A population-based analysis of germline BRCA1 and BRCA2 testing among ovarian cancer patients in an era of histotype-specific approaches to ovarian cancer prevention

Tissue-Predisposition to Cancer Driver Mutations

Driver mutations are considered the cornerstone of cancer initiation. They are defined as mutations that convey a competitive fitness advantage, and hence, their mutation frequency in premalignant tissue is expected to exceed the basal mutation rate. In old terms, that translates to "the survival of the fittest" and implies that a selective process underlies the frequency of cancer driver mutations. In that sense, each tissue is its own niche that creates a molecular selective pressure that may favor the propagation of a mutation or not. At the heart of this stands one of the biggest riddles in cancer biology: the tissue-predisposition to cancer driver mutations. The frequency of cancer driver mutations among tissues is non-uniform: for instance, mutations in APC are particularly frequent in colorectal cancer, and 99% of chronic myeloid leukemia patients harbor the driver BCR-ABL1 fusion mutation, which is rarely found in solid tumors. Here, we provide a mechanistic framework that aims to explain how tissue-specific features, ranging from epigenetic underpinnings to the expression of viral transposable elements, establish a molecular basis for selecting cancer driver mutations in a tissue-specific manner.

Advanced ovarian clear cell carcinoma with RAD50 mutation treated by PARP inhibitor pamiparib combined with anti-angiogenesis therapy: a case report

Ovarian clear cell carcinoma (OCCC) is a relatively uncommon epithelial ovarian malignancy with unique clinical, histopathologic and genetic characteristics. Patients with advanced OCCC have poor outcomes and are resistant to standard chemotherapy. Targeted therapy offers a novel approach for treating OCCC. We report the case of a 45-year-old female patient with advanced OCCC who experienced relapse after standard treatment. Further, a frameshift mutation in the homologous recombination repair-related gene RAD50 (RAD50-p.I371Ffs*8) was identified by genetic testing. Next, the patient had received targeted combination therapy with poly (ADP-ribose) polymerase (PARP) inhibitor pamiparib and bevacizumab, achieving partial remission. Patient's symptoms improved significantly compared to before. To date, the patient has been followed up for more than half a year with favorable survival and high quality of life. The case report suggested that parmiparib-targeted therapy is a viable treatment option for advanced OCCC patients with RAD50 mutation.

Impact of bevacizumab and secondary cytoreductive surgery on survival outcomes in platinum-sensitive relapsed ovarian clear cell carcinoma: A multicenter study in Korea

OBJECTIVE

This study investigated survival outcomes for platinum-sensitive relapsed ovarian clear cell carcinoma (OCCC) by treatment method.

METHODS

OCCC patients with platinum-sensitive recurrence that received secondary treatment at five institutions between July 2007 and June 2021 were included. Patient characteristics and survival outcomes were compared according to the use of bevacizumab (BEV) during second-line chemotherapy and secondary cytoreductive surgery (CRS).

RESULTS

138 patients were included. The BEV (n = 36) and non-BEV (n = 102) groups had similar initial FIGO stages and proportions of secondary CRS. The BEV group showed improved progression-free survival (PFS; median, 15.4 vs. 7.5 months; P = 0.042) and overall survival (OS; P = 0.043) compared to the non-BEV group. In multivariate analyses, BEV was identified as an independent prognostic factor for PFS (adjusted hazard ratio [aHR], 0.571; 95% confidence interval [CI], 0.354-0.921; P = 0.022) and OS (aHR, 0.435; 95%CI, 0.195-0.970; P = 0.042). The secondary CRS group (n = 42) had early-stage disease at diagnosis more frequently (P = 0.009) and multi-site metastasis (P < 0.001) at recurrence less frequently than the no surgery group (n = 96). The secondary CRS group showed significantly better PFS (median, 33.7 vs. 7.2 months; P < 0.001) and OS (P < 0.001). Secondary CRS was associated with a significantly improved PFS (aHR, 0.297; 95% CI, 0.183-0.481; P < 0.001) and OS (aHR, 0.276; 95% CI, 0.133-0.576; P = 0.001). The BEV and non-BEV groups showed similar PFS and OS among the patients who underwent secondary CRS. In contrast, the BEV group showed improved PFS and OS among patients who did not undergo surgery.

