Elsevier

Clinical Radiology

Volume 61, Issue 11, November 2006, Pages 946-953
Clinical Radiology

MRI accuracy in residual disease evaluation in breast cancer patients treated with neoadjuvant chemotherapy

https://doi.org/10.1016/j.crad.2006.07.004Get rights and content

Aim

To assess the accuracy of magnetic resonance imaging (MRI) in evaluating residual disease after neoadjuvant chemotherapy in patients with large breast cancers.

Materials and methods

Forty-five women with large breast cancers underwent MRI mammography before and after neoadjuvant chemotherapy (three or six cycles). Dynamic MRI was performed using a 1.5 T unit using three-dimensional FSPGR sequences. For each patient tumour size, tumour volume and dynamic curve were obtained before and after neoadjuvant treatment. Residual tumour sizes obtained using MRI were compared with pathological findings to assess the accuracy of MRI in detecting and in measuring residual tumour.

Results

The sensitivity, specificity and accuracy of MRI in detecting residual disease was 90.5, 100, and 91.3%, respectively. The mean of largest diameters measured at histology and at MRI were 26 and 28.2 mm, respectively. The tumour size correlation coefficient between MRI and pathology measurements was very high: r2 = 0.9657 (p < 0.0001). The interclass correlation coefficient between preoperative imaging measurements and pathological measurements of residual disease was 0.944 (95% CI: 0.906–0.982).

Conclusion

The presence and size of residual disease in breast patients treated with neoadjuvant chemotherapy could be accurately evaluated using MRI.

Introduction

Neoadjuvant chemotherapy was introduced in the 1970s and has now become a standard therapeutic option for breast cancer patients with locally advanced disease.1, 2, 3, 4 Patients with large breast cancer undergoing neoadjuvant chemotherapy might be candidates for radical therapy, or in the case of optimal response, might be treated with breast-conserving surgery with no increase in the local recurrence rate.1, 5, 6, 7 Futhermore neoadjuvant chemotherapy has improved disease-free survival in most patients and overall survival rates in patients with complete response.8, 9, 10, 11

An accurate measurement of tumour size before neoadjuvant chemotherapy is important for staging, treatment monitoring and determining patients’ prognoses. Careful evaluation of residual disease after chemotherapy is important to select the optimal surgical procedure and to identify women that do not show a significant response. If non-responders could be identified, their treatment could be changed to an alternative and potentially more effective regimen or definitive surgical treatment could be considered. Thus, accurate methods of assessment of response are needed to aid the management of patients undergoing neoadjuvant therapy.12, 13, 14

Evaluation of the extent of residual tumour after neoadjuvant chemotherapy based on clinical examination and conventional breast imaging (sonography and mammography) has been shown to be insufficiently sensitive and accurate due to chemotherapy-induced necrosis and fibrosis, and consequently, the tendency to overestimate the volume of residual disease, with important limits in treatment options.9, 12, 13, 15

Magnetic resonance imaging (MRI) has been shown to be more accurate than other imaging techniques for determining the size and extent of most breast malignancies when assessment is performed before surgery for cure.12, 13, 14, 16, 17, 18, 19

The great ability of dynamic MRI compared with conventional imaging in distinguishing fibrous from vascularized tissue is based on the evaluation of tissue morphology and signal intensity changes after contrast medium administration. The contrast medium, which has an intravascular and interstitial distribution, permeates the lesion and markedly increases the signal intensity with respect to the surrounding tissue, thus identifying the angiogenic foci. This is useful in the analysis of the degree of vascularization, and therefore of the viability of residual tumour.20, 21, 22, 23, 24

Recent studies have evaluated MRI accuracy in determining residual breast tumour after neoadjuvant chemotherapy. Generally MRI was shown to be a valid tool to assess residual disease but there are cases of MRI over- or underestimation.1, 10, 11, 19, 25, 26 Only a few studies have compared size measurements of residual tumour obtained on MRI with those obtained at pathology, and generally a good correlation was found.27, 28, 29, 30

The aim of the present study was to assess MRI accuracy in evaluating the presence and size of residual disease after neoadjuvant chemotherapy in a large patient population with large breast tumours, in order to obtain a statistically better study results and also to conduct a wide survey of the radiological patterns of response to neoadjuvant chemotherapy.

Section snippets

Materials and methods

From March 2000 to June 2003, 45 consecutive women (mean age: 53.7 years; range: 30–76 years) with breast cancer receiving neoadjuvant chemotherapy, were enrolled in the study. All patients gave their informed consent to the study and underwent MRI mammography before and after (within 15 days) neoadjuvant chemotherapy.

Results

According to TNM classification, the 45 patients included in the study were at the following stages: 14 at stage 2A, 14 at stage 2B, 11 at stage 3A, and six at stage 3B. Patients’ characteristics are summarized in Table 1.

Stage 2A patients received neoadjuvant chemotherapy because of small breast size or the peri-areolar tumour localization meant that only surgery could be curative.

The initial diagnosis was obtained with fine-needle aspiration cytology. Chemotherapy was perfomed with CMF-A-CMF

Discussion

Residual disease after neoadjuvant chemotherapy represents a critical prognostic factor in determining the success of therapy and an accurate evaluation of its size is essential for planning the correct surgical approach.8, 9, 10, 11, 12, 13, 14 A method suitable for monitoring the response to treatment should be able to provide data regarding changes in tumour size and in cellularity and vascularization. The pattern of contrast medium uptake is the parameter that should be considered in the

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