The Role of Magnetic Resonance Imaging in the Preoperative Staging and Treatment of Invasive Lobular Carcinoma

INTRODUCTION

Invasive lobular carcinoma (ILC) is known for its diffuse growth pattern and its associated challenges in diagnosing. Magnetic resonance imaging (MRI) is the most accurate imaging modality and might aid in improving preoperative staging compared to full field digital mammography (FFDM) and ultrasound (US), however current literature is inconsistent. The aim of this paper is to evaluate the accuracy of MRI staging compared to FFDM/US and pathology results.

METHODS

In this single-centre retrospective study, all patients diagnosed with ILC between 2014 and 2019 who underwent preoperative MRI were included. Specific parameters studied were: (1) the need for second-look targeted biopsies, (2) detection of new tumors (ie, contralateral or multifocal), (3) changes in cTNM-classification, and (4) impact on final treatment plan. Bland-Altman plots were used to compare the tumor sizes measured on MRI and FFDM/US with actual pathological tumor sizes.

RESULTS

Ninety-nine patients were included. After performing preoperative MRI, 9 (9.1%) multifocal tumors were diagnosed after additional biopsies. Contralateral tumors were detected twice (2.0%) and cN classification was upgraded in 7 cases (7.1%). Surgical treatment or neoadjuvant treatment plans were changed in 16 patients (16.1%). Compared to histopathological results, FFDM/US underestimated tumor size with a mean of 0.4 cm (Limit of agreement (LoA): -2.8 cm to 2.0 cm) whereas MRI overestimated tumor size with a mean of 0.6 cm (LoA: -1.9 cm to 3.0 cm).

CONCLUSIONS

In our study, mean differences in tumor size measurements using FFDM/US and MRI were comparable, with similar random errors. MRI correctly diagnosed multifocal and contralateral tumors more often and provided a better cN staging.

Invasive Lobular Carcinoma: A Review of Imaging Modalities with Special Focus on Pathology Concordance

Invasive lobular cancer (ILC) is the second most common type of breast cancer. It is characterized by a unique growth pattern making it difficult to detect on conventional breast imaging. ILC can be multicentric, multifocal, and bilateral, with a high likelihood of incomplete excision after breast-conserving surgery. We reviewed the conventional as well as newly emerging imaging modalities for detecting and determining the extent of ILC- and compared the main advantages of MRI vs. contrast-enhanced mammogram (CEM). Our review of the literature finds that MRI and CEM clearly surpass conventional breast imaging in terms of sensitivity, specificity, ipsilateral and contralateral cancer detection, concordance, and estimation of tumor size for ILC. Both MRI and CEM have each been shown to enhance surgical outcomes in patients with newly diagnosed ILC that had one of these imaging modalities added to their preoperative workup.

Impact of Preoperative Magnetic Resonance Imaging on Surgical Outcomes in Women with Invasive Breast Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Currently, whether magnetic resonance imaging (MRI) should be routinely applied to patients with breast cancer before surgery remains controversial. A pooled analysis of the association between preoperative MRI and surgical outcomes in female patients with newly diagnosed invasive breast cancer was conducted to provide evidence-based medicine for clinical practice.

METHODS

Three independent researchers searched the following databases: PubMed, Medline, Embase, Ovid, Cochrane Library, and Web of Science from inception to April 2022. Literature was included and excluded according to Cochrane's principles. The basic information from eligible documents was extracted. Systematic evaluation and meta-analysis were performed, and the odds ratio (OR) was analyzed by the random-effect model. The quality of the literature was assessed using the modified Jadad scale and the Newcastle-Ottawa (NOS) mean scale.

RESULTS

A total of 19 studies were included, including 4 randomized controlled trials and 15 observational comparative studies. Among them, most studies were not limited to a specific pathological type, with the exception of 3 that were limited to invasive lobular carcinoma. The results showed that preoperative MRI examination would significantly reduce the reoperation rate (OR = 0.77, P=0.02) and increase the mastectomy rate (OR = 1.36, P=0.001). In comparison, preoperative MRI did not significantly affect the rate of secondary mastectomy (OR = 0.77, P=0.02), the rate of positive margin (OR = 1.08, P=0.66), the rate of mastectomy (OR = 1.00, P < 0.05), and reoperations (OR = 0.65, P=0.19) in the subgroup analysis of patients with invasive lobular carcinoma.

