Breast cancer
Progression after CDK4/6i + ET for HR+ HER2- MBC. What now?Emily (52 years old)
A 52-year-old woman presents with gradual fatigue and weight loss.
Assessment summary:
- No family history of breast cancer
- ECOG PS: 0
- Medical history:
- 10 years ago: diagnosis stage IIA breast cancer in left breast (3.2 cm). Tumour biology: ER 90%, PgR30%, HER2 IHC 1+, G2
- Treated with breast conserving surgery, negative sentinel lymph node
- Gene expression profiling: low risk
- Treated with 5 years of adjuvant tamoxifen
- 2 years ago (8 years after diagnosis breast cancer): presence of 3 bone metastases. Biopsy bone lesion: breast cancer, NST, ER 60%, PgR 30% HER IHC 1+, G2
- Treatment with riboclicib + OFS + letrozole started
- Tumour regression in control imaging
Today, she is postmenopausal and experiences disease progression.
- Imaging: progression of bone lesions, new lesions in liver (N=2) and mediastinal lymph nodes
- Biopsy of liver metastasis: breast cancer, NST, ER 50%, PgR 30%, HER2 IHC 1+, G2
- Haematology and biochemistry: all values normal
- Somatic PIK3CA mutation status: PIK3CA mutated
- Somatic ESR1 mutation status (on liquid biopsy): ESR1 mutated
- Germline BRCA mutation status: wild type