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Purpose: To develop a convolutional neural network (CNN) model to diagnose skull-base invasion by nasopharyngeal malignancies in CT images and evaluate the model's diagnostic performance. Materials and methods: We divided 100 malignant nasopharyngeal tumor lesions into a training (n = 70) and a test (n = 30) dataset. Two head/neck radiologists reviewed CT and MRI images and determined the positive/negative skull-base invasion status of each case (training dataset: 29 invasion-positive and 41 invasion-negative; test dataset: 13 invasion-positive and 17 invasion-negative). Preprocessing involved extracting continuous slices of the nasopharynx and clivus. The preprocessed training dataset was used for transfer learning with Residual Neural Networks 50 to create a diagnostic CNN model, which was then tested on the preprocessed test dataset to determine the invasion status and model performance. Original CT images from the test dataset were reviewed by a radiologist with extensive head/neck imaging experience (senior reader: SR) and another less-experienced radiologist (junior reader: JR). Gradient-weighted class activation maps (Grad-CAMs) were created to visualize the explainability of the invasion status classification. Results: The CNN model's diagnostic accuracy was 0.973, significantly higher than those of the two radiologists (SR: 0.838; JR: 0.595). Receiver operating characteristic curve analysis gave an area under the curve of 0.953 for the CNN model (versus 0.832 and 0.617 for SR and JR; both p < 0.05). The Grad-CAMs suggested that the invasion-negative cases were present predominantly in bone marrow, while the invasion-positive cases exhibited osteosclerosis and nasopharyngeal masses. Conclusions: This CNN technique would be useful for CT-based diagnosis of skull-base invasion by nasopharyngeal malignancies. [ABSTRACT FROM AUTHOR]

Abstract Background The aim of this study is to evaluate the prognostic value of grading MRI–detected skull-base invasion in nasopharyngeal carcinoma (NPC) with skull-base invasion after intensity-modulated radiotherapy (IMRT). Methods This study is a retrospective chart review of 469 non-metastatic NPC patients with skull-base invasion. Patients were classified as extensive skull-base invasion (ESBI) group and limited skull-base invasion (LSBI) group. Results Multivariate analysis showed that the skull-base invasion (LSBI vs. ESBI) was an independent prognostic predictor of progression free survival (PFS). The estimated 5-year local failure free survival (LFFS), distant metastasis free survival (DMFS), PFS, and overall survival (OS) rates for patients in the T3-LSBI and T3-ESBI group were 92.9% versus 93.5, 89.8% versus 86.1, 81.6% versus 76.4, and 93.5% versus 86.3%, respectively (P > 0.05). Conclusion Grading of MRI-detected skull-base invasion is an independent prognostic factor of NPC with skull-base invasion. It is scientific and reasonable for skull-base invasion as a single entity to be classified as T3 classification.

Purpose: To compare the clinical results and functional outcomes between two-dimensional conventional radiation therapy (2DRT) and intensity-modulated radiation therapy (IMRT) in nasopharyngeal carcinoma (NPC) with skull-base invasion. Methods: A total of 1258 patients were subclassified into two groups: mild skull-base invasion group (792; 63%) and severe skull-base invasion group (466; 37%). Patients were pair matched (1:1 ratio) using six clinical factors into 2DRT or IMRT groups. The Kaplan–Meier method and Cox regression model were performed to assess overall survival (OS), disease-free survival (DFS), locoregional relapse-free survival (LRRFS) and distant metastasis-free survival (DMFS). Toxicities were evaluated. Results: IMRT significantly improved four-year OS compared with 2DRT (65.6% vs. 81.8%, P = 0.000), DFS (57.3% vs. 73.3%, P = 0.000) and LRRFS (76.5% vs. 87.5%, P = 0.003) in NPC with severe skull-base invasion, but similar results were observed in patients with mild skull-base invasion (P > 0.05). In patients with severe invasion, radiation therapy techniques were found to be an independent prognostic factor for OS (HR = 0.457, P = 0.000), DFS (HR = 0.547, P = 0.000) and LRRFS (HR = 0.503, P = 0.004). IMRT was associated with better OS. In subgroups analysis, IMRT group also had a better survival in OS, DFS (P < 0.05 for all rates) for patients received concurrent chemotherapy and sequential chemotherapy compared to 2DRT in the severe invasion group. The IMRT group displayed lower incidence of mucositis, xerostomia, trismus (< 1 cm) and temporal lobe necrosis than the 2DRT group. Conclusions: IMRT significantly improved patient survival compared with 2DRT in NPC patients with severe skull-base invasion, but a similar survival rate was noted in mild invasion patients. Chemotherapy can improve survival in NPC patients with severe invasion. Among the two therapies, IMRT significantly decreased therapy-related toxicity. [ABSTRACT FROM AUTHOR]

