Robson, Mark E.

1508 Background: With the expansion of multigene panel testing for cancer susceptibility, increasing numbers of patients are identified with pathogenic/likely pathogenic variants (P/LP V) in genes which do not have a clearly actionable increased risk of ovarian cancer (OC) (lifetime risk of OC >5%). However, there is concern that patients and/or providers may ascribe OC risk to such genetic findings with the potential for unnecessary oophorectomy (ooph). Methods: The Prospective Registry of Multiplex Testing (PROMPT) is an online registry for individuals with a genetic alteration detected on multiplex panel testing for cancer susceptibility. Participants self-enroll and complete baseline and annual follow-up questionnaires. PROMPT has enrolled 7388 participants (6936; 93.9% women) since September 2014. Results: 1566 women in the PROMPT registry reported ooph, the indications for which were reported as either cancer treatment (n=481, 30.7%) or benign disease (n=432, 27.6%). An additional 186 (12.8%) reported PV in genes associated with lifetime OC risk >5% ( BRCA1, BRCA2, RAD51C, RAD51D, BRIP, or Lynch syndrome genes). The remaining 467 did not have guideline based indications for ooph due to OC risk and are described further here. 92 (19.7%) had a variant of uncertain significance (VUS) in genes associated with OC, 241 (51.6%) had a personal history of breast cancer (BC) and no VUS in OC genes, and 119 (25.5%) had no personal history of BC and no VUS in OC genes. The majority of women had no family history (FH) of OC in first or second degree relatives (Table). Most ooph occurred prior to age 50. Of the 405 women with CHEK2 P/LP, 11.4% reported ooph (59% under age 50 when age known), as did 13.2% (of 228) with CHEK2 VUS, 8.8% (of 261) with ATM P/LP (66.7% under age 50), and 8.3% (of 387) with ATM VUS. In addition, of the 184 women with PALB2 P/LP, 14.1% reported ooph (35.3% under age 50) as did 11.6% (of 198) with PALB2 VUS. Of those who reported provider discussions, 47.2% stated “my provider recommended this” (including >60% in the OC gene VUS group) and an additional 25.2% stated “my provider presented this as an option, but not a requirement”. In those with no FH of OC, 45.8% stated that their provider recommended ooph. Conclusions: 10-15% of women with PV/VUS in genes not associated with a high risk of OC reported ooph without a clear indication. [Table: see text]

PURPOSE To develop recommendations for management of patients with breast cancer (BC) with germline mutations in BC susceptibility genes. METHODS The American Society of Clinical Oncology, American Society for Radiation Oncology, and Society of Surgical Oncology convened an Expert Panel to develop recommendations based on a systematic review of the literature and a formal consensus process. RESULTS Fifty-eight articles met eligibility criteria and formed the evidentiary basis for the local therapy recommendations; six randomized controlled trials of systemic therapy met eligibility criteria. RECOMMENDATIONS Patients with newly diagnosed BC and BRCA1/ 2 mutations may be considered for breast-conserving therapy (BCT), with local control of the index cancer similar to that of noncarriers. The significant risk of a contralateral BC (CBC), especially in young women, and the higher risk of new cancers in the ipsilateral breast warrant discussion of bilateral mastectomy. Patients with mutations in moderate-risk genes should be offered BCT. For women with mutations in BRCA1/ 2 or moderate-penetrance genes who are eligible for mastectomy, nipple-sparing mastectomy is a reasonable approach. There is no evidence of increased toxicity or CBC events from radiation exposure in BRCA1/ 2 carriers. Radiation therapy should not be withheld in ATM carriers. For patients with germline TP53 mutations, mastectomy is advised; radiation therapy is contraindicated except in those with significant risk of locoregional recurrence. Platinum agents are recommended versus taxanes to treat advanced BC in BRCA carriers. In the adjuvant/neoadjuvant setting, data do not support the routine addition of platinum to anthracycline- and taxane-based chemotherapy. Poly (ADP-ribose) polymerase (PARP) inhibitors (olaparib and talazoparib) are preferable to nonplatinum single-agent chemotherapy for treatment of advanced BC in BRCA1/ 2 carriers. Data are insufficient to recommend PARP inhibitor use in the early setting or in moderate-penetrance carriers. Additional information available at www.asco.org/breast-cancer-guidelines .

AbstractPrevious transcriptome‐wide association studies (TWAS) have identified breast cancer risk genes by integrating data from expression quantitative loci and genome‐wide association studies (GWAS), but analyses of breast cancer subtype‐specific associations have been limited. In this study, we conducted a TWAS using gene expression data from GTEx and summary statistics from the hitherto largest GWAS meta‐analysis conducted for breast cancer overall, and by estrogen receptor subtypes (ER+ and ER−). We further compared associations with ER+ and ER− subtypes, using a case‐only TWAS approach. We also conducted multigene conditional analyses in regions with multiple TWAS associations. Two genes, STXBP4 and HIST2H2BA, were specifically associated with ER+ but not with ER– breast cancer. We further identified 30 TWAS‐significant genes associated with overall breast cancer risk, including four that were not identified in previous studies. Conditional analyses identified single independent breast‐cancer gene in three of six regions harboring multiple TWAS‐significant genes. Our study provides new information on breast cancer genetics and biology, particularly about genomic differences between ER+ and ER− breast cancer.