CONCLUSIONS

The use of BEV during second-line chemotherapy and secondary CRS may improve PFS and OS in patients with platinum-sensitive relapsed OCCC. Further prospective studies are warranted.

A Pan-Canadian Consensus Statement on First-Line PARP Inhibitor Maintenance for Advanced, High-Grade Serous and Endometrioid Tubal, Ovarian, and Primary Peritoneal Cancers

The majority of patients with advanced, high-grade epithelial-tubo ovarian cancer (EOC) respond well to initial treatment with platinum-based chemotherapy; however, up to 80% of patients will experience a recurrence. Poly(ADP-ribose) Polymerase (PARP) inhibitors have been established as a standard of care maintenance therapy to prolong remission and prevent relapse following a response to first-line platinum-chemotherapy. Olaparib and niraparib are the PARP inhibitors currently approved for use in the first-line maintenance setting in Canada. Selection of maintenance therapy requires consideration of patient and tumour factors, presence of germline and somatic mutations, expected drug toxicity profile, and treatment access. This paper discusses the current clinical evidence for first-line PARP inhibitor maintenance therapy in patients with advanced, high-grade EOC and presents consensus statements and a treatment algorithm to aid Canadian oncologists on the selection and use of PARP inhibitors within the Canadian EOC treatment landscape.

Identification of the most common BRCA alterations through analysis of germline mutation databases: Is droplet digital PCR an additional strategy for the assessment of such alterations in breast and ovarian cancer families?

Breast and ovarian cancer represent two of the most common tumor types in females worldwide. Over the years, several non‑modifiable and modifiable risk factors have been associated with the onset and progression of these tumors, including age, reproductive factors, ethnicity, socioeconomic status and lifestyle factors, as well as family history and genetic factors. Of note, BRCA1 and BRCA2 are two tumor suppressor genes with a key role in DNA repair processes, whose mutations may induce genomic instability and increase the risk of cancer development. Specifically, females with a family history of breast or ovarian cancer harboring BRCA1/2 germline mutations have a 60‑70% increased risk of developing breast cancer and a 15‑40% increased risk for ovarian cancer. Different databases have collected the most frequent germline mutations affecting BRCA1/2. Through the analysis of such databases, it is possible to identify frequent hotspot mutations that may be analyzed with next‑generation sequencing (NGS) and novel innovative strategies. In this context, NGS remains the gold standard method for the assessment of BRCA1/2 mutations, while novel techniques, including droplet digital PCR (ddPCR), may improve the sensitivity to identify such mutations in the hereditary forms of breast and ovarian cancer. On these bases, the present study aimed to provide an update of the current knowledge on the frequency of BRCA1/2 mutations and cancer susceptibility, focusing on the diagnostic potential of the most recent methods, such as ddPCR.

A multidisciplinary approach remains the best strategy to improve and strengthen the management of ovarian cancer (Review)

Ovarian cancer represents one of the most aggressive female tumors worldwide. Over the decades, the therapeutic options for the treatment of ovarian cancer have been improved significantly through the advancement of surgical techniques as well as the availability of novel effective drugs able to extend the life expectancy of patients. However, due to its clinical, biological and molecular complexity, ovarian cancer is still considered one of the most difficult tumors to manage. In this context, several studies have highlighted how a multidisciplinary approach to this pathology improves the prognosis and survival of patients with ovarian cancer. On these bases, the aim of the present review is to present recent advantages in the diagnosis, staging and treatment of ovarian cancer highlighting the benefits of a patient‑centered care approach and on the importance of a multidisciplinary team for the management of ovarian cancer.

