Test-Retest Data for the Assessment of Breast MRI Radiomic Feature Repeatability.

BACKGROUND: Radiomic features extracted from breast MRI have potential for diagnostic, prognostic, and predictive purposes. However, before they can be used as biomarkers in clinical decision support systems, features need to be repeatable and reproducible. OBJECTIVE: Identify repeatable radiomics features within breast tissue on prospectively collected MRI exams through multiple test-retest measurements. STUDY TYPE: Prospective. POPULATION: 11 healthy female volunteers. FIELD STRENGTH/SEQUENCE: 1.5 T; MRI exams, comprising T2-weighted turbo spin-echo (T2W) sequence, native T1-weighted turbo gradient-echo (T1W) sequence, diffusion-weighted imaging (DWI) sequence using b-values 0/150/800, and corresponding derived ADC maps. ASSESSMENT: 18 MRI exams (three test-retest settings, repeated on 2 days) per healthy volunteer were examined on an identical scanner using a fixed clinical breast protocol. For each scan, 91 features were extracted from the 3D manually segmented right breast using Pyradiomics, before and after image preprocessing. Image preprocessing consisted of 1) bias field correction (BFC); 2) z-score normalization with and without BFC; 3) grayscale discretization using 32 and 64 bins with and without BFC; and 4) z-score normalization + grayscale discretization using 32 and 64 bins with and without BFC. STATISTICAL TESTS: Features' repeatability was assessed using concordance correlation coefficient(CCC) for each pair, i.e. each MRI was compared to each of the remaining 17 MRI with a cut-off value of CCC > 0.90. RESULTS: Images without preprocessing produced the highest number of repeatable features for both T1W sequence and ADC maps with 15 of 91 (16.5%) and 8 of 91 (8.8%) repeatable features, respectively. Preprocessed images produced between 4 of 91 (4.4%) and 14 of 91 (15.4%), and 6 of 91 (6.6%) and 7 of 91 (7.7%) repeatable features, respectively for T1W and ADC maps. Z-score normalization produced highest number of repeatable features, 26 of 91 (28.6%) in T2W sequences, in these images, no preprocessing produced 11 of 91 (12.1%) repeatable features. DATA CONCLUSION: Radiomic features extracted from T1W, T2W sequences and ADC maps from breast MRI exams showed a varying number of repeatable features, depending on the sequence. Effects of different preprocessing procedures on repeatability of features were different for each sequence. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 1.

Radiomics for precision medicine: Current challenges, future prospects, and the proposal of a new framework.

The advancement of artificial intelligence concurrent with the development of medical imaging techniques provided a unique opportunity to turn medical imaging from mostly qualitative, to further quantitative and mineable data that can be explored for the development of clinical decision support systems (cDSS). Radiomics, a method for the high throughput extraction of hand-crafted features from medical images, and deep learning -the data driven modeling techniques based on the principles of simplified brain neuron interactions, are the most researched quantitative imaging techniques. Many studies reported on the potential of such techniques in the context of cDSS. Such techniques could be highly appealing due to the reuse of existing data, automation of clinical workflows, minimal invasiveness, three-dimensional volumetric characterization, and the promise of high accuracy and reproducibility of results and cost-effectiveness. Nevertheless, there are several challenges that quantitative imaging techniques face, and need to be addressed before the translation to clinical use. These challenges include, but are not limited to, the explainability of the models, the reproducibility of the quantitative imaging features, and their sensitivity to variations in image acquisition and reconstruction parameters. In this narrative review, we report on the status of quantitative medical image analysis using radiomics and deep learning, the challenges the field is facing, propose a framework for robust radiomics analysis, and discuss future prospects.

Reducing Seroma Formation and Its Sequelae After Mastectomy by Closure of the Dead Space: A Multi-center, Double-Blind Randomized Controlled Trial (SAM-Trial).

