73-year-old female, invasive ductal carcinoma (IDC) of the right breast (ER 7, PR 8, HER2/neu +1, Ki-67 20%), luminal B–like, HR-positive/HER2-negative phenotype.
• Treatment: Patient received EPCT (Nab-Paclitaxel + Carboplatin) followed by bisphosphonate therapy. MRI and PET revealed metastases to the liver, bones, lungs, and residual breast mass. After 18 cycles of EPCT, she was started on Abemaciclib + Fulvestrant, but showed disease progression with liver and bone lesions and was maintained on the same regimen due to chemotherapy intolerance.
• Further evaluation: Comprehensive liquid biopsy (OncoIndx, cfDNA) was performed to evaluate resistance mechanisms and guide therapy.
Clinical Challenges:
• Endocrine resistance despite CDK4/6 + SERD therapy.
• Low HRD/TMB restricting immunotherapy or PARP inhibitor use.
• Chemotherapy intolerance requiring precision-guided, non-invasive monitoring.
• Need for dynamic monitoring using liquid biopsy for resistance evolution.x