Monitoring therapeutic efficacy in breast carcinomas

The Role of MRI in Breast Cancer and Breast Conservation Therapy

Contrast-enhanced breast MRI has an established role in aiding in the detection, evaluation, and management of breast cancer. This article discusses MRI sequences, the clinical utility of MRI, and how MRI has been evaluated for use in breast radiotherapy treatment planning. We highlight the contribution of MRI in the decision-making regarding selecting appropriate candidates for breast conservation therapy and review the emerging role of MRI-guided breast radiotherapy.

ACR Appropriateness Criteria® Monitoring Response to Neoadjuvant Systemic Therapy for Breast Cancer: 2022 Update

Imaging plays a vital role in managing patients undergoing neoadjuvant chemotherapy, as treatment decisions rely heavily on accurate assessment of response to therapy. This document provides evidence-based guidelines for imaging breast cancer before, during, and after initiation of neoadjuvant chemotherapy. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Surgical Planning after Neoadjuvant Treatment in Breast Cancer: A Multimodality Imaging-Based Approach Focused on MRI

Neoadjuvant chemotherapy (NACT) today represents a cornerstone in the treatment of locally advanced breast cancer and highly chemo-sensitive tumors at early stages, increasing the possibilities of performing more conservative treatments and improving long term outcomes. Imaging has a fundamental role in the staging and prediction of the response to NACT, thus aiding surgical planning and avoiding overtreatment. In this review, we first examine and compare the role of conventional and advanced imaging techniques in preoperative T Staging after NACT and in the evaluation of lymph node involvement. In the second part, we analyze the different surgical approaches, discussing the role of axillary surgery, as well as the possibility of non-operative management after-NACT, which has been the subject of recent trials. Finally, we focus on emerging techniques that will change the diagnostic assessment of breast cancer in the near future.

Breast Tumor Detection and Classification Using Intravoxel Incoherent Motion Hyperspectral Imaging Techniques

Breast cancer is a main cause of disease and death for women globally. Because of the limitations of traditional mammography and ultrasonography, magnetic resonance imaging (MRI) has gradually become an important radiological method for breast cancer assessment over the past decades. MRI is free of the problems related to radiation exposure and provides excellent image resolution and contrast. However, a disadvantage is the injection of contrast agent, which is toxic for some patients (such as patients with chronic renal disease or pregnant and lactating women). Recent findings of gadolinium deposits in the brain are also a concern. To address these issues, this paper develops an intravoxel incoherent motion- (IVIM-) MRI-based histogram analysis approach, which takes advantage of several hyperspectral techniques, such as the band expansion process (BEP), to expand a multispectral image to hyperspectral images and create an automatic target generation process (ATGP). After automatically finding suspected targets, further detection was attained by using kernel constrained energy minimization (KCEM). A decision tree and histogram analysis were applied to classify breast tissue via quantitative analysis for detected lesions, which were used to distinguish between three categories of breast tissue: malignant tumors (i.e., central and peripheral zone), cysts, and normal breast tissues. The experimental results demonstrated that the proposed IVIM-MRI-based histogram analysis approach can effectively differentiate between these three breast tissue types.

ACR Appropriateness Criteria® Monitoring Response to Neoadjuvant Systemic Therapy for Breast Cancer

Patients with locally advanced invasive breast cancers are often treated with neoadjuvant chemotherapy prior to definitive surgical intervention. The primary aims of this approach are to: 1) reduce tumor burden thereby permitting breast conservation rather than mastectomy; 2) promptly treat possible metastatic disease, whether or not it is detectable on preoperative staging; and 3) potentially tailor future chemotherapeutic decisions by monitoring in-vivo tumor response. Accurate radiological assessment permits optimal management and planning in this population. However, assessment of tumor size and response to treatment can vary depending on the modality used, the measurement technique (such as single longest diameter, 3-D measurements, or calculated tumor volume), and varied response of different tumor subtypes to neoadjuvant chemotherapy (such as concentric shrinkage or tumor fragmentation). As discussed in further detail, digital mammography, digital breast tomosynthesis, US and MRI represent the key modalities with potential to help guide patient management. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Apparent Diffusion Coefficient Value to Evaluate Tumor Response After Neoadjuvant Chemotherapy in Patients with Breast Cancer

RATIONALE AND OBJECTIVES

This study explored tumor behavior in patients with breast cancer during neoadjuvant chemotherapy (NAC) by sequential measurements of tumor apparent diffusion coefficient (ADC) after each chemotherapy cycle. The aim was to determine if the tumor ADC is useful to differentiate complete pathological response (cPR) from partial pathological response (pPR) during NAC.

