Comparison of mammography, sonography, MRI and clinical examination in patients with locally advanced or inflammatory breast cancer who underwent neoadjuvant chemotherapy

Objectives

The purpose of this study was to determine the relative accuracies of mammography, sonography, MRI and clinical examination in predicting residual tumour size and pathological response after neoadjuvant chemotherapy for locally advanced or inflammatory breast cancer. Each prediction method was compared with the gold standard of surgical pathology.

Methods

43 patients (age range, 25–62 years; mean age, 42.7 years) with locally advanced or inflammatory breast cancer who had been treated by neoadjuvant chemotherapy were enrolled prospectively. We compared the predicted residual tumour size and the predicted response on imaging and clinical examination with residual tumour size and response on pathology. Statistical analysis was performed using weighted kappa statistics and intraclass correlation coefficients (ICC).

Results

The ICC values between predicted tumour size and pathologically determined tumour size were 0.65 for clinical examination, 0.69 for mammography, 0.78 for sonography and 0.97 for MRI. Agreement between the response predictions at mid-treatment and the responses measured by pathology had kappa values of 0.28 for clinical examination, 0.32 for mammography, 0.46 for sonography and 0.68 for MRI. Agreement between the final response predictions and the responses measured by pathology had kappa values of 0.43 for clinical examination, 0.44 for mammography, 0.50 for sonography and 0.82 for MRI.

Conclusion

Predictions of response and residual tumour size made on MRI were better correlated with the assessments of response and residual tumour size made upon pathology than were predictions made on the basis of clinical examination, mammography or sonography. Thus, the evaluation of predicted response using MRI could provide a relatively sensitive early assessment of chemotherapy efficacy.The advantages of neoadjuvant chemotherapy are multiple and it has been used widely during the past few years 1]. Its primary role is to induce tumour shrinkage and permit breast-conserving surgery, primarily in patients with advanced breast cancer 2-4]. Neoadjuvant chemotherapy allows earlier treatment of micrometastatic disease and the study of biological markers that might predict tumour response 5]. The effectiveness of chemotherapeutic agents in treating both primary breast cancer and potential metastatic disease may be enhanced by the presence of tumour neovascularity. If chemotherapy is given before surgery, while tumour vascularity remains intact, the chemotherapeutic agents may be better able to reach the tumour and thus be more effective.Neoadjuvant chemotherapy of locally advanced breast cancer (LABC) has also been shown to improve the resectability rate, offering disease-free and overall survival rates that are at least equivalent to those offered by surgery alone 6,7]. Pathological complete response (pCR) is clinically significant because it is associated with improved long-term prognosis and decreased risk of recurrence 6,8]. Decisions regarding the continuation of current regimens and the appropriate type and timing of surgery depend on the radiological and clinical assessment of residual tumour size during neoadjuvant chemotherapy 9,10]. Until now, many studies have shown that physical examinations, mammography and sonography provide suboptimal evaluations of lesion extent that do not allow accurate assessments of pathological response or residual tumour size 5^,11-13]. In the case of LABC, physical examination, mammography or sonography may be suitable for detecting the larger lesions of non-responders, but they have limited sensitivity for responders with smaller residual lesions 14,15]. For mammography, calcifications may persist or even increase in patients who respond to neoadjuvant chemotherapy 14,16,17].Many previous studies have shown that MRI is the most reliable technique for evaluating residual disease after neoadjuvant chemotherapy, although initial reports described frequent false-negatives with smaller-volume disease 18-27]. Recent studies have increased the sensitivity of MRI, with increased resolution, reduced slice thickness and lower enhancement thresholds being used to minimise the underestimation of residual disease 15^,22-27]. It is still difficult, however, to distinguish residual scarring, necrosis and fibrosis from viable residual malignancy and to predict accurate response after neoadjuvant chemotherapy, especially in responders. Few published studies have described work with patients with inflammatory breast cancer who underwent neoadjuvant chemotherapy because the incidence of this disease is very low 28,29]. The purpose of our study was to determine the relative accuracies of mammography, sonography, MRI and clinical examination in predicting residual tumour size and pathological response after neoadjuvant chemotherapy for locally advanced and inflammatory breast cancer. We compared each prediction method with the gold standard of surgical pathology.