Role of Dynamic Magnetic Resonance Imaging in the Evaluation of Tumor Response to Preoperative Concurrent Radiochemotherapy for Large Breast Cancers: A Prospective Phase II Study

Comparison of automated breast volume scanning with conventional ultrasonography, mammography, and MRI to assess residual breast cancer after neoadjuvant therapy by molecular type

AIM

To compare the accuracy of hand-held ultrasonography (US), mammography (MG), magnetic resonance imaging (MRI), and automated breast volume scanning (ABVS) in defining residual breast cancer tumour size after neoadjuvant therapy (NAT).

MATERIALS AND METHODS

Patients diagnosed breast cancer and who received NAT at the Breast Center, Peking University People's Hospital, were enrolled prospectively. Imaging was performed after the last cycle of NAT. The residual tumour size, intraclass correlation coefficients (ICCs), and receiver operating characteristic (ROC) to predict pathological complete response (pCR) were analysed.

RESULTS

A total of 156 patients with 159 tumours were analysed. ABVS had a moderate correlation with histopathology residual tumour size (ICC = 0.666), and showed high agreement among triple-positive tumours (ICC = 0.797). With 5 mm as the threshold, the coincidence rate reached 64.7% between ABVS and pathological size, which was significantly higher than that between US, MG, MRI, and pathological size (50%, 45.1%, 41.4%; p=0.009, p=0.001, p<0.001, respectively). For ROC analysis, ABVS demonstrated a higher area under the ROC curve, but with no statistical difference, except for MG (0.855, 0.816, 0.819, and 0.788, respectively; p=0.183 for US, p=0.044 for MG, and p=0.397 for MRI, with ABVS as the reference).

CONCLUSIONS

The longest tumour diameter on ABVS had a moderate correlation with pathological residual invasive tumour size. ABVS was shown to have good ability to predict pCR and would appear to be a potential useful tool for the assessment after NAT for breast cancer.

Staging Breast Cancer with MRI, the T. A Key Role in the Neoadjuvant Setting

Breast cancer (BC) is the most common cancer among women worldwide. Neoadjuvant chemotherapy (NACT) indications have expanded from inoperable locally advanced to early-stage breast cancer. Achieving a pathological complete response (pCR) has been proven to be an excellent prognostic marker leading to better disease-free survival (DFS) and overall survival (OS). Although diagnostic accuracy of MRI has been shown repeatedly to be superior to conventional methods in assessing the extent of breast disease there are still controversies regarding the indication of MRI in this setting. We intended to review the complex literature concerning the tumor size in staging, response and surgical planning in patients with early breast cancer receiving NACT, in order to clarify the role of MRI. Morphological and functional MRI techniques are making headway in the assessment of the tumor size in the staging, residual tumor assessment and prediction of response. Radiomics and radiogenomics MRI applications in the setting of the prediction of response to NACT in breast cancer are continuously increasing. Tailored therapy strategies allow considerations of treatment de-escalation in excellent responders and avoiding or at least postponing breast surgery in selected patients.

Prediction of pathologic complete response on MRI in patients with breast cancer receiving neoadjuvant chemotherapy according to molecular subtypes

OBJECTIVES

This study aimed to investigate the predictability of breast MRI for pathologic complete response (pCR) by molecular subtype in patients with breast cancer receiving neoadjuvant chemotherapy (NAC) and investigate the MRI findings that can mimic residual malignancy.

METHODS

A total of 506 patients with breast cancer who underwent MRI after NAC and underwent surgery between January and December 2018 were included. Two breast radiologists dichotomized the post-NAC MRI findings as radiologic complete response (rCR) and no-rCR. The diagnostic performance of MRI predicting pCR was evaluated. pCR was determined based on the final pathology reports. Tumors were divided according to hormone receptor (HR) and human epidermal growth factor receptor (HER) 2. Residual lesions on post-NAC MRI were divided into overt and subtle which classified as nodularity or delayed enhancement. Pearson's χ² and Wilcoxon rank-sum tests were used for MRI findings causing false-negative pCR.