MATERIALS AND METHODS

A total of 16 cases (in 14 patients) with diagnosis of breast cancer eligible to receive NAC were included. There were 70 magnetic resonance imaging examinations performed, 5 for each patient, during NAC cycles. Diffusion-weighted imaging was performed on a 1.5T system (b values of 0 and 700s/mm²). Four ADC ratios between the five MRI examinations were obtained to assess ADC changes during NAC. Absence of invasive breast cancer at surgical specimens (Miller-Payne 5) was considered as cPR and was used as reference for ADC cutoff ratios.

RESULTS

In this study, we were able to differentiate between cPR and pPR, after two cycles of NAC until the end of NAC before surgery (ADC ratios 2-4). The thresholds to differentiate between cPR and pPR of ADC ratios 2, 3, and 4, were 1.14 × 10^-3mm²/s, 1.08 × 10^-3mm²/s, and 1.25 × 10^-3mm²/s, respectively, and have a cross-validated sensitivity and specificity of 79.2%, 79.7% (ADC ratio 2); 100%, 66.7% (ADC ratio 3); and 100%, 83.8% (ADC ratio 4), respectively.

CONCLUSIONS

The ADC ratios were useful to differentiate cPR from pPR in breast cancer tumors after NAC. Thus, it may be useful in tailoring treatment in these patients.

Accuracy of contrast-enhanced spectral mammography for estimating residual tumor size after neoadjuvant chemotherapy in patients with breast cancer: a feasibility study

Objective

To assess the feasibility of contrast-enhanced spectral mammography (CESM) of the breast for assessing the size of residual tumors after neoadjuvant chemotherapy (NAC).

Materials and methods

In breast cancer patients who underwent NAC between 2011 and 2013, we evaluated residual tumor measurements obtained with CESM and full-field digital mammography (FFDM). We determined the concordance between the methods, as well as their level of agreement with the pathology. Three radiologists analyzed eight CESM and FFDM measurements separately, considering the size of the residual tumor at its largest diameter and correlating it with that determined in the pathological analysis. Interobserver agreement was also evaluated.

Results

The sensitivity, specificity, positive predictive value, and negative predictive value were higher for CESM than for FFDM (83.33%, 100%, 100%, and 66% vs. 50%, 50%, 50%, and 25%, respectively). The CESM measurements showed a strong, consistent correlation with the pathological findings (correlation coefficient = 0.76-0.92; intraclass correlation coefficient = 0.692-0.886). The correlation between the FFDM measurements and the pathological findings was not statistically significant, with questionable consistency (intraclass correlation coefficient = 0.488-0.598). Agreement with the pathological findings was narrower for CESM measurements than for FFDM measurements. Interobserver agreement was higher for CESM than for FFDM (0.94 vs. 0.88).

Conclusion

CESM is a feasible means of evaluating residual tumor size after NAC, showing a good correlation and good agreement with pathological findings. For CESM measurements, the interobserver agreement was excellent.

A computer-aided diagnosis (CAD) scheme for pretreatment prediction of pathological response to neoadjuvant therapy using dynamic contrast-enhanced MRI texture features

OBJECTIVE

To assess whether a computer-aided, diagnosis (CAD) system can predict pathological Complete Response (pCR) to neoadjuvant chemotherapy (NAC) prior to treatment using texture features.

METHODS

Response to treatment of 44 patients was defined according to the histopatology of resected tumour and extracted axillary nodes in two ways: (a) pCR+ (Smith's Grade = 5) vs pCR- (Smith's Grade < 5); (b) pCRN+ (pCR+ and absence of residual lymph node metastases) vs pCRN - . A CAD system was developed to: (i) segment the breasts; (ii) register the DCE-MRI sequence; (iii) detect the lesion and (iv) extract 27 3D texture features. The role of individual texture features, multiparametric models and Bayesian classifiers in predicting patients' response to NAC were evaluated.

RESULTS

A cross-validated Bayesian classifier fed with 6 features was able to predict pCR with a specificity of 72% and a sensitivity of 67%. Conversely, 2 features were used by the Bayesian classifier to predict pCRN, obtaining a sensitivity of 69% and a specificity of 61%.

CONCLUSION

A CAD scheme, that extracts texture features from an automatically segmented 3D mask of the tumour, could predict pathological response to NAC. Additional research should be performed to validate these promising results on a larger cohort of patients and using different classification strategies. Advances in knowledge: This is the first study assessing the role of an automatic CAD system in predicting the pathological response to NAC before treatment. Fully automatic methods represent the backbone of standardized analysis and may help in timely managing patients candidate to NAC.

