A 52-Year-Old Woman With HER2-Positive Breast Cancer

Ruth O’Regan, MD:We’re presented with a case of a 52-year-old lady who presents with a mass in her left breast, which she felt when she was showering. She’s otherwise very healthy, postmenopausal since the age of 49, with 2 children. Her family history is negative for cardiovascular disease or breast cancer. On examination she has a mass in the left breast, which measures just over 2 cm.

Her mammogram shows a mass in the left breast. She then has an ultrasound, which confirms the mass in her left breast measuring about 2 cm and also a suspicious axillary lymph node. A biopsy is performed of the left breast mass, which shows invasive ductal cancer, grade 2, estrogen receptor negative, progesterone receptor negative, and HER2 [human epidermal growth factor receptor 2], 3+ by IHC [immunohistochemistry].

She also has an aspirate done of the left axillary lymph node, which showed positive for metastatic cancer. Systemic imaging does not reveal any evidence of metastatic disease.

She receives neoadjuvant chemotherapy with docetaxel, carboplatin, trastuzumab, and pertuzumab for 6 cycles. She subsequently undergoes breast-conserving surgery, with removal of exudate lymph nodes, and has a pathologic complete response.

She does very well with the chemotherapy apart from having some diarrhea, which required holding up the pertuzumab for a cycle, then resolved to grade 1.

This lady presents with a pretty typical presentation for HER2-positive breast cancer. Notable things here are the size of the cancer and also the fact that she does have an involved lymph node. So I think most of us would go ahead and give her preoperative treatment. The regimen that was chosen was completely appropriate with docetaxel, carboplatin, trastuzumab, and pertuzumab. That’s generally my preference in terms of treating patients preoperatively.

Also notable is the fact that the cancer is estrogen receptor negative. Typically, cancers that are estrogen receptor negative and HER2-positive are more likely to have a complete response to preoperative chemotherapy and HER2-directed therapy, as was seen in this case.

Transcript edited for clarity.

Case: A 52-Year-Old Woman withHER2+ Breast Cancer

H & P

• A 52-year-old, postmenopausal woman presented with a mass in her left breast at her annual gynecologic exam; was referred to oncology
• 2 children, menopause at age 49
• No history of cardiovascular disease, no family history of breast cancer
• PE: reveals a slightly overweight woman (BMI = 26 kg/m²), with palpable masses in left breast and left axillary nodes

Imaging

• Mammogram reveals 2.5-cm tumor in left breast
• CT: confirms tumor in left breast and left axillary node involvement (2.6-mm metastasis in 1 node)

Biopsy and labs:

• Histology: invasive ductal adenocarcinoma
• Histologic grade: G2
• ER (-)/ PR (-)
• HER2IHC, 3+
• BRCA1/2status: unknown

Treatment

• She received neoadjuvant TCH-P (docetaxel + carboplatin + trastuzumab + pertuzumab) and achieved pathologic complete response
  • Developed grade 3 diarrhea during second cycle of chemotherapy, which required a one-level dose reduction of paclitaxel
  • Diarrhea resolved to grade 1/2
• Underwent breast-conserving surgery and removal of left axillary lymph nodes; no residual disease
• Currently completing adjuvant therapy; trastuzumab + pertuzumab (total 18 cycles)