Health system interventions to integrate genetic testing in routine oncology services: A systematic review

BACKGROUND

Integration of genetic testing into routine oncology care could improve access to testing. This systematic review investigated interventions and the tailored implementation strategies aimed at increasing access to genetic counselling and testing and identifying hereditary cancer in oncology.

METHODS

The search strategy results were reported using the PRISMA statement and four electronic databases were searched. Eligible studies included routine genetic testing for breast and ovarian cancer or uptake after universal tumour screening for colorectal or endometrial cancer. The titles and abstracts were reviewed and the full text articles screened for eligibility. Data extraction was preformed using a designed template and study appraisal was assessed using an adapted Newcastle Ottawa Scale. Extracted data were mapped to Proctor's et al outcomes and the Consolidated Framework for Implementation Research and qualitatively synthesised.

RESULTS

Twenty-seven studies, published up to May 2020, met the inclusion criteria. Twenty-five studies ranged from poor (72%), fair to good (28%) quality. Most interventions identified were complex (multiple components) such as; patient or health professional education, interdisciplinary practice and a documentation or system change. Forty-eight percent of studies with complex interventions demonstrated on average a 35% increase in access to genetic counselling and a 15% increase in testing completion. Mapping of study outcomes showed that 70% and 32% of the studies aligned with either the service and client or the implementation level outcome and 96% to the process or inner setting domains of the Consolidated Framework for Implementation Research.

CONCLUSION

Existing evidence suggests that complex interventions have a potentially positive effect towards genetic counselling and testing completion rates in oncology services. Studies of sound methodological quality that explore a greater breadth of pre and post implementation outcomes and informed by theory are needed. Such research could inform future service delivery models for the integration of genetics into oncology services.

Mutational spectrum in clinically aggressive low-grade serous carcinoma/serous borderline tumors of the ovary-Clinical significance of BRCA2 gene variants in genomically stable tumors

OBJECTIVE

The mutational spectra of low-grade serous carcinomas (LGSCs) and serous borderline tumors (SBTs) of the ovary are poorly characterized. We present 17 cases of advanced or recurrent LGSC/SBT patients who underwent molecular profiling.

METHODS

Thirteen LGSCs and four SBTs underwent targeted gene panel testing by massively parallel sequencing. Microsatellite stability and tumor mutation burdens (TMBs) were determined based on panel sequencing data.

RESULTS

The mean TMB was 5.2 mutations/megabase (range 3-10) in 14 cases. Twelve of twelve (12/12) cases were microsatellite stable. Clear driver mutations were identified in 11 cases, namely KRAS (5/17), BRAF (2/17), NRAS (2/17) and ERBB2 (2/17). Five cases harbored BRCA2 alterations (allele fractions: 44-51%), including two classified as likely benign/benign variants, and three classified as variants of uncertain significance (VUSs), with two variants being confirmed to be germline. The three BRCA2 VUSs were missense variants that were assessed to be of unlikely clinical significance, based on family cancer history and expected impact on protein function. Two patients received PARP inhibitors during their disease course, with neither of the patients demonstrating appreciable response.

CONCLUSIONS

The mutational spectra in 17 clinically aggressive SBT/LGSC cases demonstrate genomically stable tumors, frequently driven by the RTK/RAS/MAPK pathway. While BRCA2 variants were identified, our data demonstrate BRCA2 gene variants are at most VUSs and of dubious clinical significance, in contrast to disease-associated BRCA1/2 variants that may be identified in high-grade serous carcinoma. Germline testing and PARP inhibitors are thus expected to provide limited benefit to patients with LGSC/SBTs.

