Breast magnetic resonance imaging for estimation of the tumour extent in patients with pure ductal carcinoma in situ: Comparison between full diagnostic and abbreviated protocols

Update on Management of Ductal Carcinoma in Situ

Ductal carcinoma in situ (DCIS) represents 18% to 25% of all diagnosed breast cancers, and is a noninvasive, nonobligate precursor lesion to invasive cancer. The diagnosis of DCIS represents a wide range of disease, including lesions with both low and high risk of progression to invasive cancer and recurrence. Over the past decade, research on the topic of DCIS has focused on the possibility of tailoring treatment for patients according to their risk for progression and recurrence, which is based on clinicopathologic, biomolecular and genetic factors. These efforts are ongoing, with recently completed and continuing clinical trials spanning the continuum of cancer care. We conducted a review to identify recent advances on the topic of diagnosis, risk stratification and management of DCIS. While novel imaging techniques have increased the rate of DCIS diagnosis, questions persist regarding the optimal management of lesions that would not be identified with conventional methods. Additionally, among trials investigating the potential for omission of surgery and use of active surveillance, 2 trials have completed accrual and 2 clinical trials are continuing to enroll patients. Identification of novel genetic patterns is expanding our potential for risk stratification and aiding our ability to de-escalate radiation and systemic therapies for DCIS. These advances provide hope for tailoring of DCIS treatment in the near future.

Abbreviated Breast MRI: State of the Art

Abbreviated MRI is an umbrella term, defined as a focused MRI examination tailored to answer a single specific clinical question. For abbreviated breast MRI, this question is: "Is there evidence of breast cancer?" Abbreviated MRI of the breast makes maximum use of the fact that the kinetics of breast cancers and of benign tissue differ most in the very early postcontrast phase; therefore, abbreviated breast MRI focuses on this period. The different published approaches to abbreviated MRI include the following three subtypes: (a) short protocols, consisting of a precontrast and either a single postcontrast acquisition (first postcontrast subtracted [FAST]) or a time-resolved series of postcontrast acquisitions with lower spatial resolution (ultrafast [UF]), obtained during the early postcontrast phase immediately after contrast agent injection; (b) abridged protocols, consisting of FAST or UF acquisitions plus selected additional pulse sequences; and (c) noncontrast protocols, where diffusion-weighted imaging replaces the contrast information. Abbreviated MRI was proposed to increase tolerability of and access to breast MRI as a screening tool. But its widening application now includes follow-up after breast cancer and even diagnostic assessment. This review defines the three subtypes of abbreviated MRI, highlighting the differences between the protocols and their clinical implications and summarizing the respective evidence on diagnostic accuracy and clinical utility.

Imaging of breast cancer-beyond the basics

Imaging of breast cancer is the backbone of breast cancer screening, diagnosis, preoperative/treatment assessment and follow-up. The main modalities are mammography, ultrasound and magnetic resonance imaging, each with its own advantages and disadvantages. New emerging technologies have also enabled each modality to improve on their weaknesses. Imaging-guided biopsies have allowed for accurate diagnosis of breast cancer, with low complication rates. The purpose of this article is to review the common modalities for breast cancer imaging in current practice with emphasis on the strengths and potential weaknesses, discuss the selection of the best imaging modality for the specific clinical question or patient population, and explore new technologies / future directions of breast cancer imaging.

The efficacy of abbreviated breast MRI protocols using 1.5 T MRI in the preoperative staging of newly diagnosed breast cancers

PURPOSE

To determine the efficacy of abbreviated breast magnetic resonance imaging (MRI) protocols using 1.5 T MRI in the preoperative staging of newly diagnosed breast cancers.

METHODS

Eighty patients who underwent 1.5 T MRI between August 2014 and January 2018 for the preoperative staging of breast cancer were evaluated retrospectively. Three separate abbreviated breast MRI protocols (AP) were created from a full protocol, and the images were evaluated independently by two radiologists. AP1 included axial fat-saturated T2 weighted and diffusion-weighted (DW) images, while subtracted axial fat-saturated T1 weighted images were obtained 2 min after contrast administration in AP2. Finally, AP2 and DW images were evaluated in AP3. Lesion location, number, and size, and presence of axillary lymphadenopathy were evaluated in each protocol. Pathological data (lesion quadrant, lesion size, and presence of axillary metastases) from the 80 patients were compared with the abbreviated protocols and full diagnostic protocol.

RESULTS

The best correlation with the full protocol for detecting the lesion quadrant, number of lesions, and presence of axillary lymphadenopathy was achieved with AP3 for both readers (κ = 0.954, 0.954 for the lesion quadrant, κ = 0.971, 0.910 for the number of lesions, and κ = 0.973, 0.865 for the axillary lymphadenopathy). The evaluation time in all abbreviated protocols was shorter than for the full protocol (p < 0.05). Comparing the abbreviated protocols with pathological data for both readers, the best correlation for detecting the lesion quadrant, number of lesions, and presence of axillary lymphadenopathy was achieved with AP3 (κ = 0.939, 0.954 for the lesion quadrant, κ = 0.941, 0.879 for the number of lesions, and κ = 0.842, 0.740 for axillary lymphadenopathy, respectively).

CONCLUSION

Abbreviated breast MRI protocols can provide sufficient diagnostic accuracy in the preoperative staging of breast cancer, with shorter imaging and evaluation times.

