BRCA1 Mutation Carriers Research Articles

The incidence of pancreatic cancer in women with a BRCA1 or BRCA2 mutation.

The lifetime risk of pancreatic cancer in women with a germline mutation in BRCA1 and BRCA2 is not well established. In an international prospective cohort of female carriers of BRCA1 and BRCA2 mutations, the cumulative incidence of pancreatic cancer from age 40 until 80 years was estimated. A total of 8295 women with a BRCA1 or BRCA2 mutation were followed for new cases of pancreatic cancer. Subjects were followed from the date of baseline questionnaire or age 40 years (whichever came last) until a new diagnosis of pancreatic cancer, death from another cause, or date of last follow-up. Thirty-four incident pancreatic cancer cases were identified in the cohort. The annual risk of pancreatic cancer between age 40 and 80 years was 0.04% for BRCA1 carriers and 0.09% for BRCA2 carriers. Via the Kaplan-Meier method, the cumulative incidence from age 40 to 80 years was 2.2% (95% CI, 1.1%-4.3%) for BRCA1 carriers and 2.7% (95% CI, 1.3%-5.4%) for BRCA2 carriers. Only two of the 34 cases reported a first-degree relative with pancreatic cancer (hazard ratio,4.75; 95% CI, 1.13-19.9; p=.03). Risk factors for pancreatic cancer included alcohol intake and a history of diabetes. The 5-year survival rate for the 34 cases was 8.8%. The lifetime risk of pancreatic cancer is approximately 2% in women with a BRCA1 mutation and 3% for women with a BRCA2 mutation. The poor survival in hereditary pancreatic cancer underscores the need for novel antitumoral strategies.

Luminal breast epithelial cells of BRCA1 or BRCA2 mutation carriers and noncarriers harbor common breast cancer copy number alterations.

The prevalence and nature of somatic copy number alterations (CNAs) in breast epithelium and their role in tumor initiation and evolution remain poorly understood. Using single-cell DNA sequencing (49,238 cells) of epithelium from BRCA1 and BRCA2 carriers or wild-type individuals, we identified recurrent CNAs (for example, 1q-gain and 7q, 10q, 16q and 22q-loss) that are present in a rare population of cells across almost all samples (n = 28). In BRCA1/BRCA2 carriers, these occur before loss of heterozygosity (LOH) of wild-type alleles. These CNAs, common in malignant tumors, are enriched in luminal cells but absent in basal myoepithelial cells. Allele-specific analysis of prevalent CNAs reveals that they arose by independent mutational events, consistent with convergent evolution. BRCA1/BRCA2 carriers contained a small percentage of cells with extreme aneuploidy, featuring loss of TP53, BRCA1/BRCA2 LOH and multiple breast cancer-associated CNAs. Our findings suggest that CNAs arising in normal luminal breast epithelium are precursors to clonally expanded tumor genomes.

Serous Tubal Intraepithelial Carcinoma (STIC): A Review of the Literature on the Incidence at the Time of Prophylactic Surgery.

Serous tubal intraepithelial carcinoma (STIC) is an early-stage cancerous lesion found in the fallopian tubes, often at the fimbrial end. It is strongly associated with high-grade serous carcinoma (HGSC), a highly aggressive type of ovarian cancer. STIC is considered a precursor to many HGSC cases, originating in the fallopian tubes. Its development is frequently linked to mutations in the TP53 gene, leading to the formation of a p53 signature, an early abnormality that may progress to HGSC. This signature is more common in BRCA mutation carriers, explaining the higher incidence of STIC in this group. The aim of this review is to evaluate the literature on the incidence of serous tubal intraepithelial carcinoma in patients (both BRCA-positive and BRCA-negative) undergoing preventive salpingo-oophorectomy, analysing the available data and identifying associations between specific characteristics and the onset of STIC. A comprehensive review of the literature from 2016 to 2023 was conducted using PubMed, focusing on studies analysing the incidence of STIC in BRCA-positive patients undergoing preventive salpingo-oophorectomy. Data on patient characteristics, interventions, outcomes, and incidence of STIC were extracted and analysed. Nine international studies were included in the review, reporting varying incidences of STIC among patients undergoing salpingo-oophorectomy. The overall incidence of STIC in all the women included in the studies was 7.31%, while that in the BRCA-mutated women was approximately 6.08%. Notably, the presence of the TP53 signature was significantly associated with the occurrence of STIC. The etiopathogenesis of STIC involves complex interactions between genetic, environmental, and molecular factors. Further research is needed to fully understand its mechanisms and identify additional risk factors beyond BRCA mutations. Establishing a national database of STIC cases could facilitate future research and improve patient outcomes.

