Large-scale genome-wide association study of 398,238 women unveils seven novel loci associated with high-grade serous epithelial ovarian cancer risk

Background

Nineteen genomic regions have been associated with high-grade serous ovarian cancer (HGSOC). We used data from the Ovarian Cancer Association Consortium (OCAC), Consortium of Investigators of Modifiers of BRCA1/BRCA2 (CIMBA), UK Biobank (UKBB), and FinnGen to identify novel HGSOC susceptibility loci and develop polygenic scores (PGS).

Methods

We analyzed >22 million variants for 398,238 women. Associations were assessed separately by consortium and meta-analysed. OCAC and CIMBA data were used to develop PGS which were trained on FinnGen data and validated in UKBB and BioBank Japan.

Results

Eight novel variants were associated with HGSOC risk. An interesting discovery biologically was finding that TP53 3'-UTR SNP rs78378222 was associated with HGSOC (per T allele relative risk (RR)=1.44, 95%CI:1.28-1.62, P=1.76×10-9). The optimal PGS included 64,518 variants and was associated with an odds ratio of 1.46 (95%CI:1.37-1.54) per standard deviation in the UKBB validation (AUROC curve=0.61, 95%CI:0.59-0.62).

Conclusions

This study represents the largest GWAS for HGSOC to date. The results highlight that improvements in imputation reference panels and increased sample sizes can identify HGSOC associated variants that previously went undetected, resulting in improved PGS. The use of updated PGS in cancer risk prediction algorithms will then improve personalized risk prediction for HGSOC.

Differences in polygenic score distributions in European ancestry populations: implications for breast cancer risk prediction

The 313-variant polygenic risk score (PRS313) provides a promising tool for breast cancer risk prediction. However, evaluation of the PRS313 across different European populations which could influence risk estimation has not been performed. Here, we explored the distribution of PRS313 across European populations using genotype data from 94,072 females without breast cancer, of European-ancestry from 21 countries participating in the Breast Cancer Association Consortium (BCAC) and 225,105 female participants from the UK Biobank. The mean PRS313 differed markedly across European countries, being highest in south-eastern Europe and lowest in north-western Europe. Using the overall European PRS313 distribution to categorise individuals leads to overestimation and underestimation of risk in some individuals from south-eastern and north-western countries, respectively. Adjustment for principal components explained most of the observed heterogeneity in mean PRS. Country-specific PRS distributions may be used to calibrate risk categories in individuals from different countries.

Association of the CHEK2 c.1100delC variant, radiotherapy, and systemic treatment with contralateral breast cancer risk and breast cancer-specific survival

BACKGROUND

Breast cancer (BC) patients with a germline CHEK2 c.1100delC variant have an increased risk of contralateral BC (CBC) and worse BC-specific survival (BCSS) compared to non-carriers.

AIM

To assessed the associations of CHEK2 c.1100delC, radiotherapy, and systemic treatment with CBC risk and BCSS.

METHODS

Analyses were based on 82,701 women diagnosed with a first primary invasive BC including 963 CHEK2 c.1100delC carriers; median follow-up was 9.1 years. Differential associations with treatment by CHEK2 c.1100delC status were tested by including interaction terms in a multivariable Cox regression model. A multi-state model was used for further insight into the relation between CHEK2 c.1100delC status, treatment, CBC risk and death.

RESULTS

There was no evidence for differential associations of therapy with CBC risk by CHEK2 c.1100delC status. The strongest association with reduced CBC risk was observed for the combination of chemotherapy and endocrine therapy [HR (95% CI): 0.66 (0.55-0.78)]. No association was observed with radiotherapy. Results from the multi-state model showed shorter BCSS for CHEK2 c.1100delC carriers versus non-carriers also after accounting for CBC occurrence [HR (95% CI): 1.30 (1.09-1.56)].

CONCLUSION

Systemic therapy was associated with reduced CBC risk irrespective of CHEK2 c.1100delC status. Moreover, CHEK2 c.1100delC carriers had shorter BCSS, which appears not to be fully explained by their CBC risk.