CONCLUSION

Available evidence suggests that preoperative MRI examination increases the rate of mastectomy and reduces the rate of reoperations. The results indicate that preoperative MRI examination has the potential to benefit patients with breast cancer, but more high-quality studies are needed for confirmation.

Relaxation-compensated CEST (chemical exchange saturation transfer) imaging in breast cancer diagnostics at 7T

PURPOSE

To investigate whether fat-corrected and relaxation-compensated amide proton transfer (APT) and guanidyl CEST-MRI enables the detection of signal intensity differences between breast tumors and normal-appearing fibroglandular tissue in patients with newly-diagnosed breast cancer.

METHOD

Ten patients with newly-diagnosed breast cancer and seven healthy volunteers were included in this prospective IRB-approved study. CEST-MRI was performed on a 7 T-whole-body scanner followed by a multi-Lorentzian fit analysis. APT and guanidyl CEST signal intensities were quantified in the tumor and in healthy fibroglandular tissue after correction of B₀/B₁-field inhomogeneities, fat signal contribution, T₁- and T₂-relaxation; signal intensity differences of APT and guanidyl resonances were compared using Mann-Whitney-U-tests. Pearson correlations between tumor CEST signal intensities and the proliferation index Ki-67 were performed.

RESULTS

APT CEST signal in tumor tissue (6.70 ± 1.38%Hz) was increased compared to normal-appearing fibroglandular tissue of patients (3.56 ± 0.54%Hz, p = 0.001) and healthy volunteers (3.70 ± 0.68%Hz, p = 0.001). Further, a moderate positive correlation was found between the APT signal and the proliferation index Ki-67 (R² = 0.367, r = 0.606, p = 0.11). Guanidyl CEST signal was also increased in tumor tissue (5.24 ± 1.85%Hz) compared to patients' (2.42 ± 0.45%Hz, p = 0.006) and volunteers' (2.36 ± 0.54%Hz, p < 0.001) normal-appearing fibroglandular tissue and a positive correlation with the Ki-67 level was observed (R² = 0.365, r = 0.604, p = 0.11). APT and guanidyl CEST signal in normal-appearing fibroglandular tissue was not different between patients and healthy volunteers (p = 0.88; p = 0.93).

CONCLUSION

Relaxation-compensated and fat-corrected CEST-MRI allowed a non-invasive differentiation of breast cancer and normal-appearing breast tissue. Thus, this approach represents a contrast agent-free method that may help to increase diagnostic accuracy in MR-mammography.

Long-term survival outcomes in invasive lobular carcinoma patients with and without preoperative MR imaging: a matched cohort study

OBJECTIVE

To investigate and compare the effect of preoperative breast magnetic resonance (MR) imaging on recurrence-free survival (RFS) and overall survival (OS) outcomes among patients with invasive lobular carcinoma (ILC).

METHODS

A total of 287 ILC patients between January 2005 and December 2012 were included. One hundred twenty (41.8%) had undergone preoperative breast MR imaging (MR group) and 167 (58.2%) had not (no MR group). Two groups were matched for 21 covariates in terms of patient demographics, tumor characteristics, and clinical features. We compared unmatched variables between the patients with and without breast MR imaging using the chi-square or Student's t test. Comparisons of matched data were performed with McNemar's test or test of symmetry for categorical variables and paired t test for continuous variables. The RFS and OS outcomes were compared using the Kaplan-Meier estimates. MR effects were estimated after adjusting for significant potential confounders of specific outcomes in the multivariable modeling.

RESULTS

In the matched cohort, no statistically significant association was observed between MR imaging and total recurrence (hazard ratio [HR], 1.096; p = 0.821), loco-regional recurrence (HR, 1.204; p = 0.796), contralateral breast recurrence (HR, 0.945; p = 0.952), or distant recurrence (HR, 1.020; p = 0.973). MR imaging was associated with improved OS with 51% reduction, but not significantly (HR, 0.485; p = 0.231). Analysis with multivariable Cox regression model indicated that MR imaging was not significant independent factor for better RFS (HR, 0.823; p = 0.586) or improved OS (HR, 0.478; p = 0.168).

CONCLUSION

Preoperative MR imaging is not significant prognostic factor and produces no apparent recurrence or survival outcome benefits in ILC patients.

