[HER2-Positive Breast Cancer Brain Metastasis Recurred after Whole-Brain Radiotherapy and Successfully Treated with...

Area of Science:

• Oncology
• Medical Oncology
• Clinical Therapeutics

Background:

• A 50-year-old female presented with advanced HER2-positive mucinous carcinoma of the left breast.
• The patient had metastatic disease involving bone and subsequently developed brain metastases.

Purpose of the Study:

• To describe the treatment course and outcomes for a patient with metastatic HER2-positive breast cancer.
• To evaluate the efficacy of trastuzumab deruxtecan in managing refractory brain metastases.

Main Methods:

• Initial treatment involved trastuzumab + pertuzumab + docetaxel (HPD) and denosumab, followed by HPD and zoledronic acid.
• Treatment was modified to trastuzumab + pertuzumab (HP) due to edema.
• Whole brain irradiation was administered for brain metastases.
• Trastuzumab deruxtecan was initiated for recurrent brain metastases.

Main Results:

• The patient initially responded to HPD and zoledronic acid but developed brain metastases.
• Whole brain irradiation provided temporary relief.
• Trastuzumab deruxtecan led to near-complete resolution of brain metastatic lesions on MRI within 3 months.
• The patient tolerated trastuzumab deruxtecan without major adverse events.

Conclusions:

• Trastuzumab deruxtecan is a promising therapeutic option for HER2-positive breast cancer with brain metastases refractory to prior treatments.
• Sequential treatment strategies, including targeted therapy and radiation, are crucial for managing advanced metastatic breast cancer.