Shear wave elastography of breast cancer: Sensitivity according to histological type in a large cohort

Special Types of Breast Cancer: Clinical Behavior and Radiological Appearance

Breast cancer is a complex disease that includes entities with different characteristics, behaviors, and responses to treatment. Breast cancers are categorized into subgroups based on histological type and grade, and these subgroups affect clinical presentation and oncological outcomes. The subgroup of "special types" encompasses all those breast cancers with insufficient features to belong to the subgroup "invasive ductal carcinoma not otherwise specified". These cancers account for around 25% of all cases, some of them having a relatively good prognosis despite high histological grade. The purpose of this paper is to review and illustrate the radiological appearance of each special type, highlighting insights and pitfalls to guide breast radiologists in their routine work.

Clinical applications of shear wave dispersion imaging for breast lesions: a pictorial essay

Shear wave dispersion (SWD) imaging is a newly developed ultrasound technology designed to evaluate the dispersion slope of shear waves, which is related to tissue viscosity. This advanced imaging technique holds potential for distinguishing malignant lesions from benign lesions and normal breast tissue. The SWD slope, as determined by shear wave elastography (SWE), could offer crucial insights into the characterization of breast lesions. This article presents SWE and SWD images of both malignant and benign breast lesions, in addition to normal breast tissue.

Is There a Correlation between Multiparametric Assessment in Ultrasound and Intrinsic Subtype of Breast Cancer?

Molecular profile of breast cancer provides information about its biological activity, prognosis and treatment strategies. The purpose of our study was to investigate the correlation between ultrasound features and molecular subtypes of breast cancer. From June 2019 to December 2019, 86 patients (median age 57 years; range 32–88) with 102 breast cancer tumors were included in the study. The molecular subtypes were classified into five types: luminal A (LA), luminal B without HER2 overexpression (LB HER2−), luminal B with HER2 overexpression (LB HER2+), human epidermal growth factor receptor 2 positive (HER2+) and triple negative breast cancer (TNBC). Histopathological verification was obtained in core biopsy or/and post-surgery specimens in all cases. Univariate logistic regression analysis was performed to assess the association between the subtypes and ultrasound imaging features. Experienced radiologists assessed lesions according to the BIRADS-US lexicon. The ultrasound scans were performed with a Supersonic Aixplorer and Supersonix. Based on histopathological verification, the rates of LA, LB HER2−, LB HER2+, HER2+, and TNBC were 33, 17, 17, 16, 19, respectively. Both LB HER2+ and HER2+ subtypes presented higher incidence of calcification (OR = 3.125, p = 0.02, CI 0.0917–5.87) and HER2+ subtype presented a higher incidence of posterior enhancement (OR = 5.75, p = 0.03, CI 1.2257–32.8005), compared to other subtypes. The calcifications were less common in TNBC (OR = 0.176, p = 0.0041, CI 0.0469–0.5335) compared to other subtypes. There were no differences with regard to margin, shape, orientation, elasticity values and vascularity among five molecular subtypes. Our results suggest that there is a correlation between ultrasonographic features assessed according to BIRADS-US lexicon and BC subtypes with HER2 overexpression (both LB HER2+ and HER2+). It may be useful for identification of these aggressive subtypes of breast cancer.

Prediction of Invasive Breast Cancer Using Mass Characteristic Frequency and Elasticity in Correlation with Prognostic Histologic Features and Immunohistochemical Biomarkers

This purpose of this study is to correlate a new shear-wave elastography (SWE) parameter, mass characteristic frequency (fmass) and other elasticity measure with the prognostic histological factors and immunohistochemical (IHC) biomarkers for the evaluation of heterogeneous breast carcinomas. The new parameter, fmass, first introduced in this paper, is defined as the ratio of the averaged minimum shear wave speed taken spatially within regions of interest to the largest mass dimension. 264 biopsy-proven breast cancerous masses were included in this study. Mean (Emean), maximum (Emax), minimum (Emin) shear wave elasticity and standard deviation (Esd) of shear wave elasticity were found significantly correlated with tumor size, axillary lymph node (ALN) status, histological subtypes and IHC subtypes. The areas under the curve for the ALN prediction are 0.73 (95% confidence interval [CI]: 0.67-0.80) and 0.75 (95% CI: 0.69-0.81) for the combination of Emean with Breast Imaging Reporting and Data System (BI-RADS) score and Emax with BI-RADS score, respectively. fmass was significantly correlated with the presence of calcifications, ALN status, histological grade, the expressions of IHC biomarkers and IHC subtypes. To conclude, poor prognostic factors were associated with high shear wave elasticity values and low mass characteristic frequency value. Therefore, SWE provides valuable information that may help with prediction of breast cancer invasiveness.

