Physical examination (PE), mammography (MG), breast MRI, FDG-PET and pathologic evaluation are used to assess primary breast cancer. Their accuracy has not been well studied in patients receiving neoadjuvant chemotherapy. Accuracies of each modality in tumor and nodal assessment in patients with T3/4 tumors receiving neoadjuvant chemotherapy were compared.
45 patients of a prospective clinical trial studying T3-T4M0 tumors were included. Patients received neoadjuvant chemotherapy: docetaxel/carboplatin with or without trastuzumab before and/or after surgery (depending on HER-2/neu status and randomization). Tumor measurements by PE, MG, and MRI and nodal status by PE and PET were obtained before and after neoadjuvant chemotherapy. Concordance among different clinical measurements was assessed and compared with the tumor and nodal staging by pathology. Spearman corr (r) and root mean square error (RMSE) were used to measure the accuracy of measurements among all modalities and between modalities and pathological tumor size.
Comparing to the tumor size measured by PE, MRI was more accurate than MG at baseline (r 0.559, RMSE 35.4% vs. r 0.046, RMSE 66.1%). After neoadjuvant chemotherapy, PE correlated better with pathology than MG or MRI (r 0.655, RMSE 88.6% vs. r 0.146, RMSE 147.1% and r 0.364, RMSE 92.6%). Axillary nodal assessment after neoadjuvant chemotherapy showed high specificity but low sensitivity by PET and PE.
Findings suggested that MRI was a more accurate imaging study at baseline for T3/T4 tumor and PE correlated best with pathology finding. PET and PE both correctly predicted positive axillary nodes but not negative nodes.