Re-attendance in supplemental breast MRI screening rounds of the DENSE trial for women with extremely dense breasts

OBJECTIVES

Supplemental MRI screening improves early breast cancer detection and reduces interval cancers in women with extremely dense breasts in a cost-effective way. Recently, the European Society of Breast Imaging recommended offering MRI screening to women with extremely dense breasts, but the debate on whether to implement it in breast cancer screening programs is ongoing. Insight into the participant experience and willingness to re-attend is important for this discussion.

METHODS

We calculated the re-attendance rates of the second and third MRI screening rounds of the DENSE trial. Moreover, we calculated age-adjusted odds ratios (ORs) to study the association between characteristics and re-attendance. Women who discontinued MRI screening were asked to provide one or more reasons for this.

RESULTS

The re-attendance rates were 81.3% (3458/4252) and 85.2% (2693/3160) in the second and third MRI screening round, respectively. A high age (> 65 years), a very low BMI, lower education, not being employed, smoking, and no alcohol consumption were correlated with lower re-attendance rates. Moderate or high levels of pain, discomfort, or anxiety experienced during the previous MRI screening round were correlated with lower re-attendance rates. Finally, a plurality of women mentioned an examination-related inconvenience as a reason to discontinue screening (39.1% and 34.8% in the second and third screening round, respectively).

CONCLUSIONS

The willingness of women with dense breasts to re-attend an ongoing MRI screening study is high. However, emphasis should be placed on improving the MRI experience to increase the re-attendance rate if widespread supplemental MRI screening is implemented.

CLINICAL RELEVANCE STATEMENT

For many women, MRI is an acceptable screening method, as re-attendance rates were high - even for screening in a clinical trial setting. To further enhance the (re-)attendance rate, one possible approach could be improving the overall MRI experience.

KEY POINTS

• The willingness to re-attend in an ongoing MRI screening study is high. • Pain, discomfort, and anxiety in the previous MRI screening round were related to lower re-attendance rates. • Emphasis should be placed on improving MRI experience to increase the re-attendance rate in supplemental MRI screening.

Radiological, pathological and surgical outcomes after neoadjuvant endocrine treatment in patients with ER-positive/HER2-negative breast cancer with a clinical high risk and a low-risk 70-gene signature

OBJECTIVE

This study aims to evaluate the response to and surgical benefits of neoadjuvant endocrine therapy (NET) in ER+/HER2-breast cancer patients who are clinically high risk, but genomic low risk according to the 70-gene signature (MammaPrint).

METHODS

Patients with ER+/HER2-invasive breast cancer with a clinical high risk according to MINDACT, who had a genomic low risk according to the 70-gene signature and were treated with NET between 2015 and 2023 in our center, were retrospectively analyzed. RECIST 1.1 criteria were used to assess radiological response using MRI or ultrasound. Surgical specimens were evaluated to assess pathological response. Two breast cancer surgeons independently scored the eligibility of breast conserving therapy (BCS) pre- and post- NET.

RESULTS

Of 72 included patients, 23 were premenopausal (100% started with tamoxifen of which 4 also received OFS) and 49 were postmenopausal (98% started with an aromatase inhibitor). Overall, 8 (11%) showed radiological complete response. Only 1 (1.4%) patient had a pathological complete response (RCB-0) and 68 (94.4%) had a pathological partial response (RCB-1 or RCB-2). Among the 26 patients initially considered for mastectomy, 14 (53.8%) underwent successful BCS. In all 20 clinical node-positive patients, a marked axillary lymph node was removed to assess response. Four out of 20 (20%) patients had a pathological complete response of the axilla.

CONCLUSION

The study showed that a subgroup of patients with a clinical high risk and a genomic low risk ER+/HER2-breast cancer benefits from NET resulting in BCS instead of a mastectomy. Additionally, NET may enable de-escalation in axillary treatment.

Breast surgery after neoadjuvant chemotherapy in patients with lobular carcinoma: surgical and oncologic outcome

INTRODUCTION

Breast cancer patients with invasive lobular carcinoma (ILC) have an increased risk of positive margins after surgery and often show little response to neoadjuvant chemotherapy (NAC). We aimed to investigate surgical outcomes in patients with ILC treated with NAC.

METHODS

In this retrospective cohort study, all breast cancer patients with ILC treated with NAC who underwent surgery at the Netherlands Cancer Institute from 2010 to 2019 were selected. Patients with mixed type ILC in pre-NAC biopsies were excluded if the lobular component was not confirmed in the surgical specimen. Main outcomes were tumor-positive margins and re-excision rate. Associations between baseline characteristics and tumor-positive margins were assessed, as were complications, locoregional recurrence rate (LRR), recurrence-free survival (RFS), and overall survival (OS).

RESULTS

We included 191 patients. After NAC, 107 (56%) patients had breast conserving surgery (BCS) and 84 (44%) patients underwent mastectomy. Tumor-positive margins were observed in 67 (35%) patients. Fifty five (51%) had BCS and 12 (14%) underwent mastectomy (p value < 0.001). Re-excision was performed in 35 (33%) patients with BCS and in 4 (5%) patients with mastectomy. Definitive surgery was mastectomy in 107 (56%) patients and BCS in 84 (44%) patients. Tumor-positive margins were associated with cT ≥ 3 status (OR 4.62, 95% CI 1.26-16.98, p value 0.021) in the BCS group. Five-year LRR (4.7%), RFS (81%), and OS (93%) were not affected by type of surgery after NAC.

CONCLUSION

Although 33% of ILC breast cancer patients undergoing BCS after NAC required re-excision for positive resection margins, it is considered safe given that five-year RFS remained excellent and LRR and OS did not differ by extent of surgery.

Clinicopathological and prognostic value of calcification morphology descriptors in ductal carcinoma in situ of the breast: a systematic review and meta-analysis

BACKGROUND

Calcifications on mammography can be indicative of breast cancer, but the prognostic value of their appearance remains unclear. This systematic review and meta-analysis aimed to evaluate the association between mammographic calcification morphology descriptors (CMDs) and clinicopathological factors.

METHODS

A comprehensive literature search in Medline via Ovid, Embase.com, and Web of Science was conducted for articles published between 2000 and January 2022 that assessed the relationship between CMDs and clinicopathological factors, excluding case reports and review articles. The risk of bias and overall quality of evidence were evaluated using the QUIPS tool and GRADE. A random-effects model was used to synthesize the extracted data. This systematic review is reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA).

RESULTS

Among the 4715 articles reviewed, 29 met the inclusion criteria, reporting on 17 different clinicopathological factors in relation to CMDs. Heterogeneity between studies was present and the overall risk of bias was high, primarily due to small, inadequately described study populations. Meta-analysis demonstrated significant associations between fine linear calcifications and high-grade DCIS [pooled odds ratio (pOR), 4.92; 95% confidence interval (CI), 2.64-9.17], (comedo)necrosis (pOR, 3.46; 95% CI, 1.29-9.30), (micro)invasion (pOR, 1.53; 95% CI, 1.03-2.27), and a negative association with estrogen receptor positivity (pOR, 0.33; 95% CI, 0.12-0.89).

CONCLUSIONS

CMDs detected on mammography have prognostic value, but there is a high level of bias and variability between current studies. In order for CMDs to achieve clinical utility, standardization in reporting of CMDs is necessary.

CRITICAL RELEVANCE STATEMENT

Mammographic calcification morphology descriptors (CMDs) have prognostic value, but in order for CMDs to achieve clinical utility, standardization in reporting of CMDs is necessary.

SYSTEMATIC REVIEW REGISTRATION

CRD42022341599 KEY POINTS: • Mammographic calcifications can be indicative of breast cancer. • The prognostic value of mammographic calcifications is still unclear. • Specific mammographic calcification morphologies are related to lesion aggressiveness. • Variability between studies necessitates standardization in calcification evaluation to achieve clinical utility.

High-dose alkylating chemotherapy in BRCA-altered triple-negative breast cancer: the randomized phase III NeoTN trial

Exploratory analyses of high-dose alkylating chemotherapy trials have suggested that BRCA1 or BRCA2-pathway altered (BRCA-altered) breast cancer might be particularly sensitive to this type of treatment. In this study, patients with BRCA-altered tumors who had received three initial courses of dose-dense doxorubicin and cyclophosphamide (ddAC), were randomized between a fourth ddAC course followed by high-dose carboplatin-thiotepa-cyclophosphamide or conventional chemotherapy (initially ddAC only or ddAC-capecitabine/decetaxel [CD] depending on MRI response, after amendment ddAC-carboplatin/paclitaxel [CP] for everyone). The primary endpoint was the neoadjuvant response index (NRI). Secondary endpoints included recurrence-free survival (RFS) and overall survival (OS). In total, 122 patients were randomized. No difference in NRI-score distribution (p = 0.41) was found. A statistically non-significant RFS difference was found (HR 0.54; 95% CI 0.23-1.25; p = 0.15). Exploratory RFS analyses showed benefit in stage III (n = 35; HR 0.16; 95% CI 0.03-0.75), but not stage II (n = 86; HR 1.00; 95% CI 0.30-3.30) patients. For stage III, 4-year RFS was 46% (95% CI 24-87%), 71% (95% CI 48-100%) and 88% (95% CI 74-100%), for ddAC/ddAC-CD, ddAC-CP and high-dose chemotherapy, respectively. No significant differences were found between high-dose and conventional chemotherapy in stage II-III, triple-negative, BRCA-altered breast cancer patients. Further research is needed to establish if there are patients with stage III, triple negative BRCA-altered breast cancer for whom outcomes can be improved with high-dose alkylating chemotherapy or whether the current standard neoadjuvant therapy including carboplatin and an immune checkpoint inhibitor is sufficient. Trial Registration: NCT01057069.

Biopsy-Guided Pathological Response Assessment in Breast Cancer is Insufficient: Additional Pathology Findings of the MICRA Trial

BACKGROUND

Neoadjuvant systemic treatment (NST) leads to pathologic complete response (pCR) in 10-89% of breast cancer patients depending on subtype. The added value of surgery is uncertain in patients who reach pCR; however, current imaging and biopsy techniques aiming to predict pCR are not accurate enough. This study aims to quantify the residual disease remaining after NST in patients with a favorable response on MRI and residual disease missed with biopsies.

METHODS

In the MICRA trial, patients with a favorable response to NST on MRI underwent ultrasound-guided post-NST 14G biopsies followed by surgery. We analyzed pathology reports of the biopsies and the surgical specimens. Primary outcome was the extent of residual invasive disease among molecular subtypes, and secondary outcome was the extent of missed residual invasive disease.

