Stereotactic ablative radiotherapy (SABR) delivers a high dose of radiation to a small area and is frequently used to treat cancer patients with metastatic lesions in the lung. Selecting the appropriate prescription is a balance of delivering enough radiation to lesions to prevent recurrence, and minimizing the radiation delivered to organs at risk (OARs) to limit side effects. After a radiation oncologist (RO) selects a prescription, treatment planning software is used to create the dose distribution, and calculate radiation delivered to the lesions and OARs. If dose constraints are not met, a different prescription must be selected, and the process is repeated. Planning SABR treatments is resource intensive, and repeated iterations can lead to treatment delays. Recently, machine learning techniques have been used to create a dose distribution for a given SABR prescription. Thus far, these techniques only target single lesions and are not commonly implemented clinically. In this work, we create a conditional generative adversarial network (GAN) with a U-NET backbone to estimate the dose distribution of SABR treatments to 2-6 lesions in the lung. The GAN is conditioned on contours of the OARs and lesions, CT images, and an initial dose estimation. A novel loss function is used during training. Through the mean squared error and dose metrics used by ROs, the output of the GAN demonstrates good agreement with the ground truth dose. The model will allow ROs to efficiently compare prescriptions options, reduce departmental workload by the multidisciplinary team, and circumvent treatment delivery delays for patients.
Patients with oropharyngeal cancer (OPC) treated with chemoradiation experience weight loss and tumor shrinkage. As a result, many of these patients will require a replan during radiation treatment. We aimed to develop a machine learning model to predict the need for a replan in patients with OPC (n=315). A total of 78 patients (25%) required a replan. The dataset was split into independent training (n=220) and testing (n=95) datasets. Tumor volumes and organs at risk (OARs) were contoured on planning CT images prior to treatment. PyRadiomics was used to compute radiomic features from the primary tumor, nodal volumes, and parotid glands. Clinical and dose features extracted from the OARs were collected and those significantly associated with the need for a replan in the training dataset were used in a baseline model. Feature selection was applied to select the optimal radiomic features. Classifiers were built using the non-correlated selected radiomic, clinical, and dose features on the training dataset and performance was assessed in the testing dataset. Three clinical and one dose feature were incorporated into the baseline model, as well as into the combined models. Eight predictive radiomic features were selected. The baseline model achieved an AUC of 0.66 [95% CI: 0.51-0.79] in the testing dataset. The Naïve Bayes was the top-performing radiomics model and achieved an AUC of 0.80 [95% CI: 0.69-0.90] in the testing dataset, outperforming the baseline model (p=0.005). This model could assist physicians in identifying patients who may benefit from a replan, improving the replanning workflow.
Patients with oropharyngeal cancer (OPC) treated with chemoradiation suffer treatment-related toxicities which can lead to nutritional deficiencies and weight loss. As a result, many of these patients will require supportive care interventions, such as a feeding tube. We aimed to develop a machine learning model to predict feeding tube insertion in patients with OPC (n=343). A total of 116 patients (34%) required a feeding tube. Primary gross tumor volumes were contoured on planning CT images for patients prior to treatment. PyRadiomics was used to compute 1212 radiomic features from these volumes on the original and filtered images. The dataset was split into independent training (n=244) and testing (n=99) datasets. LASSO feature selection was applied to select the optimal features to predict feeding tube insertion. Support vector machine (SVM) and random forest (RF) classifiers were built using the selected features on the training dataset. The machine learning models’ performances were assessed in the testing dataset based on the metric of the AUC. Through feature selection, seven predictive features were selected. This included one original texture, two filtered first order, three filtered texture, and one clinical feature. The top performing classifier was the RF model which achieved an AUC of 0.69 [95% CI: 0.57-0.80] in the testing dataset. To the best of our knowledge, this is the first study to use radiomics to predict feeding tube insertion. This model could assist physicians in identifying patients who may benefit from prophylactic feeding tube insertion, ultimately improving quality of life for patients with OPC.
Non-small cell lung cancer (NSCLC) is one of the leading causes of death worldwide. Medical imaging is used to determine cancer staging; however, these images may hold additional information which could be utilized to aid in outcome prediction. A multi-modality radiomics approach incorporating quantitative and qualitative features from the tumor and its surrounding regions, along with clinical features, has yet to be explored. Therefore, we hypothesize that a model containing CT and PET radiomic features, in addition to clinical and qualitative features, has the potential improve risk-stratification of NSCLC patients better than cancer stage alone. Our dataset consisted of 135 NSCLC patients (training: n=94, testing: n=41) who underwent surgical resection. Each region of interest was segmented using a semi-automatic approach on both the pre-treatment CT and PET images. Radiomic features were extracted using the Quantitative Image Feature Engine. A total of 1030 features were extracted including clinical, qualitative, and radiomic features. LASSO regression was used to identify the top features to predict time to recurrence in the training cohort and the model was evaluated in the testing cohort. A total of nine features were selected, including two clinical, one CT, and six PET radiomic features. The model achieved a concordance of 0.81 in the training cohort, which was validated in the testing cohort (concordance=0.79) and outperformed stage alone (concordances=0.68-0.69). This model has the potential to assist physicians in risk-stratifying patients with NSCLC and could be used to identify patients that may benefit from more aggressive or personalized treatment options.
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