HER2-Positive Breast Cancer Treated With TPGS-Docetaxel-Based Chemotherapy: A Case Report - Dr Sanath Kandem

A 53-year-old woman with type II diabetes mellitus and a family history of carcinoma breast in her sister presented with a lump in the right breast. Examination revealed a 3 cm breast lump with axillary lymphadenopathy. Biopsy showed invasive carcinoma, with immunohistochemistry suggestive of triple-positive disease. Imaging showed a lung nodule and multiple abdominal/mediastinal lymph nodes; subsequent evaluation suggested tuberculosis.

CT-guided abdominal nodal biopsy showed necrotising granulomatous lymphadenitis. TB PCR was negative, and the case was discussed in TBM with pulmonology opinion obtained; empirical ATT was planned.

Investigations and Diagnosis

Baseline investigations showed CBC, LFT, KFT and ECG within normal limits, while 2D echocardiography demonstrated an ejection fraction of 55.7%. PET/CT demonstrated a biopsy-proven primary right breast lesion measuring 2.4 × 2.4 × 3.4 cm, with SUVmax 8.7, along with a satellite lesion measuring 1.6 × 1.5 × 2.2 cm, with SUVmax 3.8. Metabolically active right axillary, mediastinal and retroperitoneal lymph nodes were noted, measuring up to 2.2 × 1.9 cm, with SUVmax 7.1. Pleural-based thickening in the left lower lung measured 7 mm, with SUVmax 5.5, and was reported as metastatic.

Histopathology showed invasive breast carcinoma, NST, Grade 3, with a Modified Bloom Richardson score of 8/9. FNAC from the right axillary lymph node was positive for malignancy, while the periportal node biopsy showed features suggestive of necrotising granulomatous lymphadenitis.

Immunohistochemistry showed ER 90%, PR 30%, HER2 3+ and Ki-67 70%. The final diagnosis was documented as carcinoma breast (cT2N1M0[oligo]) – triple positive – for TCHP NACT, with staging documented as cT2N1M0(oligo).

Treatment

The treatment goal was to achieve systemic disease control and reduce tumour burden through chemotherapy and HER2-directed therapy.

The documented treatment comprised:

• Cycle 1: TPGS-docetaxel 80 mg IV + trastuzumab 480 mg IV (8 mg/kg) + pertuzumab 840 mg IV + pegfilgrastim 6 mg SC.
• Cycle 2: TPGS-docetaxel 80 mg IV + trastuzumab 360 mg IV (6 mg/kg) + pertuzumab 420 mg IV + pegfilgrastim 6 mg SC.
• Cycle 3: TPGS-docetaxel 80 mg IV + trastuzumab 360 mg IV (6 mg/kg) + carboplatin 300 mg IV + pertuzumab 420 mg IV + pegfilgrastim 6 mg SC.
• Cycle 4: TPGS-docetaxel 80 mg IV + trastuzumab 360 mg IV (6 mg/kg) + carboplatin 300 mg IV + pertuzumab 420 mg IV + pegfilgrastim 6 mg SC.

Follow-up and Treatment Outcome

Four cycles of systemic therapy were documented, and the patient remained clinically stable at discharge. Treatment was reported to be well tolerated, with no documented infusion-related reactions or Grade 3/4 adverse events.

The case documented continued treatment with TPGS-docetaxel-based chemotherapy along with trastuzumab and pertuzumab, with treatment continuing without documented interruption.

Treatment Experience With TPGS-Docetaxel

TPGS-docetaxel was incorporated as part of the documented chemotherapy regimen and was continued across all four documented cycles. Treatment was reported as well tolerated, without documented infusion-related reactions or Grade 3/4 adverse events.

Key Takeaways

• This case describes HER2-positive/triple-positive breast cancer treated with a TPGS-docetaxel-containing systemic chemotherapy regimen.
• The treatment regimen included TPGS-docetaxel, trastuzumab and pertuzumab, with carboplatin incorporated from Cycle 3.
• Four cycles of systemic therapy were documented, with treatment continuing without documented interruption.
• Treatment was reported as well tolerated, with no documented infusion-related reactions or Grade 3/4 adverse events

Abbreviations: HER2, human epidermal growth factor receptor 2, ER, estrogen receptor, PR, progesterone receptor, IHC, immunohistochemistry, FISH, fluorescence in situ hybridization, PET/CT, positron emission tomography/computed tomography, FDG, fluorodeoxyglucose, SUVmax, maximum standardized uptake value, CBC, complete blood count, LFT, liver function test, KFT, kidney function test, ECG, electrocardiogram, ECOG PS, Eastern Cooperative Oncology Group performance status, THP, trastuzumab–pertuzumab–docetaxel, IV, intravenous, SC, subcutaneous, TPGS, D-α-tocopheryl polyethylene glycol 1000 succinate, NA, not available, cT2N0M0, clinical tumour stage 2, node-negative, metastasis-negative.

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