RESULTS

We included 167 patients. Surgical specimen showed residual invasive disease in 69 (41%) patients. The median size of residual invasive disease was 18 mm (interquartile range [IQR] 12-30) in hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) patients, 8 mm (IQR 3-15) in HR+/HER2-positive (HER2+) patients, 4 mm (IQR 2-9) in HR-negative (HR-)/HER2+ patients, and 5 mm (IQR 2-11) in triple-negative (TN) patients. Residual invasive disease was missed in all subtypes varying from 4 to 7 mm.

CONCLUSION

Although the extent of residual invasive disease is small in TN and HER2+ subtypes, substantial residual invasive disease is left behind in all subtypes with 14G biopsies. This may hamper local control and limits adjuvant systemic treatment options. Therefore, surgical excision remains obligatory until accuracy of imaging and biopsy techniques improve.

PD-L1 blockade in combination with carboplatin as immune induction in metastatic lobular breast cancer: the GELATO trial

Invasive lobular breast cancer (ILC) is the second most common histological breast cancer subtype, but ILC-specific trials are lacking. Translational research revealed an immune-related ILC subset, and in mouse ILC models, synergy between immune checkpoint blockade and platinum was observed. In the phase II GELATO trial ( NCT03147040 ), patients with metastatic ILC were treated with weekly carboplatin (area under the curve 1.5 mg ml-1 min-1) as immune induction for 12 weeks and atezolizumab (PD-L1 blockade; triweekly) from the third week until progression. Four of 23 evaluable patients had a partial response (17%), and 2 had stable disease, resulting in a clinical benefit rate of 26%. From these six patients, four had triple-negative ILC (TN-ILC). We observed higher CD8+ T cell infiltration, immune checkpoint expression and exhausted T cells after treatment. With this GELATO trial, we show that ILC-specific clinical trials are feasible and demonstrate promising antitumor activity of atezolizumab with carboplatin, particularly for TN-ILC, and provide insights for the design of highly needed ILC-specific trials.

Three-year follow-up of de-escalated axillary treatment after neoadjuvant systemic therapy in clinically node-positive breast cancer: the MARI-protocol

Purpose

In clinically node-positive (cN+) breast cancer patients, evidence supporting response-guided treatment after neoadjuvant systemic therapy (NST) instead of axillary lymph node dissection (ALND) is increasing, but follow-up results are lacking. We assessed three-year axillary recurrence-free interval (aRFI) in cN+ patients with response-adjusted axillary treatment according to the ‘Marking Axillary lymph nodes with Radioactive Iodine seeds’ (MARI)-protocol.

Methods

We retrospectively assessed all stage II–III cytologically proven cN+ breast cancer patients who underwent the MARI-protocol between July 2014 and November 2018. Pre-NST axillary staging with FDG-PET/CT (less- or more than four suspicious axillary nodes; cALN < 4 or cALN ≥ 4) and post-NST pathological axillary response measured in the pre-NST largest tumor-positive axillary lymph node marked with an iodine seed (MARI-node; ypMARI-neg or ypMARI-pos) determined axillary treatment: no further treatment (cALN < 4, ypMARI-neg), axillary radiotherapy (ART) (cALN < 4, ypMARI-pos and cALN ≥ 4, ypMARI-neg) or ALND plus ART (cALN ≥ 4, ypMARI-pos).

Results

Of 272 women included, the MARI-node was tumor-negative in 56 (32%) of 174 cALN < 4 patients and 43 (44%) of 98 cALN ≥ 4 patients. According to protocol, 56 (21%) patients received no further axillary treatment, 161 (59%) received ART and 55 (20%) received ALND plus ART. Median follow-up was 3.0 years (IQR 1.9–4.1). Five patients (one no further treatment, four ART) had axillary metastases. Three-year aRFI was 98% (95% CI 96–100). The overall recurrence risk remained highest for patients with ALND (HR 4.36; 95% CI 0.95–20.04, p = 0.059).

Conclusions

De-escalation of axillary treatment according to the MARI-protocol prevented ALND in 80% of cN+ patients with an excellent three-year aRFI of 98%.

Factors affecting the value of diffusion-weighted imaging for identifying breast cancer patients with pathological complete response on neoadjuvant systemic therapy: a systematic review

This review aims to identify factors causing heterogeneity in breast DWI-MRI and their impact on its value for identifying breast cancer patients with pathological complete response (pCR) on neoadjuvant systemic therapy (NST). A search was performed on PubMed until April 2020 for studies analyzing DWI for identifying breast cancer patients with pCR on NST. Technical and clinical study aspects were extracted and assessed for variability. Twenty studies representing 1455 patients/lesions were included. The studies differed with respect to study population, treatment type, DWI acquisition technique, post-processing (e.g., mono-exponential/intravoxel incoherent motion/stretched exponential modeling), and timing of follow-up studies. For the acquisition and generation of ADC-maps, various b-value combinations were used. Approaches for drawing regions of interest on longitudinal MRIs were highly variable. Biological variability due to various molecular subtypes was usually not taken into account. Moreover, definitions of pCR varied. The individual areas under the curve for the studies range from 0.50 to 0.92. However, overlapping ranges of mean/median ADC-values at pre- and/or during and/or post-NST were found for the pCR and non-pCR groups between studies. The technical, clinical, and epidemiological heterogeneity may be causal for the observed variability in the ability of DWI to predict pCR accurately. This makes implementation of DWI for pCR prediction and evaluation based on one absolute ADC threshold for all breast cancer types undesirable. Multidisciplinary consensus and appropriate clinical study design, taking biological and therapeutic variation into account, is required for obtaining standardized, reliable, and reproducible DWI measurements for pCR/non-pCR identification.

Contralateral parenchymal enhancement on MRI is associated with tumor proteasome pathway gene expression and overall survival of early ER+/HER2-breast cancer patients

Purpose

To assess whether contralateral parenchymal enhancement (CPE) on MRI is associated with gene expression pathways in ER+/HER2-breast cancer, and if so, whether such pathways are related to survival.

Methods

Preoperative breast MRIs were analyzed of early ER+/HER2-breast cancer patients eligible for breast-conserving surgery included in a prospective observational cohort study (MARGINS). The contralateral parenchyma was segmented and CPE was calculated as the average of the top-10% delayed enhancement. Total tumor RNA sequencing was performed and gene set enrichment analysis was used to reveal gene expression pathways associated with CPE (N = 226) and related to overall survival (OS) and invasive disease-free survival (IDFS) in multivariable survival analysis. The latter was also done for the METABRIC cohort (N = 1355).

Results

CPE was most strongly correlated with proteasome pathways (normalized enrichment statistic = 2.04, false discovery rate = .11). Patients with high CPE showed lower tumor proteasome gene expression. Proteasome gene expression had a hazard ratio (HR) of 1.40 (95% CI = 0.89, 2.16; P = .143) for OS in the MARGINS cohort and 1.53 (95% CI = 1.08, 2.14; P = .017) for IDFS, in METABRIC proteasome gene expression had an HR of 1.09 (95% CI = 1.01, 1.18; P = .020) for OS and 1.10 (95% CI = 1.02, 1.18; P = .012) for IDFS.

Conclusion

CPE was negatively correlated with tumor proteasome gene expression in early ER+/HER2-breast cancer patients. Low tumor proteasome gene expression was associated with improved survival in the METABRIC data.

•

Contralateral parenchymal enhancement on MRI was associated with tumor proteasome gene expression in ER+/HER2-breast cancer.

•

A high contralateral parenchymal enhancement was associated with a low proteasome gene expression in the breast cancer.

•

Low proteasome tumor gene expression was associated with improved survival in an independent patient cohort.

Reducing False-Positive Screening MRI Rate in Women with Extremely Dense Breasts Using Prediction Models Based on Data from the DENSE Trial

Background High breast density increases breast cancer risk and lowers mammographic sensitivity. Supplemental MRI screening improves cancer detection but increases the number of false-positive screenings. Thus, methods to distinguish true-positive MRI screening results from false-positive ones are needed. Purpose To build prediction models based on clinical characteristics and MRI findings to reduce the rate of false-positive screening MRI findings in women with extremely dense breasts. Materials and Methods Clinical characteristics and MRI findings in Dutch breast cancer screening participants (age range, 50-75 years) with positive first-round MRI screening results (Breast Imaging Reporting and Data System 3, 4, or 5) after a normal screening mammography with extremely dense breasts (Volpara density category 4) were prospectively collected within the randomized controlled Dense Tissue and Early Breast Neoplasm Screening (DENSE) trial from December 2011 through November 2015. In this secondary analysis, prediction models were built using multivariable logistic regression analysis to distinguish true-positive MRI screening findings from false-positive ones. Results Among 454 women (median age, 52 years; interquartile range, 50-57 years) with a positive MRI result in a first supplemental MRI screening round, 79 were diagnosed with breast cancer (true-positive findings), and 375 had false-positive MRI results. The full prediction model (area under the receiver operating characteristics curve [AUC], 0.88; 95% CI: 0.84, 0.92), based on all collected clinical characteristics and MRI findings, could have prevented 45.5% (95% CI: 39.6, 51.5) of false-positive recalls and 21.3% (95% CI: 15.7, 28.3) of benign biopsies without missing any cancers. The model solely based on readily available MRI findings and age had a comparable performance (AUC, 0.84; 95% CI: 0.79, 0.88; P = .15) and could have prevented 35.5% (95% CI: 30.4, 41.1) of false-positive MRI screening results and 13.0% (95% CI: 8.8, 18.6) of benign biopsies. Conclusion Prediction models based on clinical characteristics and MRI findings may be useful to reduce the false-positive first-round screening MRI rate and benign biopsy rate in women with extremely dense breasts. Clinical trial registration no. NCT01315015 © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Imbriaco in this issue.

Prognostic value of breast MRI characteristics before and during neoadjuvant endocrine therapy in patients with ER+/HER2- breast cancer

Objective:

To investigate whether BIRADS MRI characteristics before or during neoadjuvant endocrine therapy (NET) are associated with the preoperative endocrine prognostic index (PEPI) in ER+/HER2- breast cancer patients.