Prevalence of cardiometabolic outcomes in women who underwent salpingo-oophorectomy to prevent hereditary breast and ovarian cancer: a meta-analysis.

Risk reduction salpingo-oophorectomy (RRSO) is usually performed in women with hereditary breast and ovarian cancer (HBOC) syndrome for BRCA1 and BRCA2 gene mutation carriers, resulting in surgical menopause, which is more associated with a high risk of cardiovascular and metabolic disease than in premenopausal and natural menopausal women. This study assessed the prevalence of cardiovascular and metabolic outcomes in women who underwent salpingo-oophorectomy as a preventive measure against HBOC. This meta-analysis assessed prevalence rates for four metabolic/cardiovascular conditions: myocardial infarction, hypertension, hypercholesterolemia, and type 2 diabetes mellitus. DerSimonian and Laird random-effects models were applied to all analyses, with 95% confidence interval (CI). Heterogeneity was assessed with I². We used OpenMeta Analyst software for statistical analysis. A total of five retrospective studies and one observational study involving 1,320 patients were included. The average body mass index (BMI) was 25.97kg/m2 and the average waist circumference was 87.94cm. The analysis across a mean 4.94-year follow-up revealed prevalence rates for acute myocardial infarction of 1.5% (95% CI 0.3-2.7; P = 0.077; I²=56.25%), hypertension of 28% (95% CI 6.9-49.1; P < 0.001; I2 = 98.42%), hypercholesterolemia of 27.2% (95% CI 6.8-47.6; P < 0.001; I²=98.67%), and type 2 diabetes mellitus of 3.3% (95% CI 1.1-5.5; P < 0.001; I²=82.44%). Our findings suggest that there is no marked increase in cardiovascular risk among women with HBOC undergoing RRSO.

Brca1 haploinsufficiency promotes early tumor onset and epigenetic alterations in a mouse model of hereditary breast cancer.

Germline BRCA1 mutation carriers face a high breast cancer risk; however, the underlying mechanisms for this risk are not completely understood. Using a new genetically engineered mouse model of germline Brca1 heterozygosity, we demonstrate that early tumor onset in a Brca1 heterozygous background cannot be fully explained by the conventional 'two-hit' hypothesis, suggesting the existence of inherent tumor-promoting alterations in the Brca1 heterozygous state. Single-cell RNA sequencing and assay for transposase-accessible chromatin with sequencing analyses uncover a unique set of differentially accessible chromatin regions in ostensibly normal Brca1 heterozygous mammary epithelial cells, distinct from wild-type cells and partially mimicking the chromatin and RNA-level changes in tumor cells. Transcription factor analyses identify loss of ELF5 and gain of AP-1 sites in these epigenetically primed regions; in vivo experiments further implicate AP-1 and Wnt10a as strong promoters of Brca1-related breast cancer. These findings reveal a previously unappreciated epigenetic effect of Brca1 haploinsufficiency in accelerating tumorigenesis, advancing our mechanistic understanding and informing potential therapeutic strategies.

