A nomogram to predict the probability of axillary lymph node metastasis in early breast cancer patients with positive axillary ultrasound

Among patients with a preoperative positive axillary ultrasound, around 40% of them are pathologically proved to be free from axillary lymph node (ALN) metastasis. We aimed to develop and validate a model to predict the probability of ALN metastasis as a preoperative tool to support clinical decision-making. Clinicopathological features of 322 early breast cancer patients with positive axillary ultrasound findings were analyzed. Multivariate logistic regression analysis was performed to identify independent predictors of ALN metastasis. A model was created from the logistic regression analysis, comprising lymph node transverse diameter, cortex thickness, hilum status, clinical tumour size, histological grade and estrogen receptor, and it was subsequently validated in another 234 patients. Coefficient of determination (R-2) and the area under the ROC curve (AUC) were calculated to be 0.9375 and 0.864, showing good calibration and discrimination of the model, respectively. The false-negative rates of the model were 0% and 5.3% for the predicted probability cut-off points of 7.1% and 13.8%, respectively. This means that omission of axillary surgery may be safe for patients with a predictive probability of less than 13.8%. After further validation in clinical practice, this model may support increasingly limited surgical approaches to the axilla in breast cancer

Establishment and Verification of a Bagged-Trees-Based Model for Prediction of Sentinel Lymph Node Metastasis for Early Breast Cancer Patients

Purpose: Lymph node metastasis is a multifactorial event. Several scholars have developed nomograph models to predict the sentinel lymph nodes (SLN) metastasis before operation. According to the clinical and pathological characteristics of breast cancer patients, we use the new method to establish a more comprehensive model and add some new factors which have never been analyzed in the world and explored the prospect of its clinical application.Materials and methods: The clinicopathological data of 633 patients with breast cancer who underwent SLN examination from January 2011 to December 2014 were retrospectively analyzed. Because of the imbalance in data, we used smote algorithm to oversample the data to increase the balanced amount of data. Our study for the first time included the shape of the tumor and breast gland content. The location of the tumor was analyzed by the vector combining quadrant method, at the same time we use the method of simply using quadrant or vector for comparing. We also compared the predictive ability of building models through logistic regression and Bagged-Tree algorithm. The Bagged-Tree algorithm was used to categorize samples. The SMOTE-Bagged Tree algorithm and 5-fold cross-validation was used to established the prediction model. The clinical application value of the model in early breast cancer patients was evaluated by confusion matrix and the area under receiver operating characteristic (ROC) curve (AUC).Results: Our predictive model included 12 variables as follows: age, body mass index (BMI), quadrant, clock direction, the distance of tumor from the nipple, morphology of tumor molybdenum target, glandular content, tumor size, ER, PR, HER2, and Ki-67.Finally, our model obtained the AUC value of 0.801 and the accuracy of 70.3%.We used logistic regression to established the model, in the modeling and validation groups, the area under the curve (AUC) were 0.660 and 0.580.We used the vector combining quadrant method to analyze the original location of the tumor, which is more precise than simply using vector or quadrant (AUC 0.801 vs. 0.791 vs. 0.701, Accuracy 70.3 vs. 70.3 vs. 63.6%).Conclusions: Our model is more reliable and stable to assist doctors predict the SLN metastasis in breast cancer patients before operation

Classification Of Lymph Node Metastases In Breast Cancer With Features From Tissue Images Using Machine Learning Techniques

Determining the metastatic involvement of lymph node is very crucial in designing the treatment plans in breast cancer. Traditional way of detecting the lymph node metastases involves manual histopathological examination of specimen, which is subjective and tiresome process. In this thesis, an automated system to classify lymph node metastases in breast cancer with features from digitized tissue images is proposed. The proposed system consists of applying different machine learning algorithms for classification together with various feature selection techniques. minimum Redundancy Maximum Relevance(mRMR), wrapper methods, area under the ROC curve of random forest (AUCRF), and least absolute shrinkage and selection operator (LASSO) were implemented to select the most relevant features among 214 original features. Various classification models were learned using selected features to classify between metastatic and non-metastatic samples. Among the models learned, random forest model showed to perform better than others. The results obtained from this thesis show encouraging signs for automated classification of lymph node metastases in breast cancer with features from digitized tissues images with the application of machine learning techniques. Also, results show that feature selection helps in removing irrelevant and redundant features, which not only deceases the computational time of classification algorithms but can also enhances the classification performance

Combined supervised and unsupervised learning to identify subclasses of disease for better prediction

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonDisease subtyping, which aids in the development of personalised treatments, remains a challenge in data analysis because of the many different ways to group patients based upon their data. However, if I can identify subclasses of disease, this will help to develop better models that are more specific to individuals and should therefore improve prediction and understanding of the underlying characteristics of the disease in question. In addition, patients might suffer from multiple disease complications. Models that are tailored to individuals could improve both prediction of multiple complications and understanding of underlying disease characteristics. However, AI models can become outdated over time due to either sudden changes in the underlying data, such as those caused by new measurement methods, or incremental changes, such as the ageing of the study population. This thesis proposes a new algorithm that integrates consensus clustering methods with classification in order to overcome issues with sample bias. The method was tested on a freely available dataset of real-world breast cancer cases and data from a London hospital on systemic sclerosis, a rare and potentially fatal condition. The results show that nearest consensus clustering classification improves accuracy and prediction significantly when this algorithm is compared with competitive similar methods. In addition, this thesis proposes a new algorithm that integrates latent class models with classification. The new algorithm uses latent class models to cluster patients within groups; this results in improved classification and aids in the understanding of the underlying differences of the discovered groups. The method was tested on data from patients with systemic sclerosis (SSc), a rare and potentially fatal condition, and coronary heart disease. Results show that the latent class multi-label classification (MLC) model improves accuracy when compared with competitive similar methods. Finally, this thesis implemented the updated concept drift method (DDM) to monitor AI models over time and detect drifts when they occur. The method was tested on data from patients with SSc and patients with coronavirus disease (COVID)

Sistema Inteligente de Ayuda a la Decisión para el Diagnóstico Temprano de la Meningitis

Fecha de lectura de Tesis Doctoral: 18 febrero 2020La meningitis es una enfermedad pandémica que sufren muchos países poco desarrollados, principalmente debido a la falta de recursos económicos. El tipo más grave de meningitis, la enfermedad meningocócica, exige una atención médica inmediata ya que retrasos en su diagnóstico aumentan el riesgo de mortalidad. Esta tesis propone un sistema inteligente de ayuda a la decisión, basado en una arquitectura de Sistemas Multiagente, con el objetivo de ayudar a los médicos en las diferentes etapas del diagnóstico precoz de la meningitis, a través, principalmente, de síntomas observables. El sistema integra tres componentes inteligentes que aplican técnicas de aprendizaje automático basadas en árboles y técnicas de ingeniería del conocimiento. En los estudios realizados en el marco de este trabajo para obtener estos modelos y validarlos, se emplearon un conjunto de datos reales constituido por 26.228 registros de pacientes con diagnóstico de meningitis, procedentes de Brasil. Los resultados ponen de manifiesto que el sistema es capaz de determinar con éxito si el paciente tiene meningitis, si esta es meningocócica y si es viral o bacteriana