Application of 99mTc-3PRGD2 Imaging for Early Prediction of Pathological Response to Neoadjuvant Chemotherapy in Breast Tumors and Axillary Lymph Nodes

Abstract

Background and PurposeTechnetium 99m-dimeric cyclic RGD peptides with three polyethylene glycol spacers (99mTc-3PRGD2) had a good performance for diagnosing breast cancer. The prospective study was to assess the performance of 99mTc-3PRGD2 tumor imaging for predicting pathological complete response (pCR) outcomes to neoadjuvant chemotherapy (NAC) in breast cancer patients.Materials and MethodsForty-one patients were examined using both 99mTc-3PRGD2 and 18F-fluoro-deoxy-glucose (18F-FDG) imaging before NAC (baseline), and after the first and fifth NAC cycle. The tumor-to-background (T/B) ratios for 99mTc-3PRGD2 imaging and the maximum standardized uptake values (SUVmax) from the 18F-FDG imaging in breast tumors and axillary lymph node (ALN) metastases were separately calculated and analyzed—based on receiver operating characteristic (ROC) analysis. ResultsFinally, pCR was achieved in 13 of 41 patients after NAC. The area under curve (AUC) of T/B changes (ΔT/B) in breast tumors for predicting pCR after first and fifth cycle were 0.827 and 0.687, and 0.859 and 0.778 in ALN metastases, respectively. For SUVmax changes (ΔSUVmax), the ROC-AUC were 0.859 and 0.713, as well as 0.572 and 0.802, respectively. In breast tumors, the AUCs of ΔT/B1 and ΔSUVmax1 had no significant difference (P > 0.05). However, the AUC of ΔT/B1 was significantly higher than for ΔSUVmax1 in ALN metastases (Z = 2.10, P = 0.035). Additionally, the T/B1 trends for breast tumor and ALN in pCR group were higher than for non-pCR group in HER2-positive patients (P﹤0.05). ConclusionsCompared with 18F-FDG imaging, our study shows that use of 99mTc-3PRGD2 imaging offered a similar level of predictive performance for breast cancer pCR to NAC, and early T/B1 trends of ALN showed an higher performance for predicting pCR.Trial RegistrationClinicalTrials.gov ID: NCT02742168.