Testing Ashkenazi Jewish Women for Mutations Predisposing to Breast Cancer in Genes Other Than BRCA1 and BRCA2

Association of Germline Genetic Test Type and Results With Patient Cancer Worry After Diagnosis of Breast Cancer

BACKGROUND

There are concerns that multigene panel testing compared with BRCA1/ 2-only testing after diagnosis of breast cancer may lead to unnecessary patient worry about cancer because of more ambiguous results.

METHODS

Patients with breast cancer diagnosed from 2013 to 2015 and accrued from SEER registries in Georgia and Los Angeles were surveyed (n = 5,080; response rate, 70%), and responses were merged with SEER data and germline genetic testing and results. We examined patient reports of cancer worry by test type and results in 1,063 women who linked to a genetic test and reported undergoing testing.

RESULTS

More than half of the sample (n = 640; 60.2%) received BRCA1/2-only testing versus 423 patients (39.8%) who had a multigene panel. A minority of tested patients reported substantial cancer worry after treatment: 11.1% (n = 130) reported higher impact of cancer worry, and 15.1% (n = 162) reported a high frequency of cancer worry (worrying often or almost always) in the past month. Impact of cancer worry did not substantively differ by test type, test result outcomes, or clinical or treatment factors. The odds ratio for higher impact of cancer worry was 0.81 (95% CI, 0.51 to 1.28) for multigene versus BRCA1/2-only testing. In a separate model, the odds ratios were 1.21 (95% CI, 0.54 to 2.68) and 0.90 (95% CI, 0.50 to 1.62) for pathogenic variant and variant of uncertain significance, respectively, versus a negative test (the reference group).

CONCLUSION

Compared with BRCA1/2 testing alone, multigene panel testing was not associated with increased cancer worry after diagnosis of breast cancer.

Prevalence of nonfounder BRCA1/2 mutations in Ashkenazi Jewish patients presenting for genetic testing at a hereditary breast and ovarian cancer center

BACKGROUND

Genetic assessment in Ashkenazi Jewish (AJ) patients often is limited to BRCA1/2 founder mutation testing. With access to time-efficient and cost-efficient multigene panel testing, some advocate expanding genetic testing in this population. However, to the best of the authors' knowledge, rates of nonfounder BRCA1/2 mutations and mutations in cancer-associated genes other than BRCA1/2 among AJ are not known. In the current study, the authors sought to assess the prevalence of mutations other than BRCA1/2 founder mutations among AJ patients undergoing genetic assessment.

METHODS

The authors reviewed the medical records for all AJ patients who underwent genetic assessment at a single institution between June 2013 and December 2016. Mutations were categorized as 1) BRCA1/2 AJ founder mutations (BRCA1 185delAG, BRCA1 5382insC, or BRCA2 6174delT); 2) nonfounder BRCA1/2 mutations; or 3) mutations in non-BRCA1/2 cancer-associated genes.

RESULTS

A total of 732 AJ patients underwent genetic assessment. Of these, 371 patients (51%) had a personal history of breast or ovarian cancer, 540 patients (73.8%) had a family history of breast cancer, and 132 patients (18%) had a family history of ovarian cancer. In the study population, 101 patients (13.8%) were found to have a pathogenic mutation, 78 patients (10.7%) had a BRCA1/2 founder mutation, 3 patients (0.4%) had a nonfounder BRCA1/2 mutation, and 20 patients (2.7%) had a mutation in a non-BRCA1/2 cancer-associated gene. Non-BRCA1/2 cancer-associated genes harboring mutations included RAD51D, TP53, mutS homolog 6 (MSH6), checkpoint kinase 2 (CHEK2), adenomatous polyposis coli (APC), and Fanconi anemia group C protein (FANCC).

CONCLUSIONS

Among AJ patients found to have a pathogenic mutation on genetic assessment, approximately 22.8% had a mutation that would be missed with BRCA1/2 AJ founder mutation testing. Comprehensive multigene panel sequencing can provide clinically relevant genetic information for AJ patients and should be considered for genetic assessment in this population.