BACKGROUND: Seroma is a common complication after mastectomy, with an incidence of 3% to 85%. Seroma is associated with pain, delayed wound healing, and additional outpatient clinic visits, leading potentially to repeated seroma aspiration or even surgical interventions. This study aimed to assess the effect of flap fixation using sutures or tissue glue in preventing seroma formation and its sequelae. METHODS: Between June 2014 and July 2018, 339 patients with an indication for mastectomy or modified radical mastectomy were enrolled in this randomized controlled trial in the Netherlands. Patients were randomly allocated to one of the three following arms: conventional wound closure (CON, n = 115), flap fixation using sutures (FFS, n = 111) or flap fixation using tissue glue (FFG, n = 113). The primary outcome was the need for seroma aspiration. The secondary outcomes were additional outpatient department visits, surgical-site infection, shoulder function and mobility, cosmesis, skin-dimpling, and postoperative pain scores. RESULTS: Flap fixation after mastectomy leads to fewer seroma aspirations than conventional wound closure (CON 17.5% vs FFS 7.3% vs FFG 10.8%; p = 0.057), with a significant difference between flap fixation with sutures and conventional wound closure (odds ratio [OR], 0.37; 95% confidence interval [CI], 0.16-0.89; p = 0.025). Flap fixation has no significant negative effect on surgical-site infections, shoulder function and mobility, cosmesis, skin-dimpling, or postoperative pain. CONCLUSION: Flap fixation using sutures leads to a significant reduction in aspirations of post-mastectomy seromas. The authors strongly advise surgeons to use sutures for flap fixation in patients undergoing mastectomy. (ClinicalTrials.gov no. NCT03305757). PREREGISTRATION: The trial was registered after enrollment of the first participant. However, no specific explanation exists for this except that through the years more importance has been given to central trial registration. Our research team can ensure that after enrollment of the first participant, no changes were made to the trial, analysis plan, and/or study design.

Risk of Positive Sentinel Lymph Node After Neoadjuvant Systemic Therapy in Clinically Node-Negative Breast Cancer: Implications for Postmastectomy Radiation Therapy and Immediate Breast Reconstruction.

BACKGROUND: Residual axillary lymph node involvement after neoadjuvant systemic therapy (NST) is the determining factor for postmastectomy radiation therapy (PMRT). Preoperative identification of patients needing PMRT is essential to enable shared decision-making when choosing the optimal timing of breast reconstruction. We determined the risk of positive sentinel lymph node (SLN) after NST in clinically node-negative (cN0) breast cancer. METHODS: All cT1-3N0 patients treated with NST followed by mastectomy and SLNB between 2010 and 2016 were identified from the Netherlands Cancer Registry. Rate of positive SLN for different breast cancer subtypes was determined. Logistic regression analysis was performed to determine correlated clinicopathological variables with positive SLN. RESULTS: In total 788 patients were included, of whom 25.0% (197/788) had positive SLN. cT1-3N0 ER+HER2+, cT1-3N0 ER-HER2+ , and cT1-2N0 triple-negative patients had the lowest rate of positive SLN: 7.2-11.5%, 0-6.3%, and 2.9-6.2%, respectively. cT1-3N0 ER+HER2- and cT3N0 triple-negative patients had the highest rate of positive SLN: 23.8-41.7% and 30.4%, respectively. Multivariable regression analysis showed that cT2 (odds ratio [OR] 1.93; 95% confidence interval [CI] 1.01-3.96), cT3 (OR 2.56; 95% CI 1.30-5.38), grade 3 (OR 0.44; 95% CI 0.21-0.91), and ER+HER2- subtype (OR 3.94; 95% CI 1.77-8.74) were correlated with positive SLN. CONCLUSIONS: In cT1-3N0 ER+HER2+, cT1-3N0 ER-HER2+, and cT1-2N0 triple-negative patients treated with NST, immediate reconstruction can be considered an acceptable option due to low risk of positive SLN. In cT1-3N0 ER+HER2- and cT3N0 triple-negative patients treated with NST, risks and benefits of immediate reconstruction should be discussed with patients due to the relatively high risk of positive SLN.

A systematic review of flap fixation techniques in reducing seroma formation and its sequelae after mastectomy.

BACKGROUND: Seroma formation is a common complication after mastectomy. This review aims to elucidate which surgical techniques are most effective in reducing the dead space and therefore seroma formation in patients undergoing mastectomy. METHODS: A literature search was performed to identify clinical studies comparing any form of flap fixation to conventional closure technique in patients undergoing mastectomy with or without axillary clearance. Studies were eligible for inclusion if outcome was described in terms of seroma formation and/or complications of seroma formation. Studies on animal research or breast reconstruction with tissue expanders or flap harvesting (latissimus dorsi) were excluded. RESULTS: A total of nine articles were eligible for inclusion. Five were retrospective studies and four were prospective. Retrospective and prospective studies have demonstrated the higher incidence of seroma formation in patients not undergoing mechanical flap fixation. The incidence of seroma-related complications in these studies vary. Four out of the nine studies demonstrate that patients undergoing flap fixation, need significantly fewer seroma aspirations. There are very few studies on the use of tissue glues preventing seroma formation. CONCLUSION: The scientific body of evidence favoring flap fixation after mastectomy is convincing. Mechanical flap fixation seems to reduce seroma formation and seroma aspiration after mastectomy. There are, however, no well-powered randomized controlled trials evaluating all aspects of seroma formation and its sequelae. Further research should elucidate whether flap fixation using sutures or tissue glue is superior.

