PT - JOURNAL ARTICLE AU - Sabahi, Zahra AU - Nguyen, Andrew AU - Wong, Keith AU - Li, Sherrington AU - Papa, Nathan AU - Lim, Elgene AU - Dear, Rachel F. AU - Menzies, Alexander M. AU - Boyle, Frances AU - Antill, Yoland AU - Kiely, Belinda E. AU - Forster, Benjamin C. AU - Mak, Cindy AU - Adams, Diana AU - Pugliano, Lina AU - Spillane, Andrew AU - Sharma, Shikha AU - Hickey, Adam AU - Poole, Aron AU - Agrawal, Shikha AU - Khan, Sobia AU - Ayati, Narjess AU - Emmett, Louise TI - Diagnostic Potential of <sup>68</sup>Ga-NeoB PET/CT with Estrogen Receptor– and Progesterone Receptor–Positive Breast Cancer Undergoing Staging or Restaging for Metastatic Disease AID - 10.2967/jnumed.124.268896 DP - 2025 May 01 TA - Journal of Nuclear Medicine PG - 700--706 VI - 66 IP - 5 4099 - http://jnm.snmjournals.org/content/66/5/700.short 4100 - http://jnm.snmjournals.org/content/66/5/700.full SO - J Nucl Med2025 May 01; 66 AB - 18F-FDG PET/CT has low sensitivity for estrogen receptor and progesterone receptor (ER/PR)–positive breast cancer. By contrast, gastrin-releasing peptide receptor is overexpressed in ER/PR-positive breast cancer. This study assessed the diagnostic potential of 68Ga-NeoB PET/CT in staging or restaging metastatic ER/PR-positive and human epidermal growth factor receptor 2 (HER2)–negative breast cancer. Methods: Patients with ER/PR-positive and HER2-negative breast cancer with clinical suspicion for metastatic disease undergoing staging or restaging were prospectively enrolled. All patients underwent 68Ga-NeoB PET/CT, in addition to standard 18F-FDG PET/CT. ER/PR-positive and HER2-negative status was confirmed in prior biopsy samples (primary or metastatic). Conventional imaging (18F-FDG PET/CT, bone scan, and diagnostic CT) was required within 3 wk of 68Ga-NeoB PET/CT. 18F-FDG PET/CT and 68Ga-NeoB PET/CT were assessed visually and quantitatively. Visually, all scans were read masked by 2 readers, with a third reader if results were discordant. Results: Twenty patients were enrolled, all with ER/PR-positive and HER2-negative histopathology. Of these, 75% (15/20) had lobular-subtype cancer, 40% (8/20) had suspected metastatic disease at diagnosis, and 60% (12/20) underwent restaging after systemic therapy. Overall, 75% (15/20) of the 68Ga-NeoB PET/CT scans and 65% (13/20) of the 18F-FDG PET/CT scans were positive on visual assessment. For 50% (10/20) of patients, both scans were positive, and for 10% (2/20) of patients, both scans were negative. In the staging group, 75% (6/8) of patients had positive 68Ga-NeoB PET/CT and 50% (4/8) of patients had positive 18F-FDG PET/CT. At restaging, 75% (9/12) of patients had positive 68Ga-NeoB PET/CT and 75% (9/12) of patients had positive 18F-FDG PET/CT. Sites of positive 68Ga-NeoB PET/CT and negative 18F-FDG PET/CT disease were identified in 50% (4/8) of staging patients and 42% (5/12) of restaging patients, whereas negative 68Ga-NeoB PET/CT and positive 18F-FDG PET/CT disease was found in none of the staging patients but 58% (7/12) of the restaging cohort. Of these, 71% (5/7) of patients had a reduction in their ER status in the most recent biopsy samples. Quantitatively, the median SUVmax was higher for 68Ga-NeoB PET/CT (20.5; interquartile range, 5.8–31.3) than for 18F-FDG PET/CT (7.4; interquartile range, 4.9–9.8). Conclusion: 68Ga-NeoB PET/CT has diagnostic potential in the staging of ER/PR-positive and HER2-negative breast cancer. Further evaluation is warranted.