Methods:

This retrospective observational cohort study included 35 ER+/HER2- patients with 38 tumors (3 bilateral cases) treated with NET. The pre- and midtreatment (after 3 months) MRIs were evaluated by two breast radiologists for BIRADS imaging characteristics, shrinkage pattern, and radiologic response. PEPI was used as end point. PEPI is based on the post-treatment surgical specimen’s pT- and pN-stage, Ki67, and ER-status. Tumors were assigned PEPI-1 (good prognosis) or PEPI-2/3 (poor prognosis). We investigated whether pre- and midtreatment BIRADS characteristics were associated with PEPI.

Results:

Median patient age was 65 years (interquartile interval [IQI]: 53, 70). 17 tumors (44.7%) were associated with good prognosis (PEPI-1), and 21 tumors (55.3%) with poor prognosis (PEPI-2/3). A larger reduction in tumor size after 3 months of NET was significantly associated with PEPI; 10 mm (IQI: 5, 13.5) in PEPI-1 tumors vs 4.5 mm (IQI: 3, 7; p = .045) in PEPI-2/3 tumors. Other BIRADS characteristics, shrinkage pattern or radiologic response were not associated with PEPI.

Conclusion:

Only a larger reduction in tumor size on MRI after 3 months of NET was associated with PEPI-1 (good prognosis) in ER+/HER2- breast cancer patients.

Advances in knowledge:

MRI characteristics previously reported to be associated with prognosis during neoadjuvant chemotherapy are not necessarily associated with prognosis during NET in ER+/HER2- breast cancer patients.

Minimally Invasive Complete Response Assessment of the Breast After Neoadjuvant Systemic Therapy for Early Breast Cancer (MICRA trial): Interim Analysis of a Multicenter Observational Cohort Study

BACKGROUND

The added value of surgery in breast cancer patients with pathological complete response (pCR) after neoadjuvant systemic therapy (NST) is uncertain. The accuracy of imaging identifying pCR for omission of surgery, however, is insufficient. We investigated the accuracy of ultrasound-guided biopsies identifying breast pCR (ypT0) after NST in patients with radiological partial (rPR) or complete response (rCR) on MRI.

METHODS

We performed a multicenter, prospective single-arm study in three Dutch hospitals. Patients with T1-4(N0 or N +) breast cancer with MRI rPR and enhancement ≤ 2.0 cm or MRI rCR after NST were enrolled. Eight ultrasound-guided 14-G core biopsies were obtained in the operating room before surgery close to the marker placed centrally in the tumor area at diagnosis (no attempt was made to remove the marker), and compared with the surgical specimen of the breast. Primary outcome was the false-negative rate (FNR).

RESULTS

Between April 2016 and June 2019, 202 patients fulfilled eligibility criteria. Pre-surgical biopsies were obtained in 167 patients, of whom 136 had rCR and 31 had rPR on MRI. Forty-three (26%) tumors were hormone receptor (HR)-positive/HER2-negative, 64 (38%) were HER2-positive, and 60 (36%) were triple-negative. Eighty-nine patients had pCR (53%; 95% CI 45-61) and 78 had residual disease. Biopsies were false-negative in 29 (37%; 95% CI 27-49) of 78 patients. The multivariable associated with false-negative biopsies was rCR (FNR 47%; OR 9.81, 95% CI 1.72-55.89; p = 0.01); a trend was observed for HR-negative tumors (FNR 71% in HER2-positive and 55% in triple-negative tumors; OR 4.55, 95% CI 0.95-21.73; p = 0.058) and smaller pathological lesions (6 mm vs 15 mm; OR 0.93, 95% CI 0.87-1.00; p = 0.051).

CONCLUSION

The MICRA trial showed that ultrasound-guided core biopsies are not accurate enough to identify breast pCR in patients with good response on MRI after NST. Therefore, breast surgery cannot safely be omitted relying on the results of core biopsies in these patients.

Breast-Conserving Therapy in Patients with cT3 Breast Cancer with Good Response to Neoadjuvant Systemic Therapy Results in Excellent Local Control: A Comprehensive Cancer Center Experience

BACKGROUND

Many cT3 breast cancer patients are treated with mastectomy, regardless of response to neoadjuvant systemic therapy (NST). We evaluated local control of cT3 patients undergoing breast-conserving therapy (BCT) based on magnetic resonance imaging (MRI) evaluation post-NST. In addition, we analyzed predictive characteristics for positive margins after breast-conserving surgery (BCS).

METHODS

All cT3 breast cancer patients who underwent BCS after NST between 2002 and 2015 at the Netherlands Cancer Institute were included. Local recurrence-free interval (LRFI) was estimated using the Kaplan-Meier method, and predictors for positive margins were analyzed using univariable analysis and multivariable logistic regression.

RESULTS

Of 114 patients undergoing BCS post-NST, 75 had negative margins, 16 had focally positive margins, and 23 had positive margins. Of those with (focally) positive margins, 12 underwent radiotherapy, 6 underwent re-excision, and 21 underwent mastectomy. Finally, 93/114 patients were treated with BCT (82%), with an LRFI of 95.9% (95% confidence interval [CI] 91.5-100%) after a median follow-up of 7 years. Predictors for positive margins in univariable analysis were hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) subtype, lobular carcinoma, and non-mass enhancement (NME) on pre-NST MRI. MRI response was not correlated to positive margins. In multivariable regression, the odds of positive margins were decreased in patients with HER2-positive (HER2+; odds ratio [OR] 0.27, 95% CI 0.10-0.73; p = 0.01) and TN tumors (OR 0.17, 95% CI 0.03-0.82; p = 0.028). A trend toward positive margins was observed in patients with NME (OR 2.38, 95% CI 0.98-5.77; p = 0.055).

CONCLUSION

BCT could be performed in 82% of cT3 patients in whom BCT appeared feasible on post-NST MRI. Local control in these patients was excellent. In those patients with HR+/HER2- tumors, NME on MRI, or invasive lobular carcinoma, the risk of positive margins should be considered preoperatively.

Evaluation of Early Response to Preoperative Accelerated Partial Breast Irradiation (PAPBI) by Histopathology, Magnetic Resonance Imaging, and 18F-fluorodexoyglucose Positron Emission Tomography/Computed Tomography (FDG PET/CT)

PURPOSE

This study aimed to find indicators for early response to radiation therapy in breast cancer. These would be of help in tailoring treatment for individual patients.

METHODS AND MATERIALS

We analyzed 66 patients with low-risk breast cancer (≥60 years; cT1-2pN0) treated within the Preoperative Accelerated Partial Breast Irradiation (PAPBI) trial. Patients received radiation therapy (RT; 10 x 4 Gray or 5 x 6 Gray), followed by a wide local excision after 6 weeks. Patients underwent magnetic resonance imaging (MRI) and 18F-fluorodexoyglucose (FDG) positron emission tomography/computed tomography (PET/CT) before RT and 5 weeks after RT, before surgery. We assessed the response to PAPBI using a histopathologic assessment and correlated this with responses on MRI and FDG PET/CT. We calculated the positive predictive values (PPVs) of MRI and PET/CT as the number of true positives (complete response on MRI/normalized at visual evaluation on PET/CT and pathologic complete response) divided by the number of patients with a complete response on MRI/normalized at visual evaluation on PET/CT. Similarly, the negative predictive values (NPVs) of MRI and PET/CT were calculated.

RESULTS

The pathologic response was (nearly) complete in 15 (23%) of the 66 patients and partially complete in 28 (42%). The remaining 23 patients (35%) were nonresponders. The PPV of MRI (Response evaluation criteria in solid tumors [RECIST]) was 87.5% and the NPV was 85%. The PPV and NPV of PET/CT were 25% and 92%, respectively.

CONCLUSIONS

The most accurate method to predict a response and residual disease after preoperative RT in low-risk breast cancer was MRI, using RECIST.

Cost-effectiveness of Breast Cancer Screening With Magnetic Resonance Imaging for Women at Familial Risk

Importance

For women with a 20% or more familial risk of breast cancer without a known BRCA1/2 (BRCA1, OMIM 113705; and BRCA2, OMIM 114480) or TP53 (OMIM 151623) variant, screening guidelines vary substantially, and cost-effectiveness analyses are scarce.

Objective

To assess the cost-effectiveness of magnetic resonance imaging (MRI) screening strategies for women with a 20% or more familial risk for breast cancer without a known BRCA1/2 or TP53 variant.

Design, Setting, and Participants

In this economic evaluation, conducted from February 1, 2019, to May 25, 2020, microsimulation modeling was used to estimate costs and effectiveness on a lifetime horizon from age 25 years until death of MRI screening among a cohort of 10 million Dutch women with a 20% or more familial risk for breast cancer without a known BRCA1/2 or TP53 variant. A Dutch screening setting was modeled. Most data were obtained from the randomized Familial MRI Screening (FaMRIsc) trial, which included Dutch women aged 30 to 55 years. A health care payer perspective was applied.

Interventions

Several screening protocols with varying ages and intervals including those of the randomized FaMRIsc trial, consisting of the mammography (Mx) protocol (annual mammography and clinical breast examination) and the MRI protocol (annual MRI and clinical breast examination plus biennial mammography).

Main Outcomes and Measures

Costs, life-years, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) were calculated and discounted by 3%. A threshold of €22 000 (US $24 795.87) per QALY was applied.

Results

This economic evaluation modeling study estimated that, on a lifetime horizon per 1000 women with the Mx protocol of the FaMRIsc trial, 346 breast cancers would be detected, and 49 women were estimated to die from breast cancer, resulting in 22 885 QALYs and total costs of €7 084 767 (US $7 985 134.61). The MRI protocol resulted in 79 additional QALYs and additional €2 657 266 (US $2 994 964.65). Magnetic resonance imaging performed only every 18 months between the ages of 35 and 60 years followed by the national screening program was considered optimal, with an ICER of €21 380 (US $24 097.08) compared with the previous nondominated strategy in the ranking, when applying the National Institute for Health and Care Excellence threshold. Annual screening alternating MRI and mammography between the ages of 35 and 60 years, followed by the national screening program, gave similar outcomes. Higher thresholds would favor annual MRI screening. The ICER was most sensitive to the unit cost of MRI and the utility value for ductal carcinoma in situ and localized breast cancer.

Conclusions and Relevance

This study suggests that MRI screening every 18 months between the ages of 35 and 60 years for women with a family history of breast cancer is cost-effective within the National Institute for Health and Care Excellence threshold for all densities. Higher thresholds would favor annual MRI screening. These outcomes support a change of current screening guidelines for this specific risk group and support MRI screening.

Local staging of ipsilateral breast tumor recurrence: mammography, ultrasound, or MRI?

