Breast cancer molecular phenotype and the use of HER2-targeted agents influence the accuracy of breast MRI after neoadjuvant chemotherapy

HER2 (2+)/SISH-positive vs. HER2 (3+) Breast Cancer: Pre-treatment MRI Differences and Accuracy of pCR Prediction on Post-treatment MRI

RATIONALE AND OBJECTIVES

To evaluate whether HER2 (human epidermal growth factor receptor 2) (2+)/SISH (silver-enhanced in situ hybridization)+ and HER2 (3+) breast cancers exhibit distinct imaging characteristics on pre-treatment MRI and assess differences in pCR (pathologic complete response) prediction accuracy on post-treatment MRI, considering interobserver variability.

METHODS

This retrospective study included 301 HER2-positive breast cancer patients (mean age, 54 ± 10 years) who underwent NAC and surgery. Pre-treatment MRI features were analyzed in consensus. Two radiologists independently assessed post-treatment MRI for shrinkage patterns and response according to RECIST v1.1, further categorizing complete responses into rCR (radiologic complete response) and near-rCR. Interobserver agreement was measured (Cohen's kappa), and pCR was defined as no residual invasive or in situ tumor in the breast (ypT0) on the final pathology report. Sensitivity, specificity, and AUC were used to evaluate pCR prediction.

RESULTS

Fifty-four patients had HER2 (2+)/SISH+ and 247 had HER2 (3+) tumors. pCR rates were significantly higher in HER2 (3+) (58.7% vs. 18.5%, p < 0.001). On pre-treatment MRI, HER2 (2+)/SISH+ tumors more often appeared as single masses, while HER2 (3+) tumors showed more NME (non-mass enhancement) (44.5% vs. 16.7%, p < 0.001) and mass with NME (33.6% vs. 9.3%, p = 0.005). Post-treatment MRI showed simple concentric shrinkage in HER2 (2+)/SISH+ and no enhancement in HER2 (3+). Agreement was moderate (κ = 0.541-0.588). For pCR prediction, rCR alone yielded AUCs ranging from 0.659 to 0.756. Adding near-rCR improved specificity but reduced sensitivity, with a significant AUC increase for one reader (p = 0.011).

CONCLUSION

Pre-treatment MRI revealed distinct imaging characteristics between subgroups. While pCR rates were higher in HER2 (3+), MRI-based pCR prediction showed similar performance, though near-rCR reduced sensitivity.

Pre-operative MRI in evaluating pathologic complete response to neoadjuvant chemotherapy in patients with breast cancer: a study focused on influencing factors of baseline clinical-pathological and imaging features

Purpose

To investigate what pre-treatment clinical-pathological features and MRI characteristics influence the performance of breast MRI in assessing the pathologic complete response (pCR) of breast cancer patients to Neoadjuvant Chemotherapy (NAC).

Methods

A total of 225 patients with pathologically-confirmed breast cancer who underwent pre- and post-NAC breast MRI between January 2020 and April 2023 were retrospectively analyzed. All patients were categorized into radiologic complete response (rCR) and non-rCR groups based on pre-operative MRI. Univariable and multivariable logistic regression were used to identify independent clinicopathological and imaging features associated with imaging-pathological discordance. The performance of pre-operative MRI for predicting pCR to NAC was assessed according to the baseline characteristics of the clinicopathological data and pre-NAC MRI. In addition, the discrepancy between the pre-operative MRI and post-operative pathological findings was further analyzed by a case-control approach.

Results

Among 225 patients, 99 (44.0%) achieved pCR after NAC. MRI showed the overall sensitivity of 97.6%, specificity of 58.6%, accuracy of 80.4%, a positive predictive value (PPV) of 75.0%, and a negative predictive value (NPV) of 95.1% in identifying pCR. Of baseline features, presence of ductal carcinoma in situ (DCIS) (OR, 3.975 [95% CI: 1.448-10.908], p = 0.007), luminal B (OR, 5.076 [95% CI: 1.401-18.391], p = 0.013), HER2-enriched subtype (OR, 10.949 [95% CI: 3.262-36.747], p < 0.001), multifocal or multicentric lesions (OR, 2.467 [95% CI: 1.067-5.706], p = 0.035), segmental or regional distribution of NME (OR, 8.514 [95% CI: 1.049-69.098], p = 0.045) and rim enhancement of mass (OR, 4.261 [95% CI: 1.347-13.477], p = 0.014) were significantly associated with the discrepancy between MRI and pathology.

Conclusion

Presence of DCIS, luminal B or HER2-enriched subtype, multicentric or multifocal lesions, segmental or regional distribution of NME and rim enhancement of mass may lead to a decrease in diagnostic accuracy of MRI in patients of breast cancer treated with NAC.

The percentage of unnecessary mastectomy due to false size prediction using preoperative ultrasonography and MRI in breast cancer patients who underwent neoadjuvant chemotherapy: a prospective cohort study

BACKGROUND

Imaging-estimated tumour extent after neoadjuvant chemotherapy tends to be discordant with the pathological extent. The authors aimed to prospectively determine the proportion of decisions regarding total mastectomy for potential breast-conserving surgery candidates owing to false size prediction with imaging in neoadjuvant chemotherapy and non-neoadjuvant chemotherapy patients.

MATERIALS AND METHODS

The authors prospectively enroled clinical stage II or III breast cancer patients who are scheduled for total mastectomy between 2018 and 2021. This study was conducted at Seoul National University Hospital at South Korea. Before surgery, each surgeon recorded the hypothetical maximum tumour size at which the surgeon would have been able to attempt breast-conserving surgery if the patient had actually less than the size of the tumour at that location in the breast. After surgery, the hypothetical maximum tumour size was compared with the final pathologic total extent of the tumour, including invasive and in situ cancers.

