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

Germline Testing and Somatic Tumor Testing for BRCA1/2 Pathogenic Variants in Ovarian Cancer: What Is the Optimal Sequence of Testing?

In 2020, ASCO recommended that all women with epithelial ovarian cancer have germline testing for BRCA1/2 mutations, and those without a germline pathogenic variant (PV) should have somatic tumor testing to determine eligibility for a poly (ADP-ribose) polymerase inhibitor. Consequently, the majority of patients with ovarian cancer will have both germline testing and somatic testing. An alternate strategy is tumor testing first and then germline testing if there is a PV in the tumor and/or significant family history. The objective was to conduct a cost-effectiveness analysis comparing the two testing strategies.

Tumor testing for BRCA pathogenic variants is an efficient, cost-effective triage for germline testing.

Characteristics of homologous recombination repair pathway genes mutation in ovarian cancers

Background

Few studies have investigated the characteristics of non-BRCA homologous recombination repair (HRR) pathway somatic mutations, and the impact of these mutations on efficacy of treatment in ovarian cancer patients is not clear. Therefore, we conducted this study to analyze the frequency and spectrum of somatic mutations in HRR pathway genes in patients with ovarian cancer and to examine the relationships between somatic mutations in HRR pathway genes and their effects on the efficacy of platinum-based chemotherapy.

Methods

We performed targeted sequencing of 688 genes related to the occurrence, development, treatment, and prognosis of solid tumors. Somatic mutations were identified by paired analysis of tumor tissue and germline DNA in blood cells.

Results

A total of 38 patients with ovarian cancer were included in the study, and 35 (92.1%) patients were diagnosed with high-grade serous carcinoma. All patients exhibited somatic mutations in the tumor tissue samples. The commonly mutated genes were TP53 (73.7%), BRCA2 (55.3%), NF1 (52.6%), BRCA1 (47.4%), and CDH1 (47.4%). Overall, 71.1% of the patients exhibited mutation in at least one HRR pathway gene. The most frequently altered HRR genes were BRCA2 (55.3%), followed by BRCA1 (47.4%), ATM (44.7%), BARD1 (42.1%), and CHEK1 (36.8%). The median progression-free survival (PFS) in patients with HRR pathway mutation was 36.0 months compared with 13.6 months in patients with no HRR pathway mutation (hazard ratio [HR], 0.25; 95% confidence interval [CI], 0.08-0.77; p = 0.016). Patients harboring BRCA1/2 and/or CDK12 mutations displayed a longer PFS (median, 36.0 months) compared with patients with no BRCA1/2 or CDK12 mutation (median, 13.6 months; HR, 0.21; 95% CI, 0.07-0.61; p = 0.004). In multivariate analysis Cox proportional hazards models, after adjustment for tumor stage at diagnosis and histology of initial diagnosis, patients with HRR pathway mutation had a longer PFS than patients with HRR wild-type genes (p = 0.006).

Conclusions

HRR pathway somatic mutations are common in Chinese patients with ovarian cancer. HRR pathway somatic mutations were associated with improved sensitivity to platinum-based chemotherapy. Large-scale prospective studies are needed to verify our findings.

Trends in the Incidence and Survival Rates of Primary Ovarian Clear Cell Carcinoma Compared to Ovarian Serous Carcinoma in Korea

Objective

To compare the incidence and survival rates of primary ovarian clear cell carcinoma (OCCC) and ovarian serous carcinoma (OSC) from a nationwide collected database.

Methods

We extracted information of patients with primary OCCC and OSC from the Korea Central Cancer Registry recorded between 1999 and 2018, including age at diagnosis and the Surveillance, Epidemiology, and End Results summary stage. Age-standardized incidence rates (ASRs) and annual percent changes (APCs) were calculated. Baseline characteristics and overall survival (OS) were compared between the OCCC and OSC groups.

Results

Overall, the incidence rate of primary OCCC increased markedly from 1999 (ASR, 0.16/100,000) to 2018 (0.76/100,000) (APC, 7.85%; P<0.0001). Patients with OCCC were significantly younger and had early-stage disease more frequently than those with OSC. Patients diagnosed with OCCC before the age of 50 showed better OS than those diagnosed after the age of 50 (P=0.0048). The 5-year OS of the OCCC group did not differ by study period [73.5% (1999–2008) vs. 75.4% (2009–2018), P=0.3187], whereas the 5-year OS of the OSC group improved from 54.4% to 58% (P=0.0003).

Conclusions

Our nationwide registry-based study demonstrated that the incidence of OCCC in Korea increased significantly from 1999 to 2018. Early-stage OCCC had a relatively good prognosis, but advanced-stage OCCC had a worse OS than advanced-stage OSC. Therefore, the development of optimal treatment strategies for OCCC is warranted.

Disparities between Uptake of Germline BRCA1/2 Gene Tests and Implementation of Post-test Management Strategies in Epithelial Ovarian, Fallopian Tube, or Primary Peritoneal Cancer Patients

BACKGROUND

To assess the rate of germline BRCA gene tests in epithelial ovarian cancer (EOC) patients and uptake of post-test risk management strategies in BRCA1/2-mutated patients.

METHODS

Institutional databases were searched to identify patients who were diagnosed with epithelial ovarian, fallopian tube, or primary peritoneal cancer (EOC) between 2009 and 2019 in two academic hospitals. Retrospective review on medical records was performed to collect clinico-pathologic variables, including performance of germline BRCA gene test and its results, as well as conduct of breast cancer screening tests and cascade testing. If annual mammography +/- breast ultrasonography was performed, it was considered that regular breast cancer surveillance was done.

RESULTS

A total of 840 women with EOC were identified during the study period. Of these, 454 patients (54.0%) received BRCA gene testing and 106 patients (106/454, 23.3%) were positive for BRCA1/2 mutations. The rate of BRCA tests has markedly increased from 25.8% in 2009-2012 to 62.7% in 2017-2019. Among the 93 patients with BRCA1/2 mutation without previous personal breast cancer history, 20 patients (21.5%) received annual mammography with or without breast ultrasonography for regular surveillance. Among the 106 BRCA1/2-mutated EOC patients, cascade testing on family members was performed only in 13 patients (12.3%).

CONCLUSION

Although BRCA1/2 gene tests have been substantially expanded, the uptake of post-test risk management strategies, including breast cancer screening for BRCA1/2-mutated patients and cascade testing for family members, has remained low. Strategies to increase its uptake and education about the importance of post-test risk managements are needed.