Treatment Response Monitoring Using a Tumor-Informed Circulating Tumor DNA Test in an Advanced Triple-Negative Breast Cancer Patient: A Case Report

Abstract

Triple-negative breast cancer (TNBC) is highly aggressive disease that is often refractory to surgery and multiple lines of therapy. Although the repertoire of FDA-approved treatments has expanded, there is an unmet need for biomarkers that can aid in appropriate selection and timing of therapy. We present a case of highly aggressive treatment-resistant TNBC that employed a comprehensive genomic profiling (CGP)-based assay to identify therapeutic targets, followed by longitudinal circulating tumor DNA (ctDNA) testing. For this, a tumor-naïve next-generation sequencing-based targeted panel was used to aid in therapy selection, along with longitudinal personalized and tumor-informed ctDNA testing to monitor tumor response to treatment. Longitudinal ctDNA testing using the tumor-informed assay detected post-surgical molecular residual disease, and rise in ctDNA levels during the surveillance period provided rationale for switching between four lines of therapy. Overall, the combined use of CGP assay with longitudinal ctDNA testing resulted in a potential prolonged survival in this highly aggressive case of TNBC.

Metastatic progression of breast cancer along with decreased mitochondrial cell death priming of breast cancer cells: a case report

“…Tumor evolution during progression of the metastatic breast cancer is usually accompanied by emerging clones of cancer cells with additional mutations in various oncogenes including ERBB2 and resistance to chemotherapy [ 4 ]. In fact, liquid biopsy has been shown to be an effective tool to monitor disease progression and tumor response to treatment in breast cancer patients [ 5 , 6 ]. The patient we described herein presented with liver and brain metastasis after modified-radical mastectomy and adjuvant chemotherapy.…”

Exploring Biomarkers in Breast Cancer: Hallmarks of Diagnosis, Treatment, and Follow-Up in Clinical Practice

“…Their association with residual cancer burden is an independent prognostic factor in patients with residual TNBC [161]. Case studies, like one utilizing a tumor-informed CTC test in an advanced TNBC patient, demonstrate CTCs' utility in identifying therapeutic targets and monitoring treatment response [162]. Additionally, the role of CTCs in metastasis and chemotherapy effectiveness is under investigation, suggesting their therapeutic target potential [163].…”

Maternal Malignancy After Atypical Findings on Single-Nucleotide Polymorphism–Based Prenatal Cell-Free DNA Screening

“…It is recognized that malignancies can be another source of cell-free DNA in plasma. [2][3][4][5][6][7] Rarely, cell-free DNA released by maternal cancer is detected on noninvasive prenatal screening and has led to reports of unexpected cancer diagnoses in otherwise asymptomatic pregnant people. 8 Incidental discovery of maternal malignancy through cell-free DNA screening found to be discordant with the fetal karyotype has been reported after identification of aneuploidies and copy number variants involving multiple chromosomes.…”

“…It is recognized that malignancies can be another source of cell-free DNA in plasma. 2–7 Rarely, cell-free DNA released by maternal cancer is detected on noninvasive prenatal screening and has led to reports of unexpected cancer diagnoses in otherwise asymptomatic pregnant people. 8…”