RESULTS

Among the 360 enroled patients, 130 underwent neoadjuvant chemotherapy, and 230 did not undergo neoadjuvant chemotherapy. Of the total of each group, 47.7% in the neoadjuvant chemotherapy group and 21.3% in the non-neoadjuvant chemotherapy group had a smaller pathologic tumour extent than the pre-recorded hypothetical maximum tumour size (P<0.001). Further analyses were conducted for the neoadjuvant chemotherapy group. The proportions of total mastectomy with false size prediction were higher in HER2-positive (63.3%) and triple-negative (57.6%) patients compared with ER-positive/HER2-negative (25.0%) patients (P<0.001). Both magnetic resonance imaging-pathology and ultrasonography-pathology size discrepancies were significantly associated with false decisions for total mastectomy (both P<0.001). Without magnetic resonance imaging, the false decision may be reduced by 21.5%.

CONCLUSION

A total of 47.7% of patients who received total mastectomy after neoadjuvant chemotherapy were breast-conserving surgery eligible, which was significantly higher than that of non-neoadjuvant chemotherapy patients. Magnetic resonance imaging contributed the most to false size predictions.

89Zr-Trastuzumab PET/CT Imaging of HER2-Positive Breast Cancer for Predicting Pathological Complete Response after Neoadjuvant Systemic Therapy: A Feasibility Study

BACKGROUND

Approximately 20% of invasive ductal breast malignancies are human epidermal growth factor receptor 2 (HER2)-positive. These patients receive neoadjuvant systemic therapy (NAT) including HER2-targeting therapies. Up to 65% of patients achieve a pathological complete response (pCR). These patients might not have needed surgery. However, accurate preoperative identification of a pCR remains challenging. A radiologic complete response (rCR) on MRI corresponds to a pCR in only 73% of patients. The current feasibility study investigates if HER2-targeted PET/CT-imaging using Zirconium-89 (89Zr)-radiolabeled trastuzumab can be used for more accurate NAT response evaluation.

METHODS

HER2-positive breast cancer patients scheduled to undergo NAT and subsequent surgery received a 89Zr-trastuzumab PET/CT both before (PET/CT-1) and after (PET/CT-2) NAT. Qualitative and quantitative response evaluation was performed.

RESULTS

Six patients were enrolled. All primary tumors could be identified on PET/CT-1. Four patients had a pCR and two a pathological partial response (pPR) in the primary tumor. Qualitative assessment of PET/CT resulted in an accuracy of 66.7%, compared to 83.3% of the standard-of-care MRI. Quantitative assessment showed a difference between the SUVR on PET/CT-1 and PET/CT-2 (ΔSUVR) in patients with a pPR and pCR of -48% and -90% (p = 0.133), respectively. The difference in tumor-to-blood ratio on PET/CT-1 and PET/CT-2 (ΔTBR) in patients with pPR and pCR was -79% and -94% (p = 0.133), respectively. Three patients had metastatic lymph nodes at diagnosis that were all identified on PET/CT-1. All three patients achieved a nodal pCR. Qualitative assessment of the lymph nodes with PET/CT resulted in an accuracy of 66.7%, compared to 50% of the MRI.

CONCLUSIONS

NAT response evaluation using 89Zr-trastuzumab PET/CT is feasible. In the current study, qualitative assessment of the PET/CT images is not superior to standard-of-care MRI. Our results suggest that quantitative assessment of 89Zr-trastuzumab PET/CT has potential for a more accurate response evaluation of the primary tumor after NAT in HER2-positive breast cancer.

Accuracy of Preoperative Contrast-enhanced Cone Beam Breast CT in Assessment of Residual Tumor after Neoadjuvant Chemotherapy: A Comparative Study with Breast MRI

RATIONALE AND OBJECTIVES

To compare the accuracy of preoperative contrast-enhanced cone beam breast CT (CE-CBBCT) and MRI in assessment of residual tumor after neoadjuvant chemotherapy (NAC).

MATERIALS AND METHODS

Residual tumor assessments in 91 female patients were performed on preoperative CE-CBBCT and MRI images after NAC. The agreements of tumor size between imaging and pathology were tested by Intraclass Correlation Coefficient (ICC). Subgroup analyses were set according to ductal carcinoma in situ (DCIS), calcifications and molecular subtypes. Correlated-samples Wilcoxon Signed-rank test was used to analyze the difference between imaging and pathology in total and subgroups. AUC, sensitivity, specificity, PPV, and NPV were calculated to compare the performance of CE-CBBCT and MRI in predicting pathological complete response (pCR).

RESULTS

Comparing with pathology, the agreement on CE-CBBCT was good (ICC = 0.64, 95% CI, 0.35-0.78), whereas on MRI was moderate (ICC = 0.59, 95% CI, 0.36-0.77), and overestimation on CE-CBBCT was less than that on MRI (median (interquartile range, IQR): 0.24 [0.00, 1.31] cm vs. 0.67 [0.00, 1.81] cm; p = 0.000). In subgroup analysis, CE-CBBCT showed superior accuracy than MRI when residual DCIS (p = 0.000) and calcifications (p = 0.000) contained, as well as luminal A (p = 0.043) and luminal B (p = 0.009) breast cancer. CE-CBBCT and MRI performed comparable in predicting pCR, AUCs were 0.749 and 0.733 respectively (p > 0.05).

CONCLUSION

CE-CBBCT showed superior accuracy in assessment of residual tumor compared with MRI, especially when residual DCIS or calcifications contained and luminal subtype. The performance of preoperative CE-CBBCT in predicting pCR was comparable to MRI. CE-CBBCT could be an alternative method used for preoperative assessment after NAC.