Ovarian carcinoma in patients with BRCA mutation - a correlation between the growing pattern of peritoneal implants evaluated by CT/MRI and the genotype BRCA1 and BRCA2

Background

Ovarian cancer is the leading cause of death from gynecologic cancer. The risk of developing ovarian cancer is significantly increased in patients that carry a genetic mutation of tumor suppressor gene BRCA1 or BRCA2. The majority of BRCA-associated ovarian/fallopian tube cancers are high-grade serous carcinomas (HGSC). The recognition of patterns of disease is crucial to identify distinctive imaging features that could be useful for predicting prognosis and therapeutic response.

Results

An institutional review board-approved retrospective study was performed and included 34patients (23 BRCA-mutated and 11 BRCA wild-type) with HGSC FIGO III/IV who underwent pre-operative or pre-chemotherapy contrast-enhanced CT/MRI of the abdomen and pelvis between January 2003 and December 2017. Three radiologists independently reviewed the imaging studies and looked for qualitative features of the primary tumor and peritoneal metastases (nodular versus infiltrative pattern). Two pathologists also assessed the histopathologic characteristics of the surgical specimens, with emphasis on the growth pattern of metastatic deposits (expansive/nodular and infiltrative) and inflammatory infiltrate (intra- and/or peritumoral).

No significant associations were found between the different groups of patients (BRCA1-mutant HGSC, BRCA2-mutant HGSC. and BRCA wild-type) and CT/MRI features of ovarian tumors, morphology of peritoneal metastasis, and pathologic characteristics.

Conclusion

Identification of specific imaging and pathologic features is important to pursue an optimal personalized cancer treatment strategy and to develop precision medicine in the future.

Germline and Somatic BRCA1/2 Gene Mutational Status and Clinical Outcomes in Epithelial Peritoneal, Ovarian, and Fallopian Tube Cancer: Over a Decade of Experience in a Single Institution in Korea

PURPOSE

This study aimed to present a single institutional experience with BRCA1/2 gene tests and the effects of pathogenic mutations in epithelial peritoneal, ovarian, and fallopian tube cancer (POFTC) on survival outcomes.

Materials and Methods

We identified patients with epithelial POFTCs who underwent BRCA1/2 gene testing by either germline or somatic methods between March 2007 and March 2020. Based on the BRCA1/2 test results, patients were divided into BRCA mutation and wild-type groups, followed by comparisons of clinicopathologic characteristics and survival outcomes after primary treatment.

RESULTS

The annual number of POFTC patients who received BRCA1/2 gene tests increased gradually. In total, 511 patients were included and BRCA1/2 mutations were observed in 143 (28.0%). Among 57 patients who received both germline and somatic tests, three (5.3%) showed discordant results from the two tests. Overall, no differences in progression-free survival (PFS; p=0.467) and overall survival (p=0.641) were observed between the BRCA mutation and wild-type groups; however, multivariate analyses identified BRCA1/2 mutation as an independent favorable prognostic factor for PFS (adjusted hazard ratio [aHR], 0.765; 95% confidence interval [CI], 0.593 to 0.987; p=0.040). In 389 patients with International Federation of Gynecology and Obstetrics stage III-IV, different results were shown depending on primary treatment strategy: while BRCA1/2 mutation significantly improved PFS in the subgroup of neoadjuvant chemotherapy (aHR, 0.619; 95% CI, 0.385 to 0.995; p=0.048), it did not affect patient PFS in the subgroup of primary debulking surgery (aHR, 0.759; 95% CI, 0.530 to 1.089; p=0.135).

CONCLUSION

BRCA1/2 mutations are frequently observed in patients with epithelial POFTCs, and such patients showed better PFS than did those harboring wild-type BRCA1/2.

Setting a baseline: A 7-year review of referral rates and outcomes for serous ovarian cancer prior to implementation of oncologist mediated genetic testing

OBJECTIVE

Despite guidelines recommending that all women with invasive serous ovarian cancer (SOC) are offered genetic testing, published referral and testing rates have been poor. Many centers have implemented novel genetic counseling service delivery models to increase testing rates. In light of increased awareness and implementation of small process changes at our center, this study aims to establish baseline referral rates and testing outcomes prior to diverging from the traditional model of care.

