Impact of Virtual MRI Sonography with Magnetic Navigation on Detecting Residual Tumors in Patients with Breast Cancer Who Undergo Neoadjuvant Chemotherapy; Initial Experience.

Abstract

Abstract Objective: The accurate evaluation of the extent of residual disease after neoadjuvant chemotherapy (NAC) for breast cancer appears essential for successful clinical outcomes. However, there are limited date about the success of achieving negative margins in breast conservation therapy. Recently, we have developed virtual MRI sonography with magnetic navigation (real-time virtual sonography; RVS). RVS can overlay high-resolution structural image taken by sonography with functional image reflecting vascular permeability taken by MRI of the same site in real time. The objective of our study was to determine the relative accuracy of RVS in detecting residual tumors after NAC.Materials and Methods: Between April 2007 and May 2009, 96 breast conservation therapy were performed for invasive ductal carcinoma at our hospital. Fourteen patients with stage IIA-IIIB palpable invasive ductal carcinoma were enrolled in a study investigating the effects of NAC on tumor imaging. All patients underwent mammography, sonography, MRI, and RVS before and after NAC. MRI was performed with a 1.5-T scanner in the supine position using a flexible body surface coil to achieve the same position as that used in sonography. Based on MRI results, the absence or presence of residual tumors was used to classify treatment response into a clinically complete response (cCR) or non-cCR, respectively. Nine patients received lumpectomy, and 5 received mastectomy. The surgical resection area was determined by RVS. Detection rate was determined for residual tumors with or without RVS. The pathologically complete response (pCR) was defined as no invasive carcinoma.Results: All index tumors were detected by sonography and MRI before NAC. After NAC, a cCR was seen in 5 (5 of 14, 36%) patients. MRI correctly diagnosed pCR in 4 (4 of 5, 80%) patients. Detection rate for residual tumors was 9% (1 of 11) for mammography, 33% (3 of 9) for sonography alone, 78% (7 of 9) for MRI, and 89% (8 of 9) for RVS. It was noteworthy that 5 (5 of 5, 100%) cases with cCR were accurately localized onto the body surface with supplementation using RVS combined with pre- and post-NAC imaging while we were checking sonography. Although surgical excision was incomplete in 5 (5 of 9, 56%) patients, all positive surgical margins were ductal carcinoma in situ.Conclusions: By using RVS, two different forms of diagnostic imaging can be integrated in real time and thereby complement each other. The present results suggest that RVS is a useful imaging technique for detecting residual tumors that have been associated with local recurrence after NAC. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5024.