Associations of height, body mass index, and weight gain with breast cancer risk in carriers of a pathogenic variant in BRCA1 or BRCA2: the BRCA1 and BRCA2 Cohort Consortium

INTRODUCTION

Height, body mass index (BMI), and weight gain are associated with breast cancer risk in the general population. It is unclear whether these associations also exist for carriers of pathogenic variants in the BRCA1 or BRCA2 genes.

PATIENTS AND METHODS

An international pooled cohort of 8091 BRCA1/2 variant carriers was used for retrospective and prospective analyses separately for premenopausal and postmenopausal women. Cox regression was used to estimate breast cancer risk associations with height, BMI, and weight change.

RESULTS

In the retrospective analysis, taller height was associated with risk of premenopausal breast cancer for BRCA2 variant carriers (HR 1.20 per 10 cm increase, 95% CI 1.04-1.38). Higher young-adult BMI was associated with lower premenopausal breast cancer risk for both BRCA1 (HR 0.75 per 5 kg/m2, 95% CI 0.66-0.84) and BRCA2 (HR 0.76, 95% CI 0.65-0.89) variant carriers in the retrospective analysis, with consistent, though not statistically significant, findings from the prospective analysis. In the prospective analysis, higher BMI and adult weight gain were associated with higher postmenopausal breast cancer risk for BRCA1 carriers (HR 1.20 per 5 kg/m2, 95% CI 1.02-1.42; and HR 1.10 per 5 kg weight gain, 95% CI 1.01-1.19, respectively).

CONCLUSION

Anthropometric measures are associated with breast cancer risk for BRCA1 and BRCA2 variant carriers, with relative risk estimates that are generally consistent with those for women from the general population.

Association of the CHEK2 c.1100delC variant, radiotherapy, and systemic treatment with contralateral breast cancer risk and breast cancer-specific survival

Breast cancer (BC) patients with a germline CHEK2 c.1100delC variant have an increased risk of contralateral BC (CBC) and worse BC-specific survival (BCSS) compared to non-carriers. We aimed to assess the associations of CHEK2 c.1100delC, radiotherapy, and systemic treatment with CBC risk and BCSS. Analyses were based on 82,701 women diagnosed with invasive BC including 963 CHEK2 c.1100delC carriers; median follow-up was 9.1 years. Differential associations of treatment by CHEK2 c.1100delC status were tested by including interaction terms in a multivariable Cox regression model. A multi-state model was used for further insight into the relation between CHEK2 c.1100delC status, treatment, CBC risk and death. There was no evidence for differential associations of therapy with CBC risk by CHEK2 c.1100delC status The strongest association with reduced CBC risk was observed for the combination of chemotherapy and endocrine therapy [HR(95%CI): 0.66 (0.55-0.78)]. No association was observed with radiotherapy. Results from the multi-state model showed shorter BCSS for CHEK2 c.1100delC carriers versus non-carriers also after accounting for CBC occurrence [HR(95%CI) :1.30 (1.09-1.56)]. In conclusion, systemic therapy was associated with reduced CBC risk irrespective of CHEK2 c.1100delC status. Moreover, CHEK2 c.1100delC carriers had shorter BCSS, which appears not to be fully explained by their CBC risk. (Main MS: 3201 words).

Aggregation tests identify new gene associations with breast cancer in populations with diverse ancestry

BACKGROUND

Low-frequency variants play an important role in breast cancer (BC) susceptibility. Gene-based methods can increase power by combining multiple variants in the same gene and help identify target genes.

METHODS

We evaluated the potential of gene-based aggregation in the Breast Cancer Association Consortium cohorts including 83,471 cases and 59,199 controls. Low-frequency variants were aggregated for individual genes' coding and regulatory regions. Association results in European ancestry samples were compared to single-marker association results in the same cohort. Gene-based associations were also combined in meta-analysis across individuals with European, Asian, African, and Latin American and Hispanic ancestry.