BACKGROUND

Despite increasingly effective curative breast-conserving treatment (BCT) regimens for primary breast cancer, patients remain at risk for an ipsilateral breast tumor recurrence (IBTR). With increasing interest for repeat BCT in selected patients with IBTR, a reliable assessment of the size of IBTR is important for surgical planning.

AIM

The primary aim of this study is to establish the performance in size estimation of XMG, US, and breast MRI in patients with IBTR. The secondary aim is to compare the detection of multifocality and contralateral lesions between XMG and MRI.

PATIENTS AND METHODS

The sizes of IBTR on mammography (XMG), ultrasound (US), and magnetic resonance imaging (MRI) in 159 patients were compared to the sizes at final histopathology. The accuracy of the size estimates was addressed using Pearson's coefficient and Bland-Altman plots. Secondary outcomes were the detection of multifocality and contralateral lesions between XMG and MRI.

RESULTS

Both XMG and US significantly underestimated the tumor size by 3.5 and 4.8 mm, respectively, while MRI provided accurate tumor size estimation with a mean underestimation of 1.1 mm. The sensitivity for the detection of multifocality was significantly higher for MRI compared to XMG (25.5% vs. 5.5%). A contralateral malignancy was found in 4.4% of patients, and in 1.9%, it was detected by MRI only.

CONCLUSION

The addition of breast MRI to XMG and US in the preoperative workup of IBTR allows for more accurate size estimation. MRI provides a higher sensitivity for the detection of multifocality compared to XMG.

Harmonization of Quantitative Parenchymal Enhancement in T1 -Weighted Breast MRI

Background

Differences in imaging parameters influence computer‐extracted parenchymal enhancement measures from breast MRI.

Purpose

To investigate the effect of differences in dynamic contrast‐enhanced MRI acquisition parameter settings on quantitative parenchymal enhancement of the breast, and to evaluate harmonization of contrast‐enhancement values with respect to flip angle and repetition time.

Study Type

Retrospective.

Phantom/Populations

We modeled parenchymal enhancement using simulations, a phantom, and two cohorts (N = 398 and N = 302) from independent cancer centers.

Sequence Field/Strength

1.5T dynamic contrast‐enhanced T₁‐weighted spoiled gradient echo MRI. Vendors: Philips, Siemens, General Electric Medical Systems.

Assessment

We assessed harmonization of parenchymal enhancement in simulations and phantom by varying the MR parameters that influence the amount of T₁‐weighting: flip angle (8°–25°) and repetition time (4–12 msec). We calculated the median and interquartile range (IQR) of the enhancement values before and after harmonization. In vivo, we assessed overlap of quantitative parenchymal enhancement in the cohorts before and after harmonization using kernel density estimations. Cohort 1 was scanned with flip angle 20° and repetition time 8 msec; cohort 2 with flip angle 10° and repetition time 6 msec.

Statistical Tests

Paired Wilcoxon signed‐rank‐test of bootstrapped kernel density estimations.

Results

Before harmonization, simulated enhancement values had a median (IQR) of 0.46 (0.34–0.49). After harmonization, the IQR was reduced: median (IQR): 0.44 (0.44–0.45). In the phantom, the IQR also decreased, median (IQR): 0.96 (0.59–1.22) before harmonization, 0.96 (0.91–1.02) after harmonization. Harmonization yielded significantly (P < 0.001) better overlap in parenchymal enhancement between the cohorts: median (IQR) was 0.46 (0.37–0.58) for cohort 1 vs. 0.37 (0.30–0.44) for cohort 2 before harmonization (57% overlap); and 0.35 (0.28–0.43) vs. .0.37 (0.30–0.44) after harmonization (85% overlap).

Data Conclusion

The proposed practical harmonization method enables an accurate comparison between patients scanned with differences in imaging parameters.

Level of Evidence

3

Technical Efficacy Stage

4

Synchronous Breast Cancer: Phenotypic Similarities on MRI

Background

Previous studies have shown discrepancies between index and synchronous breast cancer in histology and molecular phenotype. It is yet unknown whether this observation also applies to the MRI phenotype.

Purpose

To investigate whether the appearance of breast cancer on MRI (i.e. phenotype) is different from that of additional breast cancer (i.e. synchronous cancer), and whether such a difference, if it exists, is associated with prognosis.

Study Type

Retrospective.

Population

In all, 464 consecutive patients with early‐stage ER+/HER2– breast cancer were included; 34/464 (7.3%) had 44 synchronous cancers in total (34 ipsilateral, 10 contralateral).

Sequence

1.5T, contrast‐enhanced T₁‐weighted.

Assessment

We assessed imaging phenotype using 50 quantitative features from each cancer and applied principal component analysis (PCA) to identify independent properties. The degree of phenotype difference was assessed. An association between phenotype differences and prognosis in terms of the Nottingham Prognostic Index (NPI) and PREDICT score were analyzed.

Statistical Tests

PCA; Wilcoxon rank sum test; Benjamini–Hochberg to control the false discovery rate.

Results

PCA identified eight components in patients with ipsilateral synchronous cancer. Six out of eight were significantly different between index and synchronous cancer. These components represented features describing texture (three components, P < 0.001, P < 0.001, P = 0.004), size (P < 0.001), smoothness (P < 0.001), and kinetics (P = 0.004). Phenotype differences in terms of the six components were split in tertiles. Larger phenotype differences in size, kinetics, and texture were associated with significantly worse prognosis in terms of NPI (P = 0.019, P = 0.045, P = 0.014), but not for the PREDICT score (P = 0.109, P = 0.479, P = 0.109). PCA identified six components in patients with contralateral synchronous cancer. None were significantly different from the index cancer (P = 0.178, P = 0.178, P = 0.178, P = 0.326, P = 0.739, P = 0.423).

Data Conclusion

The MRI phenotype of ER+/HER2– breast cancer was different from that of ipsilateral synchronous cancer and a large phenotype difference was associated with worse prognosis. No significant difference was found for synchronous contralateral cancer.

Level of Evidence: 3

Technical Efficacy: Stage 4

J. Magn. Reson. Imaging 2020;51:1858–1867.

Radiogenomic Analysis of Breast Cancer by Linking MRI Phenotypes with Tumor Gene Expression

Background Better understanding of the molecular biology associated with MRI phenotypes may aid in the diagnosis and treatment of breast cancer. Purpose To discover the associations between MRI phenotypes of breast cancer and their underlying molecular biology derived from gene expression data. Materials and Methods This is a secondary analysis of the Multimodality Analysis and Radiologic Guidance in Breast-Conserving Therapy, or MARGINS, study. MARGINS included patients eligible for breast-conserving therapy between November 2000 and December 2008 for preoperative breast MRI. Tumor RNA was collected for sequencing from surgical specimen. Twenty-one computer-generated MRI features of tumors were condensed into seven MRI factors related to tumor size, shape, initial enhancement, late enhancement, smoothness of enhancement, sharpness, and sharpness variation. These factors were associated with gene expression levels from RNA sequencing by using gene set enrichment analysis. Statistical significance of these associations was evaluated by using a sample permutation test and the false discovery rate. Results Gene expression and MRI data were obtained for 295 patients (mean age, 56 years ± 10.3 [standard deviation]). Larger and more irregular tumors showed increased expression of cell cycle and DNA damage checkpoint genes (false discovery rate <0.25; normalized enrichment statistic [NES], 2.15). Enhancement and sharpness of the tumor margin were associated with expression of ribosomal proteins (false discovery rate <0.25; NES, 1.95). Smoothness of enhancement, tumor size, and tumor shape were associated with expression of genes involved in the extracellular matrix (false discovery rate <0.25; NES, 2.25). Conclusion Breast cancer MRI phenotypes were related to their underlying molecular biology revealed by using RNA sequencing. The association between enhancements and sharpness of the tumor margin with the ribosome suggests that these MRI features may be imaging biomarkers for drugs targeting the ribosome. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Cho in this issue.

Abstract GS5-06: Towards omitting breast surgery in patients with a pathologic complete response after neoadjuvant systemic treatment: interim analysis of the MICRA trial (Minimally Invasive Complete Response Assessment)

Background and Objectives: Improvements in neoadjuvant systemic therapy (NST) for breast cancer patients have led to increasing rates of pathologic complete response (pCR). In patients with an excellent response, imaging alone is not reliable enough to differentiate between patients with residual disease, who should be surgically treated or patients with pCR where surgery could be considered overtreatment. Several trials currently investigate the accuracy of minimal invasive biopsies to assess presence of pCR of the breast. We initiated the MICRA trial (Minimal Invasive Complete Response Assessment NTR6120) combining MRI and minimal invasive biopsies of the breast.

Methods: Breast cancer patients treated with NST resulting in a radiologic complete (rCR) or partial response (rPR, &gt; 30 % decrease and &lt; 2 cm residual diameter) on MRI are eligible. Post-NST, eight ultrasound-guided 14G core biopsies of the pre-NST marked tumor area are obtained. Pathology results of biopsies and surgical specimens are compared. The primary endpoint is the false-negative rate (FNR) of the biopsy procedure i.e. the proportion of patients with non-pCR in the surgical specimen but with pCR in the biopsies. Here we report results of the interim analysis.

Results: 219 patients were enrolled in the trial. Biopsies were successfully obtained and analyzed in 167 patients. Main age was 49 yrs (range 24-74). Tumor subtype was 26% hormone receptor positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-), 14% HR-/HER2+, 36% triple negative and 24% HR+HER2+. 135 patients had a rCR and 32 patients a rPR on MRI. There were 89 patients (53%) with pCR in the surgical specimen, all correctly identified by post-NST biopsies (false-positive rate 0%). Post-NST biopsies however missed residual disease in 29/78 patients (FNR 37%). FNR was higher in patients with rCR (FNR 45%; 26/55 patients with residual disease missed on biopsies) than in patients with rPR (FNR 13 %; 3/23 patients with residual disease missed with biopsies). The conditional power estimating the probability of the FNR being ≤ 8% at final analysis was &lt; 1%.

MICRA patients total n=167Specimen negSpecimen posBiopsy neg8929118FNR= 29/7837%Biopsy pos049498978167

Conclusions: Ultrasound-guided core biopsies of the breast in patients with excellent response on MRI after NST are not accurate enough to safely select patients with pCR for omission of surgery.

Citation Format: Marie-Jeanne T.F.D. Vrancken Peeters, A van Loevezijn, M EM van der Noordaa, F H van Duijnhoven, C E Loo, E van Werkhoven, K K van de Vijver, T Wiersma, H AO Winter-Warnars, G S Sonke, C. Blanken, B. Zonnevels. Towards omitting breast surgery in patients with a pathologic complete response after neoadjuvant systemic treatment: interim analysis of the MICRA trial (Minimally Invasive Complete Response Assessment) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr GS5-06.