The role of rare breast cancers in the false negative strain elastography results

PURPOSE

Elastography was primarily used as an adjunctive method along with ultrasonography in differentiation between benign from malignant lesions. Occasionally, overlaps can occur which are caused by some rare invasive breast cancers. Our aim is to analyze the role of rare breast cancers in false negative strain elastography results and to assess the relation among false negative results and tumor size, lesion distance to skin, and tumor grade.

METHODS

Patients with BI-RADS 5 category underwent strain elastography and core biopsy. All those with confirmed invasive breast cancer were included. For each rare breast cancer, four usual invasive breast cancer cases were taken as a control group. The cut-off value of strain ratio was considered as 2.3. The true positive and the false negative groups were compared in terms of histological type (rare carcinomas and the others) and the other parameters. Pearson Chi-square and Fisher's exact test were used for statistical analyses. P values < 0.05 were considered statistically significant.

RESULTS

One hundred-thirteen patients were defined as true positive (70.6%), and 47 patients were defined as false negative (29.4%). Strain ratio values of the rare breast cancers were significantly lower than those of the other breast cancers (p = 0.012). There was no statistically significant difference between the groups with respect to tumor size, distance to skin, and tumor grade (p > 0.05).

CONCLUSION

The rare breast cancers are an important cause of false negativity in elastographic evaluation of invasive breast cancers. The results should be interpreted in combination with grayscale US findings.

Radiologic Findings of a Rare Subtype of Invasive Breast Cancer with Poor Prognosis: Metaplastic Carcinoma of the Breast

BACKGROUND AND OBJECTIVES

The purpose of this study was to evaluate the mammographic, sonographic and MRI findings of metaplastic breast carcinoma.

METHODS

In this retrospective review study, we analyzed the medical files of 9600 patients who were treated for invasive breast cancers. Clinical information, histopathologic and radiologic findings of 65 patients were included in this study. All existing radiologic images and medical reports were reviewed retrospectively. Thirty-three patients had MG, 58 patients had US and 7 patients had MRI imaging results.

RESULTS

Mammographically, the most frequent presentations of MPBC were round shape, microlobulated margin and high density masses. Calcifications with or without masses were not a frequent finding. The most common sonographic findings were round shape, partially indistinct angular margin, hypoechoic and heterogeneous echo patterns and no posterior feature masses. All lesions were presented as masses rather than non-mass enhancements on magnetic resonance imaging. Features of masses had more malignant feature on MRI than other modalities in all 7 patients.

CONCLUSION

Metaplastic breast carcinoma is one of the rarest poorly differentiated invasive breast carcinomas. Interestingly, these aggressive tumors demonstrate benign or moderately malign features on imaging methods. This appearance of MPBC can cause it to be misdiagnosed as a benign breast lesion especially in young women. MPBC should be kept in mind in the differential diagnosis of large palpable breast masses. Therefore, follow-up at short intervals and/or multimodality imaging studies which include breast MRI are important for the diagnosis of MPBC.

Mucinous versus medullary breast carcinoma: mammography, ultrasound, and MRI findings

Mucinous and medullary breast cancers (BCs) have different histological substrates that manifest as different imaging features on mammography, ultrasound, and MRI. The aim of the present review is to demonstrate the differences between these two rare BC subtypes and to describe the microscopic features, review the imaging methods for detection of both cancer subtypes, illustrate the imaging findings and present useful pearls and pitfalls. Out of a total of 30 patients with mucinous BC and nine with medullary BC, we have selected typical and also unusual imaging features that best represent these cancers. The patients underwent a mammography and breast ultrasound followed by magnetic resonance imaging. We briefly exhibit histological characteristics for a better understanding of the imaging aspects.

A nomogram constructed using intraoperative ex vivo shear-wave elastography precisely predicts metastasis of sentinel lymph nodes in breast cancer

OBJECTIVE

To develop a nomogram and validate its use for the intraoperative evaluation of nodal metastasis using shear-wave elastography (SWE) elasticity values and nodal size METHODS: We constructed a nomogram to predict metastasis using ex vivo SWE values and ultrasound features of 228 axillary LNs from fifty-five patients. We validated its use in an independent cohort comprising 80 patients. In the validation cohort, a total of 217 sentinel LNs were included.