Abstract Background The purpose of this study was to estimate precise age-specific tubo-ovarian carcinoma (TOC) and breast cancer (BC) risks for carriers of pathogenic variants in RAD51C and RAD51D. Methods We analyzed data from 6178 families, 125 with pathogenic variants in RAD51C, and 6690 families, 60 with pathogenic variants in RAD51D. TOC and BC relative and cumulative risks were estimated using complex segregation analysis to model the cancer inheritance patterns in families while adjusting for the mode of ascertainment of each family. All statistical tests were two-sided. Results Pathogenic variants in both RAD51C and RAD51D were associated with TOC (RAD51C: relative risk [RR] = 7.55, 95% confidence interval [CI] = 5.60 to 10.19; P = 5 × 10-40; RAD51D: RR = 7.60, 95% CI = 5.61 to 10.30; P = 5 × 10-39) and BC (RAD51C: RR = 1.99, 95% CI = 1.39 to 2.85; P = 1.55 × 10-4; RAD51D: RR = 1.83, 95% CI = 1.24 to 2.72; P = .002). For both RAD51C and RAD51D, there was a suggestion that the TOC relative risks increased with age until around age 60 years and decreased thereafter. The estimated cumulative risks of developing TOC to age 80 years were 11% (95% CI = 6% to 21%) for RAD51C and 13% (95% CI = 7% to 23%) for RAD51D pathogenic variant carriers. The estimated cumulative risks of developing BC to 80 years were 21% (95% CI = 15% to 29%) for RAD51C and 20% (95% CI = 14% to 28%) for RAD51D pathogenic variant carriers. Both TOC and BC risks for RAD51C and RAD51D pathogenic variant carriers varied by cancer family history and could be as high as 32–36% for TOC, for carriers with two first-degree relatives diagnosed with TOC, or 44–46% for BC, for carriers with two first-degree relatives diagnosed with BC. Conclusions These estimates will facilitate the genetic counseling of RAD51C and RAD51D pathogenic variant carriers and justify the incorporation of RAD51C and RAD51D into cancer risk prediction models.

PURPOSETo estimate age-specific relative and absolute cancer risks of breast cancer and to estimate risks of ovarian, pancreatic, male breast, prostate, and colorectal cancers associated with germline PALB2 pathogenic variants (PVs) because these risks have not been extensively characterized.METHODSWe analyzed data from 524 families with PALB2 PVs from 21 countries. Complex segregation analysis was used to estimate relative risks (RRs; relative to country-specific population incidences) and absolute risks of cancers. The models allowed for residual familial aggregation of breast and ovarian cancer and were adjusted for the family-specific ascertainment schemes.RESULTSWe found associations between PALB2 PVs and risk of female breast cancer (RR, 7.18; 95% CI, 5.82 to 8.85; P = 6.5 × 10−76), ovarian cancer (RR, 2.91; 95% CI, 1.40 to 6.04; P = 4.1 × 10−3), pancreatic cancer (RR, 2.37; 95% CI, 1.24 to 4.50; P = 8.7 × 10−3), and male breast cancer (RR, 7.34; 95% CI, 1.28 to 42.18; P = 2.6 × 10−2). There was no evidence for increased risks of prostate or colorectal cancer. The breast cancer RRs declined with age ( P for trend = 2.0 × 10−3). After adjusting for family ascertainment, breast cancer risk estimates on the basis of multiple case families were similar to the estimates from families ascertained through population-based studies ( P for difference = .41). On the basis of the combined data, the estimated risks to age 80 years were 53% (95% CI, 44% to 63%) for female breast cancer, 5% (95% CI, 2% to 10%) for ovarian cancer, 2%-3% (95% CI females, 1% to 4%; 95% CI males, 2% to 5%) for pancreatic cancer, and 1% (95% CI, 0.2% to 5%) for male breast cancer.CONCLUSIONThese results confirm PALB2 as a major breast cancer susceptibility gene and establish substantial associations between germline PALB2 PVs and ovarian, pancreatic, and male breast cancers. These findings will facilitate incorporation of PALB2 into risk prediction models and optimize the clinical cancer risk management of PALB2 PV carriers.

Abstract Pathogenic sequence variants (PSV) in BRCA1 or BRCA2 (BRCA1/2) are associated with increased risk and severity of prostate cancer. We evaluated whether PSVs in BRCA1/2 were associated with risk of overall prostate cancer or high grade (Gleason 8+) prostate cancer using an international sample of 65 BRCA1 and 171 BRCA2 male PSV carriers with prostate cancer, and 3,388 BRCA1 and 2,880 BRCA2 male PSV carriers without prostate cancer. PSVs in the 3′ region of BRCA2 (c.7914+) were significantly associated with elevated risk of prostate cancer compared with reference bin c.1001-c.7913 [HR = 1.78; 95% confidence interval (CI), 1.25–2.52; P = 0.001], as well as elevated risk of Gleason 8+ prostate cancer (HR = 3.11; 95% CI, 1.63–5.95; P = 0.001). c.756-c.1000 was also associated with elevated prostate cancer risk (HR = 2.83; 95% CI, 1.71–4.68; P = 0.00004) and elevated risk of Gleason 8+ prostate cancer (HR = 4.95; 95% CI, 2.12–11.54; P = 0.0002). No genotype–phenotype associations were detected for PSVs in BRCA1. These results demonstrate that specific BRCA2 PSVs may be associated with elevated risk of developing aggressive prostate cancer. Significance: Aggressive prostate cancer risk in BRCA2 mutation carriers may vary according to the specific BRCA2 mutation inherited by the at-risk individual.

