Adjuvant endocrine therapy with cyclin-dependent kinase 4/6 inhibitor, ribociclib, for localized hormone receptor-positive/HER2- breast cancer (LEADER).

Optimal timing and dosing of adjuvant cyclin-dependent kinase (CDK) 4/6 inhibitor in early breast cancer is controversial. This prospective phase II clinical trial investigated tolerability and safety of two ribociclib dosing schedules. Patients with stage I-III hormone receptor-positive (HR+)/HER2- breast cancer on adjuvant endocrine therapy (ET) were randomized to two ribociclib dosing schedules: 400 mg continuous vs 600 mg intermittent, with initiation in early (prior ET < 2 years) vs delayed (prior ET ≥ 2 years) setting.

Deficits of Molecular Prognosis/Diagnosis Studies in Underserved Populations.

Molecular prognostic and diagnostic tools allow for targeted cancer surveillance, prognostication, and treatment, and these assays have the potential to improve the lives of patients and their relatives. The impact of these advances, however, is not uniform across populations. Underserved communities frequently do not have the same level of access to novel assays, and the clinical application of these tools is often limited by disproportionate representation of White and European ancestry populations in foundational data, as well as limited diversity in clinical trials.

A standing platform for cancer drug development using ctDNA-based evidence of recurrence.

The time required to conduct clinical trials limits the rate at which we can evaluate and deliver new treatment options to patients with cancer. New approaches to increase trial efficiency while maintaining rigor would benefit patients, especially in oncology, in which adjuvant trials hold promise for intercepting metastatic disease, but typically require large numbers of patients and many years to complete. We envision a standing platform - an infrastructure to support ongoing identification and trial enrolment of patients with cancer with early molecular evidence of disease (MED) after curative-intent therapy for early-stage cancer, based on the presence of circulating tumour DNA.

CDK4/6 Inhibitor Efficacy in -Mutant Metastatic Breast Cancer.

Background: In estrogen receptor-positive metastatic breast cancer, mutations (ESR1) are a common mechanism of acquired resistance to aromatase inhibitors (ArIh). However, the impact alterations have on CDK4/6 inhibitor (CDK4/6i) sensitivity has not been established. Analyses of CDK4/6i trials suggest that the endocrine therapy partner and specific allele may affect susceptibility.

Genomic spectrum of actionable alterations in serial cell free DNA (cfDNA) analysis of patients with metastatic breast cancer.

We aimed to study the incidence and genomic spectrum of actionable alterations (AA) detected in serial cfDNA collections from patients with metastatic breast cancer (MBC). Patients with MBC who underwent plasma-based cfDNA testing (Guardant360) between 2015 and 2021 at an academic institution were included. For patients with serial draws, new pathogenic alterations in each draw were classified as actionable alterations (AA) if they met ESCAT I or II criteria of the ESMO Scale for Clinical Actionability of Molecular Targets (ESCAT).

Molecular Residual Disease in Breast Cancer: Detection and Therapeutic Interception.

Breast cancer remains a leading cause of cancer-related death in women despite screening and therapeutic advances. Early detection allows for resection of local disease; however, patients can develop metastatic recurrences years after curative treatment. There is no reliable blood-based monitoring after curative therapy, and radiographic evaluation for metastatic disease is performed only in response to symptoms.

Circulating Tumor DNA in Breast Cancer: Current and Future Applications.

The assessment of plasma for circulating tumor DNA (ctDNA) via liquid biopsy has revolutionized our understanding of breast cancer pathogenesis and evolution. Historically, genotyping evaluation of breast cancer required invasive tissue biopsy, limiting potential for serial evaluation over the treatment course of advanced breast cancer, and not allowing for assessment for residual disease in early breast cancer after resection. However, technological advances over the years have led to an increase in the clinical use of ctDNA as a liquid biopsy for genotype-matched therapy selection and monitoring for patients undergoing treatment for advanced breast cancer.

Genetic Alterations Detected by Circulating Tumor DNA in HER2-Low Metastatic Breast Cancer.

Purpose: About 50% of breast cancers are defined as HER2-low and may benefit from HER2-directed antibody-drug conjugates. While tissue sequencing has evaluated potential differences in genomic profiles for patients with HER2-low breast cancer, genetic alterations in circulating tumor DNA (ctDNA) have not been well described.

Experimental Design: We retrospectively analyzed 749 patients with metastatic breast cancer (MBC) and ctDNA evaluation by Guardant360 from three academic medical centers.

Circulating tumour DNA characterisation of invasive lobular carcinoma in patients with metastatic breast cancer.

Background: Limited data exist to characterise molecular differences in circulating tumour DNA (ctDNA) for patients with invasive lobular carcinoma (ILC). We analysed metastatic breast cancer patients with ctDNA testing to assess genomic differences among patients with ILC, invasive ductal carcinoma (IDC), and mixed histology.

Methods: We retrospectively analysed 980 clinically annotated patients (121 ILC, 792 IDC, and 67 mixed histology) from three academic centers with ctDNA evaluation by Guardant360™.

Blood-based monitoring identifies acquired and targetable driver mutations in endocrine-resistant metastatic breast cancer.

Plasma genotyping identifies potentially actionable mutations at variable mutant allele frequencies, often admixed with multiple subclonal variants, highlighting the need for their clinical and functional validation. We prospectively monitored plasma genotypes in 143 women with endocrine-resistant metastatic breast cancer (MBC), identifying multiple novel mutations including mutations (8.4%), albeit at different frequencies highlighting clinical heterogeneity.

Detection of Cancer DNA in Early Stage and Metastatic Breast Cancer Patients.

Breast cancer is the leading cause of cancer in women and the second leading cause of cancer-related death. There are many subtypes of breast cancer, which can be identified through the process of molecular and genetic profiling. While the current standard of care utilizes tumor tissue biopsy to subclassify breast cancer, plasma tumor DNA (ptDNA) can be detected through droplet digital PCR (ddPCR) of plasma obtained from a simple blood draw.