Expectations of Surveillance for Non-BRCA Gene Mutation Carriers at Increased Risk for Breast Cancer

Management of individuals with germline pathogenic/likely pathogenic variants in CHEK2: A clinical practice resource of the American College of Medical Genetics and Genomics (ACMG)

PURPOSE

Although the role of CHEK2 germline pathogenic variants in cancer predisposition is well known, resources for managing CHEK2 heterozygotes in clinical practice are limited.

METHODS

An international workgroup developed guidance on clinical management of CHEK2 heterozygotes informed by peer-reviewed publications from PubMed.

RESULTS

Although CHEK2 is considered a moderate penetrance gene, cancer risks may be considered as a continuous variable, which are influenced by family history and other modifiers. Consequently, early cancer detection and prevention for CHEK2 heterozygotes should be guided by personalized risk estimates. Such estimates may result in both downgrading lifetime breast cancer risks to those similar to the general population or upgrading lifetime risk to a level at which CHEK2 heterozygotes are offered high-risk breast surveillance according to country-specific guidelines. Risk-reducing mastectomy should be guided by personalized risk estimates and shared decision making. Colorectal and prostate cancer surveillance should be considered based on assessment of family history. For CHEK2 heterozygotes who develop cancer, no specific targeted medical treatment is recommended at this time.

CONCLUSION

Systematic prospective data collection is needed to establish the spectrum of CHEK2-associated cancer risks and to determine yet-unanswered questions, such as the outcomes of surveillance, response to cancer treatment, and survival after cancer diagnosis.

MRI phenotypes associated with breast cancer predisposing genetic variants, a multisite review

PURPOSE

Examine MRI phenotypes of breast cancers arising in patients with various pathogenic variants, to assess for imaging trends and associations.

METHOD

Multisite retrospective review evaluated 410 patients from 2001 to 2020 with breast cancer and a predisposing pathogenic variant who underwent breast MRI at time of cancer diagnosis. Dominant malignant lesion features were reported, including lesion type (mass versus non-mass enhancement), size, shape, margin, internal enhancement pattern, plus other features. Kruskal-Wallis test, Fisher's exact test, and pairwise comparisons performed comparing imaging manifestations for the most frequent genetic results.

RESULTS

BRCA1 (29.5 %) and BRCA2 (25.9 %) variants were most common, followed by CHEK2 (16.6 %), ATM (8.0 %), and PALB2 (6.3 %), with significant associated differences in race/ethnicity (p = 0.040), age at cancer diagnosis (p = 0.005), tumor shapes (p = 0.001), margins (p < 0.001), grade (p < 0.001), internal enhancement pattern (rim enhancement) (p < 0.001), kinetics (washout) (p < 0.001), and presence of necrosis (p < 0.001). CHEK2 and ATM tumors were often lower grade with spiculated margins (CHEK2: 47.1 %, ATM: 45.5 %), rarely exhibiting washout or tumor necrosis (p < 0.001), and were mostly comprised of luminal molecular subtypes (CHEK2: 88.2 %, ATM: 90.9 %). BRCA1 tumors had the highest proportions with round shape (31.4 %), circumscribed margins (24.0 %), rim enhancement (24.0 %), washout (58.7 %), and necrosis (19.8 %), with 47.9 % comprised of triple negative subtype. Bilateral mastectomy was performed in higher proportions of patients with BRCA1 (84.3 %) and BRCA2 (75.5 %) variants compared to others.

CONCLUSIONS

Genetic and molecular profiles of breast cancers demonstrate reproducible MRI phenotypes.

Psychological and health behaviour outcomes following multi-gene panel testing for hereditary breast and ovarian cancer risk: a mini-review of the literature

INTRODUCTION

Knowledge of the genetic mechanisms driving hereditary breast and ovarian cancer (HBOC) has recently expanded due to advances in gene sequencing technologies. Genetic testing for HBOC risk now involves multi-gene panel testing, which includes well characterized high-penetrance genes (e.g. BRCA1 and BRCA2), as well as moderate- and low-penetrance genes. Certain moderate and low penetrance genes are associated with limited data to inform cancer risk estimates and clinical management recommendations, which create new sources of genetic and clinical uncertainty for patients.

PURPOSE

The aim of this review is to evaluate the psychological and health behaviour outcomes associated with multi-gene panel testing for HBOC risk. The search was developed in collaboration with an Information Specialist (Princess Margaret Cancer Centre) and conducted in the following databases: MEDLINE, EMBASE, EMCare, PsycINFO, Epub Ahead of Publication.

RESULTS

Similar to the BRCA1/2 literature, individuals with a pathogenic variant (PV) reported higher levels of testing-related concerns and cancer-specific distress, as well as higher uptake of prophylactic surgery in both affected and unaffected individuals compared to those with variant of uncertain significance (VUS) or negative result. A single study demonstrated that individuals with a PV in a moderate penetrance gene reported higher rates of cancer worry, genetic testing concerns and cancer-related distress when compared to women with high penetrance PV. Analysis of cancer screening and prevention outcomes based upon gene penetrance were limited to two studies, with conflicting findings.

CONCLUSION

The findings in this review emphasize the need for studies examining psychological and health behavior outcomes associated with panel testing to include between group differences based upon both variant pathogenicity and gene penetrance. Future studies evaluating the impact of gene penetrance on patient-reported and clinical outcomes will require large samples to be powered for these analyses given that a limited number of tested individuals are found to have a PV.