METHODS

A list of women diagnosed with SOC at Princess Margaret Cancer Center (PM) between 2010 and 2016 was obtained from the PM Cancer Registry and cross-referenced against the genetics database to determine referral rates and outcomes of genetic testing.

RESULTS

Of 724 women with SOC, 68% were referred for genetic counseling, with an overall testing rate of 61%. Higher referral rates were seen among women with younger ages at diagnosis and high-grade tumors. Of women tested, 22% were found to have a pathogenic variant in BRCA1/2 and 9% in another cancer gene. Notably, 24% of women with a pathogenic variant reported no family history of breast or ovarian cancer.

CONCLUSION

Genetic counseling referral and testing rates for women with SOC are higher than previously reported, yet barriers to referral remain. To maximize genetic testing rates and address increasing patient volumes, clinics may be faced with integrating novel genetic counseling delivery models. Findings from this study may serve as a more accurate baseline to which large scale service delivery changes can be compared.

An integrated molecular profile of endometrioid ovarian cancer

OBJECTIVE

Endometrioid ovarian carcinoma (EOVC) is an uncommon subtype of epithelial ovarian carcinoma and its molecular characteristics have been incompletely described. Prior sequencing investigations have been limited to targeted gene panels. We performed whole-exome sequencing to build an unbiased genetic profile of molecular alterations in endometrioid ovarian tumors with a goal to better understand this disease in the context of epithelial ovarian cancer and endometrioid uterine cancers.

METHODS

Whole-exome sequencing was performed on EOVC samples (n = 26) and matched normals (n = 15). Gene mutations, mutational signatures and copy number variations (CNVs) informed a multi-dimensional regression classifier allowing for comparison to endometrial carcinoma (UCEC) and high grade serous ovarian carcinoma (HGSC).

RESULTS

EOVC has a distinct and heterogeneous genomic profile. Identified significantly mutated genes in EOVC (PTEN, CTNNB1, PIK3CA, KMT2D, KMT2B, PIK3R1, ARID1A and TP53) occurred at similar frequencies in UCEC. Hypermutation, resulting from both mismatch repair deficiency (MMRd) and POLE mutation, was observed in EOVC at a frequency similar to UCEC. Like UCEC, a subset of EOVC cases closely resembled HGSC, harboring TP53 mutations, homologous recombination deficiency (HRd) mutation signatures and widespread CNVs. A machine-learning classifier confirmed the heterogeneous composition of EOVC. Potential therapeutic targets were identified in 62% of EOVC cases. We validated our findings in an orthogonal clinical sequencing registry of EOVC cases.

CONCLUSIONS

We identified that EOVC are a molecularly heterogeneous group of epithelial ovarian cancers with distinct mutational signatures. In an age of precision oncology, there is a pressing need to understand the unique molecular drivers in uncommon histologic subtypes to facilitate genomically driven oncologic treatments.

Transcriptional Characterization of Stage I Epithelial Ovarian Cancer: A Multicentric Study

Stage I epithelial ovarian cancer (EOC) represents about 10% of all EOCs. It is characterized by a complex histopathological and molecular heterogeneity, and it is composed of five main histological subtypes (mucinous, endometrioid, clear cell and high, and low grade serous), which have peculiar genetic, molecular, and clinical characteristics. As it occurs less frequently than advanced-stage EOC, its molecular features have not been thoroughly investigated. In this study, using in silico approaches and gene expression data, on a multicentric cohort composed of 208 snap-frozen tumor biopsies, we explored the subtype-specific molecular alterations that regulate tumor aggressiveness in stage I EOC. We found that single genes rather than pathways are responsible for histotype specificities and that a cAMP-PKA-CREB1 signaling axis seems to play a central role in histotype differentiation. Moreover, our results indicate that immune response seems to be, at least in part, involved in histotype differences, as a higher immune-reactive behavior of serous and mucinous samples was observed with respect to other histotypes.

