engleski

Optimal postoperative treatment of HER2 positive breast cancer with residual tumor after neoadjuvant therapy: a case report

Introduction: Neoadjuvant therapy (NAT) with dual antiHER2 treatment has become standard for most HER2-positive breast cancer patients. Pathological complete response (pCR) has been used as an early surrogate parameter to monitor NAT’s effectiveness since it was found it’s associated with fewer recurrences and better survival. Although the pCR rate is highest for triple-negative and HER2 positive tumors, there are still many of those with residual disease. Based on the Katherine trial result, which showed improved prognostic outcome, trastuzumab emtansine (T-DM1) has become a preferable option for patients with HER2 positive breast cancer with residual tumor after NAT. Case report: A 46 years old premenopausal woman presented with a clinically palpable mass of the right breast and palpable lymph node of the right axilla. MRI revealed a 3.5 cm mass in the right breast, without cious malignant nodes in the axilla. A core needle biopsy was performed, and the histopathology showed triplepositive invasive ductal breast cancer (ER 100%, PR70%, HER2 3+, Ki- 67 30%, grade 2). Cytological analysis of axillary lymph nodes was negative. The patient received a standard NAT protocol with 4 cycle dose-dense doxorubicin/ cyclophosphamide (ddAC) followed by 12 cycle weekly paclitaxel with dual antiHER2 therapy with pertuzumab/ trastuzumab. Following the 4 ddAC cycles, ultrasound and clinical exam showed partial tumor regression. After NAT, complete remission of the tumor was revealed on MRI, and the patient underwent right breastlumpectomy followed by sentinel lymph node biopsy. Histopathological report from the specimen showed a residual tumor with a partial response to NAT (RCB II, ER 80%, PR 0, HER2 1+). Multidisciplinary team decisions included post- neoadjuvant systemic therapy with T-DM1, postoperative radiation therapy of chest wall and regional lymph nodes, and 5-year endocrine treatment with tamoxifen. After 5 cycles of full dose and one cycle with reduced dose, therapy with the T-DM1 agent was discontinued because of grade 3 peripheral neuropathy and she continued with only trastuzumab to complete a one-year treatment course. Conclusion: Postoperative treatment of patients with HER2 positive breast cancer with residual tumor after NAT should be optimized to achieve favorable outcomes.

breast cancer ; neoadjuvant therapy ; residual tumor

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