Factors influencing gynecologic risk reduction surgeries for BRCA1 or BRCA2 germline mutation carriers

Factors influencing gynecologic risk reduction surgeries for BRCA1 or BRCA2 germline mutation carriers

Clinical experience on the limited role of ultrasound for breast cancer screening in BRCA1 and BRCA2 mutations carriers aged 30–39 years

PurposeIn BRCA germline pathogenic sequence variants (PSV) carriers aged 30–39 years imaging is recommended at six-month intervals. The European society for medical oncology recommendation of the use of 6-monthly MRI six-monthly MRI screening is being considered at our institution, particularly for younger carriers under the age of 35, although it is not mandatory. If 6-monthly MRI is unavailable, annual MRI may be supplemented by ultrasound (with or without mammography). The aim of this study was to evaluate the utility of ultrasound screening added to mammography, as a 6-month supplement to annual MRI in BRCA PSV carriers aged 30–39 years. Materials and methodsThis IRB approved retrospective study included BRCA PSV carriers aged 30–39 years, who underwent breast cancer screening at our institution between January 2015 and March 2023. Participants were divided into two groups, those who had supplemental whole-breast US and mammography at six months and underwent screening before March 2019, and those who had only mammography without supplemental US and enrolled in screening after March 2019. Patient characteristics, cancer detection rates and cancer characteristics were compared between the two groups. ResultsOverall, 200 asymptomatic BRCA1/2 PSV carriers undergoing screening in our institution were included in the study. Mean age was 35.7 ± 3.5 years, and mean follow-up time was 37.4 ± 38.0 months. There were 118 (59 %) women screened with supplemental US, and 82 (41 %) women without. Eight cancers were diagnosed during the study period, four in women with supplemental US and four in women without. The sensitivity of whole-breast screening US was 25 % (1/4), specificity 85.7 % (222/259), PPV 2.6 % (1/38), and NPV 98.7 % (222/225). Of the four cancers detected in women screened with supplemental US, one was diagnosed by whole-breast US, two by MRI, and one by mammography. Of eight cancers included in this study, two were not detectable by targeted second-look US. All eight cancers were detectable by MRI. ConclusionThe addition of whole-breast ultrasound to mammography and MRI screening in BRCA PSV carriers aged 30–39 years offered limited incremental benefit. MRI with 6 months supplemental mammography without US detected all cancer cases.

Hormonal Contraception and Breast Cancer Risk for Carriers of Germline Mutations in BRCA1 and BRCA2.

It is uncertain whether, and to what extent, hormonal contraceptives increase breast cancer (BC) risk for germline BRCA1 or BRCA2 mutation carriers. Using pooled observational data from four prospective cohort studies, associations between hormonal contraceptive use and BC risk for unaffected female BRCA1 and BRCA2 mutation carriers were assessed using Cox regression. Of 3,882 BRCA1 and 1,509 BRCA2 mutation carriers, 53% and 71%, respectively, had ever used hormonal contraceptives for at least 1 year (median cumulative duration of use, 4.8 and 5.7 years, respectively). Overall, 488 BRCA1 and 191 BRCA2 mutation carriers developed BC during median follow-up of 5.9 and 5.6 years, respectively. Although for BRCA1 mutation carriers, neither current nor past use of hormonal contraceptives for at least 1 year was statistically significantly associated with BC risk (hazard ratio [HR], 1.40 [95% CI, 0.94 to 2.08], P = .10 for current use; 1.16 [0.80 to 1.69], P = .4, 1.40 [0.99 to 1.97], P = .05, and 1.27 [0.98 to 1.63], P = .07 for past use 1-5, 6-10, and >10 years before, respectively), ever use was associated with increased risk (HR, 1.29 [95% CI, 1.04 to 1.60], P = .02). Furthermore, BC risk increased with longer cumulative duration of use, with an estimated proportional increase in risk of 3% (1%-5%, P = .002) for each additional year of use. For BRCA2 mutation carriers, there was no evidence that current or ever use was associated with increased BC risk (HR, 0.70 [95% CI, 0.33 to 1.47], P = .3 and 1.07 [0.73 to 1.57], P = .7, respectively). Hormonal contraceptives were associated with increased BC risk for BRCA1 mutation carriers, especially if used for longer durations. Decisions about their use in women with BRCA1 mutations should carefully weigh the risks and benefits for each individual.