RESULTS

We developed the nomogram using the nodal size and elasticity values of the development cohort to predict LN metastasis; the area under the curve (AUC) was 0.856 (95% confidence interval (CI), 0.783-0.929). In the validation cohort, 15 (7%) LNs were metastatic, and 202 (93%) were non-metastatic. The mean stiffness (23.54 and 10.41 kPa, p = 0.005) and elasticity ratio (3.24 and 1.49, p = 0.028) were significantly higher in the metastatic LNs than those in the non-metastatic LNs. However, the mean size of the metastatic LNs was not significantly larger than that of the non-metastatic LNs (8.70 mm vs 7.20 mm, respectively; p = 0.123). The AUC was 0.791 (95% CI, 0.668-0.915) in the validation cohort, and the calibration plots of the nomogram showed good agreement.

CONCLUSIONS

We developed a well-validated nomogram to predict LN metastasis. This nomogram, mainly based on ex vivo SWE values, can help evaluate nodal metastasis during surgery.

KEY POINTS

• A nomogram was developed based on axillary LN size and ex vivo SWE values such as mean stiffness and elasticity ratio to easily predict axillary LN metastasis during breast cancer surgery. • The constructed nomogram presented high predictive performance of sentinel LN metastasis with an independent cohort. • This nomogram can reduce unnecessary intraoperative frozen section which increases the surgical time and costs in breast cancer patients.

Imaging features of pure mucinous breast carcinoma: correlation with extracellular mucus content

AIM

To analyse the correlation between imaging features using multiple techniques and extracellular mucus content in pure mucinous breast carcinoma (PMBC).

MATERIALS AND METHODS

A retrospective review of available images from 25 patients with 25 PMBC tumours was conducted, with ultrasonography (US), ultrasonic elastography (USE), mammography, and breast-specific gamma imaging (BSGI) available for 25, 15, 11, and eight patients, respectively. Microscopic slides from each tumour were evaluated for extracellular mucus content. The correlation between imaging features and mucus content was analysed using linear-by-linear association chi-square tests or Spearman's rank correlation analyses.

RESULTS

On US images, a significant correlation was found between mucus content and echo pattern (p=0.042) and colour Doppler blood flow (p=0.032), with a trend that the lower mucus content present in tumours, the more likely they were detected with isoechoic echo and high blood flow. On USE images, a moderate negative correlation (r=-0.60, p=0.029) was observed between mucus content and tumour stiffness. On BSGI images, a strong negative correlation (r=-0.92, p=0.001) was shown between mucus content and lesion to non-lesion ratio (L/N) values of radioactivity counts. No significant correlation was found between mucus content and mammography imaging features (all p>0.05).

CONCLUSION

Imaging features at US, USE, and BSGI correlated with extracellular mucus content in PMBC tumours, among which the L/N value using BSGI imaging is the most relevant feature.

Histopathology and elastography discordance in evaluation of breast lesions with acoustic radiation force impulse elastography

Purpose

It is known that, besides its benefits, ultrasound (US) elastography may show discordance findings, leading to biopsy, so this technique has some limitations. The purpose of the present study was to compare histopathological results and shear wave velocity (SWV) values in patients, to reveal discordance findings, and to investigate its statistical significance in making the decision for biopsy with SWV values.

Material and methods

A total of 190 patients presenting with breast lesions were included in the study. The mean age of the patients was 39.87 ± 13.56 years. All morphological features of lesions were evaluated by B-mode US. The mean SWV values were measured using the region of interest (ROI) through all lesions with ARFI elastography. An ultrasound-guided Tru-Cut needle biopsy was performed, and histopathologic data were obtained.

Results

The SWV values of false positive benign lesions, such as: granulomatous mastitis, sclerosing adenosis, chronic inflammation, fat necrosis, fibrotic breast tissue, and scar tissue, were as high as the SWV values of malignant lesions. Sensitivity was found as 91.6% and specificity as 40.9% for SWV values in ARFI US.

Conclusions

Our results showed that breast lesions showed false positivity (59.1%) and false negativity (8.3%) in ARFI US. Elastography is useful and sensitive in the evaluation of breast lesions, but some benign lesions may mimic malignant lesions; thus, this information should not be underestimated in biopsy decision-making for elastography users.

Tumor stiffness measured by quantitative and qualitative shear wave elastography of breast cancer

OBJECTIVE

To correlate clinicoradiologic and pathological features of breast cancer with quantitative and qualitative shear wave elastographic parameters.