RESULTS

The overall pCR rate was 30.04%. The overall accuracy for predicting pCR using MRI was 76.68%. The accuracy was significantly different by subtypes (p < 0.001), as follows in descending order: HR - /HER2 - (85.63%), HR + /HER2 - (82.84%), HR + /HER2 + (69.37%), and HR - /HER2 + (62.38%). MRI in the HR - /HER2 + type showed the highest false-negative rate (18.81%) for predicting pCR. The subtle residual enhancement observed only in the delayed phase was associated with false-negative findings (76.2%, p = 0.016).

CONCLUSIONS

The diagnostic accuracy of MRI for predicting pCR differed by molecular subtypes. When the residual enhancement on MRI after NAC is subtle and seen only in the delayed phase, overinterpretation of residual tumors should be performed with caution.

KEY POINTS

• In patients with breast cancer after completion of neoadjuvant chemotherapy, the diagnostic accuracy of MRI for predicting pathologic complete response (pCR) differed according to molecular subtype. • When residual enhancement on MRI is subtle and seen only in the delayed phase, this finding could be associated with false-negative pCR results.

MRI, Clinical Examination, and Mammography for Preoperative Assessment of Residual Disease and Pathologic Complete Response After Neoadjuvant Chemotherapy for Breast Cancer: ACRIN 6657 Trial

OBJECTIVE

The objective of our study was to determine the accuracy of preoperative measurements for detecting pathologic complete response (CR) and assessing residual disease after neoadjuvant chemotherapy (NACT) in patients with locally advanced breast cancer.

SUBJECTS AND METHODS

The American College of Radiology Imaging Network 6657 Trial prospectively enrolled women with ≥ 3 cm invasive breast cancer receiving NACT. Preoperative measurements of residual disease included longest diameter by mammography, MRI, and clinical examination and functional volume on MRI. The accuracy of preoperative measurements for detecting pathologic CR and the association with final pathology size were assessed for all lesions, separately for single masses and nonmass enhancements (NMEs), multiple masses, and lesions without ductal carcinoma in situ (DCIS).

RESULTS

In the 138 women with all four preoperative measures, longest diameter by MRI showed the highest accuracy for detecting pathologic CR for all lesions and NME (AUC = 0.76 and 0.84, respectively). There was little difference across preoperative measurements in the accuracy of detecting pathologic CR for single masses (AUC = 0.69-0.72). Longest diameter by MRI and longest diameter by clinical examination showed moderate ability for detecting pathologic CR for multiple masses (AUC = 0.78 and 0.74), and longest diameter by MRI and longest diameter by mammography showed moderate ability for detecting pathologic CR for tumors without DCIS (AUC = 0.74 and 0.71). In subjects with residual disease, longest diameter by MRI exhibited the strongest association with pathology size for all lesions and single masses (r = 0.33 and 0.47). Associations between preoperative measures and pathology results were not significantly influenced by tumor subtype or mammographic density.

CONCLUSION

Our results indicate that measurement of longest diameter by MRI is more accurate than by mammography and clinical examination for preoperative assessment of tumor residua after NACT and may improve surgical planning.

Discrepancies Between Pathological Tumor Responses and Estimations of Complete Response by Magnetic Resonance Imaging After Neoadjuvant Chemotherapy Differ by Breast Cancer Subtype

INTRODUCTION

The influence of breast cancer (BC) subtype in discrepancies between pathologic complete response (pCR) and complete response by magnetic resonance imaging (MRI-CR) after neoadjuvant chemotherapy (NAC) have not been discussed well. We evaluated the association between BC subtype and pCR or only residual in situ lesion without invasive cancer (pCR/in situ⁺) in patients with MRI-CR (positive predictive value [PPV]).