RESULTS

In European ancestry samples, 14 genes were significantly associated (q < 0.05) with BC. Of those, two genes, FMNL3 (P = 6.11 × 10-6) and AC058822.1 (P = 1.47 × 10-4), represent new associations. High FMNL3 expression has previously been linked to poor prognosis in several other cancers. Meta-analysis of samples with diverse ancestry discovered further associations including established candidate genes ESR1 and CBLB. Furthermore, literature review and database query found further support for a biologically plausible link with cancer for genes CBLB, FMNL3, FGFR2, LSP1, MAP3K1, and SRGAP2C.

CONCLUSIONS

Using extended gene-based aggregation tests including coding and regulatory variation, we report identification of plausible target genes for previously identified single-marker associations with BC as well as the discovery of novel genes implicated in BC development. Including multi ancestral cohorts in this study enabled the identification of otherwise missed disease associations as ESR1 (P = 1.31 × 10-5), demonstrating the importance of diversifying study cohorts.

Cancer Risks Associated With BRCA1 and BRCA2 Pathogenic Variants

PURPOSE

To provide precise age-specific risk estimates of cancers other than female breast and ovarian cancers associated with pathogenic variants (PVs) in BRCA1 and BRCA2 for effective cancer risk management.

METHODS

We used data from 3,184 BRCA1 and 2,157 BRCA2 families in the Consortium of Investigators of Modifiers of BRCA1/2 to estimate age-specific relative (RR) and absolute risks for 22 first primary cancer types adjusting for family ascertainment.

RESULTS

BRCA1 PVs were associated with risks of male breast (RR = 4.30; 95% CI, 1.09 to 16.96), pancreatic (RR = 2.36; 95% CI, 1.51 to 3.68), and stomach (RR = 2.17; 95% CI, 1.25 to 3.77) cancers. Associations with colorectal and gallbladder cancers were also suggested. BRCA2 PVs were associated with risks of male breast (RR = 44.0; 95% CI, 21.3 to 90.9), stomach (RR = 3.69; 95% CI, 2.40 to 5.67), pancreatic (RR = 3.34; 95% CI, 2.21 to 5.06), and prostate (RR = 2.22; 95% CI, 1.63 to 3.03) cancers. The stomach cancer RR was higher for females than males (6.89 v 2.76; P = .04). The absolute risks to age 80 years ranged from 0.4% for male breast cancer to approximately 2.5% for pancreatic cancer for BRCA1 carriers and from approximately 2.5% for pancreatic cancer to 27% for prostate cancer for BRCA2 carriers.

CONCLUSION

In addition to female breast and ovarian cancers, BRCA1 and BRCA2 PVs are associated with increased risks of male breast, pancreatic, stomach, and prostate (only BRCA2 PVs) cancers, but not with the risks of other previously suggested cancers. The estimated age-specific risks will refine cancer risk management in men and women with BRCA1/2 PVs.

Recreational Physical Activity and Outcomes After Breast Cancer in Women at High Familial Risk

Background

Recreational physical activity (RPA) is associated with improved survival after breast cancer (BC) in average-risk women, but evidence is limited for women who are at increased familial risk because of a BC family history or BRCA1 and BRCA2 pathogenic variants (BRCA1/2 PVs).

Methods

We estimated associations of RPA (self-reported average hours per week within 3 years of BC diagnosis) with all-cause mortality and second BC events (recurrence or new primary) after first invasive BC in women in the Prospective Family Study Cohort (n = 4610, diagnosed 1993-2011, aged 22-79 years at diagnosis). We fitted Cox proportional hazards regression models adjusted for age at diagnosis, demographics, and lifestyle factors. We tested for multiplicative interactions (Wald test statistic for cross-product terms) and additive interactions (relative excess risk due to interaction) by age at diagnosis, body mass index, estrogen receptor status, stage at diagnosis, BRCA1/2 PVs, and familial risk score estimated from multigenerational pedigree data. Statistical tests were 2-sided.

Results

We observed 1212 deaths and 473 second BC events over a median follow-up from study enrollment of 11.0 and 10.5 years, respectively. After adjusting for covariates, RPA (any vs none) was associated with lower all-cause mortality of 16.1% (95% confidence interval [CI] = 2.4% to 27.9%) overall, 11.8% (95% CI = -3.6% to 24.9%) in women without BRCA1/2 PVs, and 47.5% (95% CI = 17.4% to 66.6%) in women with BRCA1/2 PVs (RPA*BRCA1/2 multiplicative interaction P = .005; relative excess risk due to interaction = 0.87, 95% CI = 0.01 to 1.74). RPA was not associated with risk of second BC events.

