For poorly understood reasons, Black non‐Hispanic (BNH) women meeting National Comprehensive Cancer Network (NCCN) criteria for genetic testing for breast cancer risk are less likely than White non‐Hispanic (WNH) women to undergo testing (Armstrong, Micco, Carney, Stopfer, & Putt, JAMA, 293, 1729 and 2005). We compared physician referral rates and uptake for genetic testing of BNH and WNH women meeting select NCCN criteria (breast cancer under age 50, two primary breast cancers, triple‐negative disease under age 60) in the Cancer Center at George Washington University (GWCC) between 2015 and 2018. Of the 723 BNH and WNH patients treated for breast cancer at GWCC, 28% met study criteria for genetic counseling referral (n = 252; BNH n = 115, WNH n = 137). Physician referral rates to genetic counseling differed significantly by race (BNH 75.7%, n = 87 and WNH 92.7%; n = 127; χ2 = 14.19, p‐value < .01). Once referred, though, there was no significant difference in uptake of genetic counseling by race (BNH 95.4%, n = 83; WNH 97.6%, n = 124, χ2 = 1.33, p‐value = .25) for patients appropriately referred.

Annual MRI screening is recommended as an adjunct to mammography for BRCA1 and BRCA2 mutation carriers. Prophylactic oophorectomy has been shown to decrease breast cancer risk in BRCA1/2 mutation carriers. Here, we aimed to examine the combined effects of MRI and oophorectomy. For this purpose, 93 BRCA1/2 mutation carriers were screened with yearly mammograms and yearly MRI scans. Study endpoints were defined as date of breast cancer diagnosis, date of prophylactic mastectomy, or date of most recent contact. Of 93 women, with a median age of 47, 80 (86%) had prophylactic oophorectomy. Fifty-one women (55%) had BRCA1 mutations. A total of 283 MRI scans were performed. Eleven breast cancers (9 invasive, 2 ductal carcinoma in situ) were detected in 93 women (12%) with a median follow-up of 3.2 years (incidence 40 per 1,000 person-years). Six cancers were first detected on MRI, three were first detected by mammogram, and two were “interval cancers.” All breast cancers occurred in BRCA1 mutation carriers (incidence 67 per 1,000 person-years). Apart from BRCA1 vs. BRCA2 mutation status, there were no other significant predictors of breast cancer incidence. Most invasive breast cancers were estrogen receptor negative (7 of 9) and lymph node negative (7 of 9). There have been no systemic recurrences with a median follow-up of 19 months after cancer diagnosis. Finally, it was concluded that all breast cancers occurred in BRCA1 mutation carriers, in most cases despite oophorectomy. These data suggest that surveillance and prevention strategies may have different outcomes in BRCA1 and BRCA2 mutation carriers.

PurposeTriple negative breast cancer (TNBC) is characterized by the presence of immune cells in the tumor microenvironment, however, the response to single-agent immune checkpoint inhibitor (ICI) therapy is modest. Preclinical models have demonstrated that intratumoral regulatory T cells (Tregs) dampen the antitumor response to ICI. We performed a single-arm phase II trial to evaluate the efficacy of a single low dose of cyclophosphamide (Cy) to deplete Tregs administered before initiating pembrolizumab.Patients and methods40 patients with pretreated metastatic TNBC were enrolled. The primary endpoints were progression-free survival (PFS) and change in peripheral blood Tregs after Cy. Secondary endpoints included overall response rate (ORR), duration of response, overall survival, treatment-related adverse events (AEs), and correlative evaluations.ResultsMedian PFS was 1.8 months, and the ORR was 21%. Tregs were not significantly decreased after Cy prior to ICI (−3.3%, p=0.19), and increased significantly after the first cycle of therapy (+21% between cycles 1 and 2, p=0.005). Immune-related AEs were similar to historical pembrolizumab monotherapy, and were associated with response to therapy (p=0.02). Patients with pretreatment tumors harboring increased expression of B cell metagene signatures and increased circulating B cell receptor repertoire diversity were associated with clinical response and immune-related toxicity (IRT).ConclusionsAmong patients with heavily pretreated TNBC, Cy prior to pembrolizumab did not significantly deplete Tregs, and in those with decreased numbers there was rapid recovery following therapy. Increased B cell gene expression in baseline samples was associated with clinical response and IRT.

