Abstract OT-07-01: Guardant360® related clinical outcomes in patients who share medical records-breast cancer (GRECO-B)
Authors: Fuchs Aaron , Muia Matthew , Ho Vicky , Ashton Kristi , Kumar Naveen , Marino Enrique , Yu Junhua , Lang Kathryn , Raymond Victoria M 
Published: February 2021

Abstract
Background: Cell free circulating tumor DNA (ctDNA) is a proven viable alternative to tissue molecular profiling with high sensitivity, specificity, and positive predictive value. However, there is limited data on the overall outcomes of patients following ctDNA testing. Guardant360® Related Clinical Outcomes in Patients who Share Medical Records - Breast Cancer (GRECO-Breast) is a novel, patient-centric approach to evaluate clinical data and outcomes. This real-world prospective observational study intends to assess the health outcomes of patients with advanced breast cancer who have undergone Guardant360 ctDNA testing by consenting patients through siteless methodologies to share their medical records and imaging studies documenting their clinical history.
Trial design: This is an observational study to be conducted in the United States. Patients with a diagnosis of breast cancer and a completed Guardant360 test will consent to share their medical records. Patients will be recruited by telephone or email to determine interest in the study. Should patients be interested in contributing to this study, they will be asked to consent via an electronic signature platform (e-signature) and electronic informed consent form (e-consent). Enrolled participants will be required to sign an electronic medical records release form for data review and verification by the study team. A healthcare information management organization will abstract participant demographics, cancer-related therapies, and clinical outcomes directly from source data for final analysis.
Eligibility criteria: Prospective participants will be adults (age 18+) with a diagnosis of breast cancer with a completed Guardant360 test who consent to be enrolled in the study.
Endpoints: Primary endpoint: To measure event free survival (EFS, composite endpoint of overall survival, progression events, and subjects lost to follow-up) stratified by treatment and genomic biomarker. Secondary endpoints: 1) Assess the rate of biomarker discovery compared to tissue genotyping results, when available; 2) Time to Next Treatment (TTNT); 3) Real-world Time to Tumor Progression (rwTTP); defined and documented either clinically or radiologically 4) Real-world Overall Survival (rwOS); defined as either clinically recorded death or secondary validated sources; 5) Record completeness of data and data quality.
Statistical methods: Descriptive statistics will be used to characterize the patient population. These will include frequency distributions, cross tabulations, and summary measures such as means, standard deviations, and ranges. Graphical displays will be employed, where appropriate, such as box plots, scatter plots, and survival curves for time-to-event endpoints.
Present accrual and target accrual: GRECO-Breast opened for enrollment in June 2020 with a goal of enrolling up to 300 participants.
Contact information: For more information, please visit: https://clinicaltrials.gov/ct2/show/NCT04436393
Citation Format: Aaron Fuchs, Matthew Muia, Vicky Ho, Kristi Ashton, Naveen Kumar, Enrique Marino, Junhua Yu, Kathryn Lang, Victoria M Raymond. Guardant360® related clinical outcomes in patients who share medical records-breast cancer (GRECO-B) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr OT-07-01.