Can breast MRI help in the management of women with breast cancer treated by neoadjuvant chemotherapy?

Magnetic resonance mammography has limited ability to estimate pathological complete remission after primary chemotherapy or radiofrequency ablation therapy

Recently, primary systemic chemotherapy has been used not only for locally advanced breast cancers but also for operable cases for which adjuvant chemotherapy is necessary. Moreover, various kinds of ablation therapies have been tried to treat early breast cancer non-surgically, such as radiofrequency ablation (RFA), interstitial laser surgery, cryosurgery and focused ultrasound surgery (FUS). If pathological complete remission (pCR) can be correctly assessed by magnetic resonance mammography (MRM) or ultrasonography (US), a non surgical approach can be used for treatment. MRM is now widely used to assess the effect of chemotherapy in the neoadjuvant setting. However, the ability of MRM to estimate pCR is not yet sufficient to allow a non-surgical approach to breast cancer. Conversely, ultrasonography (US) might over-diagnose fibrous change as residual invasive cancer. If both MRM and US reveal no abnormal finding, there might be no residual cancer on pathological examination. However, such circumstances are encountered in only 2-3% of cases given the neoadjuvant treatment. Other cases, such as US showing residual disease in spite of pCR on MRM, have some potential for false positivity. Therefore, US-guided needle biopsy, especially vacuum-assisted breast biopsy, might be suitable to judge whether true pCR was achieved in the targeted lesion.

Analysis of diagnostic confidence and diagnostic accuracy: a unified framework

Diagnostic confidence has been used as a measure of diagnostic efficacy, but this measure in isolation fails to take into account incorrect diagnoses. Conventional analytical approaches of diagnostic confidence ignore associated diagnostic accuracy. To address this limitation, we introduce a unifying framework which incorporates diagnostic confidence, changes in diagnoses and ultimate accuracy. The framework is illustrated using data from a study in which 62 patients with acute abdominal pain prospectively underwent CT. Admitting surgeons documented their diagnoses and graded their diagnostic confidences (on a 5-point scale) on admission and again after CT. Our approach, unlike conventional analyses, incorporates knowledge of final diagnoses, obtained from surgery or 6 months follow up, in assessing the impact of the test (on a 9-point scale). Changes in pre- and post-CT confidence scores were assessed by the one-sample t-test comparing against zero change, with the test statistic acting as a standardized quantity allowing comparison between our and conventional methodological approaches. Overall, 52% (32/62) of patients were misdiagnosed on admission and 19% (12/62) had incorrect post-CT diagnoses. Diagnostic confidence following CT increased significantly compared with pre-CT confidence on applying both analytical methods, although the level of statistical significance was less marked using our approach. Mean (95% confidence interval) increase in confidence under conventional analysis was 1.32 (1.03, 1.62), with standardized score t = 8.90 [p<0.0001], whereas our method yielded 0.69 (0.25, 1.13), with standardized score t = 3.12 [p = 0.003]. Although both analytical methods led to the same inference regarding the efficacy of CT in the illustrative case study presented, they differed somewhat in degree. It is conceivable that disparate conclusions may emerge in other studies and circumstances. Failure to take adequate account of incorrect diagnoses is potentially misleading. We suggest that a comprehensive analysis of diagnostic confidence requires the incorporation of diagnostic accuracy.

Recurrence rates after DCE-MRI image guided planning for breast-conserving surgery following neoadjuvant chemotherapy for locally advanced breast cancer patients

BACKGROUND

Neoadjuvant therapy results in a significant increase in breast-conserving surgery. However, traditional imaging methods are unable to accurately predict the extent of viable residual disease leading to uncertainty in surgical planning and some previous studies have shown a disproportionately high incidence of locoregional recurrence. Dynamic contrast enhanced-MRI (DCE-MRI) has been shown to provide a potentially more accurate prediction of residual disease.

