Abstract ES9-2: Special indications where local therapy should be considered

Abstract

Abstract Clarity for the clinical issue of which patients with metastatic breast cancer should undergo local/regional therapy (LRT) was provided by the recent presentation of the prospective randomized ECOG-ACRIN 2108 trial data. This study, which randomized Stage IV breast cancer patients (initially treated with optimal systemic therapy for 4-8 months) to early local therapy or to continued systemic therapy alone, failed to demonstrate an improvement in overall survival for patients who had early local therapy compared to continued systemic therapy alone. However, there are some special indications that fall outside of this trial, and which remain areas of controversy. For instance, the subset of patients with inflammatory breast cancer (IBC) were not included in the ECOG trial, and therefore there are no prospective randomized clinical trial data available to determine if LRT improves survival in de novo stage IV IBC patients. To further confound the issue, several retrospective studies show clear survival benefit for Stage IV IBC patients who complete LRT, versus those who do not. While we all recognize that some differences could be attributed to selection bias, the differences in outcome are so striking that we believe that it warrants further discussion of the possible value of LRT in the IBC group. Furthermore, patients with IBC are more likely to be found to have Stage IV disease at presentation, complicating the discussion of whether complete trimodal therapy (neoadjuvant chemotherapy, mastectomy, and post-mastectomy radiation therapy) should still be considered at initial treatment planning, or whether LRT should be omitted altogether. Finally, due to the skin involvement and rapid progression inherent to IBC, these patients often require LRT for palliation of advanced disease (to control fungating tumors, brachial plexus involvement, etc.), so palliative surgery plays an important role in the management of the patient with IBC. During this presentation, we plan to discuss the available data regarding optimal LRT decisions for patients with de novo Stage IV IBC. Beyond the subset of IBC patients, several studies have identified non-IBC patients with Stage IV disease who might benefit from LRT. We will also discuss subsets of Stage IV breast cancer patients, including those with HR+ tumors, those with bone-only oligometastasis, and younger age patients, where LRT has shown survival benefit, based mainly on longer follow-up data from the randomized MF07-01 trial. Our objective is to improve knowledge of the local/regional treatment recommendations of select subgroups of Stage IV patients, where the use of LRT could translate to not only improved local control, but possibly to improved survival in carefully selected patients. Citation Format: A Lucci. Special indications where local therapy should be considered [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr ES9-2.