Blood molybdenum level as a marker of cancer risk on BRCA1 carriers

ObjectiveTo investigate whether Molybdenum blood level is a marker of cancer risk on BRCA1 carriers.MethodsA prospective cohort study was conducted among 989 initially unaffected women with a BRCA1 mutation. Blood samples were collected to measure molybdenum levels, and participants were followed for an average of 7.5 years. Cox proportional hazards models were used to assess the association between blood molybdenum levels and cancer incidence, adjusting for potential confounders.ResultsHigh blood molybdenum levels (> 0.70 µg/L) were significantly associated with an increased risk of developing ovarian cancer (HR = 5.55; 95%CI: 1.59–19.4; p = 0.007) and any cancer (HR = 1.74; 95%CI: 1.17–2.61; p = 0.007) but not breast cancer (HR = 1.46, CI = 0.91–2.33; p = 0.12). The cumulative incidence of ovarian cancer at ten years was 1.2% for the lowest molybdenum tertile, 4.2% for the middle tertile, and 8.7% for the highest tertile.ConclusionElevated blood molybdenum levels are associated with an increased risk of ovarian cancer on BRCA1 mutation carriers. Lowering molybdenum levels may potentially reduce cancer risk in this population, and high molybdenum levels could serve as a marker for considering preventive oophorectomy in BRCA1 carriers. Further research is warranted to confirm these findings and explore interventions targeting molybdenum levels as a preventive measure for ovarian cancer in BRCA1 mutation carriers.

ISGylation enhances dsRNA-induced interferon response and NFκB signaling in fallopian tube epithelial cells

Heritable mutations in BRCA1 associate with increased risk of high-grade serous tubo-ovarian cancer (HGSTOC). Non-genetic risk factors associated with this cancer, which arises from fallopian tube epithelial (FTE) cells, suggests a role for repetitive ovulation wherein FTE cells are exposed to inflammatory signaling molecules within follicular fluid. We previously reported increased NFκB and EGFR signaling in BRCA1-deficient primary FTE cells, with follicular fluid exposure further increasing abundance of interferon-stimulated gene (ISG) transcripts, including the ubiquitin-like protein ISG15 and other ISGylation pathway members. Both NFκB and type I interferon signaling are upregulated by stimulation of cGAS-STING or MDA5 and RIGI pattern recognition receptors (PRRs). Since some PRRs and their signal transduction pathway members are ISGylated, we tested the impact of ISG15 and ISGylation on IRF3 and NFκB signaling through cGAS-STING or RIGI and MDA5 activation. Expression of ISG15 or UBA7, the E1-like ISG15 activating enzyme, in immortalized FTE cells was disrupted by CRISPR gene editing. Activation of IRF3 by RIGI or MDA5 but not cGAS-STING was attenuated by loss of either ISG15 or UBA7 and this was reflected by a similar effect on NFκB activation and downstream targets. Loss of ISGylation decreased levels of both MDA5 and RIGI, with knock-down of RIGI but not MDA5, decreasing IRF3 and NFκB activation in parental cells. These finding indicate that ISGylation enhances the ability of dsRNA to activate cytokine release and pro-inflammatory signaling. Further work to explore ISGylation as a target for prevention of HGSTOC in BRCA1 mutation carriers is warranted.

The guidelines for clinical practice for carriers of germline mutations in hereditary breast, ovarian, prostate, and pancreatic cancer predisposition genes BRCA1, BRCA2, PALB2, ATM, and CHEK2 (4.2024).

The Guidelines for Clinical Practice for carriers of pathogenic variants in clinically relevant cancer predisposition genes define the steps of primary and secondary prevention that should be provided to these individuals at high risk of developing hereditary cancer in the Czech Republic. The drafting of the guidelines was organized by the Oncogenetics Working Group of the Society for Medical Genetics and Genomics of J. E. Purkyně Czech Medical Society (SLG ČLS JEP) in cooperation with the representatives of oncology and oncogynecology. The guidelines are based on the current recommendations of the National Comprehensive Cancer Network (NCCN), European Society of Medical Oncology (ESMO) and take into account the capacity of the Czech healthcare system.