Supplemental MRI Screening for Women with Extremely Dense Breast Tissue

BACKGROUND

Extremely dense breast tissue is a risk factor for breast cancer and limits the detection of cancer with mammography. Data are needed on the use of supplemental magnetic resonance imaging (MRI) to improve early detection and reduce interval breast cancers in such patients.

METHODS

In this multicenter, randomized, controlled trial in the Netherlands, we assigned 40,373 women between the ages of 50 and 75 years with extremely dense breast tissue and normal results on screening mammography to a group that was invited to undergo supplemental MRI or to a group that received mammography screening only. The groups were assigned in a 1:4 ratio, with 8061 in the MRI-invitation group and 32,312 in the mammography-only group. The primary outcome was the between-group difference in the incidence of interval cancers during a 2-year screening period.

RESULTS

The interval-cancer rate was 2.5 per 1000 screenings in the MRI-invitation group and 5.0 per 1000 screenings in the mammography-only group, for a difference of 2.5 per 1000 screenings (95% confidence interval [CI], 1.0 to 3.7; P<0.001). Of the women who were invited to undergo MRI, 59% accepted the invitation. Of the 20 interval cancers that were diagnosed in the MRI-invitation group, 4 were diagnosed in the women who actually underwent MRI (0.8 per 1000 screenings) and 16 in those who did not accept the invitation (4.9 per 1000 screenings). The MRI cancer-detection rate among the women who actually underwent MRI screening was 16.5 per 1000 screenings (95% CI, 13.3 to 20.5). The positive predictive value was 17.4% (95% CI, 14.2 to 21.2) for recall for additional testing and 26.3% (95% CI, 21.7 to 31.6) for biopsy. The false positive rate was 79.8 per 1000 screenings. Among the women who underwent MRI, 0.1% had either an adverse event or a serious adverse event during or immediately after the screening.

CONCLUSIONS

The use of supplemental MRI screening in women with extremely dense breast tissue and normal results on mammography resulted in the diagnosis of significantly fewer interval cancers than mammography alone during a 2-year screening period. (Funded by the University Medical Center Utrecht and others; DENSE ClinicalTrials.gov number, NCT01315015.).

Feasibility of Micro-Computed Tomography Imaging for Direct Assessment of Surgical Resection Margins During Breast-Conserving Surgery

BACKGROUND

To analyze the feasibility and accuracy of micro-computed tomography (micro-CT) for surgical margin assessment in breast excision specimen.

MATERIALS AND METHODS

Two data sets of 30 micro-CT scans were retrospectively evaluated for positive resection margins by four observers in two phases, using pathology as a gold standard. Results of phase 1 were evaluated to define micro-CT evaluation guidelines for phase 2. Interobserver agreement was also assessed (kappa). In addition, a prospective study was conducted in which 40 micro-CT scans were directly acquired, reconstructed, and evaluated for positive resection margins by one observer. A suspect positive resection margin on micro-CT was annotated onto the specimen with ink, enabling local validation by pathology. Main outcome measures were accuracy, sensitivity, specificity, and positive predictive value (PPV).

RESULTS

Average accuracy, sensitivity, specificity, and PPV for the four observers were 63%, 38%, 70%, and 22%, respectively, in phase 1 and 72%, 40%, 78%, and 26%, respectively, in phase 2. The interobserver agreement was fair [kappa (range), 0.31 (0.12-0.80) in phase 1 and 0.23 (0-0.43) in phase 2]. In the prospective study 70% of the surgical resection margins were correctly evaluated. Ten specimens were annotated for positive resection margins, which correlated with three positive and three close (<1 mm) margins on pathology. Sensitivity, specificity, and PPV were 38%, 78%, and 30%, respectively.

CONCLUSIONS

Micro-CT imaging of breast excision specimen has moderate accuracy and considerable interobserver variation for analysis of surgical resection margins. Especially sensitivity and PPV need to be improved before micro-CT-based margin assessment can be introduced in clinical practice.

Simplex-based navigation tool for a posteriori selection of the preferred deformable image registration outcome from a set of trade-off solutions obtained with multiobjective optimization for the case of breast MRI

Multiobjective optimization approaches for deformable image registration (DIR) remove the need for manual adjustment of key parameters and provide a set of solutions that represent high-quality trade-offs between objectives of interest. Choosing a desired outcome a posteriori is potentially far more insightful as differences between solutions can be immediately visualized. The purpose of this work is to investigate whether such an approach allows clinical experts to intuitively select their preferred DIR outcome. To this end, we developed a simplex-based tool for solution navigation and asked 10 clinical experts to use it to choose their preferred DIR outcome from sets of trade-off solutions obtained for 10 breast magnetic resonance DIR cases of low (prone-prone DIR; n = 5 ) and high (prone-supine DIR; n = 5 ) difficulty, of patients and volunteers, respectively. The usability of the software is subsequently evaluated by the observers using the system usability scale. Further, the quality of the selected DIR outcomes is evaluated using the mean target registration error. Results show that the users are able to identify and select high-quality DIR outcomes, and attested to high learnability and usability of our software, supporting the validity of the presumed added value of taking a multiobjective perspective on DIR in clinical practice.

Abstract OT2-01-04: Towards omitting breast cancer surgery in patients with pathologic complete response after neoadjuvant systemic therapy: The MICRA trial (minimally invasive complete response assessment)

Background

Improvements in neoadjuvant systemic therapy (NST) for breast cancer patients have led to increasing rates of pathologic complete response (pCR). Breast-conserving surgery (BCS) after NST is considered safe, despite the fact that the original tumor bed is not entirely excised. It can therefore be hypothesized that breast surgery could be omitted in patients achieving pCR. However, since imaging modalities are insufficiently accurate to predict pCR after NST, the need for surgery is unchanged. The MICRA trial is designed to determine the value of ultrasound guided biopsy of the breast in identifying pCR after NST. The ultimate aim of our study is to eliminate surgery of the breast in patients achieving pCR, consequently improving quality of life of these patients.

Trial design

The MICRA trial is a multi-center observational prospective cohort study. Inclusion and exclusion criteria are presented in table 1. In all patients receiving NST, a marker is placed in the center of the tumor area pre-NST. Magnetic resonance imaging (MRI) is performed pre-NST and just before or after the last course of NST. Patients with radiologic complete response (rCR; complete absence of pathologic contrast enhancement) or partial response (rPR, 0.1-2.0 cm residual contrast enhancement, ≥30% decrease in tumour size) are eligible for participation. In these patients, 8 ultrasound guided biopsies are obtained in the region surrounding the marker: 4 central (&lt;0.5 cm) and 4 peripheral biopsies (0.5-1.5cm). Hereafter, conventional surgery is performed (BCS or mastectomy) and pathology results of the biopsies and resected specimen are compared. Pathology findings are scored using Miller-Payne criteria. To evaluate the quality and representativeness of the biopsies, biopsies are categorized according to length and pathology results.

Statistical analysis and accrual

The primary endpoint of the trial is the false-negative rate (FNR) of the biopsy procedure. If the true FNR is 3%, 130 patients without pCR in specimen are sufficient to show that the FNR does not exceed 8% using a one-sided binomial test with a significance α-level of 0.05. With an expected average pCR rate of 65%, 375 patients with rCR will be included. In the rPR-group the expected pCR rate is 12% and therefore 150 patients will be included. In total 525 patients will be included. Until now, 144 patients have been included.

Conclusion

The ultimate aim of the MICRA trial is to eliminate surgery of the breast in patients achieving pCR, by identifying pCR with use of ultrasound guided biopsy. In this scenario, local therapy in patients with pCR would be restricted to radiotherapy.

Table 1:Inclusion and exclusion criteriaInclusion criteriaExclusion criteriaWomen with invasive breast cancer &gt;18 years (all histological subtypes and tumor subtypes)DCIS as shown by core biopsy prior to NSTTumor histology and receptor status established by pre-NST biopsyWomen with distant metastatic diseaseComplete or partial response on post-NST MRIHistory of ipsilateral breast cancerMarker placed in tumor prior to NST Correct position of marker confirmed by mammography or ultrasound 

Citation Format: van der Noordaa ME, van Duijnhoven FH, Loo CE, van Loevezijn A, van Werkhoven E, van de Vijver KK, Wiersma T, Winter-Warnars HA, Sonke GS, Vrancken Peeters M-JT. Towards omitting breast cancer surgery in patients with pathologic complete response after neoadjuvant systemic therapy: The MICRA trial (minimally invasive complete response assessment) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT2-01-04.

Abstract P3-13-02: Breast conserving therapy after neoadjuvant systemic therapy in patients with T3 breast cancer is feasible

Background

An important advantage of neoadjuvant systemic therapy (NST) in breast cancer patients is down-sizing of the primary tumor. However, many patients with T3 tumors are treated with mastectomy regardless of response to NST. In this study, we evaluated predictive characteristics for positive margins and local control in T3 breast cancer patients who underwent breast-conserving therapy (BCT) after NST.

Methods

This single institution study included all clinical T3 breast cancer patients (determined by contrast-enhanced magnetic resonance imaging [MRI]) who underwent breast conserving surgery (BCS) after NST between 2000-2015. Clinical T3 was defined as a breast tumor &gt;50mm on MRI pre-NST. Patient, tumor and treatment characteristics were recorded, as well as response on MRI and final pathology. The local recurrence probability was estimated with the Kaplan-Meier method. Predictive characteristics for positive margins in patients undergoing BCS were analyzed using Fishers exact test.

Results

In total, 115 T3 patients were identified. Patient, tumor and MRI findings are presenting in the table. Median tumor size was 60 mm on MRI pre-NST (range 51-120 mm) and 4 mm after NST (range 0-58 mm). Overall pathologic complete response was 19%: 5% in HR+/HER2- patients, 32% in HR-/HER2+ patients and 40% in TN patients. After initial BCS, 73 patients had negative margins (63.5%), 18 focally positive margins (15.7%) and 24 more than focally positive margins (20.9%). Patients with HR+/HER2- tumors (52%) were more likely to have positive margins than patients with HR-/HER2+ and TN tumors (21% and 19%, p=0.002). In addition, positive margins rate was higher in patients with lobular carcinoma compared to patients with ductal carcinoma (57 vs 32%, p=0.031). Presence of non-mass enhancement on pre-NST MRI was predictive for positive margins (52% in patients with and 25% in patients without non-mass enhancement, p=0.003). Of patient with positive margins, 15 underwent radiotherapy with boost, 6 underwent re-excision and 21 underwent mastectomy. Finally, 94/115 patients were treated with BCT (82%). Of these patients, two had a local recurrence after a median follow-up of 6.5 years (6-year local recurrence probability 2.6% (95%-CI 0-7%).