A multi-center, double blind randomized controlled trial evaluating flap fixation after mastectomy using sutures or tissue glue versus conventional closure: protocol for the Seroma reduction After Mastectomy (SAM) trial.

BACKGROUND: Seroma formation is a common complication after mastectomy and is associated with delayed wound healing, infection, skin flap necrosis, patient discomfort and repeated visits to the out patient clinic to deal with seroma and its sequelae. Closing the dead space after mastectomy seems to be key in reducing seroma and its complications. Various methods have been described to reduce the dead space after mastectomy: closed suction drainage, quilting of the skin flaps and application of adhesive tissue glues. The aim of this trial is to compare seroma formation and its sequelae in the various methods of flap fixation. METHODS: This is a multicenter, double-blind, randomized controlled trial in female breast cancer patients undergoing mastectomy, with or without axillary clearance. Exclusion criteria consist of breast conserving therapy, direct breast reconstruction and incapacity to comprehend implications and extent of study and unable to sign for informed consent. A total of 336 patients will be randomized. Patients will be randomly allocated to one of three treatment arms consisting of flap fixation using ARTISS tissue glue with a low suction drain, flap fixation using sutures and a low suction drain or conventional wound closure (without flap fixation) and low suction drainage. Follow up will be conducted up to twelve months post surgery. The primary outcome is the number of seroma aspirations and secondary outcomes consist of number of out patient clinic visits, surgical skin infection rate, shoulder function, cosmesis, health-related quality of life and costs and cost-effectiveness (cost/QALY). DISCUSSION: This is the first study of its kind to evaluate the effect of flap fixation and its sequelae (ie seroma aspirations, number of out patient clinic visits, infection, shoulder function, patient assessed cosmesis, quality of life and cost-effectiveness) in a double blind randomized controlled trial. TRIAL REGISTRATION: This trial was approved by the hospitals' joint medical ethical committee (14-T-21, 2 June 2014). The SAM Trial is registered in ClinicalTrials.gov since October 2017, Identifier: NCT03305757 .

Economic evaluation of flap fixation techniques after mastectomy: Results of a double-blind randomized controlled trial (SAM-trial).

BACKGROUND: An economic evaluation was performed alongside an RCT investigating flap fixation in reducing seroma formation after mastectomy. The evaluation focused on the first year following mastectomy and assessed cost-effectiveness from a health care and societal perspective. METHODS: The economic evaluation was conducted between 2014 and 2018 in four Dutch breast clinics. Patients with an indication for mastectomy or modified radical mastectomy were randomly assigned to: conventional closure (CON), flap fixation with sutures (FFS) or flap fixation with tissue glue (FFG). Health care costs, patient and family costs and costs due to productivity losses were assessed. Outcomes were expressed in incremental cost-effectiveness ratios (ICERs): the incremental cost per quality-adjusted life year (QALY). Bootstrapping techniques, sensitivity and secondary analyses were employed to address uncertainty. RESULTS: The FFS-group yielded most QALYs (0.810; 95%-CI 0.755-0.856), but also incurred the highest mean costs at twelve months (€10.416; 95%-CI 8.231-12.930). CON was the next best alternative with 0.794 QALYs (95%-CI 0.733-0.841) and mean annual costs of €10.051 (95%-CI 8.255-12.044). FFG incurred fewer QALYs and higher costs, when compared to the CON group. The ICER of FFS compared to CON was €22.813/QALY. Applying a willingness to pay threshold in the Netherlands of €20.000/QALY, the probability that FFS was cost-effective was 42%, compared to 37% and 21% for CON and FFG, respectively. CONCLUSION: The cost-effectiveness of FFS following mastectomy, versus CON and FFG, is uncertain from a societal perspective. Yet, from a health care and hospital perspective FFS is likely to be the most cost-effective intervention.