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.

Normalization of compression-induced hemodynamics in patients responding to neoadjuvant chemotherapy monitored by dynamic tomographic optical breast imaging (DTOBI)

We characterize novel breast cancer imaging biomarkers for monitoring neoadjuvant chemotherapy (NACT) and predicting outcome. Specifically, we recruited 30 patients for a pilot study in which NACT patients were imaged using dynamic tomographic optical breast imaging (DTOBI) to quantify the hemodynamic changes due to partial mammographic compression. DTOBI scans were obtained pre-treatment (referred to as day 0), as well as 7 and 30 days into therapy on female patients undergoing NACT. We present data for the 13 patients who participated in both day 0 and 7 measurements and had evaluable data, of which 7 also returned for day 30 measurements. We acquired optical images over 2 minutes following 4-8 lbs (18-36 N) of compression. The timecourses of tissue-volume averaged total hemoglobin (HbT), as well as hemoglobin oxygen saturation (SO₂) in the tumor vs. surrounding tissues were compared. Outcome prediction metrics based on the differential behavior in tumor vs. normal areas for responders (>50% reduction in maximum diameter) vs. non-responders were analyzed for statistical significance. At baseline, all patients exhibit an initial decrease followed by delayed recovery in HbT, and SO₂ in the tumor area, in contrast to almost immediate recovery in surrounding tissue. At day 7 and 30, this contrast is maintained in non-responders; however, in responders, the contrast in hemodynamic time-courses between tumor and normal tissue starts decreasing at day 7 and substantially disappears at day 30. At day 30 into NACT, responding tumors demonstrate "normalization" of compression induced hemodynamics vs. surrounding normal tissue whereas non-responding tumors did not. This data suggests that DTOBI imaging biomarkers, which are governed by the interplay between tissue biomechanics and oxygen metabolism, may be suitable for guiding NACT by offering early predictions of treatment outcome.

Predictive and prognostic value of FDG-PET/CT imaging and different response evaluation criteria after primary systemic therapy of breast cancer

OBJECTIVES

(1) To predict pathological complete remission (pCR) and survival after primary systemic therapy (PST) in patients diagnosed with breast cancer by using two different PET/CT based scores: a simplified PERCIST-based PET/CT score (Method 1) and a combined PET/CT score supplemented with the morphological results of the RECIST system (Method 2) and (2) to assess the effect of different breast carcinoma subtypes on tumor response and its evaluation.

METHODS

Eighty-eight patients were enrolled in the study who underwent PET/CT imaging before and after PST. PET/CTs were evaluated by changes in maximum Standardized Uptake Value (SUVmax) and tumor size. Method 1 and 2 were applied to predict pathological complete remission (pCR). Kaplan-Meier analyses for survival were performed. Classification into biological subtypes was performed based on the pre-therapeutic tumor characteristics.

RESULTS

A total of 30/88 patients showed pCR (34.1 %). Comparing pCR/non-pCR patient groups, significant differences were detected by changes in SUVmax (p < 0.001) and tumor size (p < 0.001) regarding the primary breast lesions. To predict pCR, Method 2 had higher sensitivity (72.4 % vs. 44.8 %) and negative predictive value (57.9 % vs. 45.8 %) with lower false negativity rate (16 vs. 32) than Method 1. pCR rate was higher in Her2-positive and triple negative tumors. Despite the significant differences detected between the biological subtypes regarding changes in primary tumor SUVmax (p = 0.007) and size (p = 0.015), the subtypes only had significant impact on response evaluation with Method 2 and not with Method 1. In our study, neither clinical nor pathological CR were predictors of longer progression-free survival.

CONCLUSIONS

Our results suggest that combined PET/CT criteria are more predictive of pCR. The effect of biological subtypes is significant on pCR rate as well as on the changes in FDG-uptake and morphological tumor response. Response evaluation with combined criteria was also able to reflect the differences between the biological behavior of breast tumor subtypes.