RESULTS

Patients undergoing neoadjuvant chemotherapy for breast cancer in our unit are staged with the DCE-MRI of the breast performed at 1.5 T before, during and after treatment and the final result was used to plan surgery. Two hundred and four patients with breast cancer were treated with neoadjuvant chemotherapy between 1996 and April 2005. Eighteen of these patients had distant metastases at the time of initial diagnosis and so were excluded from the present study. Following neoadjuvant chemotherapy, 186 patients underwent surgical treatment. Of these, 68 patients had breast-conserving surgery. At a median follow up of 30 months (range: 5.6-72 months) 21 patients in this group developed subsequent recurrence (21/68 - 30%) of whom 9 (9/68 - 13%) had locoregional recurrence, 7 had local recurrence (7/68 - 10%), and 17 (17/68 - 25%) had distant recurrence. Logistic regression analysis revealed only vascular invasion (p=0.006) of the tumour to be significantly associated with overall recurrence. None of the pathological factors (ER, PR status, vascular invasion, lymph node metastases, pathological complete response to neoadjuvant chemotherapy) showed a significant association with locoregional recurrence.

CONCLUSION

Breast-conserving surgery with DCE-MRI planning after neoadjuvant chemotherapy provides an acceptable level of local recurrence without the need for mastectomy.

Predicting response to breast cancer neoadjuvant chemotherapy using diffuse optical spectroscopy

Diffuse optical spectroscopy (DOS) and imaging are emerging diagnostic techniques that quantitatively measure the concentration of deoxy-hemoglobin (ctHHb), oxy-hemoglobin (ctO(2)Hb), water (ctH(2)O), and lipid in cm-thick tissues. In early-stage clinical studies, diffuse optical imaging and DOS have been used to characterize breast tumor biochemical composition and monitor therapeutic response in stage II/III neoadjuvant chemotherapy patients. We investigated whether DOS measurements obtained before and 1 week into a 3-month adriamycin/cytoxan neoadjuvant chemotherapy regimen can predict final, postsurgical pathological response. Baseline DOS measurements of 11 patients before therapy revealed significant increases in tumor ctHHb, ctO(2)Hb, ctH(2)O, and spectral scattering slope, and decreases in bulk lipids, relative to normal breast tissue. Tumor concentrations of ctHHb, ctO(2)Hb, and ctH(2)O dropped 27 +/- 15%, 33 +/- 7%, and 11 +/- 15%, respectively, within 1 week (6.5 +/- 1.4 days) of the first treatment for pathology-confirmed responders (n = 6), whereas nonresponders (n = 5) and normal side controls showed no significant changes in these parameters. The best single predictor of therapeutic response 1 week posttreatment was ctHHb (83% sensitivity, 100% specificity), while discrimination analysis based on combined ctHHb and ctH(2)O changes classified responders vs. nonresponders with 100% sensitivity and specificity. In addition, the pretreatment tumor-to-normal ctO(2)Hb ratio was significantly higher in responders (2.82 +/- 0.44) vs. nonresponders (1.82 +/- 0.49). These results highlight DOS sensitivity to tumor cellular metabolism and biochemical composition and demonstrate its potential for predicting and monitoring an individual's response to treatment.

MR imaging for assessment of breast cancer response to neoadjuvant chemotherapy

Contrast-enhanced MR imaging is being used increasingly because of its high sensitivity to breast cancer and superior ability to demonstrate the extent and distribution of disease. In addition to this direct clinical use, MR imaging in the neoadjuvant treatment setting allows exploration of its potential value in quantifying primary tumor response. The high sensitivity and staging accuracy of MR imaging may yield more accurate classification of objective tumor response using RECIST criteria than clinical examination or mammography. Functional measurements hold the promise of greater sensitivity for detecting biologic effects of targeted treatments than simple anatomic methods.

