# Management of Musculoskeletal Oligometastatic Disease in Breast Cancer

## TL;DR

This paper reviews the best ways to treat breast cancer that has spread to the bones or muscles, focusing on patient-specific factors and treatment options.

## Contribution

The paper provides a comprehensive review of treatment strategies for musculoskeletal oligometastatic breast cancer, emphasizing patient selection and prognostic factors.

## Key findings

- Skeletal surgery is recommended for patients with pathologic fractures or neurologic compromise and expected survival over 3 months.
- ER-positivity, solitary bone metastases, and metachronous metastases are associated with better survival outcomes.
- SBRT and interventional radiology offer effective local control for bone metastases, especially in fragile patients.

## Abstract

Oligometastatic breast cancer refers to an intermediate state between localized and disseminated disease. Recent advances in surgery, radiotherapy, and systemic treatments are improving outcomes for these patients. However, choosing the right treatment can be challenging and must consider the patient’s overall condition and life expectancy. This article provides a comprehensive review of the literature to determine the optimal approach to the management of musculoskeletal oligometastatic disease in breast cancer. Indications for orthopedic surgery include pathologic fractures, neurologic compromise, and a long-expected survival. Favorable prognostic factors include solitary bone metastasis, preserved performance status, adequate surgical margins, absence of pathologic fracture, metachronous metastases, and ER-positivity status. As oligometastatic breast cancer still lacks standardized treatment strategies, further research is needed to develop treatment protocols suitable for broader clinical application.

Oligometastatic breast cancer represents an intermediate state between localized and disseminated disease with reasonable potential for clinical cure. Advancements in surgery, radiotherapy, and systemic therapy have improved prognosis. Due to the high prevalence of bone metastases, an increasing number of studies are evaluating new treatment strategies for oligometastatic bone disease. The decision to perform skeletal surgery is complex and depends on optimal patient selection. Major criteria include impending or pathologic long bone fractures, severe neurologic compromise, and an expected survival of over 3 months. Factors associated with improved survival include solitary bone metastases, preserved performance status, adequate surgical margins, absence of pathologic fracture, metachronous metastases, and ER-positivity status. Radiotherapy, especially SBRT, offers effective local control and palliation. Interventional radiology techniques such as percutaneous thermal ablation have also been described as potential treatment alternatives, particularly for fragile patients. Systemic treatment varies according to the tumor subtype. For HR+ and HER2 subtypes, a combination of endocrine therapy with CDK4/6 inhibitors may be considered. HER2+ patients are often treated with HER2-targeted therapies combined with chemotherapy. For triple-negative breast cancer, chemotherapy is the primary treatment. Bone-modifying agents are also recommended to maintain bone strength, prevent skeletal-related events, and reduce the need for additional interventions. Skeletal muscle metastases in breast cancer patients are rare and typically indicate advanced disease with poor prognosis. Treatment options include chemotherapy, radiotherapy, and surgical excision, but should be tailored to the patient’s clinical condition and prognosis.