Exploring utilities of [ 64 Cu]Cu-DOTA-trastuzumab immunoPET in breast cancer: a systematic review and meta-analysis.

[ 64 Cu]Cu-DOTA-trastuzumab represents a novel immunopositron emission tomography (immunoPET) agent with emerging diagnostic applications in human epidermal growth factor receptor-2 (HER2)-expressing breast cancer (BC). This systematic review and meta-analysis evaluates the current diagnostic utilities of [ 64 Cu]Cu-DOTA-trastuzumab PET/computed tomography (CT) and explores tumor uptake metrics in HER2-positive BC lesions. A systematic literature search of PubMed , Scopus , and Ovid databases was conducted using relevant keywords to identify eligible studies. Of the 123 articles reviewed, six met the inclusion criteria. Qualitative data analysis was applied to all included studies. Several promising utilities were identified, including [ 64 Cu]Cu-DOTA-trastuzumab's capacity to detect HER2-positive primary BC lesions, lymph nodes, and distant metastases. Additionally, [ 64 Cu]Cu-DOTA-trastuzumab PET/CT demonstrated potential in predicting therapy response in HER2-positive lesions. The overall lesion detectability was 91% [95% confidence interval (CI), 81-98%] for HER2-positive BC. HER2-positive BC lesions exhibited significantly higher maximum standardized uptake values compared to HER2-negative lesions, with a weighted mean difference of 2.14 (95% CI, 0.18-4.09; P  = 0.03). These findings underscore the need for further large-scale and prospective investigations of this promising radiotracer in the near future.