Predicting pathological complete response after neoadjuvant chemotherapy: A nomogram combining clinical features and ultrasound semantics in patients with invasive breast cancer

Background

Early identification of response to neoadjuvant chemotherapy (NAC) is instrumental in predicting patients prognosis. However, since a fixed criterion with high accuracy cannot be generalized to molecular subtypes, our study first aimed to redefine grades of clinical response to NAC in invasive breast cancer patients (IBC). And then developed a prognostic model based on clinical features and ultrasound semantics.

Methods

A total of 480 IBC patients were enrolled who underwent anthracycline and taxane-based NAC between 2018 and 2020. The decrease rate of the largest diameter was calculated by ultrasound after NAC and their cut-off points were determined among subtypes. Thereafter, a nomogram was constructed based on clinicopathological and ultrasound-related data, and validated using the calibration curve, receiver operating characteristic (ROC) curve, decision curve analysis (DCA), and clinical impact curve (CIC).

Results

The optimal cut-off points for predicting pCR were 53.23%, 51.56%, 41.89%, and 53.52% in luminal B-like (HER2 negative), luminal B-like (HER2 positive), HER2 positive, and triple-negative, respectively. In addition, time interval, tumor size, molecular subtypes, largest diameter decrease rate, and change of blood perfusion were significantly associated with pCR (all p < 0.05). The prediction model based on the above variables has great predictive power and clinical value.

Conclusion

Taken together, our data demonstrated that calculated cut-off points of tumor reduction rates could be reliable in predicting pathological response to NAC and developed nomogram predicting prognosis would help tailor systematic regimens with high precision.

MRI to assess response after neoadjuvant chemotherapy in breast cancer subtypes: a systematic review and meta-analysis

This meta-analysis aimed to estimate and compare sensitivity, specificity, positive- (PPV) and negative predictive value (NPV) of magnetic resonance imaging (MRI) for predicting pathological complete remission (pCR) after neoadjuvant chemotherapy (NAC) in patients with early-stage breast cancer. We stratified for molecular subtype by immunohistochemistry (IHC) and explored the impact of other factors. Two researchers systematically searched PUBMED and EMBASE to select relevant studies and extract data. For meta-analysis of sensitivity and specificity, we used bivariate random-effects models. Twenty-six included studies contained 4497 patients. There was a significant impact of IHC subtype on post-NAC MRI accuracy (p = 0.0082) for pCR. The pooled sensitivity was 0.67 [95% CI 0.58-0.74] for the HR-/HER2-, 0.65 [95% CI 0.56-0.73] for the HR-/HER2+, 0.55 [95% CI 0.45-0.64] for the HR+/HER2- and 0.60 [95% CI 0.50-0.70] for the HR+/HER2+ subtype. The pooled specificity was 0.85 [95% CI 0.81-0.88] for the HR-/HER2-, 0.81 [95% CI 0.74-0.86] for the HR-/HER2+, 0.88[95% CI 0.84-0.91] for the HR+/HER2- and 0.74 [95% CI 0.63-0.83] for the HR+/HER2+ subtype. The PPV was highest in the HR-/HER2- subtype and lowest in the HR+/HER2- subtype. MRI field strength of 3.0 T was associated with a higher sensitivity compared to 1.5 T (p = 0.00063). The accuracy of MRI for predicting pCR depends on molecular subtype, which should be taken into account in clinical practice. Higher MRI field strength positively impacts accuracy. When intervention trials based on MRI response evaluation are designed, the impact of IHC subtype and field strength on MR accuracy should be considered.

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.

Efficacy of neoadjuvant endocrine therapy compared with neoadjuvant chemotherapy in pre-menopausal patients with oestrogen receptor-positive and HER2-negative, lymph node-positive breast cancer

Introduction

Neoadjuvant endocrine therapy (NET) has demonstrated efficacy in post-menopausal patients with hormone-responsive breast cancer. This trial was designed to compare the efficacy of neoadjuvant chemotherapy (NCT) with NET in pre-menopausal breast cancer.

Patients and methods

In this prospective, randomised, phase III study, oestrogen receptor (ER)-positive, HER2-negative, and lymph node-positive pre-menopausal breast cancer patients were recruited from 7 hospitals in South Korea. Enrolled patients were randomly assigned (1:1) to receive 24 weeks of either NCT or NET with goserelin and tamoxifen. The primary purpose was to evaluate the non-inferiority of NET compared to NCT using clinical response, assessed by MRI. Besides, pathological complete response rate (pCR), changes in Ki-67 expression, breast conservation surgery (BCS) rate, and quality of life were included as secondary endpoints.

Results

A total of 187 patients were assigned to receive NCT (n = 95) or NET (n = 92), and 87 patients in each group completed treatments. More NCT patients had complete response or partial response than NET patients using MRI (NCT 83.7% vs. NET 52.9%, 95% CI 17.6–44.0, p < 0.001) and callipers (NCT 83.9% vs. NET 71.3%, 95% CI 0.4–24.9, p = 0.046). Three NCT patients (3.4%) and one NET patient (1.2%) showed pCR (p < 0.005). No difference existed in the conversion rate of BCS (13.8% for NCT vs. 11.5% for NET, p = 0.531) and Ki-67 change (p = 0.114) between the two groups. Nineteen NCT patients had treatment-related grade 3 or worse events compared with none in the NET group.

Conclusions

Better clinical responses were observed in pre-menopausal patients after 24 weeks of NCT compared to those observed after NET.

Trial registration

Clinicaltrials.gov, NCT01622361. Registration June 19, 2012.