KEY POINTS

• Preoperative breast MR imaging in invasive lobular carcinoma was associated with a better overall survival with 51% reduction, but not statistically significant. • Preoperative breast MR imaging does not show significant prognostic value in invasive lobular carcinoma as there is no apparent benefit in terms of recurrence or survival outcomes.

Meta-analysis of pre-operative magnetic resonance imaging (MRI) and surgical treatment for breast cancer

BACKGROUND

Although there is no consensus on whether pre-operative MRI in women with breast cancer (BC) benefits surgical treatment, MRI continues to be used pre-operatively in practice. This meta-analysis examines the association between pre-operative MRI and surgical outcomes in BC.

METHODS

A systematic review was performed to identify studies reporting quantitative data on pre-operative MRI and surgical outcomes (without restriction by type of surgery received or type of BC) and using a controlled design. Random-effects logistic regression calculated the pooled odds ratio (OR) for each surgical outcome (MRI vs. no-MRI groups), and estimated ORs stratified by study-level age. Subgroup analysis was performed for invasive lobular cancer (ILC).

RESULTS

Nineteen studies met eligibility criteria: 3 RCTs and 16 comparative studies that included newly diagnosed BC of any type except for three studies restricted to ILC. Primary analysis (85,975 subjects) showed that pre-operative MRI was associated with increased odds of receiving mastectomy [OR 1.39 (1.23, 1.57); p < 0.001]; similar findings were shown in analyses stratified by study-level median age. Secondary analyses did not find statistical evidence of an effect of MRI on the rates of re-excision, re-operation, or positive margins; however, MRI was significantly associated with increased odds of receiving contralateral prophylactic mastectomy [OR 1.91 (1.25, 2.91); p = 0.003]. Subgroup analysis for ILC did not find any association between MRI and the odds of receiving mastectomy [OR 1.00 (0.75, 1.33); p = 0.988] or the odds of re-excision [OR 0.65 (0.35, 1.24); p = 0.192].

CONCLUSIONS

Pre-operative MRI is associated with increased odds of receiving ipsilateral mastectomy and contralateral prophylactic mastectomy as surgical treatment in newly diagnosed BC patients.

Breast magnetic resonance imaging use in patients undergoing neoadjuvant chemotherapy is associated with less mastectomies in large ductal cancers but not in lobular cancers

BACKGROUND

To assess the impact of breast magnetic resonance imaging (MRI) use on surgical outcome per histological breast cancer subtype in patients treated with neoadjuvant chemotherapy.

PATIENTS AND METHODS

All patients aged 18-70 years who underwent neoadjuvant chemotherapy for stage I-III invasive breast cancer in the Netherlands in the years 2011-2013 were identified from the Netherlands Cancer Registry. Patients with cT4 tumours were excluded from the analysis. Use of breast MRI and impact on surgical treatment, resection margins and detection of contralateral breast cancer were analysed by multivariable analyses.

RESULTS

Breast MRI was performed in 2879 (83.9%) out of 3433 patients treated with neoadjuvant chemotherapy. Younger age (odds ratio [OR] 1.42; 95% confidence interval [CI] 1.17-1.71 for 18-50 years compared with 50-70 years), larger tumour stage (OR 1.46 [95% CI 1.15-1.86] for cT3, compared to cT1-2 tumours) and multifocality (OR 1.30; 95% CI 1.04-1.61, versus unifocality) were associated with increased breast MRI use. In ductal breast cancer, after stratification for cT-status, breast MRI use is associated with a significant lower OR for mastectomy as final surgery in cT3 tumours (OR 0.45, 95% CI 0.21-0.99). Resection margin involvement and detection of contralateral breast cancer were not associated with breast MRI use.

CONCLUSION

In patients treated with neoadjuvant chemotherapy, the use of breast MRI was associated with a reduced mastectomy rate, particularly in patients with large invasive ductal breast tumours but not in patients with lobular breast cancer.

Breast MRI increases the number of mastectomies for ductal cancers, but decreases them for lobular cancers

PURPOSE

In this retrospective population-based cohort study, we analyzed breast MRI use and its impact on type of surgery, surgical margin involvement, and the diagnosis of contralateral breast cancer.