METHODS

82 breast cancers in 75 patients examined by B-mode ultrasound and shear wave elastography (SWE) were included. SWE parameters including quantitative factors [maximum elasticity (E_max), mean elasticity (E_mean), elasticity ratio (E_ratio) and standard deviation (SD)] and qualitative factor (color pattern) were correlated with clinicoradiologic and pathological features using univariate and multivariate linear regression analyses.

RESULTS

Presence of symptoms and larger tumor size on ultrasound were significantly associated with higher E_max, E_mean, E_ratio, and SD (all p < 0.05) on univariate analysis. Older age was significantly correlated with higher E_max and E_mean (p = 0.026, 0.018). Lymphovascular invasion and larger pathologic size were significantly associated with higher E_max (p = 0.036, 0.043) and SD (p < 0.001, 0.019). No immunohistochemical biomarkers were significantly correlated with SWE parameters. There was no significant correlation between color pattern and any variable. Multivariate logistic regression analysis showed that the symptom, tumor size on ultrasound and lymphovascular invasion were independent factors that influenced the SWE values.

CONCLUSION

Tumor stiffness as measured by SWE and B-mode ultrasound could help predict cancer prognosis. Advances in knowledge: Clinicoradiologic factors had correlation with quantitative and qualitative SWE parameters. Using SWE parameters and B-mode ultrasound, we can predict breast cancer prognosis.

Breast lesions diagnosed by ultrasound-guided core needle biopsy: Can shearwave elastography predict histologic upgrade after surgery or vaccuum assisted excision?

PURPOSE

To compare breast stiffness based on shear-wave elastography (SWE) quantitative parameters with histopathologic results diagnosed by ultrasound (US)-guided core needle biopsy (CNB) to determine their association with upgrade rates after surgical excision or follow-up US as well as clinico-radiologic differences between upgrade and non-upgrade groups.

MATERIALS AND METHODS

This retrospective study enrolled 225 breast lesions from 225 patients, including 159 benign lesions, 38 high risk lesions and 28 ductal carcinoma in situ (DCIS) diagnosed by US-guided CNB. Quantitative SWE parameters of breast lesions were measured before CNB and compared according to histopathologic results (benign, high risk and DCIS) and lesion size (<20 mm and >20 mm). Clinico-radiologic and pathologic factors were compared between upgrade and non-upgrade groups after surgical excision or follow-up US.

RESULTS

After surgical excision or follow-up US after more than one year, 29 lesions were upgraded for an overall upgrade rate of 12.9% (29/225). There were significant differences between upgrade and non-upgrade groups in age, mammographic category, US category, and sonographic features, including shape, margin, orientation, imaging-histologic correlation and E ratio. Patients with lesion upgrade were much older and had lesions characterized by significantly higher mammographic and US category (>4b), irregular shape, nonparallel orientation, microlobulated or angular margin, calcification in a mass, larger size on US (>20 mm) and greater imaging-histologic discordance. Multivariate analysis showed only mean and minimum elasticity values displayed a borderline association with histologic underestimation.

CONCLUSION

Upgrade of breast lesions diagnosed by US-guided CNB can be predicted using E_mean and E_min among quantitative SWE parameters.

Three-dimensional versus two-dimensional shear-wave elastography: Associations of mean elasticity values with prognostic factors and tumor subtypes of breast cancer

PURPOSE

To explore associations between prognostic factors and subtypes of invasive breast cancer (IBC) and elasticity values using three-dimensional (3D) and two-dimensional (2D) shear-wave elastography (SWE).

MATERIALS AND METHODS

Mean elasticity values (kPa) of 121 IBCs were measured using both 3D and 2D SWE. Associations between these values and prognostic factors and subtypes were analyzed using linear regression model.

RESULTS

In both 3D and 2D SWE, larger size and presence of lymphovascular invasion were independent factors influencing higher mean elasticity on multivariate analyses (all p values<0.05).

CONCLUSIONS

Using either 3D or 2D SWE, higher mean elasticity values are associated with poor prognostic factors of IBC.

Diagnostic Value of ARFI (Acoustic Radiation Force Impulse) in Differentiating Benign From Malignant Breast Lesions

RATIONALE AND OBJECTIVES

The aim of this study was to correlate acoustic radiation force impulse (ARFI) imaging velocities with the pathology results and to evaluate the ability of ARFI in distinguishing benign from malignant breast lesions.