Breast imaging and reporting data system (BIRADS): magnetic resonance imaging

This article reviews the technical aspects and interpretation criteria in breast MR imaging based on the first edition of breast imaging and reporting data system (BIRADS) published by the American College of Radiology (ACR) in 2003. In a second article, practical cases will be proposed for training the readers. The major aims of using this lexicon are: first to use a logical and standardized description of MR lesions, secondly to obtain a structured MR report with a clear final impression (BIRADS assessment categories), and thirdly to help comparison between different clinical studies based on similar breast MRI terminology.

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

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 28.2mm, respectively. The tumour size correlation coefficient between MRI and pathology measurements was very high: r(2)=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.

The diagnostic impact of contrast-enhanced MRI in management of breast disease

For effective use, the diagnostic impact of contrast-enhanced breast MRI (CE MRI) needs to be quantified. This is a retrospective study of 441 women who have undergone CE MRI of the breast from 1 July 1997 to 25 March 2002. Indications for CE MRI studies were diagnostic in 176, monitoring chemotherapy in 126 and study of MRI screening for breast cancer (MARIBS) cases in 139. CE MRI results were confusing or incorrect in 6% of the diagnostic group, 13% of the chemotherapy group and 9% of the MARIBS group. In 18 of 38 of these cases CE MRI stimulated further tests to clarify a clinical query. CE MRI resulted in an increase in confidence or change in clinical plan in 46% of the diagnostic group, 72% of the chemotherapy group and 80% of the MARIBS group. In 44 of 283 of these, CE MRI caused a beneficial change in the clinical plan based on conventional radiology. CE MRI results in a positive diagnostic impact above conventional imaging in a clinically important proportion of patients, but gives some false calls in a smaller proportion (8.6%).

Function-preserving surgery for breast cancer

Breast-conserving treatment is well established as a safe method of treatment for the majority of breast cancers. Issues to be addressed concerning breast-conserving treatment include the omission of radiation therapy in low-risk patients, optimal local and systemic treatment for ipsilateral breast tumor recurrence, classification of ipsilateral breast tumor recurrence into true recurrences and new primary cancers, and the selection of patients who are eligible for breast conservation after neoadjuvant chemotherapy. There is much evidence that sentinel node biopsy is an accurate method of screening for axillary nodal status in patients with early breast cancer. Clearly, the avoidance of axillary dissection improves quality of life. The feasibility, accuracy, and timing of sentinel node biopsy in patients undergoing neoadjuvant chemotherapy are not yet clear. Also, the clinical significance of micrometastasis should be evaluated to determine the optimal application of sentinel node biopsy. There is interest in replacing breast-conserving treatment by nonsurgical ablation, although additional findings are needed to show that this technique is a true advance in breast cancer treatment.

Accuracy of the Combination of Mammography and Sonography in Predicting Tumor Response in Breast Cancer Patients After Neoadjuvant Chemotherapy

BACKGROUND

Residual tumor size after neoadjuvant chemotherapy is an important consideration in surgical planning. We examined the accuracy of the combination of mammography and sonography in predicting pathologic residual tumor size.

METHODS

Tumor size was evaluated by physical examination, mammography, and sonography at diagnosis and before surgery in 162 breast cancer patients who received neoadjuvant chemotherapy. Agreement between the predicted and the pathologic responses and the predicted and the pathologic tumor sizes was calculated. The effect of invasive lobular carcinoma, high nuclear grade, hormone receptor positivity, and the presence of an extensive intraductal component on the accuracy of mammography and sonography in predicting pathologic residual tumor size was analyzed.

RESULTS

Forty-two patients (25.9%) had a pathologic complete response (pCR). Overall agreement between predicted and pathologic responses was 53% for physical examination, 67% for mammography plus sonography, and 63% for physical examination plus mammography and sonography. The sensitivity of mammography and sonography in predicting pCR was 78.6%, and the specificity was 92.5%; the accuracy was 88.9%. Residual tumor size determined by mammography and sonography correlated with pathologic residual tumor size (r = .662); pathologic tumor size was within .5 cm of predicted in 69.1% of patients. Multivariate analysis showed that pathologic residual tumor size was underestimated for lobular carcinoma and overestimated for poorly differentiated tumors.

