HER2+ BC: Residual Disease After Neoadjuvant Therapy

Case: A 49-Year-Old Woman With HER2+ Breast Cancer

H & P

• A 49-year-old woman was referred by gynecology for a mass in her right breast
• No children, menopause at age 45
• No history of cardiovascular disease, otherwise good health
• PE: revealed a woman of normal weight (BMI = 21 kg/m²), with a palpable mass in her right breast

Imaging

• Mammogram revealed 3.5-cm tumor in right breast
• CT: confirmed a tumor in right breast with no lymph node involvement

Biopsy and labs:

• Histology: ductal, grade 2
• ER(-), PR (-)
• HER2IHC: 3+
• BRCA1/2: negative

Treatment

• Diagnosed with ER/PR negativeHER2+ breast cancer; she received neoadjuvant TCH-P (docetaxel + carboplatin + trastuzumab + pertuzumab and achieved a partial response
  • Residual disease of 1.5 cm after neoadjuvant therapy
• Underwent mastectomy
• After discussing with her the options for adjuvant therapy, benefits and risks of each, and her goals, she was started on ado-trastuzumab emtansine (T-DM1)
• At present, she has completed 3 cycles of T-DM1
  • Reports numbness in her fingers, “like wearing gloves” that sometimes interferes with small tasks like buttoning a shirt