TRK inhibitor in a patient with metastatic triple-negative breast cancer and NTRK fusions identified via cell-free DNA analysis

Tissue-agnostic indications for targeted therapies have expanded options for patients with advanced solid tumors. The Food and Drug Administration approvals of the programmed death-ligand 1 inhibitor pembrolizumab and the TRK inhibitors larotrectinib and entrectinib provide rationale for next-generation sequencing (NGS) in effectively all advanced solid tumor patients given potential for clinical responses even in otherwise refractory disease. As proof of concept, this case report describes a 64-year-old woman with triple-negative breast cancer refractory to multiple lines of therapy, found to have a rare mutation on NGS which led to targeted therapy with meaningful response. She initially presented with metastatic recurrence 5 years after treatment for a localized breast cancer, with rapid progression through four lines of therapy in the metastatic setting, including immunotherapy, antibody-drug conjugate-based therapy, and chemotherapy. Germline genetic testing was normal. Ultimately, NGS evaluation of cell-free DNA via an 83-gene assay (Guardant Health, Inc.) identified two NTRK3 fusions: an ETV6-NTRK3 fusion associated with the rare secretory breast carcinoma, and CRTC3-NTRK3, a novel fusion partner not previously described in breast cancer. Liver biopsy was sent for whole exome sequencing and RNA-seq analysis of tissue (BostonGene, Inc., Boston, MA, USA), which provided orthogonal confirmation of both the ETV6-NTRK3 and CRTC3-NTRK3 fusions. She was started on the TRK inhibitor larotrectinib with a marked clinical and radiographic response after only 2 months of therapy. The patient granted verbal consent to share her clinical story, images, and data in this case report. This case demonstrates the significant potential benefits of NGS testing in advanced cancer and the lessons we may learn from individual patient experiences.

Abstract B124: Breast cancer treatment delays at an urban safety net hospital among women experiencing homelessness

Abstract Disparities in outcomes for vulnerable women is a persistent, ongoing problem. Timely treatment improves breast cancer outcomes and efforts to improve delays among underserved patients is needed. Specifically, homelessness and breast cancer treatment outcomes are understudied. This is a novel and descriptive study exploring types of homelessness and treatment delays at an urban safety net hospital providing care to a vulnerable patient population. Experimental Procedures This study is a retrospective chart review of homeless female patients diagnosed with breast cancer between January 1, 2000 and December 31, 2014. Data for this study were acquired from the hospital cancer registry and electronic medical record. Homelessness was categorized as transitionally, episodically or chronically homeless. Other variables collected included demographic characteristics and time to treatment. A detailed chart review was conducted to identify delays to breast cancer treatment and the potential reasons for delay between diagnosis and first treatment. All demographic characteristics, time to treatment and factors related to delays to treatment were analyzed descriptively, reporting frequencies and proportions. Delay to treatment was calculated as date of pathologically confirmed biopsy of breast cancer to date of first treatment (surgery or chemotherapy). Summary of Data The total number of individuals analyzed was 24. All except two subjects were delayed to treatment (> 30 days from diagnosis to treatment). Most women in this cohort were categorized as chronically homeless (46%) with the rest categorized as transitionally (29%) or episodically (12%) homeless. The majority of subjects (70%) were Black, non-Hispanic. Most women identified as single (58%) or divorced (21%) at the time of breast cancer diagnosis. All except one subject were publicly insured (71% Medicaid; 12% Medicare) or uninsured (8%). Regardless of type of homelessness, most subjects were either 30-60 or 60-90 days delayed. Those who were chronically homeless experienced significantly more delays to first treatment (56% of those who were delayed 30-60 days and 57% of those who were delayed 60-90 days; p-value 0.006) than those who were episodically or transitionally homeless. Conclusions Significant delays and barriers to breast cancer treatment exist among women experiencing homelessness. Further studies and focused efforts to improve timely breast cancer care for homeless women is warranted.

Citation Format: Kate Festa, Ariel E Hirsch, Michael R Cassidy, Lauren Oshry, Kathryn Quinn, Margaret M Sullivan, Naomi Y Ko. Breast cancer treatment delays at an urban safety net hospital among women experiencing homelessness [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr B124.

Abstract P5-12-03: Socio-demographic differences in utilization of genomic testing and receipt of endocrine therapy in the National Cancer Database

Background & Objectives Breast cancer outcome disparities for racial and ethnic minorities continues to be a problem in the United States. Genomic testing in early stage hormone positive breast cancer is the current standard of care given the useful predictive and prognostic value of testing. However, chemotherapy treatment decisions based on genomic testing results are predicated on the assumption that patient adhere to adjuvant endocrine treatment. Factors that could contribute to ongoing disparities for racial and ethnic minorities include both the utilization of genomic testing and adherence to hormonal therapy. Understanding these patterns of care across the United States with a large dataset has not yet been done. Methods We analyzed a cohort from the National Cancer Database (NCDB) of 387,008 female patients diagnosed with Stage I-II, ER+ breast cancer between 2010 and 2014. Demographic variables included age, race, ethnicity, insurance status, income, education, Charlson-Deyo comorbidity score. Clinicopathologic and treatment variables included tumor grade, histology, receptor status, facility type, delivery of treatment at >1 facility and receipt of genomic testing. Descriptive statistics using chi-square testing were computed to describe patient, tumor and treatment characteristics. Logistic regression analysis was used to calculate odds of genomic testing and receipt of hormone therapy among patients who did or did not receive genomic testing.