CONCLUSIONS

The combination of mammography and sonography has a high accuracy in predicting pCR after neoadjuvant chemotherapy. Agreement of residual tumor size in mammography and sonography with pathologic residual tumor size was moderate.

Monitoring therapeutic efficacy in breast carcinomas

The aim of imaging during and after neoadjuvant therapy is to document and quantify tumor response: has the tumor size been accurately measured? Certainly, the most exciting information for the oncologists is: can we identify good or nonresponders, and can we predict the pathological response early after the initiation of treatment? This review article will discuss the role and the performance of the different imaging modalities (mammography, ultrasound, magnetic resonance imaging and FDG-PET imaging) for evaluating this therapeutic response. It is important to emphasize that, at this time, clinical examination and conventional imaging (mammography and ultrasound) are the only methods recognized by the international criteria. Magnetic resonance imaging and FDG-PET imaging are very promising for predicting the response early after the initiation of neoadjuvant chemotherapy.

Postchemotherapy MRI Overestimates Residual Disease Compared with Histopathology in Responders to Neoadjuvant Therapy for Locally Advanced Breast Cancer

The utility of breast magnetic resonance imaging in patients receiving neoadjuvant chemotherapy is not well defined. We compared serial magnetic resonance imaging examinations with histologic posttreatment examinations in patients treated with primary chemotherapy for locally advanced breast cancer.

PATIENTS AND METHODS

Eligible patients with locally advanced breast cancer received doxorubicin 60 mg/m(2) and docetaxel 60 mg/m(2) (with granulocyte colony stimulating factor support) every 14 days for a maximum of six cycles. Breast magnetic resonance imaging was performed at baseline and repeated every two cycles. Surgery (either local excision or mastectomy) was performed after six cycles in responding or stable patients. Residual tumor size on pathology and preoperative magnetic resonance imaging was compared; concordance was defined as a < or = 0.5-cm difference.

RESULTS

To date, three of 17 enrolled subjects (17.6%) attained pathologic complete response, and three additional patients attained near pathologic complete response, with residual foci of < or = 1 mm. Of these six patients, only one was disease-free by magnetic resonance imaging. Discordance between magnetic resonance imaging findings and pathologic evaluation was found in four of six patients (66.6%) who obtained pathologic complete response or near pathologic complete response. In the three patients in whom four axillary lesions were followed with magnetic resonance imaging, discordance was found in all four lesions, with magnetic resonance imaging overestimating pathologic disease in all cases.

DISCUSSION

Our findings caution that magnetic resonance imaging may frequently overestimate residual invasive carcinoma after neoadjuvant chemotherapy. These results contradict previous studies suggesting that postchemotherapy magnetic resonance imaging may underestimate residual cancer. The use of magnetic resonance imaging in evaluating response to therapy in locally advanced breast cancer should be further studied.

Magnetic resonance-guided, vacuum-assisted breast biopsy: results from a European multicenter study of 538 lesions

BACKGROUND

The objective of this study was to determine the accuracy, reproducibility, and clinical value of magnetic resonance (MR)-guided, vacuum-assisted breast biopsy (MR-VAB) in a prospective, multicenter study.

METHODS

In 5 European centers, MR-VAB was performed or attempted on 538 suspicious lesions that were visible or could targeted only by MR imaging (MRI). Verification of malignant or borderline lesions included reexcision of the biopsy cavity. Benign biopsy results were verified by retrospective correlation of histology with preinterventional and postinterventional MRI studies. Follow-up of 24-48 months (median, 32 months) was available for 491 of 538 patients.