The role of FDG-PET-CT in the evaluation of primary systemic therapy in breast cancer: links between metabolic and pathological remission

Introduction: FDG-PET-CT is highly sensitive in detection of viable tumour tissue, giving an importance for that in oncological diagnostics. Aim: The authors analysed retrospectively the relationship between metabolic response and changes in Ki-67, a proliferation marker. Methods: Staging FDG-PET-CT scans (before and after therapy) SUVs (Standardized Uptake Value), and morphological changes in the primary tumour and axillary lymph node region were evaluated in 30 patients with breast cancer. Calculated ΔSUV were compared with Ki-67 proliferation marker (measured in biopsies and surgical specimens). Results: The decrease of SUV and size were significant in the primary tumour and the axillary lymph node region. Decrease of Ki-67 was significant. Significant correlation was found between Ki-67 and SUV before therapy, initial Ki-67 and ΔSUV, and ΔKi-67 and ΔSUV. Conclusions: The metabolic changes were more sensitive in the measurement of the therapeutic response than morphological remission, and they correlated well with the pathological response, in not standardized clinical conditions even. Orv. Hetil., 2012, 153, 1958–1964.

Preoperative systemic therapy in locoregional management of early breast cancer: highlights from the Kyoto Breast Cancer Consensus Conference

Data reviewed at the Kyoto Breast Cancer Consensus Conference (KBCCC) showed that preoperative systemic therapy (PST) could optimize surgery through the utilization of information relating to pre- and post-PST tumor stage, therapeutic sensitivity, and treatment-induced changes in the biological characteristics of the tumor. As such, it was noted that the biological characteristics of the tumor, such as hormone receptors, human epidermal growth factor receptor-2, histological grade, cell proliferative activity, mainly defined by the Ki67 labeling index, and the tumor's multi-gene signature, should be considered in the planning of both systemic and local therapy. Furthermore, the timing of axillary sentinel lymph node diagnosis (i.e., before or after the PST) was also noted to be critical in that it may influence the likelihood of axillary preservation, even in node positive cases. In addition, axillary diagnosis with ultrasound and concomitant fine needle aspiration cytology or core needle biopsy (CNB) was reported to contribute to the construction of a treatment algorithm for patient-specific or individualized axillary surgery. Following PST, planning for breast surgery should therefore be based on tumor subtype, tumor volume and extent, therapeutic response to PST, and patient preference. Nomograms for predicting nodal status and drug sensitivity were also recognized as a tool to support decision-making in the selection of surgical treatment. Overall, review of data at the KBCCC showed that PST increases the likelihood of patients receiving localized surgery and individualized treatment regimens.

Diffuse optical imaging using spatially and temporally modulated light

The authors describe the development of diffuse optical imaging (DOI) technologies, specifically the use of spatial and temporal modulation to control near infrared light propagation in thick tissues. We present theory and methods of DOI focusing on model-based techniques for quantitative, in vivo measurements of endogenous tissue absorption and scattering properties. We specifically emphasize the common conceptual framework of the scalar photon density wave for both temporal and spatial frequency-domain approaches. After presenting the history, theoretical foundation, and instrumentation related to these methods, we provide a brief review of clinical and preclinical applications from our research as well as our outlook on the future of DOI technology.

Can diffusion-weighted MR imaging and contrast-enhanced MR imaging precisely evaluate and predict pathological response to neoadjuvant chemotherapy in patients with breast cancer?

Clinical evidence regarding the value of MRI for therapy responses assessment in breast cancer is increasing. The objective of this study is to compare the diagnostic capability of diffusion-weighted MR imaging (DW-MRI) and contrast-enhanced MR imaging (CE-MRI) to evaluate and predict pathological response in breast cancer patients receiving neoadjuvant chemotherapy (NAC). We performed a meta-analysis of all available studies of the diagnostic performance of DW-MRI or CE-MRI to evaluate and predict pathological response to NAC in patients with breast cancer. We determined sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-), diagnostic odds ratio (DOR) and constructed summary receiver operating characteristic curves using hierarchical regression models. Methodological quality was assessed by QUADAS tool. Thirty-four studies met the inclusion criteria and involved 1,932 pathologically confirmed patients in total. Methodological quality was relatively high. DW-MRI sensitivity was 0.93 (95 % CI 0.82-0.97) and specificity was 0.82 (95 % CI 0.70-0.90). Overall LR+ was 5.09 (95 % CI 3.09-8.38), LR- was 0.09 (95 % CI 0.04-0.22), and DOR was 55.59 (95 % CI 21.80-141.80). CE-MRI sensitivity was 0.68 (95 % CI 0.57-0.77) and specificity was 0.91 (95 % CI 0.87-0.94). Overall LR+ was 7.48 (95 % CI 5.29-10.57), LR- was 0.36 (95 % CI 0.27-0.48), and DOR was 20.98 (95 % CI 13.24-33.24). Our study confirms that DW-MRI is a high sensitive and CE-MRI is a high specific modality in predicting pathological response to NAC in breast cancer patients. The combined use of DW-MRI and CE-MRI has the potential to improve the diagnostic performance in monitoring NAC. Further large prospective studies are warranted to assess the actual value of this combination in breast cancer preoperative treatment screening.

