RT Journal Article SR Electronic T1 Impact of 18F-FES PET/CT on Clinical Decisions in the Management of Recurrent or Metastatic Breast Cancer JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1689 OP 1694 DO 10.2967/jnumed.124.267913 VO 65 IS 11 A1 Ryu, Jeongryul A1 Hyung, Jaewon A1 Han, Sangwon A1 Jeong, Jae Ho A1 Lee, Sae Byul A1 Yoo, Tae-Kyung Robyn A1 Kim, Jisun A1 Kim, Hee Jeong A1 Chung, Il Yong A1 Ko, Beom Seok A1 Lee, Jong Won A1 Son, Byung Ho A1 Jeong, Hyehyun A1 Ahn, Jin-Hee A1 Jung, Kyung Hae A1 Kim, Sung-Bae A1 Moon, Dae Hyuk YR 2024 UL http://jnm.snmjournals.org/content/65/11/1689.abstract AB The clinical impact of 16α-18F-fluoro-17β-estradiol (18F-FES) PET/CT on patient management has not been well investigated. The aim of this study was to assess the clinical impact of 18F-FES PET/CT on the management of patients with recurrent or metastatic breast cancer. Methods: Study subjects were identified retrospectively from a database of a prospective trial for postmarketing surveillance of 18F-FES between 2021 and 2023. Patients who were suspected or known to have recurrent or metastatic estrogen receptor–positive breast cancer based on a routine standard workup were included. Planned management before and actual management after 18F-FES PET/CT were assessed by 2 experienced medical oncologists via medical chart review. A 5-point questionnaire was provided to evaluate the value of 18F-FES PET/CT for management planning. The rate of intention-to-treat and interdisciplinary changes, and the impact of 18F-FES PET/CT according to PET/CT result or clinical indication, were examined. Results: Of the 344 included patients, 120 (35%) experienced a change in management after 18F-FES PET/CT. In 139 (40%) patients,18F-FES PET/CT supported the existing management decision without a change in management. Intention-to-treat and interdisciplinary changes accounted for 64% (77/120) and 68% (82/120) of all changes, respectively. A higher rate of change was observed when lesions were 18F-FES–negative (44% [36/81]) than 18F-FES–positive (30% [51/172]) or mixed 18F-FES–positive/negative (36% [33/91]). Regarding clinical indications, the highest rate of change was shown when evaluating the origins of metastasis of double primary cancers (64% [9/14]). Conclusion: 18F-FES PET/CT modified the management of recurrent or metastatic breast cancer, serving as an impactful imaging modality in clinical practice.