HER2-targeted PET/CT in breast cancer: a systematic review of lesion-level concordance with pathology.
Affinity protein HER2 PET detects 75% of HER2-positive lesions confirmed by biopsy
HER2-targeted PET/CT in breast cancer: a systematic review of lesion-level concordance with pathology.
This systematic review evaluated lesion-level concordance between HER2-targeted PET and pathology-defined HER2 expression.
PubMed, EMBASE, and Web of Science were searched through January 27, 2026, for clinical trials of HER2-targeted PET in breast cancer reporting lesion-level findings with tissue verification by immunohistochemistry and/or in situ hybridization.
affinity protein PET correctly flagged three in four HER2-positive lesions on biopsy
Ten reports comprising 195 lesions with paired PET-biopsy HER2 classification met inclusion criteria.
Both affinity protein- and monoclonal antibody (mAb)-based tracers detected HER2-positive lesions.
Specificity for excluding HER2-positive disease was 79% (95% CI, 68-87%) for affinity protein-based tracers and was not estimable for mAb-based tracers.
Most false-positive lesions were HER2-low rather than HER2-zero (≥86%).
HER2-targeted PET shows moderate-to-good lesion-level concordance with biopsy results, with uptake observed in both HER2-positive and HER2-low disease, whereas HER2-zero lesions are less consistently visualized.
Although these findings support a continuum of HER2 expression and a potential complementary role in treatment selection, diagnostic performance estimates are constrained by small study populations, selective lesion verification, and heterogeneous imaging methodologies.