Pathologic complete response after neoadjuvant systemic therapy for breast cancer in BRCA mutation carriers and noncarriers

BRCA1 and BRCA2 pathogenic variant carriers develop breast cancers with distinct pathological characteristics and mutational signatures that may result in differential response to chemotherapy. We compared rates of pathologic complete response (pCR) after NAC between BRCA1/2 variant carriers and noncarriers in a cohort of 1426 women (92 [6.5%] BRCA1 and 73 [5.1%] BRCA2) with clinical stage I–III breast cancer treated with NAC followed by surgery from 11/2013 to 01/2022 at Memorial Sloan Kettering Cancer Center. The majority received doxorubicin/cyclophosphamide/paclitaxel therapy (93%); BRCA1/2 carriers were more likely to receive carboplatin (p < 0.001). Overall, pCR was achieved in 42% of BRCA1 carriers, 21% of BRCA2 carriers, and 26% of noncarriers (p = 0.001). Among clinically node-positive (cN+) patients, nodal pCR was more frequent in BRCA1/2 carriers compared to noncarriers (53/96 [55%] vs. 371/856 [43%], p = 0.015). This difference was seen in HR+/HER2− (36% vs. 20% of noncarriers; p = 0.027) and TN subtypes (79% vs. 45% of noncarriers; p < 0.001). In a multivariable analysis of the overall cohort, BRCA1 status, and TN and HER2+ subtypes were independently associated with pCR. These data indicate that BRCA1 carriers may be more likely to achieve overall and nodal pCR in response to NAC compared with BRCA2 carriers and patients with sporadic disease. Further studies with a larger cohort of BRCA1/2 mutation carriers are needed, as a small sample size may have a restricted ability to detect a significant association between mutational status and pCR in sensitivity analyses stratified by subtype and adjusted for clinically relevant factors.

P-536 Preimplantation Genetic Testing for hereditary breast and ovarian cancer syndrome due to BRCA pathogenic variant : the parisian center experience

Abstract Study question What are the outcomes of Preimplantation genetic testing for monogenic disease (PGT-M) for BRCA pathogenic variants? Summary answer Among couples entering a PGT-M program for BRCA pathogenic variants, 23.5% achieved a live-birth. What is known already BRCA pathogenic variants are associated with an oncologic predisposition with variable penetrance and are accessible to screening and preventive procedures to avoid or early detect the development of cancer. Transmission of BRCAmutations to offspring poses a significant reproductive concern for BRCA mutation carriers. PGT-M offers a solution to prevent this mutation transmission. Despite reproductive challenges related to BRCA status, there are no existing international guidelines for applying PGT-M in these situations. In France, authorization for BRCA related PGT-M is case-specific, considering the personal and familial severity of the disease and submitted to a multidisciplinary prenatal diagnosis center (CPDPN). Study design, size, duration This retrospective observational study, is a single-center analysis of 46 requests for PGT-M related to BRCA pathogenic variants at our PGT center from January 2015 to December 2022. Participants/materials, setting, methods Forty-six couples asked for PGT-M for BRCA pathogenic variant carried by one of the partner. The present study involves the examination of data encompassing referrals, decisions as well as clinical outcomes associated with PGT-M. Main results and the role of chance Forty-six requests for PGT-M due to the risk of hereditary predisposition to breast and ovarian cancer have been received: 36 for a pathogenic variant in the BRCA1 gene and 10 for BRCA2. Nine couples ultimately did not proceed and dropped out. Eight requests were declined, either due to the refusal of the multidisciplinary prenatal diagnosis center (CPDPN) based on family history (n = 4) or alteration of ovarian reserve (n = 4), the 2 latter requests are still under investigation. In total, requests from 27 couples (55%) were considered eligible and feasible. Among them, 17 (63%) underwent at least one PGT-M cycles (5 dropped out before the beginning and 5 are still pending). Overall, 33 ovarian stimulation cycles for in vitro fertilization were initiated, resulting in the retrieval of 192 mature oocytes and the formation of 145 embryos. Of these, 97 were biopsied, and 38 did not carried the BRCA pathogenic variant. A total of 21 fresh or frozen embryo transfers were performed and 8 pregnancies were achieved, leading to 4 deliveries and 5 live births (23.5% of couples who started a PGT-M cycle). Limitations, reasons for caution In the absence of established guidelines, there is variability in information regarding PGT-M among oncogeneticists. Thus, only selected carriers of BRCA pathogenic variants are addressed to our PGT centers. Additionally, women participating in a fresh PGT cycle were selected on several criteria including ovarian reserve parameters. Wider implications of the findings PGT-M provides a viable alternative for couples seeking to prevent the transmission of BRCA mutations. To increase the PGT-M cumulative live birth rate, the transfer of male embryos carrying the variant, assumed to have lower tumor risks, should be considered and discussed with patients. Trial registration number Not applicable