Conclusion

Findings support that RPA is associated with lower all-cause mortality in women with BC, particularly in women with BRCA1/2 PVs.

Association of germline genetic variants with breast cancer-specific survival in patient subgroups defined by clinic-pathological variables related to tumor biology and type of systemic treatment

BACKGROUND

Given the high heterogeneity among breast tumors, associations between common germline genetic variants and survival that may exist within specific subgroups could go undetected in an unstratified set of breast cancer patients.

METHODS

We performed genome-wide association analyses within 15 subgroups of breast cancer patients based on prognostic factors, including hormone receptors, tumor grade, age, and type of systemic treatment. Analyses were based on 91,686 female patients of European ancestry from the Breast Cancer Association Consortium, including 7531 breast cancer-specific deaths over a median follow-up of 8.1 years. Cox regression was used to assess associations of common germline variants with 15-year and 5-year breast cancer-specific survival. We assessed the probability of these associations being true positives via the Bayesian false discovery probability (BFDP < 0.15).

RESULTS

Evidence of associations with breast cancer-specific survival was observed in three patient subgroups, with variant rs5934618 in patients with grade 3 tumors (15-year-hazard ratio (HR) [95% confidence interval (CI)] 1.32 [1.20, 1.45], P = 1.4E-08, BFDP = 0.01, per G allele); variant rs4679741 in patients with ER-positive tumors treated with endocrine therapy (15-year-HR [95% CI] 1.18 [1.11, 1.26], P = 1.6E-07, BFDP = 0.09, per G allele); variants rs1106333 (15-year-HR [95% CI] 1.68 [1.39,2.03], P = 5.6E-08, BFDP = 0.12, per A allele) and rs78754389 (5-year-HR [95% CI] 1.79 [1.46,2.20], P = 1.7E-08, BFDP = 0.07, per A allele), in patients with ER-negative tumors treated with chemotherapy.

CONCLUSIONS

We found evidence of four loci associated with breast cancer-specific survival within three patient subgroups. There was limited evidence for the existence of associations in other patient subgroups. However, the power for many subgroups is limited due to the low number of events. Even so, our results suggest that the impact of common germline genetic variants on breast cancer-specific survival might be limited.

Comparing models of delivery for cancer genetics services among patients receiving primary care who meet criteria for genetic evaluation in two healthcare systems: BRIDGE randomized controlled trial

BACKGROUND

Advances in genetics and sequencing technologies are enabling the identification of more individuals with inherited cancer susceptibility who could benefit from tailored screening and prevention recommendations. While cancer family history information is used in primary care settings to identify unaffected patients who could benefit from a cancer genetics evaluation, this information is underutilized. System-level population health management strategies are needed to assist health care systems in identifying patients who may benefit from genetic services. In addition, because of the limited number of trained genetics specialists and increasing patient volume, the development of innovative and sustainable approaches to delivering cancer genetic services is essential.

METHODS

We are conducting a randomized controlled trial, entitled Broadening the Reach, Impact, and Delivery of Genetic Services (BRIDGE), to address these needs. The trial is comparing uptake of genetic counseling, uptake of genetic testing, and patient adherence to management recommendations for automated, patient-directed versus enhanced standard of care cancer genetics services delivery models. An algorithm-based system that utilizes structured cancer family history data available in the electronic health record (EHR) is used to identify unaffected patients who receive primary care at the study sites and meet current guidelines for cancer genetic testing. We are enrolling eligible patients at two healthcare systems (University of Utah Health and New York University Langone Health) through outreach to a randomly selected sample of 2780 eligible patients in the two sites, with 1:1 randomization to the genetic services delivery arms within sites. Study outcomes are assessed through genetics clinic records, EHR, and two follow-up questionnaires at 4 weeks and 12 months after last genetic counseling contactpre-test genetic counseling.

