Curative-intent tri-modality treatment of de novo bone-only oligometastatic breast cancer: single-center patient outcomes

It is estimated that 10–25% of breast cancer patients have metastatic disease upon diagnosis with roughly 20% having limited metastatic sites. The optimal management of patients with de novo bone-only oligometastatic breast cancer (OMBC), particularly curative-intent approaches, continues to evolve given extremely limited evidence in survival outcomes with this strategy. This was a single-center retrospective review of the survival outcomes and details of treatment of patients with de novo OMBC who received tri-modality treatment with systemic therapy (chemotherapy with or without endocrine treatment and/or HER2-directed therapy), surgery, and radiotherapy to local and metastatic site/s. Progression-free survival (PFS) was defined as the time from initiation of treatment (either surgery, or neoadjuvant systemic therapy) to date of clinical or radiologic progression. From January 2014-March 2024, we identified 10 women who fit the inclusion criteria. Seven had isolated bone metastasis, and none had more than 3 metastatic sites. The included cohort had a mean age of 44.2 years. Nine had hormone receptor-positive disease, and 5 were HER2-positive. All patients were discussed in a multidisciplinary meeting. Median PFS by Kaplan-Meier analysis was 40.2 months. Nine patients were still alive at the time of analysis, and 6 of them remain disease free with a median follow-up duration of 30.8 months. Our cohort of women with de novo bone-only oligometastatic breast cancer who underwent standard curative-intent tri-modality approach and ablative radiation to metastatic sites had a long median PFS and was rendered disease-free for many years using this approach.