Use of breast surveillance between women with pathogenic variants and variants of uncertain significance in breast cancer susceptibility genes.

BACKGROUND: Use of surveillance mammography and magnetic resonance imaging (MRI) has been understudied among women with variant of uncertain significance (VUS) compared to pathogenic and likely pathogenic variants (P/LP). METHODS: Using data from two cancer settings, we calculated use of risk-reducing mastectomy (RRM) and surveillance during each 13-month span after genetic testing up to 6 years afterwards for a cohort of genetically elevated risk women. RESULTS: Of 889 women, VUS carriers were less likely to undergo RRM compared to those with P/LP (hazard ratio [HR], 0.17; p = <.001) and high-risk women were more likely to undergo RRM than average-risk women (HR, 3.91; p = .005). Longitudinally, surveillance use among unaffected women decreased from 49.8% in the first year to 31.2% in the sixth year after genetic testing. In comparison, a greater proportion of women with a personal history of breast cancer underwent surveillance, which increased from 59.3% in the first year to 63.6% in the sixth year after genetic testing. Mammography rates did not differ between women with P/LP and VUS within the first 13 months after genetic testing and up to 4 years afterward. Over the first 4 years after genetic testing, women with VUS were less likely to undergo annual MRIs compared to P/LP. CONCLUSION: The authors found that VUS, whether in high or moderate penetrance breast cancer susceptibility genes, was associated with lower use of annual breast MRI compared to P/LP variants and equivalent use of annual mammography. These results add important evidence regarding VUS-related breast surveillance.

Uptake of cancer risk management strategies among women who undergo cascade genetic testing for breast cancer susceptibility genes.

BACKGROUND: Uptake of cancer risk management based on inherited predispositions, which encompasses bilateral mastectomy (BLM), bilateral salpingo-oophorectomy (BSO), and intensified screening, is the primary motivation for cascade testing for hereditary breast and ovarian cancer (HBOC). However, long-term outcome data for cascade testers are lacking. METHODS: Medical records were abstracted for all unaffected women with pathogenic variants in HBOC genes from 2 cancer hospitals (2013-2019) with at least 1 year of follow-up to compare the uptake of surgery and screening between cascade and noncascade testers. RESULTS: Cascade testers (79.8%) were younger than noncascade testers (mean age, 37.6 vs 43.5 years; P = .002). Among women aged ≥40 years, 43% underwent BLM, and 71.6% underwent BSO, with no significant difference in uptake between cascade and noncascade testers. The mean time to BSO among cascade testers was shorter among women aged ≥40 years versus those aged <40 years (11.8 vs 31.9 months; P = .04); no such difference was observed among noncascade testers. Mammography and breast magnetic resonance imaging rates were low in the recorded 6 years for both groups after genetic counseling. CONCLUSIONS: Management uptake among cascade testers is high with rates comparable to those for unaffected BRCA-positive women. A large proportion of women act on cascade test results, and this represents a novel report of utilization of cancer management strategies.

Success of referral to genetic counseling after positive lynch syndrome screening test.

PURPOSE: Lynch syndrome (LS) is a hereditary condition that increases one's risk of developing colorectal, endometrial, and other extracolonic cancers. MD Anderson Cancer Center at Cooper implemented a reflex screening protocol for DNA mismatch repair (dMMR) deficiency. Those with findings suspicious for LS were referred for genetic counseling (GC). Our goal was to assess compliance with GC and factors associated with successful follow-up. METHODS: Immunohistochemistry (IHC) for the MMR proteins MSH2, MLH1, MSH6, and PMS2 was performed on all colorectal tumor resections from patients ≤70 years old and all stage II cancers. Tumors with loss of MLH1/PMS2 were subsequently tested for BRAF mutation or MLH1 promoter methylation to identify tumors with likely epigenetic inactivation of MLH1. Patients with loss of MLH1/PMS2 without BRAF mutations or with absence of MLH1 promoter methylation and those with loss of MSH2/MSH6 were referred to GC. Compliance with GC was assessed. RESULTS: Between March 2014 and August 2016, 203 tumors were tested by IHC. Fifteen (7.4%) patients had abnormal MMR protein expression patterns in the absence of BRAF mutation or MLH1 promoter methylation suggestive of possible LS. GC compliance was 35.7% overall and 85.7% in those with family history of LS-associated cancers. CONCLUSIONS: Overall, GC compliance was relatively low in our study. Interestingly, patients with a strong family history of LS-associated neoplasms were more likely to pursue GC. In the future, assessing and addressing barriers to seeking GC will provide opportunities to improve patient care through increased identification of patients with cancer predisposition syndromes.