89Zr-atezolizumab PET Scan and Lobular Breast Cancer

The exploratory single center feasibility ImaGelato study is conducted as an imaging side study to the Dutch GELATO trial (Assessing efficacy of carboplatin and atezolizumab in metastatic lobular breast cancer). Ten patients with lobular metastatic breast cancer, who are included in the GELATO trial at the UMCG, are eligible for the ImaGelato study. All patients will undergo two Zirconium-89 (89Zr)-atezolizumab positron emission tomography (PET) scans, one at baseline and one after two doses carboplatin induction treatment. The 89Zr-atezolizumab PET scan will be performed 4 days after tracer injection. Procedures within the ImaGelato study will be completed after the two 89Zr-atezolizumab PET scans, but patients will continue treatment with carboplatin combined with atezolizumab in the GELATO trial.