Assessment of CAD-generated tumor volumes measured using MRI in breast cancers before and after neoadjuvant chemotherapy

OBJECTIVE

To evaluate inter-observer agreement and the predictive value of tumor size measurements using MRI for breast cancer under neoadjuvant chemotherapy (NAC) by comparing the measurements of the longest diameters (LD), total enhanced volumes (TEV) and washout volumes (WOV).

METHODS

Thirty-seven female breast cancer patients were prospectively enrolled from August 2008 to October 2010. Two of these patients had locally advanced disease. MRI examinations were acquired within 2 weeks before and after NAC. Interim scans were also conducted in 30 patients. Tumor resection was undertaken within 2 weeks after the cessation of NAC. MRI images were independently measured for LD, TEV and WOV by two experienced radiologists. Inter-observer agreement was evaluated using concordance correlation coefficients (CCCs). Tumor sizes after NAC were evaluated relative to their initial sizes for early prediction of a pathological complete response (pCR).

RESULTS

The CCCs were 0.93 (CI: 0.90-0.95) for LD, 0.98 (CI: 0.97-0.98) for TEV and 0.99 (CI: 0.991-0.996) for WOV. All measurements had high inter-observer agreement, but the CCCs were significantly increased in the aforementioned order (P<0.0001). WOV measured after the completion of chemotherapy had significant discriminating ability (P=0.0056) when evaluated using receiver operating characteristic analysis, and was found to be superior to LD (P=0.045). The average WOV size was significantly smaller in pCR cases than in non-pCR cases (P=0.016).

CONCLUSION

Computer-aided detection-generated tumor volumes had significantly higher inter-observer concordance than conventional LD measurements. WOV measurements had the highest concordance, and WOV could better predict pCR after NAC at smaller tumor sizes.

Diffuse optical spectroscopic imaging correlates with final pathological response in breast cancer neoadjuvant chemotherapy

Diffuse optical spectroscopic imaging (DOSI) non-invasively and quantitatively measures tissue haemoglobin, water and lipid. Pilot studies in small groups of patients demonstrate that DOSI may be useful for longitudinal monitoring and predicting breast cancer neoadjuvant chemotherapy pathological response. This study evaluates the performance of a bedside DOSI platform in 34 breast cancer patients followed for several months. DOSI optical endpoints obtained at multiple timepoints are compared with final pathological response. Thirty-six stage II/III breast cancers (34 patients) were measured in vivo with DOSI prior to, in the middle of and after the completion of pre-surgical neoadjuvant chemotherapy. Cancer therapies ranged from standard anthracyclines to targeted therapies. Changes in DOSI-measured parameters at each timepoint were compared against final surgical pathology. Absolute changes in the tumour-to-normal (T/N) ratio of tissue deoxyhaemoglobin concentration (ctHHb) and relative changes in the T/N ratio of a tissue optical index (TOI) were most sensitive and correlate to pathological response. Changes in ctHHb and TOI were significantly different between tumours that achieved pathological complete response (pCR) versus non-pCR. By therapy midpoint, mean TOI-T/N changes were 47±8 versus 20±5 per cent for pCR versus non-pCR subjects, respectively (Z=0.011). Changes in ctHHb and TOI scaled significantly with the degree of pathological response (non-, partial and complete). DOSI measurements of TOI separated pCR from non-pCR by therapy midpoint regardless of drug or dosing strategy. This approach is well suited to monitoring breast tumour response and may provide feedback for optimizing therapeutic outcomes and minimizing side-effects.

Diffusion-weighted and dynamic contrast-enhanced MRI in evaluation of early treatment effects during neoadjuvant chemotherapy in breast cancer patients

PURPOSE

To use dynamic contrast-enhanced (DCE) and diffusion-weighted (DW) MRI at 3 Tesla (T) for early evaluation of treatment effects in breast cancer patients undergoing neoadjuvant chemotherapy (NAC), and assess the reliability of DW-MRI.

MATERIALS AND METHODS

DW- and DCE-MRI acquisitions of 15 breast cancer patients were performed before and after one cycle of NAC. MRI tumor diameter and volume, apparent diffusion coefficient (ADC) and kinetic parameters (K(trans), v(e)) were derived. The reliability of ADC before NAC was assessed. Changes in MRI parameters after NAC were analyzed, and logistic regression analysis was used to find the best predictors for pathologic response.