DISCUSSION

BRIDGE is being conducted in two healthcare systems with different clinical structures and patient populations. Innovative aspects of the trial include a randomized comparison of a chatbot-based genetic services delivery model to standard of care, as well as identification of at-risk individuals through a sustainable EHR-based system. The findings from the BRIDGE trial will advance the state of the science in identification of unaffected patients with inherited cancer susceptibility and delivery of genetic services to those patients.

TRIAL REGISTRATION

BRIDGE is registered as NCT03985852 . The trial was registered on June 6, 2019 at clinicaltrials.gov .

Association of breast cancer with MRI background parenchymal enhancement: the IMAGINE case-control study

Background

Background parenchymal enhancement (BPE) on breast magnetic resonance imaging (MRI) may be associated with breast cancer risk, but previous studies of the association are equivocal and limited by incomplete blinding of BPE assessment. In this study, we evaluated the association between BPE and breast cancer based on fully blinded assessments of BPE in the unaffected breast.

Methods

The Imaging and Epidemiology (IMAGINE) study is a multicenter breast cancer case-control study of women receiving diagnostic, screening, or follow-up breast MRI, recruited from three comprehensive cancer centers in the USA. Cases had a first diagnosis of unilateral breast cancer and controls had no history of or current breast cancer. A single board-certified breast radiologist with 12 years’ experience, blinded to case-control status and clinical information, assessed the unaffected breast for BPE without view of the affected breast of cases (or the corresponding breast laterality of controls). The association between BPE and breast cancer was estimated by multivariable logistic regression separately for premenopausal and postmenopausal women.

Results

The analytic dataset included 835 cases and 963 controls. Adjusting for fibroglandular tissue (breast density), age, race/ethnicity, BMI, parity, family history of breast cancer, BRCA1/BRCA2 mutations, and other confounders, moderate/marked BPE (vs minimal/mild BPE) was associated with breast cancer among premenopausal women [odds ratio (OR) 1.49, 95% CI 1.05–2.11; p = 0.02]. Among postmenopausal women, mild/moderate/marked vs minimal BPE had a similar, but statistically non-significant, association with breast cancer (OR 1.45, 95% CI 0.92–2.27; p = 0.1).

Conclusions

BPE is associated with breast cancer in premenopausal women, and possibly postmenopausal women, after adjustment for breast density and confounders. Our results suggest that BPE should be evaluated alongside breast density for inclusion in models predicting breast cancer risk.

Characterization of the Cancer Spectrum in Men With Germline BRCA1 and BRCA2 Pathogenic Variants: Results From the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA)

Importance

The limited data on cancer phenotypes in men with germline BRCA1 and BRCA2 pathogenic variants (PVs) have hampered the development of evidence-based recommendations for early cancer detection and risk reduction in this population.

Objective

To compare the cancer spectrum and frequencies between male BRCA1 and BRCA2 PV carriers.

Design, Setting, and Participants

Retrospective cohort study of 6902 men, including 3651 BRCA1 and 3251 BRCA2 PV carriers, older than 18 years recruited from cancer genetics clinics from 1966 to 2017 by 53 study groups in 33 countries worldwide collaborating through the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). Clinical data and pathologic characteristics were collected.

Main Outcomes and Measures

BRCA1/2 status was the outcome in a logistic regression, and cancer diagnoses were the independent predictors. All odds ratios (ORs) were adjusted for age, country of origin, and calendar year of the first interview.

Results

Among the 6902 men in the study (median [range] age, 51.6 [18-100] years), 1634 cancers were diagnosed in 1376 men (19.9%), the majority (922 of 1,376 [67%]) being BRCA2 PV carriers. Being affected by any cancer was associated with a higher probability of being a BRCA2, rather than a BRCA1, PV carrier (OR, 3.23; 95% CI, 2.81-3.70; P < .001), as well as developing 2 (OR, 7.97; 95% CI, 5.47-11.60; P < .001) and 3 (OR, 19.60; 95% CI, 4.64-82.89; P < .001) primary tumors. A higher frequency of breast (OR, 5.47; 95% CI, 4.06-7.37; P < .001) and prostate (OR, 1.39; 95% CI, 1.09-1.78; P = .008) cancers was associated with a higher probability of being a BRCA2 PV carrier. Among cancers other than breast and prostate, pancreatic cancer was associated with a higher probability (OR, 3.00; 95% CI, 1.55-5.81; P = .001) and colorectal cancer with a lower probability (OR, 0.47; 95% CI, 0.29-0.78; P = .003) of being a BRCA2 PV carrier.

