Purpose Women who are newly diagnosed with breast cancer may consider contralateral prophylactic mastectomy (CPM) to reduce their future risk of cancer in their unaffected breast. Pre-surgical BRCA1/2 genetic testing can provide valuable risk information to guide this choice. However, little is understood about why BRCA1/2 mutation noncarriers, who are generally not at substantially elevated risk of contralateral disease, select CPM. Methods We examined the uptake of CPM among breast cancer patients identified as BRCA1/2 mutation noncarriers (n=92) as part of a larger prospective study of the impact of pre-surgical BRCA1/2 testing. Data obtained from self-report questionnaires and patient medical records were used to examine associations between theoretically-relevant background and psychosocial factors and BRCA1/2 mutation noncarriers’ decisions to undergo CPM. Results Among BRCA1/2 mutation noncarriers, 25% (n=23) elected to undergo CPM. Psychosocial factors including a self-reported physician recommendation for CPM, greater perceived contralateral breast cancer risk, and greater perceived benefits of CPM were all significantly associated with the uptake of CPM. Conclusions A sizeable minority of BRCA1/2 mutation noncarriers choose to undergo CPM after learning their mutation status through pre-surgical genetic testing. BRCA1/2 mutation noncarriers’ cognitive perceptions and social influences appear to be important in shaping their decisions regarding CPM. This work highlights the importance of several psychosocial factors in influencing patients’ surgical decisions. Future research is needed that examines the formation of BRCA1/2 mutation noncarriers’ beliefs regarding their disease and available treatment options, and that characterizes the physician-patient communication that occurs in this complex decision-making context.

Our results indicate that the BRCA1 c.5332+4delA variant contributes to cancer predisposition through disruption of normal mRNA splicing. We classify this variant as likely pathogenic.

BRCA1/2 large rearrangement (LR) testing has been available to patients since 2006. Three existing models commonly used in cancer genetics clinical and research settings (BRCAPRO, Penn II and Myriad II) have not been assessed for their performance in predicting the presence of BRCA1/2 large genomic rearrangements in patients who do not have mutations detectable by the traditional Sanger sequencing approach. This study sought to determine if there is an optimal pre-test probability "cut off" value, calculated using these models, to optimize detection of large rearrangements (LRs). Our cohort consisted of 3,301 probands seen for genetic counseling and BRCA1/2 clinical testing from September 2006 to September 2011. A detailed personal and three-generation family history, including self-reported ethnicity, was taken as part of our standard clinical practice. We applied the BRCAPRO, Penn II, and Myriad II models to the probands with LRs. In our cohort of 3,301 probands, 150 carried a non-Ashkenazi mutation in BRCA1 or BRCA2. Seventeen unrelated probands carried a private BRCA1/2 LR (17/150, 11.3 % of all detectable non-AJ mutations). At a pre-test probability cutoff of 10 %, all three empiric risk models would have failed to identify almost 30 % of probands with LRs. Our study shows that BRCA1/2 LR testing should be offered to all women who meet criteria for BRCA1/2 sequence analysis.

IORT; PB-IORT) or deep inspiratory breath hold external beam radiation therapy (EBRT-DIBH) for early stage left sided breast cancers at our institution. Materials/Methods: We retrospectively identified the 17 patients with left sided breast cancers treated with PB-IORT on a phase I clinical trial. 17 patients with left-sided tumors who had undergone lumpectomy and adjuvant EBRT-DIBH during a similar time period were identified for comparison. Dosimetric data was obtained for mean and maximum heart and left anterior descending artery (LAD) doses. T-testing analysis was performed, and biologically effective doses (BED) were calculated using an alpha/beta ratio for heart of 2 Gy. Results: Mean heart dose was found to be significantly lower in the EBRT-DIBH group compared to the IORT group (0.61 vs. 0.87 Gy, pZ0.006). Nominal maximum heart dose was significantly higher in the EBRT-DIBH group (11.37 vs. 4.81 Gy, pZ0.004). BED for maximum heart dose was similar between the EBRT-DIBH and IORT groups, 16.63 vs. 19.36 Gy, respectively (pZ0.64). No difference was found in mean left anterior descending (LAD) artery dose: 2.18 Gy in the EBRT-DIBH group and 1.89 Gy in the IORT group (pZ0.446). The maximum LAD doses were 9.63 Gy and 3.62 Gy in the EBRT-DIBH and IORT groups, respectively (pZ0.016). Conclusion: Heart doses were found to be low in both groups. Expected increase in cardiac risk at these doses is minimal. It is unlikely that there will be a clinically significant difference in cardiac toxicity in patients treated with EBRT-DIBH or PB-IORT.

PURPOSE NTHL1 and MSH3 have been implicated as autosomal recessive cancer predisposition genes. Although individuals with biallelic NTHL1 and MSH3 pathogenic variants (PVs) have increased cancer and polyposis risk, risks for monoallelic carriers are uncertain. We sought to assess the prevalence and characterize NTHL1 and MSH3 from a large pan-cancer patient population. MATERIALS AND METHODS Patients with pan-cancer (n = 11,081) underwent matched tumor-normal sequencing with consent for germline analysis. Medical records and tumors were reviewed and analyzed. Prevalence of PVs was compared with reference controls (Genome Aggregation Database). RESULTS NTHL1-PVs were identified in 40 patients including 39 monoallelic carriers (39/11,081 = 0.35%) and one with biallelic variants (1/11,081 = 0.009%) and a diagnosis of isolated early-onset breast cancer. NTHL1-associated mutational signature 30 was identified in the tumors of the biallelic patient and two carriers. Colonic polyposis was not identified in any NTHL1 patient. MSH3-PVs were identified in 13 patients, including 12 monoallelic carriers (12/11,081 = 0.11%) and one with biallelic MSH3 variants (1/11,081 = 0.009%) and diagnoses of later-onset cancers, attenuated polyposis, and abnormal MSH3-protein expression. Of the 12 MSH3 carriers, two had early-onset cancer diagnoses with tumor loss of heterozygosity of the wild-type MSH3 allele. Ancestry-specific burden tests demonstrated that NTHL1 and MSH3 prevalence was not significantly different in this pan-cancer population versus controls. CONCLUSION NTHL1 and MSH3 germline alterations were not enriched in this pan-cancer patient population. However, tumor-specific findings, such as mutational signature 30 and loss of heterozygosity of the wild-type allele, suggest the potential contribution of monoallelic variants to tumorigenesis in a subset of patients.