Cancer genome landscape: a radiologist's guide to cancer genome medicine with imaging correlates

The introduction of high throughput sequence analysis in the past decade and the decrease in sequencing costs has made available an enormous amount of genomic data. These data have shaped the landscape of cancer genome, which encompasses mutations determining tumorigenesis, the signaling pathways involved in cancer growth, the tumor heterogeneity, and its role in development of metastases. Tumors develop acquiring a series of driver mutations over time. Of the many mutated genes present in cancer, only few specific mutations are responsible for invasiveness and metastatic potential, which, in many cases, have characteristic imaging appearance. Ten signaling pathways, each with targetable components, have been identified as responsible for cancer growth. Blockage of any of these pathways form the basis for molecular targeted therapies, which are associated with specific pattern of response and toxicities. Tumor heterogeneity, responsible for the different mutation pattern of metastases and primary tumor, has been classified in intratumoral, intermetastatic, intrametastatic, and interpatient heterogeneity, each with specific imaging correlates. The purpose of this article is to introduce the key components of the landscapes of cancer genome and their imaging counterparts, describing the types of mutations associated with tumorigenesis, the pathways of cancer growth, the genetic heterogeneity involved in metastatic disease, as well as the current challenges and opportunities for cancer genomics research.

Evaluation of MRI accuracy after primary systemic therapy in breast cancer patients considering tumor biology: optimizing the surgical planning

Background

We analyzed the accuracy of magnetic resonance imaging (MRI) after primary systemic therapy (PST) according to tumor subtype.

Patients and methods

Two-hundred and four breast cancer patients treated with PST were studied. MRI findings after PST were compared with pathologic findings, and results were stratified based on tumor subtype.

Results

Of the two-hundred and four breast cancer patients, eighty-four (41.2%) achieved a pathologic complete response (pCR) in the breast. The MRI accuracy for predicting pCR was highest in triple-negative (TN) and HER2-positive (non-luminal) breast cancer (83.9 and 80.9%, respectively). The mean size discrepancy between MRI-measured and pathologic residual tumor size was lowest in TN breast cancer and highest in luminal B-like (HER2-negative) breast cancer (0.45cm vs. 0.98 cm, respectively; p = 0.003). After breast conserving surgery (BCS), we found a lower rate of positive margins in TN breast cancer and a higher rate of positive margins in luminal B-like (HER2-negative) breast cancer (2.4% vs. 23.6%, respectively).

Conclusions

If tumor response after PST is assessed by MRI, tumor subtype should be considered when BCS is planned. The accuracy of MRI is highest in TN breast cancer.

Comparing Accuracy of Mammography and Magnetic Resonance Imaging for Residual Calcified Lesions in Breast Cancer Patients Undergoing Neoadjuvant Systemic Therapy

BACKGROUND

Neoadjuvant systemic therapy (NST) is performed to increase the rate of breast-conserving surgery in advanced breast cancer patients. Although magnetic resonance imaging (MRI) is accurate in predicting residual cancer, if calcification remains, the issue of whether to perform the surgery on the basis of the residual tumor prediction range in mammography (MMG) or MRI has not yet been elucidated. This study aimed to estimate the accuracy of predicting residual tumor after NST for residual microcalcification on mammographic and enhancing lesion on MRI.

PATIENTS AND METHODS

This was a single-center, retrospective study. We included breast cancer patients who underwent NST, had microcalcifications in the post-NST MMG, and underwent surgery from January 2, 2013 to December 30, 2014 at Asan Medical Center. Patients with post-NST MMG as well as MRI were included. Final pathologic tumor size with histopathology and biomarker status were obtained postoperatively.

RESULTS

In total, 151 patients were included in this study. Overall, MRI correlated better than MMG in predicting the tumor size (intraclass correlation coefficient [ICC], 0.769 vs. 0.651). For hormone receptor (HR)-positive (HR⁺)/HER2^- subtype, MMG had higher correlation than MRI (ICC = 0.747 vs. 0.575). In HR^- subtype, MRI had a strong correlation with pathology (HR^-/HER2⁺ or triple negative (TN), ICC = 0.939 vs. 0.750), whereas MMG tended to overestimate the tumor size (HR^-/HER2⁺ or TN, ICC = 0.543 vs. 0.479).

CONCLUSION

Post-NST residual microcalcifications on MMG have a lower correlation with residual tumor size than MRI. Other than HR⁺/HER2^- subtype, the extent of calcifications on preoperative evaluation might not be accurate in evaluating the residual extent of the tumor after NST.

An objective nodal staging system for breast cancer patients undergoing neoadjuvant systemic treatment

BACKGROUND

In this study, we aimed to develop an objective staging system to determine the degree of nodal metastasis in breast cancer patients undergoing neoadjuvant systemic treatment (NST).

METHODS

We reviewed the pretreatment computed tomography (CT) images of 392 breast cancer patients who received NST. The association between the patterns of the enlarged regional lymph nodes and treatment outcome was analyzed.

RESULTS

In the development cohort of 260 patients, 88 (33.8%) patients experienced tumor recurrence and had a significantly higher number of enlarged lymph nodes on the pretreatment CT compared to patients with no recurrence. When patients were classified according to the numbers and locations of enlarged lymph nodes on pretreatment CT, the number of lymph nodes larger than 1 cm was most significantly associated with tumor recurrence. The accuracy of the CT-based nodal staging system was validated in an independent cohort of 132 patients. The presence of the enlarged supraclavicular nodes was associated with worse outcome, but the effect seemed to originate from the accompanied extensive axillary nodal burden. The prognostic effect of the objectively measured axillary nodal metastasis was more pronounced in hormone receptor-negative tumors.

CONCLUSIONS

We have developed and validated an objective method of nodal staging in breast cancer patients who undergo NST based on the number of enlarged axillary lymph nodes. Our system can improve the current subjective approach, which uses physical examination alone.