RESULTS

The reliability for ADC values was high, with intraclass correlation coefficient of 0.84 (P = 0.001). After one cycle of NAC, MRI tumor diameter (8%, P = 0.005) and tumor volume (30%, P = 0.008) was reduced for all patients, while ADC mean values increased (0.12 mm(2)/s, P = 0.008). The best predictor for treatment response was a change in MRI tumor diameter with mean error rate of 0.167 (13% for responders, 5% for nonresponders, P = 0.291).

CONCLUSION

Changes in MRI derived tumor diameter and ADC after only one cycle of NAC could provide a valuable tool for early evaluation of treatment effects in breast cancer patients.

Optical imaging of breast cancer oxyhemoglobin flare correlates with neoadjuvant chemotherapy response one day after starting treatment

Approximately 8-20% of breast cancer patients receiving neoadjuvant chemotherapy fail to achieve a measurable response and endure toxic side effects without benefit. Most clinical and imaging measures of response are obtained several weeks after the start of therapy. Here, we report that functional hemodynamic and metabolic information acquired using a noninvasive optical imaging method on the first day after neoadjuvant chemotherapy treatment can discriminate nonresponding from responding patients. Diffuse optical spectroscopic imaging was used to measure absolute concentrations of oxyhemoglobin, deoxyhemoglobin, water, and lipid in tumor and normal breast tissue of 24 tumors in 23 patients with untreated primary breast cancer. Measurements were made before chemotherapy, on day 1 after the first infusion, and frequently during the first week of therapy. Various multidrug, multicycle regimens were used to treat patients. Diffuse optical spectroscopic imaging measurements were compared with final postsurgical pathologic response. A statistically significant increase, or flare, in oxyhemoglobin was observed in partial responding (n = 11) and pathologic complete responding tumors (n = 8) on day 1, whereas nonresponders (n = 5) showed no flare and a subsequent decrease in oxyhemoglobin on day 1. Oxyhemoglobin flare on day 1 was adequate to discriminate nonresponding tumors from responding tumors. Very early measures of chemotherapy response are clinically convenient and offer the potential to alter treatment strategies, resulting in improved patient outcomes.

Variation of breast vascular maps on dynamic contrast-enhanced MRI after primary chemotherapy of locally advanced breast cancer

OBJECTIVE

The purpose of this article is to assess changes in breast vascular maps on dynamic contrast-enhanced MRI (DCE-MRI) after primary chemotherapy in patients with locally advanced breast cancer (LABC).

SUBJECTS AND METHODS

Thirty-four patients with unilateral LABC underwent DCE-MRI before and after anthracycline- and taxane-based primary chemotherapy. The number of vessels 30 mm or longer in length and 2 mm or larger in maximum transverse diameter were counted on maximum intensity projections of the first subtracted phase for each of the two breasts. Patients achieving pathologic response or small clusters of residual cancer cells after primary chemotherapy were considered as responders, and those with an inferior pathologic response were considered as nonresponders.

RESULTS

The mean (± SD) number of vessels in the breast harboring the cancer and in the contralateral breast was 2.7 ± 1.3 and 1.1 ± 1.0 (p < 0.001), respectively, before primary chemotherapy and 1.3 ± 1.1 and 1.1 ± 1.1 (p = 0.147), respectively, after primary chemotherapy. Overall, primary chemotherapy was associated with a significant reduction in DCE-MRI vascular maps in the breast harboring the cancer only (p < 0.001). Of the 34 patients, 10 were considered responders and 24 were nonresponders. The mean number of vessels in the breast harboring the cancer changed from 2.7 ± 1.1 to 0.6 ± 0.8 for the 10 responders and from 2.7 ± 1.4 to only 1.6 ± 0.9 for the 24 nonresponders. The mean reduction of vascular map in the breast harboring the cancer was significantly higher in responders compared with nonresponders (p = 0.017).

CONCLUSION

Before primary chemotherapy, DCE-MRI vascular maps were asymmetrically increased ipsilaterally to the LABC. After primary chemotherapy, vascular maps significantly changed only in the breast harboring the cancer, with significant differences between responders and nonresponders.