Conclusion

In this series, BCT after NST was successful in 82% of patients with T3 breast cancer and local control in this group was excellent. The positive margin rate after BCS was higher in patients with HR+ tumors, lobular carcinoma and tumors with non-mass enhancement on MRI pre-NST. BCT should always be considered in T3 cancers after NST.

CharacteristicTotal (n=115)Positive margins (focally+ &gt;focally), n=42(%)p-valueHistology   0.031Ductal9229(32) Lobular2313(57) Subtype   0.002HR+/HER2-6132(52) HER2+347(21) TN203(15) MRI morphology of mass pre-NST   0.948Unifocal288(29) Multifocal4012(33) Multicentric134(31) Only non-mass enhancement34   MRI non-mass enhancement before NST   0.003Absent6516(25) Present5026(52) MRI response after NST   0.952rCR5218(35) non-rCR6221(38) Missing1   

Citation Format: van der Noordaa ME, Vrancken Peeters M-JM, Ioan I, Loo CE, van Urk J, van Werkhoven E, Voorthuis R, Wiersma T, Groen E, Rutgers ET, van Duijnhoven FH. Breast conserving therapy after neoadjuvant systemic therapy in patients with T3 breast cancer is feasible [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-13-02.

Towards the use of diffuse reflectance spectroscopy for real-time in vivo detection of breast cancer during surgery

Background

Breast cancer surgeons struggle with differentiating healthy tissue from cancer at the resection margin during surgery. We report on the feasibility of using diffuse reflectance spectroscopy (DRS) for real-time in vivo tissue characterization.

Methods

Evaluating feasibility of the technology requires a setting in which measurements, imaging and pathology have the best possible correlation. For this purpose an optical biopsy needle was used that had integrated optical fibers at the tip of the needle. This approach enabled the best possible correlation between optical measurement volume and tissue histology. With this optical biopsy needle we acquired real-time DRS data of normal tissue and tumor tissue in 27 patients that underwent an ultrasound guided breast biopsy procedure. Five additional patients were measured in continuous mode in which we obtained DRS measurements along the entire biopsy needle trajectory. We developed and compared three different support vector machine based classification models to classify the DRS measurements.

Results

With DRS malignant tissue could be discriminated from healthy tissue. The classification model that was based on eight selected wavelengths had the highest accuracy and Matthews Correlation Coefficient (MCC) of 0.93 and 0.87, respectively. In three patients that were measured in continuous mode and had malignant tissue in their biopsy specimen, a clear transition was seen in the classified DRS measurements going from healthy tissue to tumor tissue. This transition was not seen in the other two continuously measured patients that had benign tissue in their biopsy specimen.

Conclusions

It was concluded that DRS is feasible for integration in a surgical tool that could assist the breast surgeon in detecting positive resection margins during breast surgery.

Trail registration NIH US National Library of Medicine–clinicaltrails.gov, NCT01730365. Registered: 10/04/2012 https://clinicaltrials.gov/ct2/show/study/NCT01730365

Eligibility of patients for minimally invasive breast cancer therapy based on MRI analysis of tumor proximity to skin and pectoral muscle

There is growing interest in minimally invasive breast cancer therapy. Eligibility of patients is, however, dependent on several factors related to the tumor and treatment technology. The aim of this study is to assess the proportion of patients eligible for minimally invasive breast cancer therapy for different safety and treatment margins based on breast tumor location. Patients with invasive ductal cancer were selected from the MARGINS cohort. Semiautomatic segmentation of tumor, skin, and pectoral muscle was performed in Magnetic Resonance images. Shortest distances of tumors to critical organs (ie, skin and pectoral muscle) were calculated. Proportions of eligible patients were determined for different safety and treatment margins. Three-hundred-forty-eight patients with 351 tumors were included. If a 10 mm safety margin to skin and pectoral muscle is required without treatment margin, 72.3% of patients would be eligible for minimally invasive treatment. This proportion decreases to 45.9% for an additional treatment margin of 5 mm. Shortest distances between tumors and critical organs are larger in older patients and in patients with less aggressive tumor subtypes. If a 10 mm safety margin to skin and pectoral muscle is required, more than two-thirds of patients would be eligible for minimally invasive breast cancer therapy.

Breast conserving surgery for extensive DCIS using multiple radioactive seeds

BACKGROUND AND OBJECTIVES

Breast conserving surgery (BCS) can be challenging for large regions of ductal carcinoma in situ (DCIS), resulting in high rates of positive resection margins. Radioactive seed localization (RSL) using multiple radioactive iodine (¹²⁵I) seeds can be used to bracket extensive DCIS (eDCIS). The goal of this study was to retrospectively compare the use of a single or multiple ¹²⁵I seeds in RSL to enable BCS in patients with eDCIS.

METHODS

All patients with eDCIS (area of ≥3.0 cm) who underwent either single or multiple-seed RSL between January 2008 and December 2016 were included. Patient, tumor and surgery characteristics were compared between both groups. Primary outcome measures were positive resection margin and re-operation rates.

RESULTS

Respectively 48 and 58 patients with eDCIS underwent single- and multiple-seed RSL and subsequent BCS. The rate of positive resection margin (focal and more than focal) with single-seed RSL was 47.9%, compared to 29.3% with multiple-seed RSL (p = 0.06). The re-operation rate was 39.6% with single-seed RSL and 20.7% in the multiple-seed RSL group (p = 0.05).

CONCLUSION

Multiple-seed RSL enables bracketing of large areas of DCIS, with the potential to decrease the high rate of positive resection margins in this patient group.

Complementary Value of Contralateral Parenchymal Enhancement on DCE-MRI to Prognostic Models and Molecular Assays in High-risk ER+/HER2- Breast Cancer

Purpose: To determine whether markers of healthy breast stroma are able to select a subgroup of patients at low risk of death or metastasis from patients considered at high risk according to routine markers of the tumor.Experimental Design: Patients with ER⁺/HER2^- breast cancer were consecutively included for retrospective analysis. The contralateral parenchyma was segmented automatically on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), where upon the average of the top-10% late enhancement was calculated. This contralateral parenchymal enhancement (CPE) was analyzed with respect to routine prognostic models and molecular assays (Nottingham Prognostic Index, Dutch clinical chemotherapy-selection guidelines, 70-gene signature, and 21-gene recurrence score). CPE was split in tertiles and tested for overall and distant disease-free survival. CPE was adjusted for patient and tumor characteristics, as well as systemic therapy, using inverse probability weighting (IPW). Subanalyses were performed in patients at high risk according to prognostic models and molecular assays.Results: Four-hundred-and-fifteen patients were included, constituting the same group in which the association between CPE and survival was discovered. Median follow-up was 85 months, 34/415(8%) patients succumbed. After IPW-adjustment for patient and tumor characteristics, patients with high CPE had significantly better overall survival than those with low CPE in groups at high risk according to the Nottingham Prognostic Index [HR (95% CI): 0.08 (0.00-0.40), P < 0.001]; Dutch clinical guidelines [HR (95% CI): 0.22 (0.00-0.81), P = 0.021]; and 21-gene recurrence score [HR (95% CI): 0.14 (0.00-0.84), P = 0.030]. One group showed a trend [70-gene signature: HR (95% CI): 0.25 (0.00-1.02), P = 0.054].Conclusions: In patients at high risk based on the tumor, subgroups at relatively low risk were identified using pretreatment enhancement of the stroma on breast DCE-MRI. Clin Cancer Res; 23(21); 6505-15. ©2017 AACR.

Supine Breast MRI Using Respiratory Triggering

RATIONALE AND OBJECTIVES

This study aims to evaluate if navigator-echo respiratory-triggered magnetic resonance acquisition can acquire supine high-quality breast magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Supine respiratory-triggered magnetic resonance imaging (Trig-MRI) was compared to supine non-Trig-MRI to evaluate breathing-induced motion artifacts (group 1), and to conventional prone non-Trig-MRI (group 2, 16-channel breast coil), all at 3T. A 32-channel thorax coil was placed on top of a cover to prevent breast deformation. Ten volunteers were scanned in each group, including one patient. The acquisition time was recorded. Image quality was compared by visual examination and by calculation of signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and image sharpness (IS).

RESULTS

Scan time increased from 56.5 seconds (non-Trig-MRI) to an average of 306 seconds with supine Trig-MRI (range: 120-540 seconds). In group 1, the median values (interquartile range) of SNR, CNR, and IS improved from 11.5 (6.0), 7.3 (3.1), and 0.23 (0.2) cm on supine non-Trig-MRI to 38.1 (29.1), 32.8 (29.7), and 0.12 (0) cm (all P < 0.01) on supine Trig-MRI. All qualitative image parameters in group 1 improved on supine Trig-MRI (all P < 0.01). In group 2, SNR and CNR improved from 14.7 (6.8) and 12.6 (5.6) on prone non-Trig-MRI to 36.2 (12.2) and 32.7 (12.1) (both P < 0.01) on supine Trig-MRI. IS was similar: 0.10 (0) cm vs 0.11 (0) cm (P = 0.88).

CONCLUSIONS

Acquisition of high-quality supine breast MRI is possible when respiratory triggering is applied, in a similar setup as during subsequent treatment. Image quality improved when compared to supine non-triggered breast MRI and prone breast MRI, but at the cost of increased acquisition time.

