Evaluation of the response to breast cancer neoadjuvant chemotherapy using 18F-FDG Positron Emission Mammography compared with whole-body 18F-FDG PET.

Objectives Fluorine-18 fluorodeoxyglucose Positron Emission Mammography (PEM) has become one of the useful diagnostic modalities for breast cancer. The aim of this study is to assess therapeutic response to breast cancer naoadjuvant chemotherapy(NAC) by using PEM compared with whole-body 18F-FDG PET (WBPET) .

Methods Twenty patients underwent WBPET and PEM three times each; the first time was before NAC, the second time after two courses of NAC, and the last time after all courses of NAC. Pathologic complete response (pCR) was defined as no evidence of residual invasive cancer. Absence of in situ carcinoma was not required to define pCR. The relationships between each modality’s maximum standardized uptake value (SUVmax) and pathologic response were evaluated.

Results Nine patients achieved pCR, whereas the other 11 patients were diagnosed with non-pCR. The SUVmax of the WBPET after two courses of NAC was lower in the pCR group (1.4 ± 0.4) than in the non-pCR group (2.7 ± 2.1, P = 0.0334). There were no significant differences in the SUVmax of PEM [PEM uptake value (PUV)] after two courses of NAC between the groups. SUVmax of WBPET [area under the receiver-operating characteristic curve (AUC) = 0.761] was superior to PUVmax(AUC = 0.648) in predicting pCR at interim. The sensitivity and specificity for predicting non-pCR with WBPET using a SUVmax cutoff value of 1.2 were 91% and 56%, respectively. After all courses of chemotherapy, there were no significant differences in the SUVmax of WBPET between the groups; however, PUVmax was lower (1.0 ± 0.2) in the pCR group than in the non-pCR group (2.5 ± 2.7, p = 0.0351). After all courses of NAC, PUVmax(AUC=0.796) was suporior to SUVmax of WBPET(AUC=0.671 ) for detecting non-pCR. The sensitivity and specificity for detecting residual cancer using a PUVmax cutoff value of 1.1 were 82% and 63%, respectively.

Conclusions PEM seemed to be useful for evaluating residual cancer after all courses of NAC.$$graphic_{DCD02EDD-7AB7-4E76-AE56-40BC601146D7}$$ $$table_{13B563D3-BECB-4EEA-9784-57D31A28DD3C}$$

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