MATERIAL AND METHODS

From the data of 716 patients with primary BC who were diagnosed with invasive cancer and treated with NAC and then surgery from January 2009 to May 2014 at St. Luke's International Hospital, 180 patients were determined to have MRI-CR by retrospective chart review. BC subtypes at baseline were classified into 6 subtypes, as strong estrogen receptor (ER⁺⁺), moderately positive ER (ER⁺), negative ER (ER^-), and HER2 status expression.

RESULTS

Three subtypes had PPV (pCR) ≥ 50%: ER^-/HER2⁺ (56.3%, 27/48), ER^-/HER2^- (57.6%, 34/59), and ER⁺/HER2⁺ (56.2%, 9/16). However, PPV (pCR) for the ER⁺⁺/HER2^- and ER⁺⁺/HER2⁺ subtypes was < 30%; notably, only 12.0% (3/25) for the ER⁺⁺/HER2^- subtype, which was significantly low (P < .001) compared with ER⁺⁺/HER2^- and other subtypes. PPV (pCR/in situ⁺) was significantly low at 20.0% in the ER⁺⁺/HER2^- subtype (P < .001 compared with other subtypes). PPV (pCR/in situ⁺) in other subtypes was collectively greater than 60%, and was 91.7% in the ER^-/HER2⁺ subtype.

CONCLUSION

We should interpret carefully MRI-CR of NAC to evaluate residual disease for ER⁺⁺/HER2^- BC.

Prediction of pathological complete response to neoadjuvant chemotherapy by magnetic resonance imaging in breast cancer patients

The purpose of this study was to evaluate whether the baseline breast MRI findings would be useful for the prediction for pathological complete response (pCR) by breast cancer patients to neoadjuvant chemotherapy. Primary breast cancer patients (stage II-III) preoperatively treated with sequential paclitaxel (12 cycles) and fluorouracil, epirubicin, and cyclophosphamide (4 cycles), followed by surgery were retrospectively enrolled, and 229 patients were eligible. Before chemotherapy, breast MRI studies were performed. Breast tumors were dichotomized into round + oval and irregular types based on MRI morphology. The round + oval tumors showed a significantly higher pCR rate than the irregular tumors (42.0% vs 17.3%; P < 0.001). In addition, PAM50 analysis revealed that basal and HER2-enriched tumors were significantly more prevalent among round + oval than irregular type tumors (P = 0.015). Baseline MRI morphology appears to be a significant predictor for pCR. The higher rate of the basal and HER2-enriched tumors among the round + oval tumors may explain their better chemo-sensitivity.

Agreement between MRI and pathologic breast tumor size after neoadjuvant chemotherapy, and comparison with alternative tests: individual patient data meta-analysis

Background

Magnetic resonance imaging (MRI) may guide breast cancer surgery by measuring residual tumor size post-neoadjuvant chemotherapy (NAC). Accurate measurement may avoid overly radical surgery or reduce the need for repeat surgery. This individual patient data (IPD) meta-analysis examines MRI’s agreement with pathology in measuring the longest tumor diameter and compares MRI with alternative tests.

Methods

A systematic review of MEDLINE, EMBASE, PREMEDLINE, Database of Abstracts of Reviews of Effects, Heath Technology Assessment, and Cochrane databases identified eligible studies. Primary study authors supplied IPD in a template format constructed a priori. Mean differences (MDs) between tests and pathology (i.e. systematic bias) were calculated and pooled by the inverse variance method; limits of agreement (LOA) were estimated. Test measurements of 0.0 cm in the presence of pathologic residual tumor, and measurements >0.0 cm despite pathologic complete response (pCR) were described for MRI and alternative tests.

Results

Eight studies contributed IPD (N = 300). The pooled MD for MRI was 0.0 cm (LOA: +/−3.8 cm). Ultrasound underestimated pathologic size (MD: −0.3 cm) relative to MRI (MD: 0.1 cm), with comparable LOA. MDs were similar for MRI (0.1 cm) and mammography (0.0 cm), with wider LOA for mammography. Clinical examination underestimated size (MD: −0.8 cm) relative to MRI (MD: 0.0 cm), with wider LOA. Tumors “missed” by MRI typically measured 2.0 cm or less at pathology; tumors >2.0 cm were more commonly “missed” by clinical examination (9.3 %). MRI measurements >5.0 cm occurred in 5.3 % of patients with pCR, but were more frequent for mammography (46.2 %).

