Prediction of Outcomes of Brain Irradiation in Correlation with Molecular Subtypes in Patients with Metastatic Breast Cancer

Document Type : Research Articles

Authors

1 Department of Clinical Oncology, Menoufia University, Shebin Elkom, Egypt.

2 Department of Clinical Oncology, Ain Shams University, Cairo, Egypt.

3 Department of radiotherapy, south Egypt Cancer Institute, Assiut University, Assiut, Egypt.

Abstract

Background: Brain metastases (BM) are a major complication in metastatic breast cancer, especially in HER2-positive and triple-negative subtypes. Despite advances in systemic therapy, BM remains associated with a poor prognosis and often requires radiotherapy. This study evaluates the outcomes of brain irradiation across subtypes and proposes a prognostic scoring system to guide treatment. Methods: This retrospective study analyzed data from 348 breast cancer patients with BM to develop a prognostic scoring system for radiotherapy decisions. The data included molecular subtypes, number of brain lesions, and survival outcomes. Kaplan–Meier and Cox proportional hazards models were used to identify prognostic factors. The scoring system, based on the significance of predictors, was compared with physician-selected radiotherapy techniques to assess its potential for optimizing care. Results: Luminal breast cancer was most prevalent (42.6%), followed by HER2-positive and triple-negative (19% each). Median BM onset was 23 months; headache was the most common symptom (48%). HER2-positive and triple-negative patients developed metastases earlier than luminal and triple-positive (P=0.001). Survival was better for luminal and triple-positive, poorer for HER2-positive and triple-negative. Patients with fewer than five brain lesions had higher survival rates (P=0.001). The scoring system incorporated molecular subtype, lesion burden, and patient characteristics. Scores above 3.5 predicted worse survival, with higher scores strongly linked to poorer outcomes (P=0.001). Conclusion: This study identifies key prognostic factors influencing survival in breast cancer patients with BM and proposes a scoring system to guide radiotherapy decisions. Molecular subtypes, metastatic burden, and clinical characteristics significantly affect outcomes, with HER2-positive and triple-negative subtypes showing the poorest survival. The system provides a structured approach for treatment selection, though further validation is needed to ensure its accuracy and clinical utility in personalized radiotherapy planning.

Keywords

Asian Pacific Journal of Cancer Prevention
Volume 27, Issue 4
April 2026
Pages 1303-1311

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History

  • Receive Date: 13 August 2025
  • Revise Date: 02 December 2025
  • Accept Date: 16 March 2026

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