Prognosis of a HER2+ Breast Cancer Patient

Joyce O'Shaughnessy, MD: This young perimenopausal woman, age 54, otherwise healthy, presented with a pretty serious breast cancer. It was estrogen receptor-positive, strongly HER2 [human epidermal growth factor receptor 2]-positive, 3+ score by IHC [immunohistochemistry], grade 3 disease, nodes positive at presentation, and a pretty substantially sized cancer. That is a prognosis that definitely is associated with risk, and you’re really thinking about utilizing the very best therapies that you have. Before the introduction of trastuzumab, her risk of death from breast cancer would have been very high, probably somewhere in excess of 50%, closer probably to a 70%, 80% chance of dying eventually of breast cancer because the recurrences can be late.

With the introduction of the trastuzumab as adjuvant therapy, she probably would be looking more at about an 80% chance of remaining disease free for long term. With the then introduction of pertuzumab in the overall trial, like the APHINITY trial, that was further improved, probably up to the 85%-plus, 88% chance. Switching then to the T-DM1 [trastuzumab emtansine] in the adjuvant setting when she did not have a pathologic complete response, those patients in the KATHERINE trial, that resets the prognosis because now you know something, which is that she responded to the TCHP [docetaxel, carboplatin, trastuzumab, pertuzumab], but she did not have a pathologic complete response. So she was still going to be looking at a 20%, 25% chance of recurrence with just trastuzumab and pertuzumab.

Switching to the T-DM1 when she had residual disease took her from a disease-free survival rate of the mid-to-high 70% range, up to the mid-to-high 80% chance of remaining disease free. Unfortunately, that still leaves her with risk. So she does have risk; she still probably has somewhere between a 10% and 15% residual risk of recurrence.

Transcript edited for clarity.

Case: A 54-Year-Old Woman With Stage 2HER2+ Breast Cancer

Initial presentation

• A 54-year-old, postmenopausal woman presented with a painless palpable mass on the right upper outer quadrant of her right breast
• PMH/SH: unremarkable, no family history of cancer
• PE: ~ 4-cm palpable right breast mass, clinically node negative, no visible sink involvement

Clinical workup

• Labs: WNL
• Ultrasound showed a right breast mass, and two axillary lymph nodes
• Mammogram confirmed a right—sided, poorly defined speculated 4.2-cm mass
• PET/CT showed increased uptake in the right breast diffusely, with 2 FDG—avid axillary lymph node involvement; no evidence of distant metastases
• Ultrasound—guided FNA biopsy of the breast mass confirmed grade 3 infiltrative ductal carcinoma
  • Hormone receptor/HER2 Status:HER2+:3+ by IHC,80%ER+, PR-
• Stage T2N1M0; ECOG PS 0

Treatment and Follow-Up

• The patient was started on preoperative docetaxel + carboplatin + trastuzumab + pertuzumab (TCHP), and pegfilgrastim every 3 weeks for 6 cycles;
  • Achieved clinical complete response
• She underwent right mastectomy; residual disease: 1 positive axillary lymph node, and 1-cm RD in the right breast; 4 sentinel lymph nodes removed, 1 positive for disease; she also received post mastectomy radiation therapy of her chest wall and regional lymphatics
• She was started on trastuzumab emtansine every 3 weeks for 14 cycles + aromatase inhibitor PMRT + letrozole planned for 10 years
• Extended adjuvant neratinib was initiated
  • Week 1: 160 mg (4 tablets) PO qDay; week 2: 200 mg (5 tablets) PO qDay; week 3: 240 mg (6 tablets) PO qDay for 1 year
  • IV zoledronic acid every 6 months was added to her regimen for 3-5 years