The feasibility of manual parameter tuning for deformable breast MR image registration from a multi-objective optimization perspective

Deformable image registration is typically formulated as an optimization problem involving a linearly weighted combination of terms that correspond to objectives of interest (e.g. similarity, deformation magnitude). The weights, along with multiple other parameters, need to be manually tuned for each application, a task currently addressed mainly via trial-and-error approaches. Such approaches can only be successful if there is a sensible interplay between parameters, objectives, and desired registration outcome. This, however, is not well established. To study this interplay, we use multi-objective optimization, where multiple solutions exist that represent the optimal trade-offs between the objectives, forming a so-called Pareto front. Here, we focus on weight tuning. To study the space a user has to navigate during manual weight tuning, we randomly sample multiple linear combinations. To understand how these combinations relate to desirability of registration outcome, we associate with each outcome a mean target registration error (TRE) based on expert-defined anatomical landmarks. Further, we employ a multi-objective evolutionary algorithm that optimizes the weight combinations, yielding a Pareto front of solutions, which can be directly navigated by the user. To study how the complexity of manual weight tuning changes depending on the registration problem, we consider an easy problem, prone-to-prone breast MR image registration, and a hard problem, prone-to-supine breast MR image registration. Lastly, we investigate how guidance information as an additional objective influences the prone-to-supine registration outcome. Results show that the interplay between weights, objectives, and registration outcome makes manual weight tuning feasible for the prone-to-prone problem, but very challenging for the harder prone-to-supine problem. Here, patient-specific, multi-objective weight optimization is needed, obtaining a mean TRE of 13.6 mm without guidance information reduced to 7.3 mm with guidance information, but also providing a Pareto front that exhibits an intuitively sensible interplay between weights, objectives, and registration outcome, allowing outcome selection.

Monitoring tumor response to neoadjuvant chemotherapy using MRI and 18F-FDG PET/CT in breast cancer subtypes

Purpose

To explore guidelines on the use of MRI and PET/CT monitoring primary tumor response to neoadjuvant chemotherapy (NAC), taking breast cancer subtype into account.

Materials and methods

In this prospective cohort study, 188 women were included with stages II and III breast cancer. MRI and ¹⁸F-FDG-PET/CT were acquired before and during NAC. Baseline pathology was assessed from tumor biopsy. Tumors were stratified into HER2-positive, ER-positive/HER2-negative (ER-positive), and ER-negative/PR-negative/HER2-negative (triple-negative) subtypes, and treated according to subtype. Primary endpoint was pathological complete response (pCRmic) defined as no or only small numbers of scattered invasive tumor cells. We evaluated imaging scenarios using MRI only, PET/CT only, and combinations.

Results

pCRmic was found in 35/46 (76.1%) of HER2-positive, 11/87 (12.6%) of ER-positive, and 31/55 (56.4%) of triple-negative tumors. For HER2-positive tumors, MRI yielded the strongest predictor (AUC: 0.735; sensitivity 36.2%), outperforming PET/CT (AUC: 0.543; p = 0.04), and with comparable results to combined imaging (AUC: 0.708; p = 0.213). In ER-positive tumors, the combination of MRI and PET/CT was slightly superior (AUC: 0.818; sensitivity 55.8%) over MRI alone (AUC: 0.742; p = 0.117) and PET/CT alone (AUC: 0.791). However, even though relatively large numbers of ER-positive tumor patients were included, no significant differences were yet found. For triple-negative tumors, MRI (AUC: 0.855; sensitivity 45.4%), PET/CT (AUC: 0.844; p = 0.220) and combined imaging (AUC: 0.868; p = 0.213) yielded comparable results.

Conclusions

For HER2-positive tumors, MRI shows significant advantage over PET/CT. For triple-negative tumors, comparable results were seen for MRI, PET/CT and combined imaging. For ER-positive tumors, combining MRI with PET/CT may result in optimal response monitoring, although not yet significantly.

MRI predicts pathologic complete response in HER2-positive breast cancer after neoadjuvant chemotherapy

BACKGROUND

Neoadjuvant treatment of HER2-positive breast cancer frequently leads to a pathologic complete response (pCR), which is associated with favourable long-term outcome. Treatment regimens typically consist of 6-9 cycles of trastuzumab-based chemotherapy, although many patients achieve early radiologic complete response (rCR). If rCR accurately predicts pCR, the number of chemotherapy cycles can possibly be reduced.

METHODS

We performed a diagnostic accuracy study to determine the association between rCR and pCR in patients with stage II-III HER2-positive breast cancer treated with neoadjuvant trastuzumab-based chemotherapy at the Netherlands Cancer Institute. RCR was defined as the disappearance of pathologic contrast enhancement in the original tumour region on repeated magnetic resonance imaging (MRI). PCR was defined as the absence of invasive tumour cells in the resected breast specimen (ypT0/is). Diagnostic accuracy was estimated in the overall population and in subgroups based on hormone receptor (HR) status. The prognostic value of rCR for recurrence-free interval was evaluated as an exploratory analysis.

RESULTS

We identified 296 eligible patients with 297 HER2-positive tumours (154 HR-negative and 143 HR-positive) treated with neoadjuvant trastuzumab-based chemotherapy between 2004 and 2016. Overall, the rCR rate was 69% (206/297) and the pCR rate was 61% (181/297). Among 206 patients with rCR, 150 also had pCR (negative predictive value [NPV] = 150/206 = 73%). Among 91 patients without rCR, 60 had residual tumour at pathology (positive predictive value [PPV] = 60/91 = 66%). The NPV was better in HR-negative compared to HR-positive tumours (88 vs. 57%), while the PPV was better in HR-positive tumours (50 vs. 78%). Achieving rCR was associated with a 5-year recurrence-free interval of 88% compared to 68% without rCR (hazard ratio 0.34, 95% confidence interval 0.17-0.65, P = 0.001).

CONCLUSION

Achieving rCR corresponds well with pCR in HER2-positive breast cancer, particularly in the HR-negative subgroup. RCR is also associated with improved long-term outcome.

Feasibility of magnetic marker localisation for non-palpable breast cancer

OBJECTIVES

Accurate tumour localisation is essential for breast-conserving surgery of non-palpable tumours. Current localisation technologies are associated with disadvantages such as logistical challenges and migration issues (wire guided localisation) or legislative complexities and high administrative burden (radioactive localisation). We present MAgnetic MArker LOCalisation (MaMaLoc), a novel technology that aims to overcome these disadvantages using a magnetic marker and a magnetic detection probe. This feasibility study reports on the first experience with this new technology for breast cancer localisation.

MATERIALS AND METHODS

Fifteen patients with unifocal, non-palpable breast cancer were recruited. They received concurrent placement of the magnetic marker in addition to a radioactive iodine seed, which is standard of care in our clinic. In a subset of five patients, migration of the magnetic marker was studied. During surgery, a magnetic probe and gammaprobe were alternately used to localise the markers and guide surgery. The primary outcome parameter was successful transcutaneous identification of the magnetic marker. Additionally, data on radiologist and surgeon satisfaction were collected.

RESULTS

Magnetic marker placement was successful in all cases. Radiologists could easily adapt to the technology in the clinical workflow. Migration of the magnetic marker was negligible. The primary endpoint of the study was met with an identification rate of 100%. Both radiologists and surgeons reflected that the technology was intuitive to use and that it was comparable to radioactive iodine seed localisation.

CONCLUSION

Magnetic marker localisation for non-palpable breast cancer is feasible and safe, and may be a viable non-radioactive alternative to current localisation technologies.

Using DRS during breast conserving surgery: identifying robust optical parameters and influence of inter-patient variation

Successful breast conserving surgery consists of complete removal of the tumor while sparing healthy surrounding tissue. Despite currently available imaging and margin assessment tools, recognizing tumor tissue at a resection margin during surgery is challenging. Diffuse reflectance spectroscopy (DRS), which uses light for tissue characterization, can potentially guide surgeons to prevent tumor positive margins. However, inter-patient variation and changes in tissue physiology occurring during the resection might hamper this light-based technology. Here we investigate how inter-patient variation and tissue status (in vivo vs ex vivo) affect the performance of the DRS optical parameters. In vivo and ex vivo measurements of 45 breast cancer patients were obtained and quantified with an analytical model to acquire the optical parameters. The optical parameter representing the ratio between fat and water provided the best discrimination between normal and tumor tissue, with an area under the receiver operating characteristic curve of 0.94. There was no substantial influence of other patient factors such as menopausal status on optical measurements. Contrary to expectations, normalization of the optical parameters did not improve the discriminative power. Furthermore, measurements taken in vivo were not significantly different from the measurements taken ex vivo. These findings indicate that DRS is a robust technology for the detection of tumor tissue during breast conserving surgery.

Survival is associated with complete response on MRI after neoadjuvant chemotherapy in ER-positive HER2-negative breast cancer

Background

Pathological complete remission (pCR) of estrogen receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer is rarely achieved after neoadjuvant chemotherapy (NAC). In addition, the prognostic value of pCR for this breast cancer subtype is limited. We explored whether response evaluation by magnetic resonance imaging (MRI) is associated with recurrence-free survival after NAC in ER-positive/HER2-negative breast cancer.

Methods

MRI examinations were performed in 272 women with ER-positive/HER2-negative breast cancer before, during and after NAC. MRI interpretation included lesion morphology at baseline, changes in morphology and size, and contrast uptake kinetics. These MRI features, clinical characteristics and final pathology were correlated with recurrence-free survival.

Results

The median follow up time was 41 months. There were 35 women with events, including 19 breast-cancer-related deaths. On multivariable analysis, age younger than 50 years (hazard ratio (HR) = 2.55, 95 % confidence interval (CI) 1.3, 5.02, p = 0.007), radiological complete response after NAC (HR = 14.11, CI 1.81, 1818; p = 0.006) and smaller diameters of washout/plateau enhancement at MRI after NAC (HR = 1.02, CI 1.00, 1.04, p = 0.036) were independently associated with best recurrence-free survival. Pathological response was not significant; HR = 2.12, CI 0.86, 4.64, p = 0.096.

Conclusions

MRI after NAC in ER-positive/HER2-negative tumors may be predictive of recurrence-free survival. A radiological complete response at MRI after NAC is associated with an excellent prognosis.

Abstract P4-02-07: Association between computer-derived features of the ipsilateral breast on DCE-MRI and the 70-gene signature in patients with invasive breast cancer

Introduction

Molecular assays such as the 70-gene signature are increasingly used as prognostic indicators to select chemotherapy in individual patients. These assays are typically derived from postoperative excision specimens and require several weeks to complete. Earlier assessment of the results of such assays could open up new therapeutic options in subgroups of patients, potentially avoiding overtreatment of early breast cancer. Although molecular assays may be derived from biopsied tissue, tumor heterogeneity may cause uncertainty. Dynamic contrast-enhanced MRI (DCE-MRI) depicts some of the hallmarks of cancer that are tested by these molecular essays. The goal of this study was to investigate the association between the postoperatively derived 70-gene signature and computer-derived DCE-MRI features of the ipsilateral breast prior to surgery.