Conclusions and Relevance

Significant differences in the cancer spectrum were observed in male BRCA2, compared with BRCA1, PV carriers. These data may inform future recommendations for surveillance of BRCA1/2-associated cancers and guide future prospective studies for estimating cancer risks in men with BRCA1/2 PVs.

Comparative effectiveness of second-line ipilimumab vs. nivolumab in combination with ipilimumab in patients with advanced melanoma who received frontline anti-PD-1 antibodies

Introduction

Anti-PD-1 antibodies are commonly used as frontline therapy for patients with metastatic melanoma. Although these medications can cause long term responses, a significant number of patients will not respond or will lose response. Optimal second-line therapy after losing response to anti-PD-1 antibodies is not well established. Therefore, we retrospectively compared the overall survival of patients who lost response to anti-PD1 antibodies between patients treated with single agent ipilimumab or ipilimumab and nivolumab.

Methods

A de-identified U.S. nationwide electronic health record-derived database was reviewed for patients with advanced melanoma treated with single agent anti-PD1 antibodies in the frontline setting and who subsequently received second-line ipilimumab or combination ipilimumab and nivolumab. Overall survival from initiation of second-line therapy was compared using Kaplan Meier curves and log-rank analysis. Other known prognostic markers for melanoma were analyzed for correlation with survival in a similar fashion. Disease characteristics between the two groups were compared using chi-square analysis.

Results

A total of 842 patients with advanced melanoma who received frontline anti-PD-1 antibodies were included for analysis. Of these, 57 received either ipilimumab ( n = 22) or ipilimumab in combination with nivolumab ( n = 35) in the second-line setting. Median survival from second-line therapy initiation for those treated with ipilimumab alone was 6 months and was 5.6 months for those treated with combination ipilimumab and anti-PD-1 antibodies, p = 0.81.

Conclusions

In this small, retrospective analysis, for patients who lost response to frontline anti-PD-1 therapy, patients treated with ipilimumab had similar survival to those who received ipilimumab in combination with anti-PD-1 antibodies.

Comparative-effectiveness of pembrolizumab vs. nivolumab for patients with metastatic melanoma

Background: Pembrolizumab (P) and nivolumab (N) are commonly used therapies for advanced melanoma. However, their effectiveness has never been directly compared, leaving little guidance for clinicians to select the best therapy. Therefore, we sought to retrospectively compare the overall survival of patients with metastatic melanoma treated with front line P or N in the real-world setting.Material and methods: This study included patients with advanced melanoma, diagnosed between 1 January 2011 and 31 July 2018, treated with frontline P or N who were included in a nationwide, longitudinal de-identified electronic health record (EHR)-derived database. Overall survival (OS) was estimated for each treatment group using Kaplan-Meier curves with a log-rank test. Comparison of OS was estimated using an inverse probability weighting model to reduce bias between the groups. The model was adjusted using age, sex, ECOG, LDH (elevated or not), BRAF (mutated or not), Kit (mutated or not), NRAS (mutated or not), PD-L1 expression (0% or greater), Body Mass Index, and primary site.Results: 888 patients with advanced disease who received treatment with frontline P (n = 486) or N (n = 402) were identified. Median OS for all patients treated with P was 22.6 months (m) and was 23.9 m for those treated with N (p = 0.91). In the inverse probability weight analysis there was no difference in survival between patients treated with P or N 1.06 (95% CI 0.84-1.33).Concluding Statement: In our retrospective, real-world analysis of patients with advanced melanoma, no statistical difference in OS was noted between patients treated with frontline P compared to N. This supports the current practice of choosing either P or N based on patient and provider preference.