RESULTS

MR-VAB was unsuccessful or was not completed in 21 of 538 patients, for which an immediate repeat biopsy was recommended. Five hundred seventeen of 538 performed VAB procedures (96%) were successful. Histology yielded 138 (27%) malignancies, 17 (3%) atypical ductal hyperplasias, and 362 (70%) benign entities. No false-negative diagnoses occurred among the 517 successful MR-VAB procedures. The positive predictive value of VAB depended on patient preselection, which differed according to the indication for the initial MRI study.

CONCLUSIONS

The results of this study indicated that MR-VAB offers excellent accuracy. Small lesion size did not prove to be a limitation.

Breast-conserving surgery after chemotherapy: value of MDCT for determining tumor distribution and shrinkage pattern

OBJECTIVE

For this study, we investigated the usefulness of MDCT in assessing the extent of residual breast cancer after neoadjuvant chemotherapy. To ensure the success of breast-conserving surgery, we evaluated the usefulness of determining the tumor distribution before neoadjuvant chemotherapy and the shrinkage pattern after neoadjuvant chemotherapy.

SUBJECTS AND METHODS

MDCT before and after neoadjuvant chemotherapy was performed in 46 consecutive patients with 47 locally advanced breast cancers. The distribution pattern of contrast enhancement on MDCT before neoadjuvant chemotherapy was classified into five categories: solitary lesion, grouped lesion (localized lesion with linear, spotty, or linear and spotty enhancement), separated lesion (multiple foci of contrast enhancement), mixed lesion (grouped lesion with multiple foci), and replaced lesion (diffuse contrast enhancement in whole quadrants).

RESULTS

There was agreement between the MDCT assessment and pathologic findings in 44 (94%) of the 47 tumors. In the partial response group with nonreplaced lesions, MDCT revealed three shrinkage patterns: pattern 1a, concentric shrinkage without surrounding lesions; pattern 1b, concentric shrinkage with surrounding lesions; and pattern 2, shrinkage with residual multinodular lesions. Breast-conserving surgery was performed successfully in 14 patients including complete response cases that were detected on the basis of MDCT findings and partial response cases that were detected on the basis of observation of pattern 1 shrinkage. In all five patients with pattern 2 shrinkage, CT underestimated the residual tumor extent by more than 2 cm.

CONCLUSION

MDCT classification of tumor distribution before neoadjuvant chemotherapy and of shrinkage patterns after neoadjuvant chemotherapy is important in the preoperative evaluation of patients undergoing breast-conserving surgery.

How do we measure a residual tumor size in histopathology (the gold standard) after neoadjuvant chemotherapy?

Accurate reporting of the residual tumor size by pathologists after neoadjuvant chemotherapy is an important component of a breast cancer. Recent literature reported comparisons regarding the accuracy of clinical and radiological residual tumor size findings using the histopathology as a "gold standard". However, the histopathological methods of measuring the residual tumor size are not standardized. Most pathologists use the tumor size measured by the gross examination. We collected 32 patient samples and compared the residual tumor size by gross and microscopic pathologic examinations. Using microscopic tumor size as the gold standard, our study showed gross tumor size is overestimated in 25%, underestimated in 56% and correlated to the final microscopic tumor size in 19% of the cases after neoadjuvant chemotherapy. Determining accurate residual tumor size to estimate pathologic response to chemotherapy is essential. We attempted to provide guidelines for pathology reporting post-neoadjuvant chemotherapy on breast cancers.

Sonographic evaluation of early-stage breast cancers that undergo neoadjuvant chemotherapy

OBJECTIVE

We prospectively evaluated low-stage breast cancers treated with neoadjuvant chemotherapy using whole-volume sonography and color Doppler imaging.

METHODS

Thirty-four women with breast cancer (mean maximum size, 2.4 cm) received neoadjuvant chemotherapy with doxorubicin and docetaxel. Targeted whole-volume sonography of tumor sites was performed before and after chemotherapy to assess mass size, color pixel speed-weighted density, and American College of Radiology Breast Imaging Reporting and Data System sonographic characteristics. After chemotherapy, tumor sites were excised by lumpectomy or mastectomy.