Conclusions

There was no systematic bias in MRI tumor measurement, but LOA are large enough to be clinically important. MRI’s performance was generally superior to ultrasound, mammography, and clinical examination, and it may be considered the most appropriate test in this setting. Test combinations should be explored in future studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1664-4) contains supplementary material, which is available to authorized users.

Meta-analysis of agreement between MRI and pathologic breast tumour size after neoadjuvant chemotherapy

BACKGROUND

Magnetic resonance imaging (MRI) has been proposed to guide breast cancer surgery by measuring residual tumour after neoadjuvant chemotherapy. This study-level meta-analysis examines MRI's agreement with pathology, compares MRI with alternative tests and investigates consistency between different measures of agreement.

METHODS

A systematic literature search was undertaken. Mean differences (MDs) in tumour size between MRI or comparator tests and pathology were pooled by assuming a fixed effect. Limits of agreement (LOA) were estimated from a pooled variance by assuming equal variance of the differences across studies.

RESULTS

Data were extracted from 19 studies (958 patients). The pooled MD between MRI and pathology from six studies was 0.1 cm (95% LOA: -4.2 to 4.4 cm). Similar overestimation for MRI (MD: 0.1 cm) and ultrasound (US) (MD: 0.1 cm) was observed, with comparable LOA (two studies). Overestimation was lower for MRI (MD: 0.1 cm) than mammography (MD: 0.4 cm; two studies). Overestimation by MRI (MD: 0.1 cm) was smaller than underestimation by clinical examination (MD: -0.3 cm). The LOA for mammography and clinical examination were wider than that for MRI. Percentage agreement between MRI and pathology was greater than that of comparator tests (six studies). The range of Pearson's/Spearman's correlations was wide (0.21-0.92; 16 studies). Inconsistencies between MDs, percentage agreement and correlations were common.

CONCLUSION

Magnetic resonance imaging appears to slightly overestimate pathologic size, but measurement errors may be large enough to be clinically significant. Comparable performance by US was observed, but agreement with pathology was poorer for mammography and clinical examination. Percentage agreement can provide supplementary information to MDs and LOA, but Pearson's/Spearman's correlation does not provide evidence of agreement and should be avoided. Further comparisons of MRI and other tests using the recommended methods are warranted.

Meta-analysis of magnetic resonance imaging in detecting residual breast cancer after neoadjuvant therapy

BACKGROUND

It has been proposed that magnetic resonance imaging (MRI) be used to guide breast cancer surgery by differentiating residual tumor from pathologic complete response (pCR) after neoadjuvant chemotherapy. This meta-analysis examines MRI accuracy in detecting residual tumor, investigates variables potentially affecting MRI performance, and compares MRI with other tests.

METHODS

A systematic literature search was undertaken. Hierarchical summary receiver operating characteristic (HSROC) models were used to estimate (relative) diagnostic odds ratios ([R]DORs). Summary sensitivity (correct identification of residual tumor), specificity (correct identification of pCR), and areas under the SROC curves (AUCs) were derived. All statistical tests were two-sided.

RESULTS

Forty-four studies (2050 patients) were included. The overall AUC of MRI was 0.88. Accuracy was lower for "standard" pCR definitions (referent category) than "less clearly described" (RDOR = 2.41, 95% confidence interval [CI] = 1.11 to 5.23) or "near-pCR" definitions (RDOR = 2.60, 95% CI = 0.73 to 9.24; P = .03.) Corresponding AUCs were 0.83, 0.90, and 0.91. Specificity was higher when negative MRI was defined as contrast enhancement less than or equal to normal tissue (0.83, 95% CI = 0.64 to 0.93) vs no enhancement (0.54, 95% CI = 0.39 to 0.69; P = .02), with comparable sensitivity (0.83, 95% CI = 0.69 to 0.91; vs 0.87, 95% CI = 0.80 to 0.92; P = .45). MRI had higher accuracy than mammography (P = .02); there was only weak evidence that MRI had higher accuracy than clinical examination (P = .10). No difference in MRI and ultrasound accuracy was found (P = .15).

