Guardant360® Related Clinical Outcomes in Patients Who Share Medical Records-Breast Cancer

Study Overview
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Brief Summary
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The purpose of this study is to observe the routine clinical care of patients who have been diagnosed with breast cancer and have undergone Guardant360 testing.

Detailed Description
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Patients who have been diagnosed with breast cancer and have undergone Guardant360 testing will be approached regarding participation in the study. After being informed about the study and potential risks, all patients providing informed consent and access to their medical records, will provide a list of their health care providers related to their cancer treatment. Data related to their routine clinical care will be abstracted from medical records.

Official Title
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Guardant360® Related Clinical Outcomes in Patients Who Share Medical Records-Breast Cancer

Conditions
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Advanced Breast Cancer

Intervention / Treatment
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* Diagnostic Test: Guardant360 test


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adults (18 years of age and older) with a diagnosis of breast cancer Guardant360 test results released to the patient's physician no less than 14 days prior to initial patient contact Patient has previously provided contact information (either email or phone) to Guardant Health Able and willing to complete the electronic informed consent process Must have access to a computer terminal or personal computing device Willingness to consent to the release of medical records Exclusion Criteria: 1. Unable to understand English

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Advanced Breast Cancer<br>Patients with diagnosis of advanced breast cancer | Diagnostic Test: Guardant360 test<br>* tumor cfDNA testing<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Overall Survival | The Primary Outcome measure is a composite endpoint of: overall survival, progression events, and subjects lost-to-follow-up Overall Survival is the length of time from either the date of diagnosis or the start of treatment for a disease, such as cancer, that patients diagnosed with the disease are still alive. | 18 months post Guardant360 testing | 
| Progression Events | The Primary Outcome measure is a composite endpoint of: overall survival, progression events, and subjects lost-to-follow-up Progression events (or progression-free survival) is the length of time during and after the treatment of a disease, such as cancer, that a patient lives with the disease but it does not get worse. | 18 months post Guardant360 testing | 
| Subject Lost-to-Follow-Up | The Primary Outcome measure is a composite endpoint of: overall survival, progression events, and subjects lost-to-follow-up The length of time from date of study consent to date subject exited study prematurely due being considered lost-to-follow-up (ex. lack of response following consent) | 18 months post Guardant360 testing | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rate of biomarker discovery | Assess the rate of biomarker discovery compared to tumor genotyping results | 18 months post Guardant360 testing | 
| Time to Next Treatment | Assess time to next treatment decision compared to tumor genotyping results | 18 months post Guardant360 testing | 
| Real-world Time to Tumor Progression | Documented tumor progression either clinically or radiologically | 18 months post Guardant360 testing | 
| Real-world Overall Survival | Date of death per clinical record or secondary sources (e.g. national death registries) | 18 months post Guardant360 testing | 
| Demographics | Descriptive statistics of patient demographics | 18 months post Guardant360 testing |