Background Breast cancer survivors (BCSs) are a growing population with a higher prevalence of insomnia than women of the same age without a history of cancer. Cognitive behavioral therapy for insomnia (CBT-I) has been shown to be effective in this population, but it is not widely available to those who need it. Objective This study aimed to better understand BCSs’ experiences with insomnia and to explore the feasibility and acceptability of delivering CBT-I using a virtual assistant (Amazon Alexa). Methods We first conducted a formative phase with 2 focus groups and 3 in-depth interviews to understand BCSs’ perceptions of insomnia as well as their interest in and comfort with using a virtual assistant to learn about CBT-I. We then developed a prototype incorporating participant preferences and CBT-I components and demonstrated it in group and individual settings to BCSs to evaluate acceptability, interest, perceived feasibility, educational potential, and usability of the prototype. We also collected open-ended feedback on the content and used frequencies to describe the quantitative data. Results We recruited 11 BCSs with insomnia in the formative phase and 14 BCSs in the prototype demonstration. In formative work, anxiety, fear, and hot flashes were identified as causes of insomnia. After prototype demonstration, nearly 79% (11/14) of participants reported an interest in and perceived feasibility of using the virtual assistant to record sleep patterns. Approximately two-thirds of the participants thought lifestyle modification (9/14, 64%) and sleep restriction (9/14, 64%) would be feasible and were interested in this feature of the program (10/14, 71% and 9/14, 64%, respectively). Relaxation exercises were rated as interesting and feasible using the virtual assistant by 71% (10/14) of the participants. Usability was rated as better than average, and all women reported that they would recommend the program to friends and family. Conclusions This virtual assistant prototype delivering CBT-I components by using a smart speaker was rated as feasible and acceptable, suggesting that this prototype should be fully developed and tested for efficacy in the BCS population. If efficacy is shown in this population, the prototype should also be adapted for other high-risk populations.

265 Background: Healthcare delivery via telemedicine has increased substantially amid COVID-19. The George Washington Cancer Center (GWCC) now provides cancer care services via tele-visits for patients at high risk of morbidity and mortality secondary to COVID-19. This study was performed to assess usability of virtual cancer care delivery for patients and providers across specialties. Methods: Participants included patients and providers surveyed to assess baseline usability after initiating tele-visits. Surveys included demographics, Telehealth Usability Questionnaire (TUQ), and questions on perceived safety and preferences around telemedicine. Subjects also provided open-ended feedback for quality improvement. Results: For patients (n = 105), 96% of surveys sent were completed and analyzed. Most patients were ages 50-59 (22%), 60-69 (25%), 70-79 (25%). Breast cancer (38%) was the most commonly reported cancer type. Median patient TUQ scores were: 5/5 for Interaction Quality (ItQ) and Ease of Use (EU), 4/5 for Usefulness (U), Interface Quality (IfQ) and Satisfaction (S), and 3/5 for Reliability (R). No association was found between TUQ scores and age groups (p = 0.15), sex (p = 0.69), or timing of diagnosis in relation to telemedicine visit (p = 0.67). Compared to in-person visits, 70% of patients agreed/strongly agreed that telemedicine made them feel safer, 63% agreed/strongly agreed that it reduced stress, and 59% expressed interest in using it with other medical specialties. For providers (n = 85), 88% of surveys sent were completed and analyzed. Most providers were ages 30-39 (37%), 50-59 (23%), and 47% had 50 or more experiences with telemedicine. The predominant specialty participating was Internal Medicine (31%). Median provider TUQ scores were 4/5 for ItQ, EU, U, IfQ and S, and 2/5 for R. No association was found between TUQ scores and experience with telemedicine (p = 0.31), though providers aged 60-79 had significantly more negative views of telemedicine (p = 0.02) as compared to other age groups. The majority (97%) agreed/strongly agreed that telemedicine improves access to care, yet 57% expressed concern about missing something they may have caught in person. Conclusions: The use of telemedicine in cancer care was perceived favorably by patients and providers. All patient groups scored highly on perceived safety, reduced stress and improved access, independently of subject characteristics. Providers demonstrated some dissent, particularly in older age groups. These findings provide a useful benchmark for advancement of virtual care delivery in cancer care.

