Finally an Effective Cancer Treatment for Stage IV HER2-Positive Breast Cancer

When Koh Kim Hun, 51 years old Malaysian was diagnosed in August 2025, staging investigations confirmed Stage IV triple-positive breast cancer with metastatic spread beyond the breast. PET-CT performed on 27 August 2025 demonstrated metabolically active left axillary lymphadenopathy, with the largest node measuring 2.0 cm (SUVmax 19.1), along with mediastinal and bilateral hilar lymphadenopathy (SUVmax up to 13.9). Multiple lung nodules were identified, the largest measuring 0.6 cm, in addition to FDG-avid bone metastases involving the sternum, right scapula, and right anterior ninth rib. Baseline tumor markers on September 3, 2025 showed a CEA level of 11 and a CA 15-3 level of 129.8. Histopathology confirmed strong estrogen receptor positivity (100%), progesterone receptor positivity (10%), HER2 overexpression (3+), and a Ki-67 index of approximately 30%. She commenced first-line systemic treatment with combination chemotherapy together with dual HER2-targeted therapy (Trastuzumab and Pertuzumab).

On October 18, 2025, ECCT was incorporated into her treatment plan under continued oncology supervision as an adjunct to systemic therapy. In the months that followed, measurable radiologic improvement was documented. A multiphase CT scan performed on 7 January 2026, compared with the initial PET-CT, showed reduction of the left axillary lymph node mass from 3.0 × 2.4 cm to approximately 1.4 cm. Previously noted mediastinal and hilar lymphadenopathy were no longer identified. Pulmonary nodules demonstrated marked size reduction, with residual nodules measuring only 1–2 mm compared to the prior largest nodule of 6 mm. The known bone metastases remained present but were stable, without evidence of new destructive lesions. Overall, the findings were consistent with partial response and disease stabilization rather than progression.

Tumor markers showed a sustained and progressive decline during this period. CEA decreased from 11 to 3.2, and CA 15-3 declined from 129.8 to 3.5, representing approximately a 97 percent reduction from baseline. These values normalized and remained stable on serial follow-up testing without rebound elevation. In metastatic breast cancer, sustained normalization of CA 15-3 over several months is considered clinically meaningful and often correlates with reduced tumor biological activity when aligned with imaging improvement.

Throughout the plan for Effective Cancer Treatment, systemic organ function remained preserved. Despite receiving chemotherapy and dual HER2-targeted therapy, regimens known to impose hepatic, renal, and hematologic stress, her liver and kidney function tests remained within normal limits on repeated monitoring. There was no evidence of treatment-related hepatic or renal impairment. Hematologic parameters showed only mild anemia consistent with chemotherapy exposure, without severe bone marrow suppression or recurrent infections. She continues HER2-targeted therapy under structured follow-up, with stable disease control and preserved organ function.

Her course illustrates that in Stage IV HER2-positive breast cancer, meaningful progress is not defined solely by complete disappearance of lesions. Objective tumor reduction, sustained biomarker normalization, stabilization of metastatic sites, and preservation of systemic physiology together represent a measurable shift toward biological control. She shares her experience not as a declaration of cure, but as documented evidence of response and maintained strength during the management of advanced metastatic disease.