Abstract P2-03-07: Prediction of the pathological response to neoadjuvant chemotherapy in patients with breast cancer using sonazoid-enhanced ultrasonography

Abstract

Abstract Background: Altered blood flow in malignant tumors is evidenced by contrast-enhanced ultrasonography (CEUS) because of its image perfusion capabilities. This study aimed to investigate the value of CEUS in the evaluation of the response of breast cancer lesions to neoadjuvant chemotherapy (NAC). We evaluated whether the prediction of a pathological complete response (pCR) using CEUS was more precise than that using other standard evaluation methods such as magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT). Methods: Ten patients (mean age, 50.2 years) who underwent NAC for invasive breast cancer between September 2012 and April 2013 were eligible for this cohort study. Clinical tumor response was evaluated using contrast-enhanced MRI, PET/CT, and CEUS following NAC. A pCR was defined as the absence of invasive cancer in the breast and lymph nodes according to the Japanese Breast Cancer Society criteria. A clinically complete response (cCR) was defined as the absence of residual disease on MRI and PET/CT. The HI VISION ASCENDUS (Hitachi Aloka Medical Corp.) was used for ultrasonography. Tumors were observed 50 s after Sonazoid injection at a dose of 0.01 ml/kg. A time-intensity curve of tumor signal intensity was drawn. The brightness of the tumor was digitized and the curve was created on the basis of brightness changes over time. The intensity of brightness of the breast cancer lesions was calculated as the increased rate of brightness (IRB) using the following formula: maximal intensity/intensity before contrast. Results: Four (40%) of the 10 patients were diagnosed with pCR by NAC. Among 4 (40%) patients diagnosed with cCR by MRI, 1 (25%) achieved pCR. All patients were diagnosed with pCR by PET/CT. The IRB values of the 10 patients who received CEUS before surgery were 1.0, 1.1, 1.2, 1.2, 1.3, 1.6, 1.8, 1.9, 2.5, and 4.2. The IRB values of the 4 patients diagnosed with pCR were 1.0, 1.1, 1.2, and 1.2. IRB values were significantly lower in patients who achieved pCR than in those who did not (pCR vs. no pCR, 1.1 ± 0.9 vs. 2.2 ± 1.0, P < 0.05). Furthermore, among the patients who achieved pCR, the IRB values of 2 patients with no residual ductal carcinoma in situ (DCIS) were 1.0 and 1.1, whereas those of 2 patients with residual DCIS were both 1.2. In the 4 patients who achieved cCR as diagnosed by MRI and PET/CT, 3 with pathological residual disease had detectable IRB by CEUS. table 1caseageStageSub typeMRIPET-CTpathological responseIncrease rate of brightness (IRB)167T2N1 IIBLuminal HER2PRCRCR1237T2N0 IIAHER2 positivePRCRCR1.1346T3N1 IIIAHER2 positiveCRCRCR1.2446T2N3c IIICLuminal HER2PRCRCR1.2564T2N0 IIAHER-2 positiveCRCRPR1.3658T2N1 IIBLuminal BCRCRPR1.6738T2N0 IIALuminal BPRCRPR1.8857T1cN0 ILuminal HER-2PRCRPR1.9939T2N1 IIBLuminalBSDCRSD2.51050T2N1 IIBTriple negativePRCRSD4.2 Conclusions: The prediction of pCR after NAC in patients with breast cancer is more precise with Sonazoid-enhanced ultrasonography than with standard methods such as MRI and PET/CT. Furthermore, CEUS may be useful for predicting residual DCIS on the basis of brightness intensity. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-03-07.