PARP Inhibitor Addition to Androgen Receptor Pathway Inhibitors in Metastatic Castration-resistant Prostate Cancer Should Be Limited to BRCA Mutation Carriers

For patients with metastatic castration-resistant prostate cancer whose tumors harbor BRCA1/2 alterations, the potential benefits of combining a PARP inhibitor and an androgen receptor pathway inhibitor for first-line treatment outweigh the potential side effects. Further research is required to identify patients without detectable BRCA1/2 defects who would benefit from this approach.

Incidence of peritoneal cancer after oophorectomy among BRCA1 and BRCA2 mutation carriers.

To estimate the incidence of primary peritoneal cancer after preventive bilateral oophorectomy in women with a BRCA1 or BRCA2 mutation. A total of 6310 women with a BRCA1 or BRCA2 mutation who underwent a preventive bilateral oophorectomy were followed for a mean of 7.8 years from oophorectomy. The 20-year cumulative incidence of peritoneal cancer post-oophorectomy was estimated using the Kaplan-Meier method. A left-truncated Cox proportional hazards analysis was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) associated with the age at oophorectomy, year of oophorectomy, and family history of ovarian cancer as well as hormonal and reproductive risk factors. Fifty-five women developed primary peritoneal cancer (n = 45 in BRCA1, 8 in BRCA2, and 2 in women with a mutation in both genes). Their mean age at oophorectomy was 48.9 years. The annual risk of peritoneal cancer was 0.14% for women with a BRCA1 mutation and 0.06% for women with a BRCA2 mutation. The 20-year cumulative risk of peritoneal cancer from the date of oophorectomy was 2.7% for BRCA1 carriers and 0.9% for BRCA2 mutation carriers. There were no peritoneal cancers in BRCA1 carriers who had the operation before age 35 or in BRCA2 carriers who had the operation before age 45. For BRCA1 mutation carriers, the annual risk of peritoneal cancer for 20 years post-oophorectomy is 0.14% per year. The risk is lower for BRCA2 carriers (0.06% per year).

Pedigree analysis exploring the inconsistency between diverse phenotypes and testing criteria for germline TP53 mutations in Chinese women with breast cancer

PurposeIn the present study, we addressed the inconsistency between the testing criteria and diverse phenotypes for germline TP53 mutation in patients with breast cancer in the Chinese population.MethodWe proposed a new added item (synchronous or metachronous bilateral breast cancer) as one of the testing criteria (aimed at high-penetrance breast cancer susceptibility genes) and applied it for determining TP53 germline mutation status in 420 female patients with breast cancer using multigene panel-based next-generation sequencing, Sanger sequencing, and mass spectrometry.ResultsWe found that 1.4% of patients carried a pathogenic or likely pathogenic germline TP53 mutation. Compared with BRCA mutation carriers (8.0%) and non-carriers (7.1%), TP53 mutation carriers (33.3%) developed breast cancer earlier. The majority of TP53 mutation carriers (66.7%) developed breast cancer after age 30 and had bilateral breast cancer (33.3%). Pedigree investigation of four TP53 carriers and a patient with a TP53 variant of unknown significance revealed that neither of their parents harbored the same mutations as the probands, indicating that the mutations might occur de novo.ConclusionOur study revealed distinguishing features of TP53 carriers among Chinese women with breast cancer, which is inconsistent with the currently used testing criteria; therefore, the newly proposed testing criteria may be more appropriate.

Decision aids for female BRCA mutation carriers: a scoping review

ObjectivesWomen who inherit a pathogenic BRCA1 or BRCA2 mutation are at substantially higher risk of developing breast and ovarian cancer than average. Several cancer risk management strategies exist to address...