MATERIALS AND METHODS

B-mode ultrasonography (US) and ARFI were performed in patients with previously diagnosed and selected breast lesions for biopsy. Shear wave velocity (SWV) was measured inside lesions and in the surrounding parenchyma (m/s). SWV measurements as well as lesion-to-parenchyma ratio (LPR) were compared between benign and malignant lesions, and receiver operating characteristic (ROC) curves were plotted. Two blinded readers independently classified the lesions as benign or malignant in two separate reading sessions, one using B-mode US alone and the other using a combined set of B-mode US and ARFI.

RESULTS

Eighty-one patients with a total of 92 breast lesions were included (57 benign and 35 malignant nodules). SWV inside lesions were significantly higher for malignant neoplasms compared to benign (medians of 9.1 m/s vs 3.5 m/s; P < 0.001). LPR was also significantly higher for malignant lesions (3.0 vs 1.4; P < 0.001). Parenchyma SWV had no differences between groups (P = 0.071). ROC curves showed a significant discriminative power for lesion SWV (area under the curve [AUC] = 0.980; P < 0.001) and LPR (AUC = 0.954; P < 0.001). For lesion measures, a cutoff of 6.593 m/s was obtained, with sensitivity and specificity of 88.6% and 96.5%, respectively.

CONCLUSIONS

ARFI provides quantitative elasticity measurements, adding valuable complementary information to B-mode ultrasound, that can potentially help in breast lesion characterization and assisting the decision for biopsy recommendations.

Imaging biobanks in oncology: European perspective

Imaging biobanks as defined by the European Society of Radiology are "organised databases of medical images, and associated imaging biomarkers (radiology and beyond), shared among multiple researchers, linked to other biorepositories". Oncologic imaging biobanks are developed mainly for research purposes. These biobanks may be developed in academic centers, or with the support of industry. The awareness of their importance is gradually increasing in the oncologic community. It is difficult to determine which oncologic domain of research will benefit from the implementation of imaging biobanks. One of the most foreseeable applications could be the correlation between imaging phenotype and genotype. For this reason imaging biobanks should be embedded in wider biobanks networks, as for example the European-based Biobanking and BioMolecular resources Research Infrastructure.

Correlating Tumor Stiffness with Immunohistochemical Subtypes of Breast Cancers: Prognostic Value of Comb-Push Ultrasound Shear Elastography for Differentiating Luminal Subtypes

PURPOSE

The purpose of our study is to correlate quantitatively measured tumor stiffness with immunohistochemical (IHC) subtypes of breast cancer. Additionally, the influence of prognostic histologic features (cancer grade, size, lymph node status, and histological type and grade) to the tumor elasticity and IHC profile relationship will be investigated.

METHODS

Under an institutional review board (IRB) approved protocol, B-mode ultrasound (US) and comb-push ultrasound shear elastography (CUSE) were performed on 157 female patients with suspicious breast lesions. Out of 157 patients 83 breast cancer patients confirmed by pathology were included in this study. The association between CUSE mean stiffness values and the aforementioned prognostic features of the breast cancer tumors were investigated.

RESULTS

Our results demonstrate that the most statistically significant difference (p = 0.0074) with mean elasticity is tumor size. When considering large tumors (size ≥ 8mm), thus minimizing the statistical significance of tumor size, a significant difference (p< 0.05) with mean elasticity is obtained between luminal A of histological grade I and luminal B (Ki-67 > 20%) subtypes.

CONCLUSION

Tumor size is an independent factor influencing mean elasticity. The Ki-67 proliferation index and histological grade were dependent factors influencing mean elasticity for the differentiation between luminal subtypes. Future studies on a larger group of patients may broaden the clinical significance of these findings.

Progress in the clinical detection of heterogeneity in breast cancer

Breast cancer is currently the most common form of cancer and the second‐leading cause of death from cancer in women. Though considerable progress has been made in the treatment of breast cancer, the heterogeneity of tumors (both inter‐ and intratumor) remains a considerable diagnostic and prognostic challenge. From clinical observation to genetic mutations, the history of understanding the heterogeneity of breast cancer is lengthy and detailed. Effectively detecting heterogeneity in breast cancer is important during treatment. Various methods of depicting this heterogeneity are now available and include genetic, pathologic, and imaging analysis. These methods allow characterization of the heterogeneity of breast cancer on a genetic level, providing greater insight during the process of establishing an effective therapeutic plan. This study reviews how the understanding of tumor heterogeneity in breast cancer evolved, and further summarizes recent advances in the detection and monitoring of this heterogeneity in patients with breast cancer.