Best practices: consensus on performing positron emission tomography-computed tomography for radiation therapy planning and for therapy response assessment

The incorporation of positron emission tomography-computed tomography (PET-CT) into oncological imaging has expanded rapidly since the hybrid scanners were introduced approximately 10 years ago. PET-CT is becoming the standard of practice for the imaging diagnosis and staging of most cancers. Since its introduction, hardware-registered PET and CT images produced by a PET-CT scan were recognized as valuable not only for detection, staging and restaging applications but also for optimizing radiation treatment planning. Even before the introduction of PET-CT, the value of metabolic imaging with the use of FDG PET was recognized as a potentially powerful means of assessing response to various therapies, particularly chemotherapy regimens. To better understand the optimal use of PET-CT in radiation therapy planning and the role of PET-CT in assessing response to therapy, we invited experts from various disciplines to participate in focus group meetings that took place in 2009 and 2010. The Symposia focused on the use of PET-CT imaging in radiation therapy planning (2009) and the use of PET-CT in therapy response assessment (2010). This article will summarize areas of consensus reached by the group regarding many of the discussion topics. The consensus summaries covered in this article are meant to provide direction for future discussions on how to improve the application of this hybrid modality to optimize patient care.

Predicting pathological response to neoadjuvant chemotherapy in breast cancer with quantitative 1H MR spectroscopy using the external standard method

PURPOSE

To assess the efficacy of quantitative (1)H MR spectroscopy (MRS) using the external standard method to predict the pathological response to neoadjuvant chemotherapy with an anthracycline-based regimen in breast cancer patients.

MATERIALS AND METHODS

Sixteen patients with breast cancer were included. Tumor response to chemotherapy was evaluated after the second cycle using MRI and MRS. Final histopathology following surgery after four cycles of chemotherapy served as reference.

RESULTS

The average normalized choline (Cho) signal was 1.2 (range, 0.40 to 2.8). There were no significant differences in the baseline tumor size and normalized Cho signals between the pathological responders (n = 8) and nonresponders (n = 8). The reduction rates of the normalized Cho signal were statistically significantly different between the pathological responders and nonresponders (P = 0.004), whereas the reduction rates of the lesion size were not significantly different between the two groups. When 40-50% of the reduction rates of the normalized Cho was chosen as the cutoff value, the positive and negative predictive values of MRS were 89% (8/9) and 100% (7/7), respectively.

CONCLUSION

The changes in Cho after the second cycle of chemotherapy as determined by quantitative MRS may be more sensitive than changes in the tumor size to predict the pathological response.

Current Status and Future Prospects of Proton MR Spectroscopy of the Breast with a 1.5T MR Unit

Proton MR spectroscopy of the mammary gland area is used to be considered in the realm of basic research, but as a result of the advances in MR techniques, it is now being performed in ordinary clinical practice. It is particularly noteworthy that useful clinical data are now being accumulated with 1.5T MR units, which are the standard units. We think that, at this point, it is very important to systematically review the techniques, clinical applications, and future prospects of proton MR spectroscopy. We have performed proton MR spectroscopy with a 1.5T MR unit in over 3000 cases at our hospital. In this paper, we will comment on the current status of proton MR spectroscopy of the breast, primarily in regard to differentiation between benign and malignant lesions and prediction of the efficacy of chemotherapy while describing the data obtained at our hospital.

[MRI evaluation of residual breast carcinoma after neoadjuvant chemotherapy]

PURPOSE

This study aims to evaluate the sensibility and specificity of MRI in the detection and size measuring of residual breast cancer in patients treated with neoadjuvant chemotherapy before surgery.

PATIENTS AND METHODS

This is a retrospective study of 32 women, who underwent breast MRI before and after neoadjuvant treatment. MRI has been confronted to surgical pathology results.

RESULTS

The sensibility of MRI to assess pathologic Complete Response (no invasive residual tumor) was excellent (100%) but the specificity was low (55,5%). There was no false negative case and four false positive cases (Two ductal carcinomas in situ and two scars-like fibrosis). When MRI outcomes were compared with the presence or absence of invasive or in situ residual carcinoma, only one false negative case was noticed (one "in situ" residual tumor). The correlation between tumor size measured by MRI and histopathology was low (r=0,32). Underestimations of tumor size were due to non-continuous tumor regression or invasive lobular carcinoma or association of invasive carcinoma and intra ductal breast cancer. Over estimations of tumor size were due to chemotherapy-induced changes.

CONCLUSION

MRI is a sensitive but poorly specific method to assess the pathological complete response after neoadjuvant chemotherapy. Estimation of tumor size and detection of isolated residual in situ carcinoma are fare. Therefore, surgical intervention remains necessary whatever the MRI outcomes.

Accuracy of ultrasonography and mammography in predicting pathologic response after neoadjuvant chemotherapy for breast cancer

BACKGROUND

Neoadjuvant chemotherapy reduces tumor size before surgery in women with breast cancer. The aim of this study was to assess the ability of mammography and ultrasound to predict residual tumor size following neoadjuvant chemotherapy.