The prognostic and predictive value of homologous recombination deficiency status in patients with advanced stage epithelial ovarian carcinoma after first-line platinum-based chemotherapy.

Homologous recombination (HR) comprises series of interrelated pathways that repair double-stranded DNA breaks and inter-strand crosslinks. It provides support for DNA replication to recover stalled or broken replication forks. Compared with homologous recombination proficiency (HRP), cancers with homologous recombination deficiency (HRD) are more likely to undergo cell death when treated with DNA-damaging agents, such as platinum agents, and have better disease control. Patients diagnosed with stage III/IV ovarian cancer, early stages with recurrence, who received adjuvant chemotherapy after debulking surgery, and who also had known HR status were eligible. Forty-four patients were included, with 21 in the HRD group (including 8 with germline mutations) and 23 in the HRP group. The HRD group was composed predominantly of serous carcinoma (95.2%), while mucinous (n=3) and clear cell (n=1) cases were all found in the HRP group. Stage III/IV disease was 66.7% and 91.3% in HRD and HRP groups, respectively (p=0.064). Patients who were optimally debulked to no residual disease was 90.0% and 72.7% (p=0.243), respectively. Late line use of PARP inhibitors was 33.3% and 17.4% (p=0.303). Median PFS was 22.5 months (95% CI, 18.5 - 66.6) and 21.5 months (95% CI, 18.3-39.5) (p=0.49) in HRD and HRP respectively. Median platinum free interval (PFI) was 15.8 months (95% CI 12.4-60.4) and 15.9 months (95% CI 8.3-34.1) (p=0.24), respectively. Median OS was 88.2 months (95% CI 71.2-NA) and 49.7 months (95% CI 35.1-NA) (p=0.21). The PFS of the patients with germline BRCA mutations (n=5) was 54.3 months (95% CI 23.1-NA) and 21.5 months (95% CI 18.3-39.5) in the HRP group (p=0.095); the PFI difference was 47.7 months (95% CI 17.6-NA) in the BRCA mutation group, and 15.9 months (95% CI 12.4-60.4) in HRP, showing statistical significance (p=0.039); while the median OS was NA and 49.7 months (95% CI 35.1-NA) respectively (p=0.051). When adding two additional patients with somatic BRCA mutations to the germline BRCA mutation carriers, the median OS is NA (95% CI 73, NA) versus 49.7 months (95% CI 35.1, NA) for HRP (p=0.045). HRD status was not associated with longer PFS or PFI in advanced ovarian cancer who received first line adjuvant platinum-based chemotherapy. Its role as a prognostic marker for overall survival is suggested, particularly in the subgroup with germline and somatic BRCA mutations.

Real-world clinical outcomes and prognostic factors of olaparib maintenance in Korean patients with primary or recurrent high-grade ovarian cancer with exploratory analysis of location of BRCA1 and BRCA2 mutations.