Guideline-based management is frequently altered by genetic testing, including panel testing, in patients at risk for cancer. We recommend that obstetrics and gynecology providers routinely refer at-risk patients for genetic counseling and testing when clinically appropriate.

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Background: While immunotherapy holds promise in the treatment of mTNBC, response rates (RR) in unselected patients (pts) are approximately 20%. Strategies to augment response to immunotherapy include depletion of regulatory T cells (Tregs). A single dose of cyclophosphamide (Cy) given prior to checkpoint inhibition achieved this goal in preclinical models of TNBC (Taylor et al., JCI, 2017). Thus, we designed a phase II study to evaluate this strategy in the clinical setting of mTNBC. Patients/Methods: In cycle 1 (C1), eligible pts with mTNBC received a single dose of Cy 300mg/m2 IV on day 1 (C1D1) followed by pembrolizumab 200mg IV on day 2 (C1D2), then every 3 weeks thereafter. The co-primary objectives were (1) progression free survival (PFS, null 1.9 mos vs. 2.9 mos, 80% power, alpha 0.05) and (2) reduction in Tregs in peripheral blood measured by flow cytometry. Secondary endpoints were response rate (RR), survival (OS), and RNA-based correlative endpoints. Results: 40 patients were evaluable for efficacy: mean age 54.5 yrs (33 – 82 yrs), 75% white, 22% black, 3% American Indian. All patients had received 1 prior line of chemotherapy in the metastatic setting; 29% received 5 or more prior lines. The most common grade 3 adverse events (AE's), all 5%, were neutropenia, anemia, elevated AST, and fatigue. Immune-related grade 3 AE's, all 3%, included colitis, dry mouth, pneumonitis. Overall RR was 21% (0 CR, 8 PR), 3 pts had stable disease. Median PFS was 1.8 months (mos) (95% CI 1.4–2.5) and OS was 6.3 mos (95% CI 2.8–8.4). There was a non-significant decrease in Tregs from C1D1 to C1D2 (-3.3%, p=0.19); but from C1D2 to C2D1, Tregs increased 21.7% (p=0.005). There was no association between changes in Tregs or number of prior lines of therapy with RR (p&gt;0.09), while immune-related AE's were associated with response (p=0.02). Correlatives studies illustrate B cell immune gene signature expression and B cell receptor repertoire diversity were enriched in responders, while genes/pathways associated with neutrophils, anti-apoptosis, PI3K/AKT and down-regulation of MHC class 1 were associated with non-response. Conclusions: While pembroliuzumab plus Cy was well-tolerated among pts with mTNBC, efficacy was similar to historical control, likely due to minimal effect of Cy on Tregs. Correlative analyses illustrate that study of adaptive immune features, including B cell biology, is a promising strategy for understanding response to PD-1 inhibition in breast cancer. Further strategies to deplete Tregs in a more sustained manner are worthy of future exploration (NCT02768701). Citation Format: Anders CK, Moore D, Sambade M, Cuaboy L, Garrett A, Woodcock M, McKinnon K, Cowens K, Bortone D, Calhoun B, Carey L, Dees C, Jolly T, Muss H, Reeder-Hayes K, Kaltman R, Jankowitz R, Gudena V, Olajide O, Perou C, Vincent B, Serody J. LCCC 1525: A phase II study of a priming dose of cyclophosphamide prior to pembrolizumab to treat metastatic triple negative breast cancer (mTNBC) [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 P2-09-05.