Performance of Mid-Treatment Breast Ultrasound and Axillary Ultrasound in Predicting Response to Neoadjuvant Chemotherapy by Breast Cancer Subtype

BACKGROUND

The primary objective was to determine whether mid-treatment ultrasound measurements of index breast tumors and index axillary nodes of different cancer subtypes associate with residual cancer burden (RCB).

METHODS

Patients with invasive breast cancer who underwent neoadjuvant chemotherapy and had pre-treatment and mid-treatment breast and axillary ultrasound were included in this single-institution, retrospective cohort study. Linear regression analysis assessed associations between RCB with (a) change in index breast tumor size, (b) change in index node size, and (c) absolute number of abnormal nodes at mid-treatment. Multivariate linear regression was used to calculate best-fit models for RCB.

RESULTS

One hundred fifty-nine patients (68 triple negative breast cancer [TNBC], 45 hormone receptor [HR]+/human epidermal growth factor receptor 2 [HER2]-, and 46 HR-/HER2+) were included. Median age at diagnosis was 50 years, range 30-76. Median tumor size was 3.4 cm, range 0.9-10.4. Pathological complete response/RCB-I rates were 36.8% (25/68) for TNBC patients, 24.4% (11/45) for HR+/HER2- patients, and 71.7% (33/46) for HR-/HER2+ patients. Linear regression analyses demonstrated associations between percent change in tumor ultrasound measurements at mid-treatment with RCB index score in TNBC and HR+/HER2- (p < .05) but not in HR-/HER2+ (p > .05) tumors and an association between axillary ultrasound assessment of number of abnormal nodes at mid-treatment with RCB index score across all subtypes (p < .05).

CONCLUSION

Performance characteristics of breast ultrasound associated with RCB vary by cancer subtype, whereas the performance characteristics of axillary ultrasound associated with RCB are consistent across cancer subtype. Breast and axillary ultrasound may be valuable in monitoring response to neoadjuvant therapy. The Oncologist 2017;22:394-401 IMPLICATIONS FOR PRACTICE: The differential performance characteristics of breast ultrasound by molecular subtype and the consistent performance characteristics of axillary ultrasound across molecular subtypes can have clinical utility in monitoring response to neoadjuvant therapy.

MYC Amplification as a Predictive Factor of Complete Pathologic Response to Docetaxel-based Neoadjuvant Chemotherapy for Breast Cancer

BACKGROUND

Neoadjuvant chemotherapy is a standard treatment for stage II and III breast cancer. The identification of biomarkers that may help in the prediction of response to neoadjuvant therapies is necessary for a more precise definition of the best drug or drug combination to induce a better response.

MATERIAL AND METHODS

We assessed the role of Ki67, hormone receptors expression, HER2, MYC genes and their protein status, and KRAS codon 12 mutations as predictor factors of pathologic response to anthracycline-cyclophosphamide (AC) followed by taxane docetaxel (T) neoadjuvant chemotherapy (AC+T regimen) in 51 patients with invasive ductal breast cancer.

RESULTS

After neoadjuvant chemotherapy, 82.4% of patients showed pathologic partial response, with only 9.8% showing pathologic complete response. In multivariate analysis, MYC immunoreactivity and high MYC gain defined as MYC/nucleus ≥ 5 were significant predictor factors for pathologic partial response. Using the receiver operating characteristic curve analysis, the ratio of 2.5 MYC/CEP8 (sensitivity of 80% and specificity of 89.1%) or 7 MYC/nuclei copies (sensitivity of 80% and specificity of 73.9%) as the best cutoff in predicting a pathologic complete response was identified. Thus, MYC may have a role in chemosensitivity to AC and/or docetaxel drugs. Additionally, MYC amplification may be a predictor factor of pathologic response to the AC+T regimen in patients with breast cancer. Moreover, patients with an increased number of MYC copies showed pathologic complete response to this neoadjuvant treatment more frequently.

CONCLUSION

The analysis of MYC amplification may help in the identification of patients that may have a better response to AC+T treatment.

Diagnostic accuracy of MRI to evaluate tumour response and residual tumour size after neoadjuvant chemotherapy in breast cancer patients

Background

The aim, of the study was to estimate the accuracy of magnetic resonance imaging (MRI) in assessing residual disease in breast cancer patients receiving neoadjuvant chemotherapy (NAC) and to identify the clinico-pathological factors that affect the diagnostic accuracy of breast MRI to determine residual tumour size following NAC.

Patients and methods

91 breast cancer patients undergoing NAC (92 breast lesions) were included in the study. Breast MRI was performed at baseline and after completion of NAC. Treatment response was evaluated by MRI and histopathological examination to investigate the ability of MRI to predict tumour response. Residual tumour size was measured on post-treatment MRI and compared with pathology in 89 lesions. Clinicopathological factors were analyzed to compare MRI-pathologic size differences.

Results

The overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for diagnosing invasive residual disease by using MRI were 75.00%, 78.57%, 88.89%, 57.89%, and 76.09% respectively. The Pearson’s correlation coefficient (r) between tumour sizes determined by MRI and pathology was r = 0.648 (p < 0.001). The size discrepancy was significantly lower in cancers with initial MRI size ≤ 5 cm (p = 0.050), in cancers with high tumour grade (p < 0.001), and in patients with hormonal receptor-negative cancer (p = 0.033).

Conclusions

MRI is an accurate tool for evaluating tumour response after NAC. The accuracy of MRI in estimating residual tumour size varies with the baseline MRI tumour size, the tumour grade and the hormonal receptor status.

Magnetic Resonance Imaging after Completion of Neoadjuvant Chemotherapy Can Accurately Discriminate between No Residual Carcinoma and Residual Ductal Carcinoma In Situ in Patients with Triple-Negative Breast Cancer

Background

The accurate evaluation of favorable response to neoadjuvant chemotherapy (NCT) is critical to determine the extent of surgery. We investigated independent clinicopathological and radiological predictors to discriminate no residual carcinoma (ypT0) from residual ductal carcinoma in situ (ypTis) in breast cancer patients who received NCT.

