biostudies-literatureMakhlin ISusan G. KomenNational Cancer InstituteNCI NIH HHSe220032https://www.ebi.ac.uk/biostudies/studies/S-EPMC9713595biostudies-literatureUnknown4(6)Fluorine 18 (¹⁸F) fluorodeoxyglucose (FDG) PET/CT has shown promise for use in assessing treatment response in patients with bone-only or bone-dominant (BD) metastatic breast cancer (mBC). In this single-institution, prospective single-arm study of 23 women (median age, 59 years [range, 38-81 years]) with biopsy-proven estrogen receptor-positive bone-only or BD mBC about to begin new endocrine therapy between October 3, 2013, and August 3, 2018, the value of early 4-week ¹⁸F-FDG PET/CT in predicting progression-free survival (PFS) was evaluated. ¹⁸F-FDG PET/CT was performed at baseline, 4 weeks, and 12 weeks. Maximum standardized uptake value (SUV_max) and peak SUV (SUV_peak) were measured for up to five index lesions. The primary end point was PFS. Secondary end points were overall survival (OS) and time to skeletal-related events (tSREs). All end points were compared between responders (reduction of 30% or more in the sum of SUV_max for target lesions) and nonresponders at 4 weeks and 12 weeks. Percentage change from baseline in SUV_max at 4- and 12-week ¹⁸F-FDG PET/CT were highly correlated (<i>r</i> = 0.81). At the 4-week time point PET responders had numerically longer PFS (14.2 months vs 6.3 months; <i>P</i> = .53), OS (44.0 months vs 29.7 months; <i>P</i> = .47), and tSRE (27.4 months vs 25.2 months; <i>P</i> = .66) compared with nonresponders, suggesting the clinical utility of 4-week ¹⁸F-FDG PET/CT as an early predictor of treatment failure. <b>Keywords:</b> Breast Cancer, Metastatic Breast Cancer, Bone-Dominant Metastatic Breast Cancer, FDG PET/CT, Estrogen-Receptor Positive Metastatic Breast Cancer <i>Supplemental material is available for this article.</i> Clinical trial registration no. NCT04316117 © RSNA, 2022.Radiology. Imaging cancer¹⁸F-FDG PET/CT for the Evaluation of Therapy Response in Hormone Receptor-Positive Bone-Dominant Metastatic Breast Cancer.PMC9713595T32 CA009615-30T32 CA009615Gillman JMakhlin IPantel ARMankoff DAClark ASKorhonen KEMartin MLSchubert Efalse¹⁸F-FDG PET/CT for the Evaluation of Therapy Response in Hormone Receptor-Positive Bone-Dominant Metastatic Breast Cancer.Fluorine 18 (¹⁸F) fluorodeoxyglucose (FDG) PET/CT has shown promise for use in assessing treatment response in patients with bone-only or bone-dominant (BD) metastatic breast cancer (mBC). In this single-institution, prospective single-arm study of 23 women (median age, 59 years [range, 38-81 years]) with biopsy-proven estrogen receptor-positive bone-only or BD mBC about to begin new endocrine therapy between October 3, 2013, and August 3, 2018, the value of early 4-week ¹⁸F-FDG PET/CT in predicting progression-free survival (PFS) was evaluated. ¹⁸F-FDG PET/CT was performed at baseline, 4 weeks, and 12 weeks. Maximum standardized uptake value (SUV_max) and peak SUV (SUV_peak) were measured for up to five index lesions. The primary end point was PFS. Secondary end points were overall survival (OS) and time to skeletal-related events (tSREs). All end points were compared between responders (reduction of 30% or more in the sum of SUV_max for target lesions) and nonresponders at 4 weeks and 12 weeks. Percentage change from baseline in SUV_max at 4- and 12-week ¹⁸F-FDG PET/CT were highly correlated (<i>r</i> = 0.81). At the 4-week time point PET responders had numerically longer PFS (14.2 months vs 6.3 months; <i>P</i> = .53), OS (44.0 months vs 29.7 months; <i>P</i> = .47), and tSRE (27.4 months vs 25.2 months; <i>P</i> = .66) compared with nonresponders, suggesting the clinical utility of 4-week ¹⁸F-FDG PET/CT as an early predictor of treatment failure. <b>Keywords:</b> Breast Cancer, Metastatic Breast Cancer, Bone-Dominant Metastatic Breast Cancer, FDG PET/CT, Estrogen-Receptor Positive Metastatic Breast Cancer <i>Supplemental material is available for this article.</i> Clinical trial registration no. NCT04316117 © RSNA, 2022.2022-01-01T00:00:00Z2022 Nov2025-04-04T21:00:41.501Z2025-04-04T21:00:41.501ZS-EPMC97135953626915410.1148/rycan.220032