Reddy JP, Sherry AD, Fellman B, Liu S, Bathala T, Haymaker C, Cohen L, Smith BD, Ramirez D, Shaitelman SF, Chun SG, Medina-Rosales M, Teshome M, Brewster A, Barcenas CH, Reuben A, Ghia AJ, Ludmir EB, Weed D, Shah SJ, Mitchell MP, Woodward WA, Gomez DR, and Tang C
Purpose: Prior evidence suggests a progression-free survival (PFS) benefit from adding metastasis-directed therapy (MDT) to standard-of-care (SOC) systemic therapy for patients with some oligometastatic solid tumors. Randomized trials testing this hypothesis in breast cancer have yet to be published. We sought to determine whether adding MDT to SOC systemic therapy improves PFS in oligometastatic breast cancer., Methods: EXTEND is a multicenter phase II randomized basket trial testing the addition of MDT to SOC systemic therapy in patients with ≤5 metastases (NCT03599765). Patients were randomized 1:1 to MDT (definitive local treatment to all sites of disease, plus SOC systemic therapy) or to SOC systemic therapy only. Primary endpoint was PFS, and secondary endpoints included overall survival (OS), time to subsequent line of systemic therapy, and time to the appearance of new metastases. Exploratory analyses included quality of life (QOL) and systemic immune response measures., Results: From September 2018 through July 2022, 22 and 21 patients were randomized to the MDT and no-MDT arms, respectively. At a median follow-up of 24.8 months, PFS was not improved with the addition of MDT to SOC systemic therapy (median PFS 15.6 months MDT vs 24.9 months no-MDT [hazard ratio {HR} 0.91; 95% CI 0.34-2.48, p=0.86]). Similarly, MDT did not improve OS, time to subsequent line of systemic therapy, or time to the appearance of new metastases (all p>0.05). No significant differences were found in QOL measures, systemic T-cell activation, or T-cell stimulatory cytokine concentration., Conclusion: Among patients with oligometastatic breast cancer, the addition of MDT to SOC systemic therapy did not improve PFS. These findings suggest that MDT may have no systemic benefit in otherwise unselected oligometastatic breast cancer patients, although this trial was limited by a heterogenous and small sample size and overperformance of both treatment arms., Competing Interests: Declaration of competing interest Mr Fellman reported receiving grants from the National Institutes of Health (NIH) to The University of Texas MD Anderson Cancer Center during the conduct of the study. Dr Haymaker reported receiving grants from Avenge Bio, Sanofi, Dragonfly, BTG, Iovance Biotherapeutics, and TriSalus Life Sciences; receiving personal fees from Nanobiotix; receiving speaker honoraria from the Southwest Oncology Group and the Society for Immunotherapy of Cancer; and receiving stock options from BriaCell as a member of the scientific advisory board outside the submitted work. Dr Smith reported receiving salary support from Varian Medical Systems for a strategic alliance between MD Anderson Cancer Center and Varian Medical Systems outside the submitted work and royalty and equity interest in Oncora Medical. Dr Shaitelman reported funding from the Emerson Collective Foundation and contracted research agreements with Alpha Tau, Exact Sciences, TAE Life Sciences, and Artios Pharmaceuticals, outside the submitted work. Dr. Chun declares in the past 36 months support from grants or contracts from NIH R50 CA275822 and MD Anderson; consulting fees from Curio Science, Norton Healthcare, and AstraZeneca; honoraria from Binaytara Foundation, Curio Science, Henry Ford Health Systems, Japanese Society for Radiation Oncology and Hong Kong Precision Oncology society; and support for attending meetings and/or travel from ViewRay, American Board of Radiology, Binaytara Foundation, Japanese Society for Radiation Oncology, and AstraZeneca outside the submitted work. Dr Reuben reported receiving consulting fees and honoraria from Adaptive Biotechnologies outside the submitted work. Dr Ghia reported receiving consulting fees and honoraria from Brainlab outside the submitted work. Dr. Woodward reported personal fees from Exact Sciences and Epic Sciences, outside the submitted work. Dr Gomez reported receiving grants from AstraZeneca, Merck, Varian, and Bristol Myers Squibb and receiving consulting fees and honoraria from Grail, AstraZeneca, Olympus, Johnson & Johnson, Varian, Medtronic, and Med Learning Group outside the submitted work. Dr Tang reported receiving grants from the Cancer Prevention & Research Institute of Texas (CPRIT) and the Andrew Sabin Family Foundation and being an Andrew Sabin Scholar during the conduct of the study and receiving royalties from Wolters Kluwer and consulting fees and honoraria from Bayer, Diffusion Pharmaceuticals, and The Osler Institute Lecture Series outside the submitted work. No other disclosures were reported., (Copyright © 2024. Published by Elsevier Inc.)