Real-world survival of patients with advanced BRAF V600 mutated melanoma treated with front-line BRAF/MEK inhibitors, anti-PD-1 antibodies, or nivolumab/ipilimumab

BACKGROUND

The optimal treatment sequence for patients with advanced BRAF V600 mutant melanoma is unknown. BRAF/MEK inhibition (BRAF/MEKi), single agent anti-PD-1 (aPD-1) antibodies and combination immune checkpoint inhibition with nivolumab and ipilimumab (niv/ipi) are all approved; however, they have not been prospectively compared. Therefore, we sought to compare overall survival of patients with advanced BRAF mutant melanoma treated with either front-line BRAF/MEKi, aPD-1, or niv/ipi.

METHODS

Patients with advanced BRAF mutant melanoma who had received BRAF/MEKi, niv/ipi, or aPD-1 in the front-line setting were identified from a nationwide database comprising de-identified patient-level structured and unstructured data derived from electronic health records. Survival was compared using Kaplan-Meier curves and log-rank analysis. Univariate and multivariate Cox regression models were used to measure the effect of front-line treatment, age (>64 or not), LDH (elevated or not), and Eastern Cooperative Oncology Group (ECOG) performance status (>1 or not) on survival.

RESULTS

Five hundred and sixty seven patients with advanced disease and treated with front-line aPD-1 (n = 162), BRAF/MEKi (n = 297) or niv/ipi (n = 108) were identified. With a median follow-up of 22.4 months, median overall survival (OS) for patients treated with front-line niv/ipi was not reached (NR) while median OS for patients treated with aPD-1 or BRAF/MEKi was 39.5 months and 13.2 months, respectively. Front-line treatment with PD-1 and niv/ipi were associated with statistically longer survival than BRAF/MEKi in multivariate analyses.

CONCLUSIONS

In our real-world retrospective analysis, patients with advanced BRAF mutant melanoma treated with front-line niv/ipi or aPD-1 had longer survival compared to those treated with front-line BRAF/MEKi.

Abstract P1-10-06: High participation of African-American women veterans in high risk breast cancer screening pilot program

SPECIFIC AIMS: To assess breast cancer risk in Women Veterans.

BACKGROUND/RATIONALE: Women are the fastest growing segment of patients numbering over 2 million and breast cancer incidence has more than tripled from 1995 to 2012 within the Veterans Health Administration (VHA). Preliminary data suggest that Women Veterans may be at an increased breast cancer risk based on unique service-related exposures (e.g., burn pits, depleted uranium) and Post Traumatic Stress Disorder (PTSD). Historically, breast cancer rates among African Americans (AA) are lower than those seen in the general population (8.2-13.3%).

METHODS: A pilot study was conducted at Bronx, NY and Washington, DC Veterans Affairs Medical Centers. Participants were enrolled at their regular visit to Women's Health Clinics or at breast cancer education and awareness events. 5-year and lifetime risks of developing invasive breast cancer were calculated using the Gail Breast Cancer Risk Assessment Tool (BCRAT). Demographics, PTSD status, eligibility for chemoprevention and genetic counseling using the Breast Cancer Genetics Referral Screening Tool (B-RST), were also determined.

ELIGIBILITY CRITERIA: Women Veterans age ≥ 35 years with no personal history of breast cancer.

RESULTS: A total of 99 Women Veterans with an average age of 54 years participated between 2015 and 2018; 60% African American (AA); 13% Hispanic; 14% non-Hispanic White and 13% as other. In total, 35% (35/99) were considered high risk with a 5-year BCRAT of &gt;1.66% and of these, 51% were AA; 14% Hispanic and 17 % were other. Prior breast biopsies were performed in only 22% (22/99) of our entire Veteran population; 57% (56/99) having a family history positive for breast cancer. Comparatively, in our high risk AA alone, 33% (6/18) had prior breast biopsies with 94% (17/18) having a positive family history. High risk patients were referred for chemoprevention; 5 (19%) accepted; and 13/35 (37%) patients were referred for genetic counseling. PTSD was present in 29% overall and in 31% of the high risk subgroup.

