Aspects of radiotherapy of breast cancer metastases to the brain: A literature review

Abstract

Relevance: Breast cancer (BC) is one of the most common diseases among women in developed countries worldwide. BC ranks first in incidence and third in mortality among malignant neoplasms in women. Despite many advances in the treatment of BC, the prognosis for patients with metastatic BC remains poor. The life expectancy of these patients is usually about one year. The accuracy of diagnosis and determining the number and sizes of oligometastases by contrasted brain MRI or PET-CT with methionine is vital for effective cancer treatment. The emergence of treatment techniques, such as stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRSR), significantly improved the disease prognosis. The use of high-tech radiation therapy in patients with oligometastases from breast carcinoma improves local control of intracranial lesions, prevents death, 
maintains the quality of life, and improves overall survival.
The study aimed to analyze the results of key prospective studies on aspects of radiation therapy for BC metastases to the brain.
Methods: This review included key randomized trials on the use of radiation therapy for BC metastases in the brain. The search was conducted in the PubMed database for 2005-2020 by the keywords “radiation therapy,” “breast cancer,” and “brain metastases.”
Results: Reduced treatment time due to stereotactic radiosurgery and radiotherapy allows for maintaining productive life without expressed neurological symptoms. SRS is efficient in patients with up to five oligometastases in BC. More metastases require total brain exposure, which is a poor prognostic factor. In prospective studies, SRS in BC with brain metastases is recommended to improve the quality of life.
Conclusion: The treatment of BC with brain metastases requires a multidisciplinary approach based on the prevalence of the process, previous therapy, general somatic status, comorbidities, and available therapy options. Systemic therapy for BC patients with brain metastases follows several schemes that demonstrate their therapeutic effectiveness.