METHODS

All Dutch patients with cT_1-4N_0-3M₀ breast cancer diagnosed in 2011-2013 and treated with primary surgery were eligible for inclusion. Using multivariable analyses, we analyzed in different categories whether MRI use was related to surgery type, margin involvement, and diagnosis of contralateral breast cancer (CBC).

RESULTS

MRI was performed in 10,740 out of 36,050 patients (29.8%). Patients with invasive ductal cancer undergoing MRI were more likely to undergo primary mastectomy than those without MRI (OR 1.30, 95% confidence interval (CI) 1.22-1.39, p < 0.0001). Patients with invasive lobular cancer undergoing MRI were less likely to undergo primary mastectomy than those without MRI (OR 0.86, 95% CI 0.76-0.99, p = 0.0303). A significantly lower risk of positive surgical margins after breast-conserving surgery was only seen in patients with lobular cancer who had undergone MRI as compared to those without MRI (OR 0.59, 95% CI 0.44-0.79, p = 0.0003) and, consequently, a lower risk of secondary mastectomy (OR 0.61, 95% CI 0.42-0.88, p = 0.0088). Patients who underwent MRI were almost four times more likely to be diagnosed with CBC (OR 3.55, 95% CI 3.01-4.17, p < 0.0001).

CONCLUSIONS

Breast MRI use was associated with a reduced number of mastectomies and less positive surgical margins in invasive lobular cancer, but with an increased number of mastectomies in ductal cancers. Breast MRI use was associated with a fourfold higher incidence of CBC.

Impact of preoperative breast MRI on surgical decision making and clinical outcomes: a systematic review

BACKGROUND

Preoperative magnetic resonance imaging (MRI) is increasingly used in the workup of breast cancer patients and could lead to changes in surgical management. It is unclear how the information gained from MRI studies affects surgical decision making and influences clinical outcomes. These issues are addressed in this review.

METHODS

PubMed database searches were performed to retrieve and analyze respective original research and review articles on preoperative MRI in the evaluation of breast cancer patients.

RESULTS

Preoperative MRI is a highly sensitive but nonspecific method that leads to changes in surgical management with increased numbers of more extended surgical interventions. It appears that a relatively large proportion of MRI-driven changes in surgical management result in overtreatment without conclusively proven beneficial effects on such clinical outcomes as decrease in reoperation rates or improved patient survival.

CONCLUSIONS

Thus, routine use of supplementary preoperative breast MRI should be discouraged until compelling evidence of its effectiveness is available.

Magnetic resonance imaging in patients with newly diagnosed breast cancer: a review of the literature

The use of magnetic resonance imaging (MRI) in patients with newly diagnosed breast cancer remains controversial. Here we review the current use of breast MRI and the impact of MRI on short-term surgical outcomes and rates of local recurrence. In addition, we address the use of MRI in specific patient populations, such as those with ductal carcinoma in situ, invasive lobular carcinoma, and occult primary breast cancer, and discuss the potential role of MRI for assessing response to neoadjuvant chemotherapy. Although MRI has improved sensitivity compared with conventional imaging, this has not translated into improved short-term surgical outcomes or long-term patient benefit, such as improved local control or survival, in any patient population. MRI is an important diagnostic test in the evaluation of patients presenting with occult primary breast cancer and has shown promise in monitoring response to neoadjuvant chemotherapy; however, the data do not support the routine use of perioperative MRI in patients with newly diagnosed breast cancer. Cancer 2014;120:120:2080-2089. © 2014 American Cancer Society.

Controversies in breast MRI

When used for appropriate indications, breast magnetic resonance imaging (MRI) is a powerful diagnostic tool. However, breast MRI has its share of controversies. These controversies can be a source of confusion for the radiologist or referring physician. This paper addresses 4 breast MRI controversies that we frequently encounter at our university hospital practice: (1) what are the appropriate indications for screening breast MRI? (2) what are the appropriate indications for the use of breast MRI as a problems-solving modality? (3) how does one interpret MRI imaging features that have substantial overlap between benign and malignant conditions? and (4) what are the appropriate indications for preoperative breast MRI? Illustrative case examples are provided.