IMPLICATIONS: The VHA, which leads the nation in mammogram compliance, is an untapped potential resource for the study of breast cancer. To our knowledge, this is the only study with 60% AA Women Veterans. High participation rates among AA in this pilot study have uncovered the potential for further inquiry into this population, which is otherwise dramatically under-represented in research. Over half (51%) of AA in this pilot study had a high risk score, likely linked to a high rate of prior breast biopsies and family history. Limitations of this study include the small sample size, exclusively urban population, geography and self-selection for screening due to a higher level of concern for breast cancer. If Women Veterans are at higher risk of breast cancer, it has been assumed that this would be related to service-related exposures, PTSD and other factors. However this pilot study, which was not designed or powered to do more than raise questions, suggests the additional possibility of an innate or genetic risk, especially in AAs. Future directions include the evaluation of genetic and molecular mutations in high risk AA Women Veterans, possibly even a role for PTSD epigenetic changes and tumorigenesis.

Citation Format: Park Y-HA, Keller AT, Bidassie B, Venne VL, Heron BB, Hoffman-Hōgg L, Hawley DK, Hsu T-CM, Colonna SV, Aggarwal A. High participation of African-American women veterans in high risk breast cancer screening pilot program [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-10-06.

Analysis of Risk of Recurrence by Subtype in ≤ 1-cm Breast Tumors

INTRODUCTION

Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer with higher recurrence rates than other breast cancer subtypes. Increasing numbers of women are being diagnosed with early-stage breast cancer because of improvements in screening mammography. TNBC is known to be highly sensitive to chemotherapy; however, the benefit of adjuvant chemotherapy among women with ≤ 1-cm, lymph node-negative TNBC is unknown.

MATERIALS AND METHODS

We evaluated the recurrence rates and recurrence-free survival of 437 women diagnosed with stage T1a-T1bN0 breast cancer from 1997 to 2009 at 2 institutions, with a median follow-up time of 6.2 years. Furthermore, we examined the treatment regimens of these women and evaluated the association of adjuvant chemotherapy with recurrence-free survival.

RESULTS

Chemotherapy was administered more often to younger women and to women with high-grade, human epidermal growth factor receptor 2-positive or TNBC. Recurrence-free survival did not differ significantly between TNBC and estrogen receptor-positive breast cancer (hazard ratio [HR], 0.33; 95% confidence interval [CI], 0.10-1.04; P = .058). After appropriate adjustments, no significant differences were detected in recurrence-free survival between the women who had received chemotherapy and those who had not among the women with TNBC (P = .132) or within any of the breast cancer subtypes (HR, 0.6; 95% CI, 0.2-1.9; P = .392).

CONCLUSION

Prospective trials of this subcentimeter node-negative breast cancer population are warranted to guide adjuvant chemotherapy decisions.

Analysis of recurrence risk by subtype in ≤1 cm breast tumors

1034

Background: Triple-negative breast cancers (TNBC) comprise 15% of breast cancers and lack ER, PR, and HER2 expression. TNBC is biologically aggressive with high rates of recurrence, but little is known about the prognosis of small (≤1cm) TNBCs compared to similarly sized breast cancers with other receptor profiles. The role of adjuvant chemotherapy for TNBC that is ≤1cm remains unclear. Methods: Electronic medical records of all women aged ≥ 18 years with ≤1 cm, node negative, invasive breast cancer from 1997-2007 diagnosed or treated at Vanderbilt or Wake Forest were reviewed. Tumor grade, receptor status, treatment details, and follow up and recurrence information were tabulated. Rates of local and distant recurrence among three different receptor subtype categories, ER+ or PR+, HER2 negative; ER-/PR-, HER2 negative; or any ER/PR, HER2 positive were compared using chi-square tests. Results: 437 women with ≤1cm breast tumors were identified. Women with TNBC not given chemotherapy were more likely to have distant recurrence at 9% compared to 2% for ER+ or PR+, HER2 negative and 4% for any ER/PR, HER2 positive. There were no recurrences among the 14 women with ≤1cm TNBC who received chemotherapy. Conclusions: Based on our two institution review, women with ≤1 cm TNBC are at an increased risk for distant recurrence compared to other subtypes when not treated with adjuvant chemotherapy. Further studies to determine the benefit of adjuvant chemotherapy in this population are needed. [Table: see text]