e17561 Background: Olaparib is approved for first-line (1L) and second or subsequent-line (2L+) maintenance therapy in BRCA-mutated ovarian cancer (OC). However, the correlation between location of BRCA mutation and benefit of olaparib maintenance therapy has not been thoroughly investigated. We aimed to analyze real-world clinical outcomes and identify prognostic factors for olaparib maintenance therapy in Korean patients with BRCA-mutated OC, focusing on BRCA mutation sites. Methods: This retrospective cohort study included Korean patients with BRCA-mutated OC who received olaparib as 1L or 2L+ at the single center between January 2015 and April 2023. Survival outcomes and toxicity were correlated with BRCA mutation location summaries and patient characteristics by maintenance therapy line. Results: For the 1L group (n = 70), 2-year PFS and 3-year OS were 75.5% (95% CI, 56.4–87.1) and 98.5% (95% CI, 90.0–99.8). For the 2L+ group (n = 83), 2-year PFS and 3-year OS were 54.8% (95% CI, 56.4–87.1) and 87.3% (95% CI, 76.7–93.3). Primary stage (IV vs. ≤ III) was a prognostic factor for PFS in the 1L group (adjusted hazard ratio [aHR], 5.74; 95% CI, 1.23–26.73; P = 0.026). Notably, Korean-specific pathogenic variant p.Leu1780Pro BRCA1 mutation carriers (n= 8) showed significantly worse PFS than non-carriers (n = 32) in the 1L group (Log-rank P = 0.014). For the 2L+ group, platinum-free interval ≥ 12 months was a good prognostic factor for both PFS (aHR, 0.42; 95% CI, 0.23–0.75) and OS (aHR, 0.31; 95% CI, 0.11–0.91). Additionally, somatic BRCA1 mutation was a poor prognostic factor for PFS in the 2L+ group (hazard ratio [HR], 3.39; 95% CI, 1.22–9.38; P = 0.029). In the 1L group, the longer interval between the last chemotherapy and maintenance therapy was associated with the lower risk of hematologic toxicity induced by olaparib (odd ratio [OR], 0.75; 95% CI 0.57–0.99; P = 0.04). In addition, age ≥ 65 years (OR, 3.33; 95% CI, 1.05–10.63; P = 0.04) and the dose reduction of the last chemotherapy (OR, 3.80; 95% CI, 1.02–14.18; P = 0.047) were associated with a higher risk of hematologic toxicity in the 1L group. In the 2L+ group, germline BRCA1 (OR, 0.36; 95% CI, 0.14–0.92; P = 0.03) and BRCA2 (OR, 7.47; 95% CI, 1.96–28.39; P = 0.003) mutations showed contrariwise risks for hematologic toxicity. Drug discontinuation due to toxicity was 1.4% and 6.0% in the 1L and the 2L+ groups and no acute myeloid leukemia/myelodysplastic syndrome cases were observed. Conclusions: Olaparib maintenance therapy was effective and tolerable in Korean patients with BRCA-mutated OC. Prognostic factors for survival outcomes and risk factors of hematologic toxicity in olaparib maintenance therapy were different between 1L and 2L+. The prognostic significance of Korean-specific p.Leu1780Pro BRCA1 mutation on olaparib should be further researched.

Long-term oncologic outcome of breast-conserving surgery in breast cancer with BRCA 1/2 mutation (ON-BRCA II, KoREa-BSG 06).

552 Background: Among patients with sporadic breast cancer, it is well known that prognoses are similar following breast-conserving surgery (BCS) versus mastectomy. However, previous data assessing oncologic outcomes between BCS and mastectomy in patients with BRCA mutation are limited and inconsistent. Thus, this study aims to compare the oncologic outcomes including locoregional recurrence (LRR), distant recurrence (DR), and overall survival (OS) among this population. Methods: Patients with BRCA mutation and index breast cancer who underwent BCS or mastectomy between January 2008 and December 2015 were retrospectively screened from 13 institutions. We included patients aged from 20-80 with invasive breast cancer (pT1-3 N0-3). Patients with de novo metastasis were excluded. To minimize selection bias from retrospective nature, the propensity score matching (PSM) with Greedy nearest neighbor method was performed for covariates including age, molecular subtype, and tumor stage. Results: A total of 553 patients with BRCA mutation were identified. Among them, 367 (66.2%) patients received BCS and 186 (33.8%) were treated with mastectomy. After 1:1 PSM, there was no significant differences in age, molecular subtype, tumor size, nodal status, and histologic tumor grade between patients undergoing BCS versus mastectomy. At 8.3 years of median follow up, LRR, DR, and OS rates did not differ between groups (all p &gt; 0.05). On multivariate analysis, type of breast surgery (BCS vs. mastectomy) was not significantly associated with the oncologic outcomes after adjusting covariates including age, molecular subtype, tumor stage, and histologic grade (all p &gt; 0.05). Additionally, we performed subgroup analysis in matched patients based on tumor size, LN metastasis, HG, and subtype. In all subgroup, the type of breast surgery was not a significant risk factor influencing disease recurrence. Conclusions: Our findings suggest that there was no difference in oncologic outcomes among BRCA mutation carriers who underwent BCS or mastectomy. Breast conservation with close surveillance is a reasonable treatment option for BRCA mutation carriers. Further studies combined with prospectively collected data are warranted to validate our findings.