Tamoxifen and the risk of breast cancer in women with a BRCA1 or BRCA2 mutation

PurposeChemoprevention with a selective estrogen receptor modulator (tamoxifen or raloxifene) is a non-surgical option offered to high-risk women to reduce the risk of breast cancer. The evidence for tamoxifen benefit is based on trials conducted among predominantly postmenopausal women from the general population and on studies of contralateral breast cancer in women with a pathogenic variant (mutation hereafter) in BRCA1 or BRCA2. Tamoxifen has not been assessed as a primary prevention agent in women with an inherited BRCA mutation.MethodsWe conducted a prospective analysis of tamoxifen chemoprevention and the risk of breast cancer in women with a BRCA1 or BRCA2 mutation. Data on tamoxifen (and raloxifene) use was collected by questionnaire and updated biennially. Information on incident cancers was collected by self-report and was confirmed by medical record review. In a matched analysis, we estimated the hazard ratio (HR) and 95% confidence intervals (CI) for developing a first primary breast cancer associated with tamoxifen or raloxifene use, using Cox proportional hazards analysis.ResultsThere were 4578 unaffected women in the cohort, of whom 137 reported tamoxifen use (3%), 83 reported raloxifene use (2%) and 12 used both drugs (0.3%). Women who used tamoxifen or raloxifene were matched 1:3 with women who used neither drug on year of birth, country of residence, year of study entry and gene (BRCA1 or BRCA2). We generated 202 matched pairs. After a mean follow-up of 6.8 years, there were 22 incident breast cancers diagnosed among tamoxifen/raloxifene users (10.9% of users) and 71 cases diagnosed among non-users (14.3% of non-users; HR = 0.64; 95% CI 0.40-1.03; P = 0.07).ConclusionChemoprevention may be an effective risk-reduction option for BRCA mutation carriers, but further studies with longer follow-up are necessary

Bilateral Oophorectomy and All-Cause Mortality in Women With BRCA1 and BRCA2 Sequence Variations

ImportancePreventive bilateral salpingo-oophorectomy is offered to women at high risk of ovarian cancer who carry a pathogenic variant in BRCA1 or BRCA2; however, the association of oophorectomy with all-cause mortality has not been clearly defined.ObjectiveTo evaluate the association between bilateral oophorectomy and all-cause mortality among women with a BRCA1 or BRCA2 sequence variation.Design, setting, and participantsIn this international, longitudinal cohort study of women with BRCA sequence variations, information on bilateral oophorectomy was obtained via biennial questionnaire. Participants were women with a BRCA1 or BRCA2 sequence variation, no prior history of cancer, and at least 1 follow-up questionnaire completed. Women were followed up from age 35 to 75 years for incident cancers and deaths. Cox proportional hazards regression was used to estimate the hazard ratios (HRs) and 95% CIs for all-cause mortality associated with a bilateral oophorectomy (time dependent). Data analysis was performed from January 1 to June 1, 2023.ExposuresSelf-reported bilateral oophorectomy (with or without salpingectomy).Main outcomes and measuresAll-cause mortality, breast cancer-specific mortality, and ovarian cancer-specific mortality.ResultsThere were 4332 women (mean age, 42.6 years) enrolled in the cohort, of whom 2932 (67.8%) chose to undergo a preventive oophorectomy at a mean (range) age of 45.4 (23.0-77.0) years. After a mean follow-up of 9.0 years, 851 women had developed cancer and 228 had died; 57 died of ovarian or fallopian tube cancer, 58 died of breast cancer, 16 died of peritoneal cancer, and 97 died of other causes. The age-adjusted HR for all-cause mortality associated with oophorectomy was 0.32 (95% CI, 0.24-0.42; P < .001). The age-adjusted HR was 0.28 (95% CI, 0.20-0.38; P < .001) and 0.43 (95% CI, 0.22-0.90; P = .03) for women with BRCA1 and BRCA2 sequence variations, respectively. For women with BRCA1 sequence variations, the estimated cumulative all-cause mortality to age 75 years for women who had an oophorectomy at age 35 years was 25%, compared to 62% for women who did not have an oophorectomy. For women with BRCA2 sequence variations, the estimated cumulative all-cause mortality to age 75 years was 14% for women who had an oophorectomy at age 35 years compared to 28% for women who did not have an oophorectomy.Conclusions and relevanceIn this cohort study among women with a BRCA1 or BRCA2 sequence variation, oophorectomy was associated with a significant reduction in all-cause mortality

MRI Surveillance and Breast Cancer Mortality in Women With BRCA1 and BRCA2 Sequence Variations

