Correlation of Pathological Complete Response with Radiological Evaluation after Neoadjuvant Chemotherapy of Breast Carcinoma

Abstract

Introduction: Neoadjuvant chemotherapy is the standard treatment modality in locally advanced breast cancer, and accepted as an alternate modality in operable breast cancer. Pathological Complete Response (pCR) is a surrogate for better outcome. The identification of the most sensitive clinical and radiological method to pCR will be helpful in patient’s management. Patients and methods: Multicenterprospective study assessed the correlation between (pCR) and radiological Complete Response (rCR) using different radiological modalities. 125 female with primary measurable stage II or III non inflammatory breast cancer, were enrolled in the study after pathological confirmation using image guided core biopsy. Pathological assessment was done. All eligible cases received neoadjuvant chemotherapy (FEC) IV every 3 weeks for three cycles followed by Docetaxel IV every 3 weeks for three cycles. Trastuzumab was added in Her2neu positive patients concomitantly with docetaxel. Radiological evaluation was done before chemotherapy and prior to definitive surgery. pCR was defined as complete disappearance of invasive tumor cells in both breast surgical specimen and lymph nodes. Patients who achieved pCR were correlated with truly positive rCR by different modalities. The results were statistically analyzed using the Kappa method for agreement. Results: 20% of the patients achieved pCR 25/125. All these patients received 6 cycles of chemotherapy, only 4 patients received Trastuzumab. Conservative surgery was performed in 80% of cases and MRM in 5/25 of them. True radiological Complete Response (rCR) was achieved in 56% of patients by mammography, 17/25 (68%) of patients by ultrasonography who showed complete disappearance of the mass. 23/25 (92%) achieved rCR morphologically by Dynamic MR-Mammography and in 24/25 (96%) of cases using the kinetic data. MR Spectroscopy showed rCR in (92%) cases. In our study, predictions made on the basis of MRI showed a better correlation with the pathological response after neoadjuvant chemotherapy than did estimations made on the basis of mammography or sonography. The sensitivity, specificity, PPV and NPV for Dynamic MRI in predicting complete pathological response were 96%, 94%, 89% and 99% respectively. The sensitivity, specificity, PPV and NPV for MRS were 92%, 92%, 85% and 97% respectively while the sensitivity, specificity, PPV and NPV for Mammography were 44%, 87%, 61% and 87% respectively and the sensitivity, specificity, PPV and NPV for ultrasonography were 68%, 90%, 77% and 92% respectively. Conclusion: The most sensitive radiological methods correlated with pCR were dynamic MR mammography and MR Spectroscopy, further studies using new modalities and larger number of patients is required to confirm our results.