Patients and Methods

Parameters of 117 patients attaining pathological complete response (CR) in the breast after NCT between January 2010 and December 2013 were retrospectively evaluated by univariate and multivariate analyses. All patients underwent mammography, ultrasound, and magnetic resonance imaging (MRI) before and after NCT.

Results

There were 67 (57.3%) patients with ypT0. These patients were associated with hormone receptor-negative status, human epidermal growth factor receptor-2 (HER2)-negative tumors, and a higher likelihood of breast-conservation surgery. Baseline mammographic and MRI presentation of the main lesion, absence of associated microcalcifications, shape, posterior features, and absence of calcifications on ultrasound were significantly associated with ypT0. CR in mammography, ultrasound, or MRI after NCT was also related to ypT0. By multivariate analysis, independent predictors of ypT0 were the triple-negative subtype [Odds ratio (OR), 4.23; 95% confidence interval (CI), 1.11–16.09] and CR in MRI after NCT (OR, 5.23; 95% CI, 1.53–17.85). Stratified analysis by breast cancer subtype demonstrated that MRI well predicted ypT0 in all subtypes except the HER2-positive subtype. In particular, of 40 triple-negative subtypes, 22 showed CR in MRI and 21 (95.5%) were ypT0 after NCT.

Conclusion

Among imaging modalities, breast MRI can potentially distinguish between ypT0 and ypTis after NCT, especially in patients with triple-negative breast cancer. This information can help clinicians evaluate tumor response to NCT and plan surgery for breast cancer patients of all subtypes except for those with HER2-enriched tumors after NCT.

Residual Mammographic Microcalcifications and Enhancing Lesions on MRI After Neoadjuvant Systemic Chemotherapy for Locally Advanced Breast Cancer: Correlation with Histopathologic Residual Tumor Size

PURPOSE

To evaluate the accuracy of residual microcalcifications on mammogram (MG) in predicting the extent of the residual tumor after neoadjuvant systemic treatment (NST) in patients with locally advanced breast cancer and to evaluate factors affecting the accuracy of MG microcalcifications using magnetic resonance imaging (MRI) as a reference.

METHODS

The patients who underwent NST and showed suspicious microcalcifications on MG comprised our study population. Clinicopathologic and imaging (MG, MRI) findings were investigated. Agreement between image findings and pathology was assessed and factors affecting the discrepancy were analyzed.

RESULTS

Among 207 patients, 196 had residual invasive ductal carcinoma or ductal carcinoma-in-situ (mean size, 3.78 cm). The overall agreement of residual microcalcifications on MG predicting residual tumor extents was lower than MRI in all tumor subtypes (intraclass correlation coefficient [ICC] = 0.368 and 0.723, p < 0.0001). The agreement of residual MG microcalcifications and pathology was highest in HR(+)/HER2(+) tumors and lowest in the triple-negative tumors (ICC = 0.417 and 0.205, respectively). Multivariate linear regression analysis revealed that a size discrepancy between microcalcifications and histopathology was correlated with molecular subtype (p = 0.005). In HR(+)/HER2(-) and triple-negative subtypes, the mean extents of residual microcalcification were smaller than residual cancer, and overestimation of tumor extent was more frequent in HR(+)/HER2(+) and HR(-)/HER2(+) tumors.

CONCLUSIONS

The extent of microcalcifications on MG after NST showed an overall lower correlation with the extent of the pathologic residual tumor than enhancing lesions on MRI. The accuracy of residual tumor evaluation after NST with MG and MRI is affected by their molecular subtype.

Prognostic and functional importance of the engraftment-associated genes in the patient-derived xenograft models of triple-negative breast cancers

We aimed to identify the factors affecting the successful tumor engraftment in breast cancer patient-derived xenograft (PDX) models. Further, we investigated the prognostic significance and the functional importance of the PDX engraftment-related genes in triple-negative breast cancers (TNBC). The clinico-pathologic features of 81 breast cancer patients whose tissues were used for PDX transplantation were analyzed to identify the factors affecting the PDX engraftment. A gene signature associated with the PDX engraftment was discovered and its clinical importance was tested in a publicly available dataset and in vitro assays. Nineteen out of 81 (23.4 %) transplanted tumors were successfully engrafted into the PDX models. The engraftment rate was highest in TNBC when compared to other subtypes (p = 0.001) and in recurrent or chemotherapy-resistant tumors compared to newly diagnosed primary tumors (p = 0.024). PDX tumors originated from the TNBC cases showed more rapid tumor growth in mice. Gene expression profiling showed that down-regulation of genes involved in the tumor-immune interaction was significantly associated with the successful PDX engraftment. The engraftment gene signature was associated with worse survival outcome when tested in publicly available mRNA datasets of TNBC cases. Among the engraftment-related genes, PHLDA2, TKT, and P4HA2 showed high expression in triple-negative breast cancer cell lines, and siRNA-based gene silencing resulted in reduced cell invasion and proliferation in vitro. Our results show that the PDX engraftment may reflect the aggressive phenotype in breast cancer. Genes associated with the PDX engraftment may provide a novel prognostic biomarker and therapeutic targets in TNBC.

Evaluation with 3.0-T MR imaging: predicting the pathological response of triple-negative breast cancer treated with anthracycline and taxane neoadjuvant chemotherapy

BACKGROUND

Triple-negative breast cancer (TNBC) which expresses neither hormonal receptors nor HER-2 is associated with poor prognosis and shorter survival. Several studies have suggested that TNBC patients attaining pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) show a longer survival than those without pCR.

