Survival and prognostic factors in oligometastatic breast cancer

• Published in: Breast (Edinburgh) 2023-02, Vol.67, p.14-20
• Main Authors: van Ommen-Nijhof, Annemiek, Steenbruggen, Tessa G., Capel, Laura, Vergouwen, Michel, Vrancken Peeters, Marie-Jeanne T., Wiersma, Terry G., Sonke, Gabe S.
• Format: Article
• Language: English
• Subjects: Breast cancer; Breast Neoplasms - pathology; Chemotherapy; Disease-Free Survival; Female; Humans; Local ablative therapy; Multimodality treatment; Neoplasm Recurrence, Local; Oligometastasis; Original; Prognosis; Retrospective Studies; Treatment Outcome
• ISSN: 0960-9776; 1532-3080
• DOI: 10.1016/j.breast.2022.12.007

Guidelines for oligometastatic breast cancer (OMBC) propagate multimodality treatment including polychemotherapy and local ablative treatment (LAT) of all lesions. The aim of this approach is prolonged disease remission, or even cure. Long-term outcomes in OMBC and factors associated with prognosis are largely unknown, due to the rarity of this condition. We report overall survival (OS), event-free survival (EFS), and prognostic factors in a large real-world cohort of patients with OMBC. Patients with breast cancer and 1–3 distant metastatic lesions, treated in the Netherlands Cancer Institute between 1997 and 2020, were identified via text mining of medical files. We collected patient, tumor and treatment characteristics. The Kaplan-Meier method was used to calculate OS and EFS estimates, and Cox regression analyses to assess prognostic factors. The cohort included 239 patients, of whom 54% had ERpos/HER2neg, 20% HER2pos and 20% triple negative disease. Median follow-up was 88.0 months (95% confidence interval (CI) 82.9–93.1) during which 107 patients died and 139 developed disease progression/recurrence; median OS was 93.0 months (95%CI 66.2–119.8). Factors associated with OS in multivariable analysis were subtype, disease-free interval and radiologic response to first-line systemic therapy; LAT was associated with EFS, but not OS. In this large real-world cohort of patients with OMBC, OS and EFS compare favorably to survival in the general MBC population. Radiologic complete response to first-line systemic therapy was associated with favorable OS and EFS, indicating the importance of early optimal systemic therapy. The value of LAT in OMBC requires further study. [Display omitted] •Patients with OMBC have favorable prognosis compared to the general MBC population.•Complete response to first-line systemic therapy is associated with better OS and EFS.•Optimizing systemic therapy for patients with OMBC should be a research priority.•The value of local ablative therapy in OMBC is unclear and requires further study.