Abstract P2-09-04: Timing and acceptance of bilateral prophylactic salpingo-oophorectomy among BRCA1 and BRCA2 mutation carriers enrolled in an integrated community-based health care system
Authors: Kwan Karen W , Morton Stephanie W , Chung Joanie 
Published: March 2022

Abstract
BACKGROUND Risk reducing bilateral salpingo-oophorectomy (rrBSO) can provide up to a 90% reduction in the risk of developing ovarian cancer in women who are carriers of pathogenic variants in the BRCA1 and BRCA2 genes. National guidelines recommend risk reducing rrBSO once childbearing is complete and/or between the ages of 35-45. Previous studies have found that a large percentage of women who are eligible for rrBSO do not undergo the procedure and surgery is often done at later ages than recommended in the national guidelines. Research on factors associated with the uptake and timing of rrBSO is limited. Our study describes the percentages of women who are BRCA1 or BRCA2 carriers who elected rrBSO and ascertains the timing of the surgery relative to recommended age guidelines. We also identify patient characteristics associated with uptake of rrBSO. METHODS We conducted a retrospective cohort study in a large, integrated healthcare system in Southern California. The study population included women who were identified as BRCA1 or BRCA2 carriers in our electronic health record by ICD 9 and ICD 10 codes, and by review of our internal Cancer DNA database. Inclusion criteria included adults 18 years and older who were members of Kaiser Permanente Southern California between 2008 - 2018. Exclusion criteria included patients with an established diagnosis of ovarian cancer, with rrBSO at the time of study entry, and who were KP members for less than 12 months. Crude logistic regression models were used to determine odds ratios and 95% confidence intervals for associations between patient variables and uptake of rrBSO. RESULTS Of the 2,592 patients in the cohort, 1,326 were BRCA1 carriers and 1,266 were BRCA2 carriers. 1,003 (38.6%) women underwent rrBSO at a median age of 48.0 years (IQR: 42.0, 57.0). For the entire cohort, 38.6% identified as Caucasian, 30% identified as Hispanic/Latin American/Caribbean, 9.4% identified as Ashkenazi Jewish, 8.6% identified as Asian/Pacific Islander, and 1.5% identified as Black/African, and 1.4% identified as Near East/Middle Eastern. The baseline characteristics of our cohort can be seen in Table 1. Ovarian malignancy was incidentally detected on pathology evaluation in 1.5% of patients who elected rrBSO. The odds of rrBSO were lower among those who had used oral contraceptives for more than one year compared to those who hadn’t (OR=0.18, 95% CI: 0.11-0.30). A family history of ovarian cancer or breast cancer were also associated with higher odds of rrBSO, (OR=1.45, 95% CI: 1.21-1.73) and (OR=1.75; 95% CI: 1.48-2.08), respectively. The odds of rrBSO were also higher for those with a personal history of breast cancer (OR=2.29, 95% CI: 1.95-2.70). CONCLUSIONS In this large cohort of women who were BRCA1 and BRCA2 carriers and who were eligible for rrBSO, only a third of patients underwent risk reducing surgery. Among those who did undergo surgery, the median age at the time of procedure was higher than what is recommended in national guidelines. Family history of breast cancer and/or ovarian cancer, as well as personal history of breast cancer were associated with women selecting rrBSO.
Table 1.No Oophorectomy (N=1589)rrBSO (N=1003)Total (N=2592)p valueAge at BRCA diagnosis&lt;0.00011 N158910032592 Mean (SD)43.9 (15.73)49.5 (11.11)46.1 (14.38) Median42.048.345.5 Range(18.1-95.7)(19.8-79.7)(18.1-95.7)Gene0.03522 BRCA1839 (52.8%)487 (48.6%)1326 (51.2%) BRCA2750 (47.2%)516 (51.4%)1266 (48.8%)Race/Ethnicity0.01002 African72 (4.5%)61 (6.1%)133 (5.1%) Ashkenazi Jewish134 (8.4%)110 (11%)244 (9.4%) Asian/Pacific Islander138 (8.7%)86 (8.6%)224 (8.6%) Black24 (1.5%)14 (1.4%)38 (1.5%) Hispanic/Latin American/Caribbean486 (30.6%)291 (29%)777 (30%) Multiple2 (0.1%)2 (0.2%)4 (0.2%) Native American/Alaskan2 (0.1%)0 (0%)2 (0.1%) Near East/Mideast24 (1.5%)13 (1.3%)37 (1.4%) White/Caucasian (Western/Northern/Central European)611 (38.5%)389 (38.8%)1000 (38.6%) Other77 (4.8%)37 (3.7%)114 (4.4%) Unknown19 (1.2%)0 (0%)19 (0.7%)Oral contraceptive use ≥ 1 year&lt;0.00012 N1456 (91.6%)987 (98.4%)2443 (94.3%) Y133 (8.4%)16 (1.6%)149 (5.7%)Family history of ovarian cancer0.00012 N1236 (77.8%)710 (70.8%)1946 (75.1%) Y353 (22.2%)293 (29.2%)646 (24.9%)Family history of breast cancer&lt;0.00012 N650 (40.9%)284 (28.3%)934 (36%) Y939 (59.1%)719 (71.7%)1658 (64%)Personal history of breast cancer&lt;0.00012 N1094 (68.8%)492 (49.1%)1586 (61.2%) Y495 (31.2%)511 (50.9%)1006 (38.8%)Age at prophylactic surgery NN/A893893 Mean (SD)49.6 (10.36)49.6 (10.36) Median48.048.0 Q1, Q342.0, 57.042.0, 57.0 Range(21.0-80.0)(21.0-80.0)Ovarian cancer&lt;0.00012 N1589 (100%)988 (98.5%)2577 (99.4%) Y0 (0%)15 (1.5%)15 (0.6%)1Kruskal Wallis 2Chi-Square
Citation Format: Karen W Kwan, Stephanie W Morton, Joanie Chung. Timing and acceptance of bilateral prophylactic salpingo-oophorectomy among BRCA1 and BRCA2 mutation carriers enrolled in an integrated community-based health care system [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-09-04.