Table 1.
Summary of PET radiopharmaceuticals in breast cancer investigated in clinical studies
| Target | Imaging targeting agent | Tumor entity | Characteristics | Limitations | |
| [18F]FDG | Glycolysis | Glucose analog | Invasive ductal BC, ER+/− BC, PR+/− BC, TNBC | 1. Diagnostic accuracy comparable to MRI 2. Reflects cellular glycolysis 3. Applied in breast cancer staging, re-staging, treatment planning and monitoring |
1. Invasive lobular BC, ER+/PR+ BC and BC with low proliferation show low FDG-avidity 2. Central nervous system cannot be explored due to FDG physiological uptake 3. Limited spatial resolution |
| [18F]FES | ER | Estradiol | ER+ BC | FES-PET demonstrated approximately 77% positive agreement and 100% negative agreement compared with ER IHC, and quantitative FES-PET analysis leads to differentiating ER+ from ER− lesions | 1. Therapy can interfere with the kinetics and biodistribution of 18F-FES 2. Preferential affinity for ERα over ERβ |
| [68Ga]FAPi | FAP (CAFs) | Quinoline FAP inhibitor | FAP+ BC | 1. High accuracy in detecting primary breast lesions 2. High tumor to background ratio 3. Can be used as therapeutic agent (radioligand therapy) |
Limited clinical evidence currently available |
| [89Zr]Trastuzumab | HER2 | Antibody | HER2+ BC | 1. Optimal TBR especially in the liver, spleen, kidneys, and brain 2. Tumor lesion SUVmax is higher in patients with HER2+ BC than in HER2− 3. Support clinical decision-making when HER2 expression cannot be assessed with biopsy |
1. SUV values only helps to differentiate between IHC0 and IHC1–2–3 lesions only 2. Liver and spleen have high uptake in both HER2+ and HER2− BC patients, leading to potential understaging |
| [64Cu]DOTA-Trastuzumab | HER2 | Antibody | HER2+ BC | 1. Radiation exposure comparable to FDG-PET 2. Differentiation of HER2+ from HER2− BC |
1. High liver uptake leading to potential understaging of small lesions 2. Clinical data are still limited |
| [18F]Galacto-RGD | Integrin αvβ3 | Amino acids | αvβ3 integrin+ BC | Allow imaging of αvβ3 expression that is correlated with its uptake in PET image | Low sensitivity for lymph node staging |
| [89Zr]Bevacizumab | VEGF | Antibody | VEGF+ BC | 1. Higher uptake in tumor lesions than in healthy tissues 2. The replication rate was directly related to the radiotracer uptake |
Low sensitivity for lymph node staging |
BC, breast cancer; ER, estrogen receptor; FAP, fibroblast activation protein; FDG, 2-deoxy-2-[18F]-fluoro-d-glucose; HER2, human epidermal growth receptor-2; IHC, immunohistochemistry; PET, positron emission tomography; VEGF, vascular endothelial growth factor.