Prolonged survival associated with anti-HER2 therapy: case report

Abstract

Introduction: The advent of targeted therapy for human epidermal growth factor receptor 2 (HER-2), introduced by trastuzumab, represented a significant advancement in the treatment of breast cancer, impacting the survival of patients who overexpress this protein. Long-term survival (> 5 years) remains rare according to the literature, with an average of 25%. Case Report: This is a single-case observational report of a patient with extended survival in HER-2+ breast cancer treatment with trastuzumab combined with other medications. Clinical, pathological, treatment history, and survival data were retrospectively collected from the medical records. Patient, female, 37 years old, premenopausal, without associated comorbidities, physically active, no history of smoking or alcohol consumption, diagnosed in March 2015. She underwent intravenous chemotherapy for palliative purposes, achieving a maximal response. Trastuzumab was continued, combined with anastrozole, and she currently presents stable disease and extended survival (> 5 years). Targeted therapies significantly improve survival outcomes for HER2+ breast cancer patients. Recent studies demonstrate that clinical outcomes are better for triple-positive patients (ER, PR, and HER-2 positive), highlighting how this therapy has altered the natural course of the disease. There is evidence that the continuation of targeted therapy after disease progression results in clinical benefit, however, there is no consensus on the duration of treatment. Conclusion: This case, of a young patient diagnosed with HER2+ metastatic breast cancer, with long-term survival exceeding that described in the literature, demonstrates that the extended use of targeted therapy with trastuzumab, in combination with various chemotherapy and hormone-therapies regimens, can lead to the prolongation and improvement of the quality of life for patients whose prognosis at diagnosis was discouraging. This fact may assist in future decision-making regarding the use of targeted therapy after disease progression, filling this gap in knowledge.