Preoperative breast MRI and surgical outcomes in elderly women with invasive ductal and lobular carcinoma: a population-based study

Existing evidence suggests that preoperative breast magnetic resonance imaging (MRI) might not improve surgical outcomes in the general breast cancer population. To determine if patients differentially benefit from breast MRI, we examined surgical outcomes-initial mastectomy, reoperation, and final mastectomy rates-among patients grouped by histologic type. We identified women diagnosed with early-stage breast cancer from 2004 to 2007 in the SEER-Medicare dataset. We classified patients as having invasive ductal carcinoma (IDC), invasive lobular carcinoma (ILC), mixed ductal/lobular carcinoma (IDLC) or other histologic type. Medicare claims were used to identify breast MRI and definitive surgeries during the initial surgical treatment episode. We used propensity score methods to account for the differential likelihood of exposure to MRI. Of the 20,332 patients who met our inclusion criteria for this study, 12.2 % had a preoperative breast MRI. Patients with ILC as compared to other histologic groups were most likely to receive MRI [OR 2.32; 95 % CI (2.02-2.67)]. In the propensity score-adjusted analyses, breast MRI was associated with an increased likelihood of an initial mastectomy for all patients and among all histologic subgroups. Among patients with ILC, having a breast MRI was associated with lower odds of a reoperation [OR 0.59; 95 % CI (0.40-0.86)], and an equal likelihood of a final mastectomy compared to similar patients without a breast MRI. Overall and among patients with IDC and IDLC, breast MRI was not significantly associated with a likelihood of a reoperation but was associated with greater odds of a final mastectomy. Our study provides evidence in support of the targeted use of preoperative breast MRI among patients with ILC to improve surgical planning; it does not provide evidence for the routine use of breast MRI among all newly diagnosed breast cancer patients or among patients with IDC.

The role of magnetic resonance imaging in early breast cancer

Despite recent evidence that fails to detect a benefit in surgical and local recurrence outcomes in those who receive optimal surgery and adjuvant systemic and radiotherapy, magnetic resonance imaging (MRI) is still being employed. We review the recent literature to clarify the role in the use of MRI in early breast cancer. A literature search using the Medline and Ovid databases was conducted between 2004 and 2011 using the terms "magnetic resonance imaging' and 'early breast cancer'. Only articles with clinical trials published in English in adult humans with available abstracts were included. Articles on high-risk women, response to neoadjuvant therapy, advanced breast cancer, the occult primary, the contralateral breast and technical articles were excluded. Articles examining the role of MRI in the staging of early breast cancer were retained. Over 260 articles regarding breast MRI have been published in the last 5 years. Additional foci may be found in 16% of patients but the impact on the extent of surgery and local recurrence rate is yet to be defined. Certain sub-groups who may benefit include those with invasive lobular carcinoma and mammographically dense breasts and those for consideration of partial breast irradiation. With standard adjuvant radiotherapy, there is no benefit in routine MRI with respect surgical extent and local recurrence. Should MRI be used, pre-operative biopsy to confirm additional disease must be undertaken prior to a change in surgical extent of resection. However, MRI may be useful in the evaluation of those who can be considered for partial breast irradiation. Centres undertaking breast MRI must have MRI-biopsy capabilities and constantly audit the reporting of MRI with correlation to the final pathology.

Do patients with invasive lobular breast cancer benefit in terms of adequate change in surgical therapy from a supplementary preoperative breast MRI?

BACKGROUND

Breast magnetic resonance imaging (MRI) has been introduced in the preoperative management of invasive lobular breast cancer (ILC). We analysed if MRI leads to adequate changes in surgical management.

PATIENTS AND METHODS

We carried out a single-centre retrospective confirmatory analysis of 92 patients with ILC and a preoperative breast MRI. By applying a blinded tumour board method, we analysed if surgical procedures were altered due to breast MRI. In case of alteration, we analysed whether the change was adequate according to the postoperative pathology findings. We considered an adequate rate of change>5% to be a clinically relevant benefit.

RESULTS

A change in surgical therapy due to the MRI findings occurred in 23 of 92 patients (25%). According to the postoperative pathology findings, this change was adequate for 20 of these patients (22%; 95% confidence interval [CI] 14%-31%, P<0.0001). An overtreatment occurred for three patients (3%; 95% CI 0%-6%) who underwent a mastectomy following the results of breast MRI. Patients with larger tumours did likely benefit more from preoperative breast MRI.

CONCLUSIONS

Patients with ILC might benefit from a preoperative breast MRI. Possible harm from overtreatment should be minimised by diligent use of preoperative histological clarification.