The accuracy of magnetic resonance imaging in predicting the size of pure ductal carcinoma in situ: a systematic review and meta-analysis

Ductal carcinoma in situ (DCIS) is a putative precursor of invasive breast cancer and MRI is considered the most sensitive imaging technique for its detection. This study aims to evaluate the accuracy of MRI measuring the pure DCIS size, against pathology, to better understand the role of MRI in the management of this intraductal neoplasm.Potentially eligible studies in MEDLINE, Embase and Google Scholar, up to January 2021 were considered, and a systematic review and meta-analysis according to the published protocol (Prospero-CRD42021232228) was performed. Outcomes of mean differences and accuracy rates were analysed using IBM^® SPSS^® v26 and random-effect models in platform R v3.3.Twenty-two cross-sectional studies were selected and 15 proceeded to meta-analysis. MRI accurately predicted 55% of the tumours' sizes and, according to Bland-Altman plots, concordance between MRI and pathology was greater for smaller tumours. In the meta-analysis, difference of the means between MRI and pathology was 3.85 mm (CI 95% [-0.92;8.60]) with considerable heterogeneity (I2 = 96.7%). Subgroup analysis showed similar results for sizes between different MRI fields, temporal resolution, slice thickness and acquisition times, but lower heterogeneity in studies using 3-T MRI (I2 = 57.2%). Results were concordant with low risk of bias studies (2.46, CI 95% [0.57-4.36]), without heterogeneity (I2 = 0%).Therefore, MRI is shown to be an accurate method in pure DCIS size assessment. Once the best MRI protocol is established, evaluation of the impact of pure DCIS size in predicting treatment outcomes will contribute to clarifying current issues related to intraductal breast carcinoma.

Abbreviated and Standard Breast MRI in Neoadjuvant Chemotherapy Response Evaluation: A Comparative Study

OBJECTIVES

To investigate the efficacy of abbreviated breast magnetic resonance imaging (MRI) in neoadjuvant chemotherapy (NAC) response evaluation.

METHODS

MR images of 50 locally advanced breast cancer patients who underwent standard protocol (SP) breast MRI before and after NAC, were re-evaluated retrospectively. Abbreviated protocol (AP) was obtained by extracting images from SP and then evaluating them in a separate session. Protocols were compared with the histological findings after surgery as the reference standard.

RESULTS

A statistically significant difference was found between two protocols in response evaluation by the McNemar test (p=0.018). But, the Kappa value was 0.62 (p<0.001) which indicates substantial agreement. No statistically significant differences were found between the two protocols (AP and SP) and pathological results in the McNemar test (p=0.12, p=0.60, respectively). Kappa values were 0.48 (p<0.001), 0.60 (p<0.001), respectively which indicates moderate agreement for both protocols with higher values by SP evaluation. The residual maximum median diameters were smaller than the pathology, with both protocols (p<0.001).

CONCLUSION

Although statistical difference, there was a substantial correlation between the two protocols in response evaluation. Both protocols were moderately correlated with pathological results with slightly higher in SP. However, the residual maximum median diameters were smaller than the pathology, with both protocols. These results may limit the use of AP in evaluating the local extent of the tumor, especially in patients who will undergo breast-conserving surgery.

Background Parenchymal Enhancement on Breast MRI: Assessment and Clinical Implications

Purpose of Review

To present recent literature regarding the assessment and clinical implications of background parenchymal enhancement on breast MRI.

Recent Findings

The qualitative assessment of BPE remains variable within the literature, as well as in clinical practice. Several different quantitative approaches have been investigated in recent years, most commonly region of interest-based and segmentation-based assessments. However, quantitative assessment has not become standard in clinical practice to date. Numerous studies have demonstrated a clear association between higher BPE and future breast cancer risk. While higher BPE does not appear to significantly impact cancer detection, it may result in a higher abnormal interpretation rate. BPE is also likely a marker of pathologic complete response after neoadjuvant chemotherapy, with decreases in BPE during and after neoadjuvant chemotherapy correlated with pCR. In contrast, pre-treatment BPE does not appear to be predictive of pCR. The association between BPE and prognosis is less clear, with heterogeneous results in the literature.

Summary

Assessment of BPE continues to evolve, with heterogeneity in approaches to both qualitative and quantitative assessment. The level of BPE has important clinical implications, with associations with future breast cancer risk and treatment response. BPE may also be an imaging marker of prognosis, but future research is needed on this topic.

Abbreviated magnetic resonance imaging in breast cancer: A systematic review of literature

BACKGROUND

: magnetic resonance imaging (MRI) has been increasingly used to study breast cancer for screening high-risk cases, pre-operative staging, and problem-solving because of its high sensitivity. However, its cost-effectiveness is still debated. Thus, the concept of abbreviated MRI (ABB-MRI) protocols was proposed as a possible solution for reducing MRI costs.

PURPOSE

: to investigate the role of the abbreviated MRI protocols in detecting and staging breast cancer.

METHODS

: a systematic search of the literature was carried out in the bibliographic databases: Scopus, PubMed, Medline, and Science Direct.

RESULTS

: forty-one articles were included, which described results of the assessment of fifty-three abbreviated protocols for screening, staging, recurrence assessing, and problem-solving or clarification.

CONCLUSIONS

: the use of ABB-MRI protocols allows reducing the acquisition and reading times, maintaining a high concordance with the final interpretation, in comparison to a complete protocol. However, larger prospective and multicentre trials are necessary to validate the performance in specific clinical environments.