MRI-based radiomics in breast cancer: feature robustness with respect to inter-observer segmentation variability.

Radiomics is an emerging field using the extraction of quantitative features from medical images for tissue characterization. While MRI-based radiomics is still at an early stage, it showed some promising results in studies focusing on breast cancer patients in improving diagnoses and therapy response assessment. Nevertheless, the use of radiomics raises a number of issues regarding feature quantification and robustness. Therefore, our study aim was to determine the robustness of radiomics features extracted by two commonly used radiomics software with respect to variability in manual breast tumor segmentation on MRI. A total of 129 histologically confirmed breast tumors were segmented manually in three dimensions on the first post-contrast T1-weighted MR exam by four observers: a dedicated breast radiologist, a resident, a Ph.D. candidate, and a medical student. Robust features were assessed using the intraclass correlation coefficient (ICC > 0.9). The inter-observer variability was evaluated by the volumetric Dice Similarity Coefficient (DSC). The mean DSC for all tumors was 0.81 (range 0.19-0.96), indicating a good spatial overlap of the segmentations based on observers of varying expertise. In total, 41.6% (552/1328) and 32.8% (273/833) of all RadiomiX and Pyradiomics features, respectively, were identified as robust and were independent of inter-observer manual segmentation variability.

Exploring breast cancer response prediction to neoadjuvant systemic therapy using MRI-based radiomics: A systematic review.

PURPOSE: MRI-based tumor response prediction to neoadjuvant systemic therapy (NST) in breast cancer patients is increasingly being studied using radiomics with outcomes that appear to be promising. The aim of this study is to systematically review the current literature and reflect on its quality. METHODS: PubMed and EMBASE databases were systematically searched for studies investigating MRI-based radiomics for tumor response prediction. Abstracts were screened by two reviewers independently. The quality of the radiomics workflow of eligible studies was assessed using the Radiomics Quality Score (RQS). An overview of the methodologies used in steps of the radiomics workflow and current results are presented. RESULTS: Sixteen studies were included with cohort sizes ranging from 35 to 414 patients. The RQS scores varied from 0 % to 41.2 %. Methodologies in the radiomics workflow varied greatly, especially region of interest segmentation, features selection, and model development with heterogeneous outcomes as a result. Seven studies applied univariate analysis and nine studies applied multivariate analysis. Most studies performed their analysis on the pretreatment dynamic contrast-enhanced T1-weighted sequence. Entropy was the best performing individual feature with AUC values ranging from 0.83 to 0.85. The best performing multivariate prediction model, based on logistic regression analysis, scored a validation AUC of 0.94. CONCLUSION: This systematic review revealed large methodological heterogeneity for each step of the MRI-based radiomics workflow, consequently, the (overall promising) results are difficult to compare. Consensus for standardization of MRI-based radiomics workflow for tumor response prediction to NST in breast cancer patients is needed to further improve research.

Analysis of TNF-α and interleukin-6 in seroma of patients undergoing mastectomy with or without flap fixation: is there a predictive value for seroma formation and its sequelae?

BACKGROUND: Seroma formation is a common complication after mastectomy. Flap fixation has the potential to prevent seroma formation, but identifying patients that are at risk of developing seroma, remains challenging. The aim of this study was to assess the association between pro-inflammatory cytokines in seroma fluid one day after surgery and seroma formation and it sequelae. METHODS: Patients undergoing mastectomy were randomized into one of three groups: no flap fixation, flap fixation using sutures or flap fixation using tissue glue. Seroma samples from 40 consecutive patients undergoing mastectomy were collected on the first postoperative day for analysis of interleukin-6 and tumor necrosis factor-α. Seroma formation and its sequelae were assessed in the outpatient clinic ten days, six weeks and three months after surgery. RESULTS: TNF-α concentrations were not detectable in the seroma samples of any of the 40 patients. BMI (p = 0.001) and weight of the resected surgical specimen (p = 0.003) were associated with higher IL-6 levels in seroma on the first postoperative day after mastectomy. A higher seroma concentration of IL-6 was associated with significantly fewer patients with clinical seroma formation three months after surgery (p = 0.027). CONCLUSION: IL-6 is associated with clinical seroma formation three months after surgery. There is however no evident association between IL-6 and complications related to seroma formation. Higher IL-6 levels are predictive of less long-term seroma formation. Application of flap fixation does not seem to influence the level of IL-6.