Current management practices of de novo oligometastatic breast cancer: Real-world data from a physician survey.

1104 Background: De novo oligometastatic breast cancer (oligo-mBC) is generally defined as < 5 lesions at the time of diagnosis and represent a steadily increasing subset of metastatic cancers. Several retrospective studies demonstrated prolonged overall survival (OS) for select patients with oligo-mBC when treated with multimodality therapy (chemotherapy, surgery, and radiation). However, randomized trials that tested surgical resection of the primary tumor, or radiation of oligometastases (including recurrent and de novo disease) showed no OS benefit. No randomized trials to date have tested all 3 treatment modalities combined (as used with curative intent in early-stage disease). Current NCCN guidelines do not include specific recommendations for de novo oligo-mBC, the St Gallen International guidelines allow multimodality therapy for carefully selected patients. We surveyed practicing medical oncologists through the ASCO survey pool regarding their use of multimodality therapy in de novo oligo-mBC. Methods: An online survey was sent to the ASCO Research survey pool (N=999) between 11/14/23 – 12/29/23, 193 ASCO members completed the survey. Data was confidential and anonymous. Results: The majority (76-79%) of respondents recommend starting with palliative systemic chemotherapy. If patients have a response to initial chemotherapy, 42-54% recommend ablative radiation to all residual lesions, and 38-52% recommended surgical resection of the primary tumor. Overall, multimodality therapy is recommended sometimes by 29-36%, often by 19-29%, almost never by 32-41%, and never by 2-7% of respondents. Recommendations varied by disease subtype (Table). Conclusions: These survey data indicate varied practices in the treatment of de novo oligo-mBC. This highlights the need for future randomized clinical trials to investigate whether there may be survival benefit by receptor subtype in de novo oligo-mBC treated with curative intent multimodality therapy as used in locally advanced cancers. Table: see text