[Comparing Prediction Performances of F-FDG PET and CGFL/Curie Nomogram to Predict Pathologic Complete Response After Neoadjuvant Chemotherapy for HER2-positive Breast Cancers]

Objectives: The aim of this study was to compare the value of F-fluorodesoxyglucose positron emission tomography (F-FDG PET/CT) with CGFL/Curie nomogram to predict a pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) in women with human epidermal growth factor 2 (HER2)-positive breast cancer treated by trastuzumab.

Methods: Fifty-one women with HER2-positive breast cancer treated with trastuzumab plus taxane-based NAC were retrospectively included from January 2005 to December 2015. For F-FDG PET/CT, the analyzed predictor was the maximum standardized uptake value of the primary tumor and axillary nodes after the first course of NAC (PET.SUV). pCR was defined by no residual infiltrative tumor but in situ tumor was accepted. Accuracy of CGFL/Curie nomogram and PET.SUV was evaluated measuring sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV). Combined prediction was evaluated testing predictor's associations.

Results: For CGFL/Curie nomogram's performances, Se, Sp, PPV and NPV were respectively: 76% (95%CI: 58-90%), 57% (95%CI: 43-66%), 55% (95%CI: 42-65), 77% (95%CI: 59-90%). For PET.SUV's performances, Se, Sp, PPV and NPV were respectively: 67% (95%CI: 48-81%), 77% (95%CI: 64-97%), 67% (95%CI: 48-82%), 77% (95%CI: 64-87%). ROC curves for these predictors were similar; the areas under the curve were 0.6 (95%CI: 0.56-0.64) for PET.SUV and 0.55 (95%CI: 0.50-0.59) for CGFL/Curie nomogram. Combined prediction was efficient with Se at 80%, VPN at 76%, Sp at 78% and VPP at 81%.

Conclusions: CGFL/Curie nomogram and PET.SUV were two efficient predictors of pCR in patients with HER2-positive breast cancer. Combined prediction has an improved accuracy.