RESULTS

Three (11.3%) of 34 patients had a complete histologic response. After chemotherapy, correlation was r = 0.716 between final histologic and sonographic sizes. Compared with histologic residual tumors, sonography had 4 false-negative results, 3 false-positive results, and 27 true-positive results (sensitivity, 87%), with no false-negative results among a subgroup of tumors of 7 mm and larger (sensitivity, 100%). The 3 cases with false-positive results were histologic fibrosis or biopsy changes. Mean speed-weighted density was 0.015 before and 0.0082 after chemotherapy (P = .03). After chemotherapy, vascularity was less common within (P = .06) or adjacent to (P = .009) masses or in tumor sites (P = .05). Prechemotherapy variables of gray scale characteristics and vascularity were compared with final histologic size, and all had P > .20.

CONCLUSIONS

Postchemotherapy sensitivity of sonography was high for residual tumors of 7 mm or larger. Correlation was moderate between histologic and sonographic final tumor sizes. False-positive results were caused by fibrosis or biopsy-related changes. False-negative results occurred with residual tumor size of 6 mm or smaller. After chemotherapy, vascularity usually decreased, and this was not specific for complete response. Before chemotherapy, no vascular or gray scale feature at initial imaging predicted complete responders.

Dynamic contrast-enhanced MRI and sonography in patients receiving primary chemotherapy for breast cancer

We compared dynamic contrast-enhanced MRI (DCE-MRI) and sonography (US) for monitoring tumour size in 21 patients with breast cancer undergoing primary chemotherapy (PCT) followed by surgery. The correlation between DCE-MRI and US measurements of tumour size, defined as the product of the two major diameters, was 0.555 (P=0.009), 0.782 (P<0.001), and 0.793 (P<0.001) at baseline, and after two and four cycles of PCT, respectively. The median tumour size was significantly larger when measured by DCE-MRI than by US at baseline (1472 vs 900 mm(2), P<0.001) and after two cycles of PCT (600 vs 400 mm(2), P=0.009). After PCT, the median tumour size measured by the two techniques was similar (256 vs 289 mm(2) for DCE-MRI and US, respectively, P=0.859). The correlation with the histopathological major tumour diameter was 0.824 (P<0.001) and 0.705 (P<0.001) for post-treatment DCE-MRI and US, respectively. Measurements of the final major tumour diameter by DCE-MRI tended to be more precise, including cases achieving a pathological complete response. Randomized trials are warranted to establish the clinical impact of the initial discrepancy in tumour size estimates between DCE-MRI and US, and the trend towards a better definition of the final tumour size provided by DCE-MRI in this clinical setting.

The use of MR imaging guided focused ultrasound in breast cancer patients; a preliminary phase one study and review

The use of high energy focused ultrasound (FUS) waves to destroy tumor tissue in breast cancer is explored. High energy FUS destroys cells by raising the temperature of the treated volume high enough to denature cell proteins and bring about cellular death. The absorbed energy results in extremely high tissue gradients between target cells and surrounding tissue, so the effect of the focused energy is concentrated only at the target, leaving the healthy tissue unscathed. This phase one trial has examined the possibility of ablating breast carcinoma using MRI Guided FUS (MRIgFUS) in place of lumpectomy. Ten female patients underwent the procedure at the Chaim Sheba Medical Center between September 2002 and August 2004, using the ExAblate 2000 (InSightec, Haifa Israel Ltd.). Seven to 10 days after the procedure, all patients underwent standard lumpectomy and axillary sampling to complete standard treatment and to allow pathological evaluation of the procedure. Two patients had a complete pathological response. The remaining 8 patients had varying amounts of residual tumor; 2 had microscopic foci of residual carcinoma, 3 had 10% residual tumor, and 3 had 10-30% of residual tumor. Although still in its infancy, the future role of this type of ablation in breast cancer and other tumors is discussed.