1527 Background: Prospective Registry of Multiplex Testing (PROMPT) is an online registry for individuals who have had multiplex panel testing for cancer susceptibility. The main objective of this registry is to ascertain families to allow penetrance calculations for mutations in less well characterized genes. Methods: Since September 2014, health care providers and commercial laboratories have given PROMPT information with the test results to eligible individuals. Participants with pathogenic mutations or variants of unknown significance in cancer susceptibility genes have self-enrolled in PROMPT. We have sent annual follow-up surveys to participants to capture updated personal and family histories, additional genetic testing in the family, and changes in cancer screening patterns. Results: To date, 5800 participants have enrolled in PROMPT and 2321 follow-up surveys are completed. Of those eligible for follow-up, 1980 (44%) have completed at least one survey. 134 (5.8%) reported a new cancer diagnosis since baseline. Breast cancer (37, 27.6%) and non-Melanoma skin cancer (35, 26.2%) were the most commonly reported new diagnoses. 5.7% of participants with an ATM variant, 5.2% of those with a BRCA2 variant, and 4.3% of those with a CHEK2 variant and at least one follow-up survey have reported a new primary cancer diagnosis (excluding non-Melanoma skin cancer). In addition, 70 (3%) participants reported a cancer recurrence since time of last follow-up. Bone (9, 12.9%) and liver (8, 11.4%) were the most common recurrence sites. 12.7% of those with a TP53 variant, 7.1% of those with a BARD1 variant, and 3.3% of those with an ATM variant and at least one follow-up survey have reported a recurrence. 59 (2.5%) participants had additional clinical genetic testing, and 555 (24%) participants reported clinical genetic testing of family members. Conclusions: PROMPT collects updated health information from participants to achieve the primary goal of determining cancer incidence among carriers of different mutations. Moreover, PROMPT has increased participant contacts through use of annual follow-up surveys and gene-specific surveys with subsets of participants. Ongoing efforts include obtaining pathology reports of new and recurrent cancer diagnoses on study.

PURPOSE Germline CDH1 pathogenic variants (PV) are associated with hereditary diffuse gastric cancer and lobular breast cancer. Although prevalence of CDH1 PV is low in the general population, detection of these variants is increasing with the growing use of multigene panel testing. Little is known about the experiences of individuals tested for CDH1 variants in the multigene panel testing era. METHODS Participants recruited from the Prospective Registry of Multiplex Testing completed a cross-sectional self-report survey regarding CDH1 genetic testing experiences, medical management, and psychosocial adaptation. RESULTS Discordance existed in interpretations of CDH1 results; 13.3% of cases had disagreements in variant classifications among commercial laboratories, and 21.4% had disagreements between participant self-report and ClinVar classification. Survey data were available from 57 individuals reporting either PV (n = 16) or variants of uncertain significance (VUS; n = 41). Those with PV were more likely than those with VUS to report receiving a recommendation for prophylactic gastrectomy, although only 40.0% of those with PV received this recommendation. Participants with VUS were less satisfied with their health care providers’ knowledge and reported less CDH1 knowledge, distress, and worry about discrimination. Participants with PV perceived greater breast cancer risks, but similar gastric cancer risks, as those with VUS. CONCLUSION Few individuals with CDH1 PV report receiving recommendations for prophylactic gastrectomy, and no differences in perceived gastric cancer risk were observed based on participants’ CDH1 results, suggesting serious unmet informational needs.

Anastrozole is a widely prescribed aromatase inhibitor for the therapy of estrogen receptor positive (ER+) breast cancer. We performed a genome‐wide association study (GWAS) for plasma anastrozole concentrations in 687 postmenopausal women with ER+ breast cancer. The top single‐nucleotide polymorphism (SNP) signal mapped across SLC38A7 (rs11648166, P = 2.3E‐08), which we showed to encode an anastrozole influx transporter. The second most significant signal (rs28845026, P = 5.4E‐08) mapped near ALPPL2 and displayed epistasis with the SLC38A7 signal. Both of these SNPs were cis expression quantitative trait loci (eQTL)s for these genes, and patients homozygous for variant genotypes for both SNPs had the highest drug concentrations, the highest SLC38A7 expression, and the lowest ALPPL2 expression. In summary, our GWAS identified a novel gene encoding an anastrozole transporter, SLC38A7, as well as epistatic interaction between SNPs in that gene and SNPs near ALPPL2 that influenced both the expression of the transporter and anastrozole plasma concentrations.