Results Among a total sample size of 387,008, median age was 63 years old, majority white (87%), non-Hispanic (95.4%), without co-morbidities (88%). A total of 147,863 (38.2%) patients underwent genomic testing. Compared to patients with ages 18-<50, older age (≥70 years) was associated with a lower adjusted odds of genomic testing (OR=0.33; 95% CI=0.32-0.34, p=<0.0001). Blacks had a lower odds of receiving genomic testing on multivariate analysis compared to whites (OR=0.82; 95% CI=0.80-0.85, p=<0.0001). Hispanic ethnicity, non-private insurance, increasing percentage of no high school degree in area of residence, CDS score of 2 or more, stage II disease, community or comprehensive community facility setting, and borderline HER2 status were also factors associated with a lower odds of receiving a genomic test. Odds of getting genomic testing improved over the years with patients diagnosed in 2014 reporting an odds ratio of 1.57 (95% CI=1.53-1.60, p=<0.0001) compared to those diagnosed in 2010. Compared to whites, blacks had a lower odds of receiving hormone therapy irrespective of genomic testing status (OR=0.86; 95% CI=0.83-0.88, p=<0.0001). Age ≥70 (OR=0.53; 95% CI=0.51-0.55, p=<0.0001), Hispanic ethnicity (OR=0.89; 95% CI=0.85-0.93, p=<0.0001), non-private insurance and non-academic treatment facilities were associated with lower odds of getting hormone therapy. Among patients undergoing a genomic test, age ≥70, black race, and non-academic treatment facilities had lower odds of receiving hormone therapy. Conclusion In a national cohort of breast cancer patients, Black women consistently were less likely to get genomic testing and less likely to receive hormonal therapy. Ensuring that all women with early stage ER+ breast cancer eligible for genomic testing and hormone therapy receive appropriate testing and hormonal treatment is a priority to addressing breast cancer disparities.

Citation Format: Naomi Y Ko, Mustafa Q Muhammad, Michael R Cassidy, Lauren Oshry, Ariel E Hirsch. Socio-demographic differences in utilization of genomic testing and receipt of endocrine therapy in the National Cancer Database [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-12-03.

The Impact of Locoregional Treatment on Survival in Patients With Metastatic Breast Cancer: A National Cancer Database Analysis

BACKGROUND

Although systemic therapy is the standard treatment for metastatic breast cancer, the value of locoregional treatment (LRT) of the primary tumor and its impact on survival is controversial. This study evaluates survival outcomes in patients with metastatic breast cancer after receiving LRT (surgery and/or radiation therapy) of the primary tumor.

MATERIALS AND METHODS

The National Cancer Database was used to identify 16,128 qualifying cases of metastatic breast cancer who received systemic therapy with or without LRT from 2004 to 2013. Treatment modality was divided into surgery (Sx), radiation therapy (RT), surgery followed by RT (Sx + RT), and no LRT. The median survival and 3-year actuarial survival rates (OS) were analyzed for each treatment group. On multivariate analyses, adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) were computed using Cox regression modeling to adjust for patient and clinicopathologic characteristics.

RESULTS

Overall, the median follow-up was 28.3 months, and the median survival for all patients was 37.2 months. With 9761 deaths reported, the estimated 3-year OS was 51.3%. The Sx + RT group (n = 2166) had the highest 3-year OS of 69.4%, followed by the Sx group (n = 4293) with 57.6%, the no LRT group (n = 8955) with 44.3%, and the RT group (n = 714) with 41.5% (P < .0001). On multivariate analysis, compared with the no LRT group, a decreased HR was noted in patients receiving Sx (adjusted HR, 0.68; 95% CI, 0.65-0.71; P < .0001) and Sx + RT (adjusted HR, 0.46; 95% CI, 0.43-0.49; P < .0001).

CONCLUSION

LRT, especially surgery followed by RT, in addition to systemic therapy, was associated with improved survival in patients with metastatic breast cancer.

Annexin-mediated membrane fusion of human neutrophil plasma membranes and phospholipid vesicles

Membrane fusion was studied using human neutrophil plasma membrane preparations and phospholipid vesicles approximately 0.15 microns in diameter and composed of phosphatidylserine and phosphatidylethanolamine in a ratio of 1 to 3. Liposomes were labeled with N-(7-nitrobenzo-2-oxa-1,3-diazol-4-yl (NBD) and lissamine rhodamine B derivatives of phospholipids. Apparent fusion was detected as an increase in fluorescence of the resonance energy transfer donor, NBD, after dilution of the probes into unlabeled membranes. 0.5 mM Ca2+ alone was sufficient to cause substantial fusion of liposomes with a plasma membrane preparation but not with other liposomes. Both annexin I and des(1-9)annexin I caused a substantial increase in the rate of fusion under these conditions while annexin V inhibited fusion. Fusion mediated by des(1-9)annexin I was observed at Ca2+ concentrations as low as approximately 5 microM, suggesting that the truncated form of this protein may be active at physiologically low Ca2+ concentrations. Trypsin treated plasma membranes were incapable of fusion with liposomes, suggesting that plasma membrane proteins may mediate fusion. Liposomes did not fuse with whole cells at any Ca2+ concentration, indicating that the cytoplasmic side of the membrane is involved. These results suggest that annexin I and unidentified plasma membrane proteins may play a role in Ca(2+)-dependent degranulation of human neutrophils.