Is "prepectoral edema" a morphologic sign for malignant breast tumors?

Can peritumoral edema evaluated by Magnetic Resonance Imaging before neoadjuvant chemotherapy predict complete pathological response in breast cancer?

BACKGROUND AND AIMS

The complete pathological response (pCR) following neoadjuvant chemotherapy (NAC) in breast cancer is essential for the accurate prediction of prognosis. We aimed to evaluate the efficacy of the presence and type of peritumoral edema detected by magnetic resonance imaging (MRI) in predicting pCR to NAC in breast cancer patients.

METHODS AND RESULTS

One hundred five patients with the diagnosis of invasive carcinoma were evaluated by MRI before NAC. Edema was evaluated in fat-suppressed T2-weighted images. The patients were categorized into three groups: patients with no peritumoral edema, patients with peritumoral edema, and patients demonstrating subcutaneous edema. The cases were categorized as being pCR and non-pCR. Molecular subtypes, lymphovascular invasion (LVI), tumor size, and apparent diffusion coefficient (ADC) were evaluated. A positive relationship was found between the presence of edema and tumor size. Subcutaneous edema was found to be statistically higher in non-pCR patients. While the number of pCR patients with subcutaneous edema was 17 (30.4%), the number of non-pCR patients with subcutaneous edema was 26 (53.1%) (p  =  0.018). LVI was found to be statistically higher in patients with edema. The number of edema-negative and LVI (+) patients was 4 (15.4%), while the number of edema-positive and LVI (+) patients was 28 (35.4%) (p = 0.042). Intratumoral and peritumoral ADC values were significantly higher in tumors with edema.

CONCLUSION

The presence of subcutaneous edema and LVI may be utilized for the prediction of pCR outcomes in breast cancer patients scheduled for NAC treatment.

The potential of predictive and prognostic breast MRI (P2-bMRI)

Magnetic resonance imaging (MRI) is an important part of breast cancer diagnosis and multimodal workup. It provides unsurpassed soft tissue contrast to analyse the underlying pathophysiology, and it is adopted for a variety of clinical indications. Predictive and prognostic breast MRI (P2-bMRI) is an emerging application next to these indications. The general objective of P2-bMRI is to provide predictive and/or prognostic biomarkers in order to support personalisation of breast cancer treatment. We believe P2-bMRI has a great clinical potential, thanks to the in vivo examination of the whole tumour and of the surrounding tissue, establishing a link between pathophysiology and response to therapy (prediction) as well as patient outcome (prognostication). The tools used for P2-bMRI cover a wide spectrum: standard and advanced multiparametric pulse sequences; structured reporting criteria (for instance BI-RADS descriptors); artificial intelligence methods, including machine learning (with emphasis on radiomics data analysis); and deep learning that have shown compelling potential for this purpose. P2-bMRI reuses the imaging data of examinations performed in the current practice. Accordingly, P2-bMRI could optimise clinical workflow, enabling cost savings and ultimately improving personalisation of treatment. This review introduces the concept of P2-bMRI, focusing on the clinical application of P2-bMRI by using semantic criteria.

The Breast Edema Enigma: Features, Diagnosis, Treatment, and Recommendations

Breast edema most commonly occurs after breast cancer treatment involving breast-conserving therapy, although it may have a variety of other causes. As compared to research on breast cancer treatment-related lymphedema, breast edema and its objective measurement and diagnosis is far behind. Consequences of this disparity contribute to uncertainty and variability in its diagnosis, its treatment, and even the characterization of its incidence and morbidity. Moreover, consensus on a standardized definition, objective diagnostic method, and treatment techniques for breast edema has not yet been reached, making it difficult to provide appropriate guidelines with respect to its management. Given the recent rise in breast edema incidence as an outcome of the increasing use of breast-conserving therapy, this timely review examines the current state of breast edema assessment and makes a case for standardization in part via quantitative methods to diagnose and track breast edema.

Evaluation of Breast Edema Findings at T2-weighted Breast MRI Is Useful for Diagnosing Occult Inflammatory Breast Cancer and Can Predict Prognosis after Neoadjuvant Chemotherapy

Background Prediction of occult inflammatory breast cancer (IBC) and breast cancer prognosis based on breast edema findings on T2-weighted MRI scans, even for patients without clinical signs of IBC, would be useful in both pretreatment planning and prognosis and may elucidate the underlying biologic mechanisms. Purpose To evaluate whether classification of breast edema on T2-weighted MRI scans is useful for predicting the prognosis of patients with breast cancer treated with neoadjuvant chemotherapy (NAC). Materials and Methods A retrospective evaluation was performed of women with breast cancer who underwent breast MRI and were treated with NAC between January 2011 and December 2018. Breast edema on T2-weighted images was scored on a scale of 1 to 4, as follows: (a) breast edema score (BES) 1, no edema; (b) BES 2, peritumoral edema; (c) BES 3, prepectoral edema; and (d) BES 4, subcutaneous edema (suspicious for occult IBC). Clinically evident IBC was classified as BES 5 (without MRI). The log-rank test was performed, and hazard ratios were calculated using the Cox hazard model to evaluate associations between BES and progression-free survival (PFS) and overall survival (OS). PFS rate at 100 months after initiation of therapy was also evaluated. Results Of 408 patients (median age, 53 years; range, 28-80 years), 65 (16%) had a recurrence and 27 (7%) died. The log-rank test revealed differences in PFS for BES 4 versus 1, BES 5 versus 1, BES 5 versus 2, and BES 5 versus 3 (adjusted P < .05 for all). PFS rates for BES 1-5 were 0.92, 0.85, 0.80, 0.62, and 0.58, respectively, and the corresponding OS rates at 100 months were 0.98, 0.91, 0.92, 0.77, 0.86, respectively. Conclusion Classification of breast edema findings on T2-weighted MRI scans using a breast edema score was related to the prognosis of patients after neoadjuvant chemotherapy. © RSNA, 2021 Online supplemental material is available for this article.