CONCLUSIONS

MRI accurately detects residual tumor after neoadjuvant chemotherapy. Accuracy was lower when pCR was more rigorously defined, and specificity was lower when test negativity thresholds were more stringent; these definitions require standardization. MRI is more accurate than mammography; however, studies comparing MRI and ultrasound are required.

MRI for breast cancer screening, diagnosis, and treatment

MRI is used widely both for screening women who are at increased risk of breast cancer and for treatment selection. Prospective studies confirm that MRI screening of women with known or suspected genetic mutation results in a higher sensitivity for cancer detection than does mammography. However, survival data are not available. In women with breast cancer, MRI detects cancer not identified with other types of screening. In two randomised trials, this increased sensitivity did not translate into improved selection of surgical treatment or a reduction in the number of operations. Data for longer-term outcomes such as ipsilateral breast tumour recurrence rates and contralateral breast cancer incidence are scarce, but to date do not show clear benefit for MRI. MRI is better than other methods of assessing the response to neoadjuvant chemotherapy, and is helpful in identifying the primary tumour in patients who present with axillary adenopathy.

Preoperative radio-chemotherapy in early breast cancer patients: long-term results of a phase II trial

PURPOSE

This phase II trial aimed to investigate the efficacy of concurrent radio- (RT) and chemotherapy (CT) in the preoperative setting for operable, non-metastatic breast cancer (BC) not amenable to initial breast-conserving surgery (BCS).

PATIENTS AND METHODS

From 2001 to 2003, 59 women were included. CT consisted of four cycles of 5-FU, 500 mg/m(2)/d, continuous infusion (d1-d5) and vinorelbine, 25 mg/m(2) (d1 and d6). Starting concurrently with the second cycle, RT delivered 50 Gy to the breast and 46 Gy to the internal mammary and supra/infra-clavicular areas. Breast surgery and lymph node dissection were then performed. Adjuvant treatment consisted of a 16 Gy boost to the tumor bed after BCS, FEC (four cycles of fluorouracil 500 mg/m(2), cyclophosphamide 500 mg/m(2), and epirubicin 100 mg/m(2), d1; d21) for pN1-3 and hormone-therapy for positive hormone receptors BC.

RESULTS

The in-breast pathological complete response rate was 27%. BCS was performed in 41 (69%) pts. Overall and distant-disease free survivals at 5 years were respectively 88% [95% CI 80-98] and 83% [95% CI 74-93] whereas locoregional and local controls were 90% [95% CI 82-97] and 97% [95% CI 92-100]. Late toxicity (CTCAE-V3) was assessed in 51 pts (86%) with a median follow-up of 7 years [5-8]. Four (8%) experienced at least one grade III toxicities (one telangectasia and three fibroses). Cosmetic results, assessed in 35 of the 41 pts (85%) who retained their breasts, were poor in four pts (11%).

CONCLUSION

Preoperative concurrent administration of RT and CT is an effective regimen. Long-term toxicity is moderate. This association deserves further evaluations in prospective trials.

Is radiotherapy an option for early breast cancers with complete clinical response after neoadjuvant chemotherapy?

PURPOSE

To determine whether the exclusive use of radiotherapy (ERT) could be a treatment option after complete clinical response (cCR) to neoadjuvant chemotherapy (NCT) for early breast cancer (EBC).

METHODS AND MATERIALS

Between 1985 and 1999, 1,477 patients received NCT for EBC considered too large for primary conservative surgery. Of 165 patients with cCR, 65 patients were treated with breast surgery (with radiotherapy) and 100 patients were treated with ERT.