METHODS

In a retrospective review of consecutive breast cancer patients treated with neoadjuvant chemotherapy, residual tumor size estimated by diagnostic imaging was compared with residual tumor size determined by surgical pathology.

RESULTS

One hundred ninety-two patients with 196 primary breast cancers were studied. Of 104 tumors evaluated by both imaging modalities, ultrasound was able to size 91.3%, and mammography was able to size only 51.9% (chi(2)P < .001). Ultrasound also was more accurate than mammography in estimating residual tumor size (62 of 104 [59.6%] vs 33 of 104 [31.7%], P < .001). There was little difference in the ability of mammography and ultrasound to predict pathologic complete response (receiver operating characteristic, 0.741 vs 0.784).

CONCLUSIONS

Breast ultrasound was more accurate than mammography in predicting residual tumor size following neoadjuvant chemotherapy. The likelihood of a complete pathologic response was 80% when both imaging modalities demonstrated no residual disease.

Preliminary study of early response to neoadjuvant chemotherapy after the first cycle in breast cancer: comparison of 1H magnetic resonance spectroscopy with diffusion magnetic resonance imaging

PURPOSE

The aim of this study was to assess the efficacy of single-voxel (1)H magnetic resonance spectroscopy (MRS) at 1.5 T to evaluate early responses to neoadjuvant chemotherapy after the first treatment in breast cancer patients and to compare it to measurements of apparent diffusion coefficient (ADC) values derived from diffusion-weighted magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Nine patients with breast cancer who were scheduled to receive neoadjuvant chemotherapy were recruited. MR examination after the first cycle was scheduled for a few days before the administration of the second dose.

RESULTS

Two patients were excluded from the study because their regimen was changed after the first cycle. MRS before chemotherapy demonstrated the presence of choline (Cho) at 3.22-3.23 ppm in six cases and at 3.27 ppm in one case. Diffusion-weighted MRI before chemotherapy demonstrated a localized high-signal lesion in all cases. The change of the integral value of Cho after the first cycle of chemotherapy showed a positive correlation with the change in lesion size (r = 0.91, P = 0.01), whereas no correlation was observed between the change of ADC values after the first cycle and the change in lesion size (r = 0.45, P = 0.32).

CONCLUSION

MRS after the first cycle may be more sensitive to diffusion-weighted MRI to predict the pathological response.

Production of hyperpolarized [1,4-13C2]malate from [1,4-13C2]fumarate is a marker of cell necrosis and treatment response in tumors

Dynamic nuclear polarization of (13)C-labeled cell substrates has been shown to massively increase their sensitivity to detection in NMR experiments. The sensitivity gain is sufficiently large that if these polarized molecules are injected intravenously, their spatial distribution and subsequent conversion into other cell metabolites can be imaged. We have used this method to image the conversion of fumarate to malate in a murine lymphoma tumor in vivo after i.v. injection of hyperpolarized [1,4-(13)C(2)]fumarate. In isolated lymphoma cells, the rate of labeled malate production was unaffected by coadministration of succinate, which competes with fumarate for transport into the cell. There was, however, a correlation with the percentage of cells that had lost plasma membrane integrity, suggesting that the production of labeled malate from fumarate is a sensitive marker of cellular necrosis. Twenty-four hours after treating implanted lymphoma tumors with etoposide, at which point there were significant levels of tumor cell necrosis, there was a 2.4-fold increase in hyperpolarized [1,4-(13)C(2)]malate production compared with the untreated tumors. Therefore, the formation of hyperpolarized (13)C-labeled malate from [1,4-(13)C(2)]fumarate appears to be a sensitive marker of tumor cell death in vivo and could be used to detect the early response of tumors to treatment. Given that fumarate is an endogenous molecule, this technique has the potential to be used clinically.

Imaging and cancer: a review

Multiple biomedical imaging techniques are used in all phases of cancer management. Imaging forms an essential part of cancer clinical protocols and is able to furnish morphological, structural, metabolic and functional information. Integration with other diagnostic tools such as in vitro tissue and fluids analysis assists in clinical decision-making. Hybrid imaging techniques are able to supply complementary information for improved staging and therapy planning. Image guided and targeted minimally invasive therapy has the promise to improve outcome and reduce collateral effects. Early detection of cancer through screening based on imaging is probably the major contributor to a reduction in mortality for certain cancers. Targeted imaging of receptors, gene therapy expression and cancer stem cells are research activities that will translate into clinical use in the next decade. Technological developments will increase imaging speed to match that of physiological processes. Targeted imaging and therapeutic agents will be developed in tandem through close collaboration between academia and biotechnology, information technology and pharmaceutical industries.