Germline and somatic mutations of homologous recombination-associated genes in Japanese ovarian cancer patients

We explored the frequency of germline and somatic mutations in homologous recombination (HR)-associated genes in major histological types of ovarian cancer. We performed targeted sequencing to assess germline and somatic mutations of 16 HR-associated genes and 4 mismatch repair (MMR) genes among 207 ovarian cancer patients (50 high-grade serous carcinomas (HGSC), 99 clear cell carcinomas (CCC), 39 endometrioid carcinomas (EC), 13 mucinous carcinomas (MC), and 6 low-grade serous carcinomas (LGSC)). Germline or somatic mutations of HR-associated genes were detected in 44% of HGSC, 28% of CCC, 23% of EC, 16% of MC, and 17% of LGSC patients. The profile of HR-associated gene mutations was remarkably different among each histological type. Germline BRCA1/2 mutations were frequently detected in HGSC and were rarely observed in CCC, EC, and MC patients. ATM somatic mutation was more frequently detected in CCC (9%) and EC patients (18%) than in HGSC patients (4%). There was a positive correlation between MMR gene mutations and HR-associated gene mutations (p = 0.0072). Our findings might be useful in selection of ovarian cancer patients that should be treated with PARP inhibitors.

Long-term mortality among women with epithelial ovarian cancer: a population-based study in British Columbia, Canada

OBJECTIVES

Among women with epithelial ovarian cancer (EOC), histotype is one of the major prognostic factors. However, few data are available on histotype- specific survival and mortality estimates among these patients. We therefore examined survival and causes of death among women with EOC by histotype.

METHODS

A population- based cohort including all ovarian cancer patients diagnosed in British Columbia (BC) between 1990 and 2014 was built using population-based administrative datasets. We compared causes of death within histotypes, by age at diagnosis, BRCA status, and time since diagnosis.

RESULTS

A total of 6975 women were identified as having been diagnosed with EOC between 1990 and 2014 in BC. The most common cause of death among these women was ovarian cancer until 10 years post diagnosis when other causes surpassed ovarian cancer as the leading cause of death. Among women with serous EOCs, ovarian cancer was the leading cause of death 12 years after diagnosis, whereas ovarian cancer was the leading cause of death for 8 years among women with non- serous EOCs. Among women with serous EOCs, ovarian cancer was the leading cause of death for 12 years among younger women (< 60 years of age) compared to 8 years among women > = 60 years of age, and those with BRCA mutations were more likely to die from ovarian cancer than those without a BRCA mutation.

CONCLUSIONS

Within 10 years from diagnosis, ovarian cancer is the leading cause of death among women diagnosed with EOC.

Evolution of genetic assessment for BRCA-associated gynaecologic malignancies: a Canadian multisociety roadmap

The landscape of genetic testing in ovarian cancer patients has changed dramatically in recent years. The therapeutic benefits of poly ADP-ribose polymerase (PARP) inhibitors in treatment of BRCA1/2-related ovarian cancers has resulted in an increased demand and urgency for genetic testing results, while technological developments have led to widespread use of multi-gene cancer panels and development of tumour testing protocols. Traditional genetic counselling models are no longer sustainable and must evolve to match the rapid evolution of genetic testing technologies and developments in personalized medicine. Recently, representatives from oncology, clinical genetics, molecular genetics, pathology, and patient advocacy came together to create a national multi-disciplinary Canadian consortium. By aligning stakeholder interests, the BRCA Testing to Treatment (BRCA TtoT) Community of Practice aims to develop a national strategy for tumour and germline BRCA1/2 testing and genetic counselling in women with ovarian cancer. This article serves to provide an overview of the recent evolution of genetic assessment for BRCA1/2-associated gynecologic malignancies and outline a Canadian roadmap to facilitate change, improve genetic testing rates, and ultimately improve outcomes for hereditary ovarian cancer patients and their families.