Associations Between Magnetic Resonance Imaging Findings and Clincopathologic Factors in Triple-Negative Breast Cancer

OBJECTIVE

The aim of the study was to evaluate the magnetic resonance imaging findings associated with clinicopathologic factors in patients with triple-negative breast cancer.

METHODS

One hundred one patients with surgically confirmed triple-negative breast cancer who underwent preoperative breast magnetic resonance imaging with diffusion-weighted imaging (DWI) were included in this study. Presence of rim enhancement on contrast-enhanced T1-weighted imaging and hyperintense rim on DWI were visually assessed. Pathologic data about presence of recurrence and presence of lymphovascular invasion (LVI) were reviewed. Statistics for relative risk of recurrence carried out.

RESULTS

Of the 101, 13 cases (12.9%) were recurred after a median follow-up of 18.5 months. Rim enhancement was more frequently seen in the LVI-positive group (P = 0.046). Hyperintense rim on DWI and apparent diffusion coefficient values showed no significant relationship with clinical-pathologic factors.

CONCLUSIONS

Rim enhancement was significantly associated with positive LVI status in patients with triple-negative breast cancer. Our study suggests that rim enhancement may be useful to predict the prognosis.

A simple classification system (the Tree flowchart) for breast MRI can reduce the number of unnecessary biopsies in MRI-only lesions

OBJECTIVES

To assess whether using the Tree flowchart obviates unnecessary magnetic resonance imaging (MRI)-guided biopsies in breast lesions only visible on MRI.

METHODS

This retrospective IRB-approved study evaluated consecutive suspicious (BI-RADS 4) breast lesions only visible on MRI that were referred to our institution for MRI-guided biopsy. All lesions were evaluated according to the Tree flowchart for breast MRI by experienced readers. The Tree flowchart is a decision rule that assigns levels of suspicion to specific combinations of diagnostic criteria. Receiver operating characteristic (ROC) curve analysis was used to evaluate diagnostic accuracy. To assess reproducibility by kappa statistics, a second reader rated a subset of 82 patients.

RESULTS

There were 454 patients with 469 histopathologically verified lesions included (98 malignant, 371 benign lesions). The area under the curve (AUC) of the Tree flowchart was 0.873 (95% CI: 0.839-0.901). The inter-reader agreement was almost perfect (kappa: 0.944; 95% CI 0.889-0.998). ROC analysis revealed exclusively benign lesions if the Tree node was ≤2, potentially avoiding unnecessary biopsies in 103 cases (27.8%).

CONCLUSIONS

Using the Tree flowchart in breast lesions only visible on MRI, more than 25% of biopsies could be avoided without missing any breast cancer.

KEY POINTS

• The Tree flowchart may obviate >25% of unnecessary MRI-guided breast biopsies. • This decrease in MRI-guided biopsies does not cause any false-negative cases. • The Tree flowchart predicts 30.6% of malignancies with >98% specificity. • The Tree's high specificity aids in decision-making after benign biopsy results.

Characterization of tumor and adjacent peritumoral stroma in patients with breast cancer using high-resolution diffusion-weighted imaging: Correlation with pathologic biomarkers

PURPOSE

To assess whether ADC values of tumor and peritumoral stroma (PS) obtained on high-resolution diffusion-weighted imaging (HR DWI) were different according to pathologic biomarkers in patients with breast cancer.

METHODS

We retrospectively enrolled 96 patients (age range, 30-75 years; mean, 52 years) with breast cancer who underwent HR DWI at 3T MR scanner. We obtained the apparent diffusion coefficient (ADC) and ADC range of tumor and PS by drawing the region of interest (ROI) of entire tumor. We assessed histopathological features of tumors. ADC values of tumor and PS were compared according to pathologic biomarkers using student t-test and Mann-Whitney U test.

RESULTS

Mean ADC of tumor boundary was significantly higher in ER-negative tumors than in ER-positive tumors (P=0.005). The ADC ranges of tumor boundary and proximal PS were significantly higher in tumors with high nuclear grade, negative ER, positive HER2, positive Ki67, and lymph node metastasis than those with low nuclear grade, positive ER, negative HER2, negative Ki67, and without lymph node metastasis (P<0.05 for all). ADC range of tumor boundary and proximal PS was significantly lower in low risk tumor than in the others (P=0.004 and 0.002). Mean ADC of whole tumor was significantly higher in low-risk tumor than in non-low-risk tumor (P=0.030).

CONCLUSION

On HR DWI, ADC ranges of tumor boundary and adjacent proximal PS were significantly lower in low-risk tumor than in non-low-risk tumors.