PURPOSE

To assess the accuracy of 3.0-T breast magnetic resonance imaging (MRI) in predicting pCR and to evaluate the clinicoradiologic factors affecting the diagnostic accuracy of 3.0-T breast MRI in TNBC patients treated with anthracycline and taxane (ACD).

MATERIAL AND METHODS

This retrospective study was approved by the institutional review board; patient consent was not required. Between 2009 and 2012, 35 TNBC patients with 3.0-T breast MRI prior to (n = 26) or after (n = 35) NAC were included. MRI findings were reviewed according to pCR to chemotherapy. The diagnostic accuracy of 3.0-T breast MRI for predicting pCR and the clinicoradiological factors affecting MRI accuracy and response to NAC were analyzed.

RESULTS

3.0-T MRI following NAC with ACD accurately predicted pCR in 91.4% of TNBC patients. The residual tumor size between pathology and 3.0-T MRI in non-pCR cases showed a higher correlation in the Ki-67-positive TNBC group (r = 0.947) than in the Ki-67 negative group (r = 0.375) with statistical trends (P = 0.069). Pre-treatment MRI in the non-pCR group compared to the pCR group showed a larger tumor size (P = 0.030) and non-mass presentation (P = 0.015).

CONCLUSION

3.0-T MRI in TNBC patients following NAC with ACD showed a high accuracy for predicting pCR to NAC. Ki-67 can affect the diagnostic accuracy of 3.0-T MRI for pCR to NAC with ACD in TNBC patients.

An overview of triple negative breast cancer for surgical oncologists

Triple negative breast cancers (TNBCs) represent a distinct subgroup of breast cancers with an immunohistochemical phenotype that is negative for oestrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2). The aim of this article is to provide a broad overview of recent developments in the diagnosis and management of TNBC for surgical oncologists. This overview discusses the subtypes of TNBC and the relationship between this type of breast cancer and the BRCA1 gene. In addition, the article explores recent advances in the treatment of TNBC from a surgical, radiation, and medical oncology point of view. Lastly, evolving therapeutic strategies that have potential to enhance outcomes for patients with TNBC are also discussed.

Can breast cancer molecular subtype help to select patients for preoperative MR imaging?

PURPOSE

To assess whether breast cancer molecular subtype classified by surrogate markers can be used to predict the extent of clinically relevant disease with preoperative breast magnetic resonance (MR) imaging.

MATERIALS AND METHODS

In this HIPAA-compliant, institutional review board-approved study, informed consent was waived. Preoperative breast MR imaging reports from 441 patients were reviewed for multicentric and/or multifocal disease, lymph node involvement, skin and/or nipple invasion, chest wall and/or pectoralis muscle invasion, or contralateral disease. Pathologic reports were reviewed to confirm the MR imaging findings and for hormone receptors (estrogen and progesterone subtypes), human epidermal growth factor receptor type 2 (HER2 subtype), tumor size, and tumor grade. Surrogates were used to categorize tumors by molecular subtype: hormone receptor positive and HER2 negative (luminal A subtype); hormone receptor positive and HER2 positive (luminal B subtype); hormone receptor negative and HER2 positive (HER2 subtype); hormone receptor negative and HER2 negative (basal subtype). All patients included in the study had a histologic correlation with MR imaging findings or they were excluded. χ(2) analysis was used to compare differences between subtypes, with multivariate logistic regression analysis used to assess for variable independence.

RESULTS

Identified were 289 (65.5%) luminal A, 45 (10.2%) luminal B, 26 (5.9%) HER2, and 81 (18.4%) basal subtypes. Among subtypes, significant differences were found in the frequency of multicentric and/or multifocal disease (luminal A, 27.3% [79 of 289]; luminal B, 53.3% [24 of 45]; HER2, 65.4% [17 of 26]; basal, 27.2% [22 of 81]; P < .001) and lymph node involvement (luminal A, 17.3% [50 of 289]; luminal B, 35.6% [26 of 45]; HER2, 34.6% [nine of 26]; basal 24.7% [20 of 81]; P = .014). Multivariate analysis showed that molecular subtype was independently predictive of multifocal and/or multicentric disease.

CONCLUSION

Preoperative breast MR imaging is significantly more likely to help detect multifocal and/or multicentric disease and lymph node involvement in luminal B and HER2 molecular subtype breast cancers. Molecular subtype may help to select patients for preoperative breast MR imaging.

Accuracy of MRI for treatment response assessment after taxane- and anthracycline-based neoadjuvant chemotherapy in HER2-negative breast cancer

BACKGROUND

Studies suggest that MRI is an accurate means for assessing tumor size after neoadjuvant chemotherapy (NAC). However, accuracy might be dependent on the receptor status of tumors. MRI accuracy for response assessment after homogenous NAC in a relative large group of patients with stage II/III HER2-negative breast cancer has not been reported before.

METHODS

250 patients from 26 hospitals received NAC (docetaxel, adriamycin and cyclophosphamide) in the context of the NEOZOTAC trial. MRI was done after 3 cycles and post-NAC. Imaging (RECIST 1.1) and pathological (Miller and Payne) responses were recorded. Accuracy measures were calculated and MRI and pathologically assessed tumor sizes were correlated. Tumor size over- and underestimation were quantified.

RESULTS

Accuracy of MRI for determining pathological complete response (pCR) was 76%. The ROC-curve of MRI response and pCR had an area under the curve value of 0.63 (95% C.I. 0.52-0.74). The correlation coefficient of MRI and histopathological tumor measurements was 0.46 (p < 0.001). Correlations were different for ER-positive (r = 0.40, p < 0.001) and ER-negative (r = 0.76, p < 0.001) breast tumors. MRI under- and overestimated the tumor size in 47% and 40% of all patients. In cases of substantial tumor size underestimation (>2 cm), surgical margins were more often tumor positive compared to the rest of the patients (33% vs.12%, p = 0.005).