RESULTS

The two groups were comparable in terms of baseline characteristics, except for larger initial tumor sizes in the ERT group. There were no significant differences in overall, disease-free and metastasis-free survival rates. Five-year and 10-year overall survival rates were 91% and 77% in the no-surgery group and 82% and 79% in the surgery group, respectively (p = 0.9). However, a nonsignificant trend toward higher locoregional recurrence rates (LRR) was observed in the no-surgery group (31% vs. 17% at 10 years; p = 0.06). In patients with complete responses on mammography and/or ultrasound, LRR were not significantly different (p = 0.45, 10-year LRR: 21% in surgery vs. 26% in ERT). No significant differences were observed in terms of the rate of cutaneous, cardiac, or pulmonary toxicities.

CONCLUSIONS

Surgery is a key component of locoregional treatment for breast cancers that achieved cCR to NCT.

Implementation of a semi-automated post-processing system for parametric MRI mapping of human breast cancer

Magnetic resonance imaging (MRI) investigations of breast cancer incorporate computationally intense techniques to develop parametric maps of pathophysiological tissue characteristics. Common approaches employ, for example, quantitative measurements of T (1), the apparent diffusion coefficient, and kinetic modeling based on dynamic contrast-enhanced MRI (DCE-MRI). In this paper, an integrated medical image post-processing and archive system (MIPAS) is presented. MIPAS demonstrates how image post-processing and user interface programs, written in the interactive data language (IDL) programming language with data storage provided by a Microsoft Access database, and the file system can reduce turnaround time for creating MRI parametric maps and provide additional organization for clinical trials. The results of developing the MIPAS are discussed including potential limitations of the use of IDL for the application framework and how the MIPAS design supports extension to other programming languages and imaging modalities. We also show that network storage of images and metadata has a significant (p < 0.05) increase in data retrieval time compared to collocated storage. The system shows promise for becoming both a robust research picture archival and communications system working with the standard hospital PACS and an image post-processing environment that extends to other medical image modalities.

Who Should Have Breast Magnetic Resonance Imaging Evaluation?

During the last two decades, tremendous advances have been made in the performance and interpretation of breast magnetic resonance imaging (MRI) examinations. Technical requirements for optimal breast imaging including the requirement for a breast MRI biopsy system are now being defined as part of a voluntary American College of Radiology (ACR) breast MRI accreditation program. The ACR BI-RADS (Breast Imaging Reporting and Data System) lexicon for breast MRI has brought uniformity to the interpretation of breast MRI examinations. With these advances in imaging technique, interpretation guidelines, and increasing availability of MR-compatible breast biopsy systems, MRI of the breast is rapidly gaining popularity in clinical practice in both the diagnostic setting and, more recently, in the screening setting. The clinical indications for breast MRI, however, remain to be defined. There are clinical indications that have emerged where MRI, as an adjunct to mammography, seems to be the imaging study of choice. There are other indications, specifically breast cancer staging, in which MRI is being utilized with increasing frequency, but in which controversy persists.

High rates of breast conservation for large ductal and lobular invasive carcinomas combining multimodality strategies

The literature reports low rates of breast conservation after neoadjuvant chemotherapy for operable breast cancers not amenable to initial breast-conserving surgery. This study aims to compare the outcome of lobular vs ductal carcinomas after neoadjuvant chemotherapy. Between 1989 and 1999, 750 patients with clinical stage II/IIIA ductal (672) or lobular (78) invasive breast carcinomas were treated at the Institut Curie with primary anthracycline-based polychemotherapy followed by either breast conservation (surgery and/or radiotherapy) or mastectomy. Median follow-up was 10 years. Clinical response to primary chemotherapy was significantly worse for lobular than for ductal carcinomas (47 vs 60%; P=0.04), but only histological grade remained predictive in multivariate analysis. Breast conservation was high for both ductal and lobular carcinomas (65 and 54%; P=0.07), due, in part, to the use of radiotherapy, either exclusive or preoperative, for respectively 26 and 40% of patients. The lobular type had no adverse effect, neither on locoregional control nor on overall survival, even in the group of patients treated with breast conservation.