ImportanceMagnetic resonance imaging (MRI) surveillance is offered to women with a pathogenic variant in the BRCA1 or BRCA2 gene who face a high lifetime risk of breast cancer. Surveillance with MRI is effective in downstaging breast cancers, but the association of MRI surveillance with mortality risk has not been well defined.ObjectiveTo compare breast cancer mortality rates in women with a BRCA1 or BRCA2 sequence variation who entered an MRI surveillance program with those who did not.Design, setting, and participantsWomen with a BRCA1 or BRCA2 sequence variation were identified from 59 participating centers in 11 countries. Participants completed a baseline questionnaire between 1995 and 2015 and a follow-up questionnaire every 2 years to document screening histories, incident cancers, and vital status. Women who had breast cancer, a screening MRI examination, or bilateral mastectomy prior to enrollment were excluded. Participants were followed up from age 30 years (or the date of the baseline questionnaire, whichever was later) until age 75 years, the last follow-up, or death from breast cancer. Data were analyzed from January 1 to July 31, 2023.ExposuresEntrance into an MRI surveillance program.Main outcomes and measuresCox proportional hazards modeling was used to estimate the hazard ratios (HRs) and 95% CIs for breast cancer mortality associated with MRI surveillance compared with no MRI surveillance using a time-dependent analysis.ResultsA total of 2488 women (mean [range] age at study entry 41.2 [30-69] years), with a sequence variation in the BRCA1 (n = 2004) or BRCA2 (n = 484) genes were included in the analysis. Of these participants, 1756 (70.6%) had at least 1 screening MRI examination and 732 women (29.4%) did not. After a mean follow-up of 9.2 years, 344 women (13.8%) developed breast cancer and 35 women (1.4%) died of breast cancer. The age-adjusted HRs for breast cancer mortality associated with entering an MRI surveillance program were 0.20 (95% CI, 0.10-0.43; P < .001) for women with BRCA1 sequence variations and 0.87 (95% CI, 0.10-17.25; P = .93) for women with BRCA2 sequence variations.Conclusion and relevanceResults of this cohort study suggest that among women with a BRCA1 sequence variation, MRI surveillance was associated with a significant reduction in breast cancer mortality compared with no MRI surveillance. Further studies of women with BRCA2 sequence variations are needed to ascertain these women obtain the same benefits associated with MRI surveillance

Contraceptive use and the risk of ovarian cancer among women with a BRCA1 or BRCA2 mutation

Background BRCA1 and BRCA2 (BRCA) mutation carriers face a high lifetime risk of developing ovarian cancer. Oral contraceptives are protective in this population; however, the impact of other types of contraception (e.g. intrauterine devices, implants, injections) is unknown. We undertook a matched case-control study to evaluate the relationship between type of contraception and risk of ovarian cancer among women with BRCA mutations. Methods A total of 1733 matched pairs were included in this analysis. Women were matched according to year of birth, date of study entry, country of residence, BRCA mutation type and history of breast cancer. Detailed information on hormonal, reproductive and lifestyle exposures were collected from a routinely administered questionnaire. Conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) associated with each contraceptive exposure. Results Ever use of any contraceptive was significantly associated with reduced risk of ovarian cancer (OR = 0.62; 95% CI 0.52-0.75; P < 0.0001), which was driven by significant inverse associations with oral contraceptives (OR = 0.66; 95% CI 0.54-0.79; P < 0.0001) and contraceptive implants (OR = 0.30; 95% CI 0.12-0.73; P = 0.008). We observed a similar effect with use of injections (OR = 0.37; 95% CI 0.10-1.38; P = 0.14), but this did not achieve significance. No significant associations were observed between patterns of intrauterine device use and risk of ovarian cancer. Conclusions These findings support a protective effect of oral contraceptives and implants on risk of ovarian cancer among women with BRCA mutations. The possible protective effect of injections requires further evaluation

Prospective evaluation of body size and breast cancer risk among BRCA1 and BRCA2 mutation carriers

BACKGROUND:Although evidence suggests that larger body size in early life confers lifelong protection from developing breast cancer, few studies have investigated the relationship between body size and breast cancer risk among BRCA mutation carriers. Therefore, we conducted a prospective evaluation of body size and the risk of breast cancer among BRCA mutation carriers. METHODS:Current height and body mass index (BMI) at age 18 were determined from baseline questionnaires. Current BMI and weight change since age 18 were calculated from updated biennial follow-up questionnaires. Cox proportional hazards models were used to estimate the hazard ratio (HR) and 95% confidence interval (CI). RESULTS:Among 3734 BRCA mutation carriers, there were 338 incident breast cancers over a mean follow-up of 5.5 years. There was no association between height, current BMI or weight change and breast cancer risk. Women with BMI at age 18 ≥22.1 kg/m2 had a decreased risk of developing post-menopausal breast cancer compared with women with a BMI at age 18 between 18.8 and 20.3 kg/m2 (HR 0.49; 95% CI 0.30-0.82; P = 0.006). BMI at age 18 was not associated with risk of pre-menopausal breast cancer. CONCLUSIONS:There was no observed association between height, current BMI and weight change and risk of breast cancer. The inverse relationship between greater BMI at age 18 and post-menopausal breast cancer further supports a role of early rather than current or adulthood exposures for BRCA-associated breast cancer development. Future studies with longer follow-up and additional measures of adiposity are necessary to confirm these findings