CONCLUSION

MRI measurements correlated moderately with tumor size on the surgical specimen. Only in ER-negative breast tumors, MRI tumor sizes correlated sufficiently with residual tumor size on the pathological specimen. Therefore, post-NAC MRI should be interpreted with caution.

Impact of factors affecting the residual tumor size diagnosed by MRI following neoadjuvant chemotherapy in comparison to pathology

BACKGROUND AND OBJECTIVES

To investigate accuracy of magnetic resonance imaging (MRI) for measuring residual tumor size in breast cancer patients receiving neoadjuvant chemotherapy (NAC).

METHODS

Ninety-eight patients were studied. Several MRI were performed during NAC for response monitoring, and the residual tumor size was measured on last MRI after completing NAC. Covariates, including age, tumor characteristics, biomarkers, NAC regimens, MRI scanners, and time from last MRI to operation, were analyzed. Univariate and Multivariate linear regression models were used to determine the predictive value of these covariates for MRI-pathology size discrepancy as the outcome measure.

RESULTS

The mean (±SD) of the absolute difference between MRI and pathological residual tumor size was 1.0 ± 2.0 cm (range, 0-14 cm). Univariate regression analysis showed tumor type, morphology, HR status, HER2 status, and MRI scanner (1.5 T or 3.0 T) were significantly associated with MRI-pathology size discrepancy (all P < 0.05). Multivariate regression analyses demonstrated that only tumor type, tumor morphology, and biomarker status considering both HR and HER-2 were independent predictors (P = 0.0014, 0.0032, and 0.0286, respectively).

CONCLUSION

The accuracy of MRI in evaluating residual tumor size depends on tumor type, morphology, and biomarker status. The information may be considered in surgical planning for NAC patients.

Prognostic and predictive significance of MYC and KRAS alterations in breast cancer from women treated with neoadjuvant chemotherapy

Breast cancer is a complex disease, with heterogeneous clinical evolution. Several analyses have been performed to identify the risk factors for breast cancer progression and the patients who respond best to a specific treatment. We aimed to evaluate whether the hormone receptor expression, HER2 and MYC genes and their protein status, and KRAS codon 12 mutations may be prognostic or predictive biomarkers of breast cancer. Protein, gene and mutation status were concomitantly evaluated in 116 breast tumors from women who underwent neoadjuvant chemotherapy with doxorubicin plus cyclophosphamide. We observed that MYC expression was associated with luminal B and HER2 overexpression phenotypes compared to luminal A (p<0.05). The presence of MYC duplication or polysomy 8, as well as KRAS mutation, were also associated with the HER2 overexpression subtype (p<0.05). MYC expression and MYC gain were more frequently observed in early-onset compared to late-onset tumors (p<0.05). KRAS mutation was a risk factor of grade 3 tumors (p<0.05). A multivariate logistic regression demonstrated that MYC amplification defined as MYC/nucleus ratio of ≥2.5 was a protective factor for chemotherapy resistance. On the other hand, age and grade 2 tumors were a risk factor. Additionally, luminal B, HER2 overexpression, and triple-negative tumors presented increased odds of being resistant to chemotherapy relative to luminal A tumors. Thus, breast tumors with KRAS codon 12 mutations seem to present a worse prognosis. Additionally, MYC amplification may help in the identification of tumors that are sensitive to doxorubicin plus cyclophosphamide treatment. If confirmed in a large set of samples, these markers may be useful for clinical stratification and prognosis.

Magnetic resonance imaging as a predictor of pathologic response in patients treated with neoadjuvant systemic treatment for operable breast cancer. Translational Breast Cancer Research Consortium trial 017

BACKGROUND

Increased pathologic complete response (pCR) rates observed with neoadjuvant chemotherapy (NCT) for some subsets of patients with invasive breast cancer have prompted interest in whether patients who achieved a pCR can be identified preoperatively and potentially spared the morbidity of surgery. The objective of this multicenter, retrospective study was to estimate the accuracy of preoperative magnetic resonance imaging (MRI) in predicting a pCR in the breast.

METHODS

MRI studies at baseline and after the completion of NCT plus data regarding pathologic response were collected retrospectively from 746 women who received treatment at 8 institutions between 2002 and 2011. Tumors were characterized by immunohistochemical phenotype into 4 categories based on receptor expression: hormone (estrogen and progesterone) receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative (n = 327), HR-positive/HER2-positive, (n = 148), HR-negative/HER2-positive, (n = 101), and triple-negative (HR-negative/HER2 negative; n = 155). In all, 194 of 249 patients (78%) with HER2-positive tumors received trastuzumab. Univariate and multivariate analyses of factors associated with radiographic complete response (rCR) and pCR were performed.

RESULT

For the total group, the rCR and pCR rates were 182 of 746 patients (24%) and 179 of 746 patients (24%), respectively, and the highest pCR rate was observed for the triple-negative subtype (57 of 155 patients; 37%) and the HER2-positive subtype (38 of 101 patients; 38%). The overall accuracy of MRI for predicting pCR was 74%. The variables sensitivity, negative predictive value, positive predictive value, and accuracy differed significantly among tumor subtypes, and the greatest negative predictive value was observed in the triple-negative (60%) and HER2-positive (62%) subtypes.

CONCLUSIONS

The overall accuracy of MRI for predicting pCR in invasive breast cancer patients who were receiving NCT was 74%. The performance of MRI differed between subtypes, possibly influenced by differences in pCR rates between groups. Future studies will determine whether MRI in combination with directed core biopsy improves the predictive value of MRI for pathologic response.