,030 (31.3%) | |||
| 45–49 | 122 (37.1%) | 1,220 (37.1%) | 1,220 (37.1%) | |||
| Follow-up (yr) | <0.001 | <0.001 | ||||
| Median | 6.9 | 10.6 | 8.6 | |||
| Min–Max | 1.1–19.9 | 1.0–22.0 | 1.0–22.0 | |||
| Breast cancer before surgery | 161 (48.9%) | 151 (4.6%) | <0.001 | 9 (0.3%) | <0.001 | |
| No | 168 (51.1%) | 3,139 (95.4%) | 3,281 (99.7%) | |||
| Other cancers | 23 (7.0%) | 310 (9.4%) | 0.175 | 252 (7.7%) | 0.743 | |
| Income quintile | <0.001 | 0.008 | ||||
| 1 | 42 (12.8%) | 670 (20.4%) | 625 (19.0%) | |||
| 2 | 61 (18.5%) | 704 (21.4%) | 650 (19.8%) | |||
| 3 | 58 (17.6%) | 655 (19.9%) | 666 (20.2%) | |||
| 4 | 81 (24.6%) | 598 (18.2%) | 694 (21.1%) | |||
| 5 | 80 (24.3%) | 588 (17.9%) | 592 (18.0%) | |||
| Missing | 7 (2.1%) | 75 (2.3%) | 63 (1.9%) | |||
| HRT after surgery | 153 (46.5%) | 2,159 (65.6%) | <0.001 | - | - | |
| History of breast cancer† | 32 (19.9%) | 8 (5.3%) | <0.001 | - | - | |
| No history of breast cancer‡ | 121 (72.0%) | 2,151 (68.5%) | 0.386 | - | - | |
| Duration HRT (years) | 0.031 | - | - | |||
| Mean±SD | 3.5±2.5 | 4.0±3.7 | ||||
| Min–Max | 0.1–10.7 | 0.1–18.4 | ||||
RRBSO, risk-reducing bilateral salpingo-oophorectomy; BO, bilateral oophorectomy; SD, standard deviation; HRT, hormone replacement therapy.
*Reference group: BRCA mutation with RRBSO; †Denominator is the number of women without prior breast cancer (n=161 and n=151, respectively); ‡Denominator is the number of women with prior breast cancer (n=168 and n=3,139, respectively).