Material and Methods

Sixty-nine patients with node-negative invasive breast cancer were enrolled between 2003 and 2006. These patients received a preoperative MRI in study setting and a postoperative 70-gene signature assay. Association between preoperative features and the 70-gene signature was evaluated using a computer prediction model combining clinical features and automatically extracted MRI features. The clinical features were age at diagnosis and largest tumor diameter on MRI. The MRI features were rate of contrast uptake in the tumor, rate of wash-out, tumor volume, and two features from the intramammary blood vessel tree (total length and mean rate of contrast uptake). The features were transformed into an orthogonal feature set using principal component analysis. Association with the 70-gene signature (positive or negative indication for systemic therapy) was evaluated using binary logistic regression. Model performance was measured using the area under the receiver operating characteristics curve (AUC) after bootstrap validation using 200 iterations. Two operating points were examined: one to predict a positive 70-gene signature with high certainty (i.e., at high positive-predictive value (PPV)) and one to predict a negative signature with high certainty (i.e., at high negative-predictive value (PPV)).

Results

The average patient age at diagnosis was 48 years (range: 32-58). The median largest tumor diameter on MRI was 17 mm (range: 5-40). The 70-gene signature was positive in 29/69 (42%) patients. The computer prediction model achieved an AUC of 0.72 after bootstrap validation. At high PPV, 10/29 (34.5%) positive 70-gene signatures were identified preoperatively at the expense of 2/40 (5.0%) false-positive. The PPV was 10/12 (83.3%). At high NPV, 12/40 (30.0%) negative 70-gene signatures were identified at the expense of 1/29 (3.5%) false-negative signature. The NPV was 12/13 (92.3%).

Conclusion

Computer-derived DCE-MRI features from the ipsilateral breast in combination with clinical parameters show potential to preoperatively assess a negative outcome of the 70-gene signature in approximately one-third of the total patient group.

Citation Format: van der Velden BHM, Schmitz AMTh, Loo CE, Gilhuijs KGA. Association between computer-derived features of the ipsilateral breast on DCE-MRI and the 70-gene signature in patients with invasive breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-02-07.

Radioactive seed localization in breast cancer treatment

Background

Breast cancer screening, improved imaging and neoadjuvant systemic therapy (NST) have led to increased numbers of non-palpable tumours suitable for breast-conserving surgery (BCS). Accurate tumour localization is essential to achieve a complete resection in these patients. This study evaluated the role of radioactive seed localization (RSL) in improving breast- and axilla-conserving surgery in patients with breast cancer with or without NST.

Methods

Patients who underwent RSL between 2007 and 2014 were included. Learning curves were analysed by the rates of minimally involved (in situ/invasive tumour cells on a length of 0–4 mm on ink) and positive resection margins (over 4 mm on ink) after BCS, and the median resection volume over time.

Results

A total of 367 patients with in situ carcinomas and 199 with non-palpable invasive breast cancer underwent RSL before primary surgery. A further 697 patients had RSL before NST, of whom 206 also underwent RSL of a histologically verified axillary lymph node metastasis. BCS was performed in 93·2 and 87·9 per cent of patients undergoing primary surgery for in situ and invasive tumours respectively, and 57·5 per cent of those in the NST group. The rate of BCS with positive resection margins was low and stable over time in the three groups (9·1, 9·7 and 11·2 per cent respectively). The median resection volume decreased significantly with time in the invasive cancer and NST groups.

Conclusion

In the present study of more than 1200 patients and 7 years of experience, RSL was shown to facilitate breast- and axilla-conserving surgery in a diverse patient population. There was a significant reduction in resection volume while maintaining low positive resection margin rates after BCS.

The prognostic value of the neoadjuvant response index in triple-negative breast cancer: validation and comparison with pathological complete response as outcome measure

The Neoadjuvant response index (NRI) has been proposed as a simple measure of downstaging by neoadjuvant treatment in breast cancer. It was previously found to predict recurrence-free survival (RFS) in triple-negative (TN) breast cancer. It was at least as accurate as the standard binary system, the absence or presence of a pathological complete remission (pCR), which is the commonly employed outcome measure. The NRI was evaluated in an independent consecutive series of patients to validate the previous findings. Univariable and multivariable analyses were done to assess the predictive value of clinical parameters and of the NRI for RFS. We combined the original and validation series of patients to build a multivariable predictive model for RFS after neoadjuvant chemotherapy in TN breast cancer. The validation set (N = 108) confirmed that patients with a higher-than-median NRI (>0.7) had excellent RFS (P = 0.002), similar to that of patients who had achieved a pCR. Multivariable analysis in 191 patients showed that the NRI was a strong independent predictor of RFS (P = 0.0002), with N-stage (P = 0.001) and T-stage (P = 0.014) ranking second and third, respectively. Importantly, among patients who did not achieve a pCR (NRI values below 1), higher NRI values were still associated with better RFS. The NRI is a simple method and a practical tool to predict RFS in TN breast cancer patients treated with neoadjuvant chemotherapy. It adds prognostic information to the presence or absence of pCR and could be useful to compare the efficacies of different chemotherapy regimens.

Abstract OT3-6-01: The LORD trial: A randomized, non-inferiority trial, between active surveillance versus standard treatment in patients with low risk ductal carcinoma in situ

Background

The goal in treating patients with ductal carcinoma in situ (DCIS) is to prevent the development of invasive breast cancer (iBC). However, a substantial number of DCIS lesions will never form a health hazard, particularly if it concerns slow-growing, low-grade DCIS. The conventional treatment of low-grade DCIS is similar to that of early-stage iBC, i.e. breast-conserving surgery (BCS) often followed by radiotherapy (RT), or mastectomy, and possibly hormonal therapy (HT). This implies that many women might be unnecessarily going through intensive treatment resulting in a decrease in quality of life and an increase in health care costs, without any survival benefit.

Trial Design

LORD is a randomized, international, multicenter, phase III non-inferiority trial. Patients will be randomized between active surveillance and standard treatment according to local policy. Active surveillance comprises monitoring by annual mammography and treatment if there is progression to iBC or higher grade DCIS. Standard treatment encompasses BCS only, BCS + RT, or mastectomy, possibly followed by HT, and follow-up by annual mammography.

Eligibility criteria

• Women ≥49 years

• Referral to the hospital solely based on microcalcifications detected by population-based or opportunistic screening mammography

• Unilateral, pure DCIS grade I based on multiple vacuum assisted biopsies

• No prior history of iBC or DCIS

Specific Aims

Our aim is to investigate whether active surveillance of low-grade DCIS is as safe as the current standard treatment, and to study the effects on quality of life of these women by saving them from intensive treatment. The primary end-point is time to ipsilateral iBC (iiBC). Secondary end-points include rate of iBC at final pathology after standard treatment, radical intervention rate, and biopsy rate during follow-up. Tissue will be collected for genomic profiling and proteomics to detect iBC risk patterns in low-grade DCIS. Furthermore we aim to develop an online informational aid for clinicians and patients to facilitate the dissemination and understanding of information on low-grade DCIS and its treatment.

Statistical Methods

We apply a special type of non-inferiority design, where the alternative hypothesis corresponds to "minor inferiority". We assume that the iiBC-free rate in the standard arm at 5 years equals 97.6%. The hazard ratio under the null hypothesis is 3.4 and the hazard ratio under the alternative hypothesis is 2.1, corresponding to iiBC-free rates in the experimental arm of 92.0% and 95.0% respectively. With a one-sided log-rank test for non-inferiority with α=0.05 and β=0.2, 124 events are needed for which 1842 low-grade DCIS patients need to be randomized during an accrual period of 5.5 years, and the accrual period will be followed by a further follow-up period of 7.5 years.

Present Accrual and Target accrual

The LORD trial is endorsed by the Dutch Breast Cancer Research Group (BOOG 2014-04) and the European Organisation for Research and Treatment of Cancer (EORTC 1401). Participating sites will be identified mid-2014. Patient accrual is expected to start early 2015.

Citation Format: Lotte E Elshof, Konstantinos Tryfonidis, Leen Slaets, A Elise van Leeuwen-Stok, Nicolas Dif, Victoria P Skinner, Claudette E Loo, Gonneke Warnars, Eveline Bleiker, Ruud M Pijnappel, Nina Bijker, Emiel JTh Rutgers, Jelle Wesseling. The LORD trial: A randomized, non-inferiority trial, between active surveillance versus standard treatment in patients with low risk ductal carcinoma in situ [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr OT3-6-01.

Heading toward radioactive seed localization in non-palpable breast cancer surgery? A meta-analysis

Wire-guided localization is the most commonly used technique for intraoperative localization of non-palpable breast cancer. Radioactive seed localization (RSL) is becoming more popular and seems to be a reliable alternative for intraoperative lesion localization. The purpose of the present meta-analysis was to evaluate the use of RSL. Primary study outcomes were irradicality and re-excision rates. In total 3168 patients were included. The clinical adaptation shows growing confidence in RSL and further growth is expected.

Cost-effectiveness of screening women with familial risk for breast cancer with magnetic resonance imaging

BACKGROUND

To reduce mortality, women with a family history of breast cancer are often screened with mammography before age 50 years. Additional magnetic resonance imaging (MRI) improves sensitivity and is cost-effective for BRCA1/2 mutation carriers. However, for women with a family history without a proven mutation, cost-effectiveness is unclear.

METHODS

We evaluated data of the largest prospective MRI screening study (MRISC). Between 1999 and 2007, 1597 women (8370 woman-years at risk) aged 25 to 70 years with an estimated cumulative lifetime risk of 15% to 50% for breast cancer were screened with clinical breast examination every 6 months and with annual mammography and MRI. We calculated the cost per detected and treated breast cancer. After incorporating MRISC data into a microsimulation screening analysis model (MISCAN), different schemes were evaluated, and cost per life-year gained (LYG) was estimated in comparison with the Dutch nationwide breast cancer screening program (biennial mammography from age 50 to 75 years). All statistical tests were two-sided.

RESULTS

Forty-seven breast cancers (9 ductal carcinoma in situ) were detected. Screening with additional MRI costs $123 672 (€93 639) per detected breast cancer. In increasing age-cohorts, costs per detected and treated breast cancer decreased, but, unexpectedly, the percentage of MRI-only detected cancers increased. Screening under the MRISC-scheme from age 35 to 50 years was estimated to reduce breast cancer mortality by 25% at $134 932 (€102 164) per LYG (3.5% discounting) compared with 17% mortality reduction at $54 665 (€41 390) per LYG with mammography only.

CONCLUSIONS

Screening with MRI may improve survival for women with familial risk for breast cancer but is expensive, especially in the youngest age categories.