Highlights • The T classification of skull-base invasion in NPC patients should be refined. • We recommend that patients with only pterygoid process and/or base of the sphenoid bone invasion not be defined as T3 but, rather, as T2. Abstract Purpose To investigate the prognostic value of skull-base invasion (SBI) for nasopharyngeal carcinoma (NPC), propose a subclassification of SBI. Methods 792 and 433 patients with pathologically proven NPC and complete clinical and magnetic resonance imaging records at Sun Yat-sen University Cancer Center and Foshan Hospital were enrolled, and investigated using heat map/cluster, network and survival analyses. Results The results of heat map/cluster analyses and network analysis showed that T3 patients with pterygoid process and/or base of the sphenoid bone invasion (T3 slight) had better treatment outcomes than those with other SBIs (T3 severe). Significant differences were observed between T3-slight and T3-severe groups with regard to 5-year overall survival (OS) (93.0% vs. 83.5%, p = 0.014) and progression-free survival (PFS) (82.5% vs. 74.1%, p = 0.044) rates. No significant difference was observed between T3-slight group and T2 patients with regard to 5-year OS (93.0% vs. 84.7%, p = 0.062) and PFS (82.5% vs. 78.9%, p = 0.459) rates. Therefore, we downgraded patients with T3 slight to T2, yielding a new T classification sample. The survival curves of the 5-year OS and PFS rates of T2 and T3 were more reasonable after sample redistribution than those before sample redistribution. The differences in the 5-year OS and PFS rates between T2 and T3 patients after sample redistribution approached significance (p = 0.075 and 0.051, respectively). Conclusions Different types of SBIs had different effects on the prognosis for NPC. We recommend patients with T3 slight not be defined as T3 but, rather, as T2. [ABSTRACT FROM AUTHOR]

Background: The aim of this study is to evaluate the prognostic value of grading MRI-detected skull-base invasion in nasopharyngeal carcinoma (NPC) with skull-base invasion after intensity-modulated radiotherapy (IMRT).Methods: This study is a retrospective chart review of 469 non-metastatic NPC patients with skull-base invasion. Patients were classified as extensive skull-base invasion (ESBI) group and limited skull-base invasion (LSBI) group.Results: Multivariate analysis showed that the skull-base invasion (LSBI vs. ESBI) was an independent prognostic predictor of progression free survival (PFS). The estimated 5-year local failure free survival (LFFS), distant metastasis free survival (DMFS), PFS, and overall survival (OS) rates for patients in the T3-LSBI and T3-ESBI group were 92.9% versus 93.5, 89.8% versus 86.1, 81.6% versus 76.4, and 93.5% versus 86.3%, respectively (P > 0.05).Conclusion: Grading of MRI-detected skull-base invasion is an independent prognostic factor of NPC with skull-base invasion. It is scientific and reasonable for skull-base invasion as a single entity to be classified as T3 classification. [ABSTRACT FROM AUTHOR]

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Background. Our aim was to grade MRI-detected skull-base invasion in nasopharyngeal carcinoma and evaluate the prognostic value of the grading. Methods. The MRI scans and medical records of 924 patients with histologically diagnosed nondisseminated nasopharyngeal carcinoma were reviewed retrospectively. Results. MRI-detected skull-base invasion was not found to be an independent prognostic factor for overall survival, distant metastasis-free survival, or local relapse-free survival ( p > .05 for all). Grading of skull-base erosion according to the site of invasion was found to be an independent prognostic factor for both overall survival ( p = .003 and p = .006, respectively) and distant metastasis-free survival ( p = .001 for both) in the 512 patients with skull-base invasions and 315 patients with T3 disease. Conclusions. MRI-detected skull-base invasion is not an independent prognostic factor for nasopharyngeal carcinoma. However, grading according to the site of invasion as either low grade or severe has prognostic value. © 2010 Wiley Periodicals, Inc. Head Neck, 2010 [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To evaluate patterns of skull base invasion and its possible impact on tumor (T)-staging in nasopharyngeal carcinoma (NPC) using magnetic resonance imaging (MRI). Materials and methods: 838 consecutive newly diagnosed by biopsy proven and untreated patients with NPC underwent MRI. The skull-base invasion of NPC was classified according to their incidence from proximal sites to more distant sites surrounding the nasopharynx as: high (≥35%), medium (≥5–35%), and low (<5%) groups. A retrospective analysis of data consisting of a 5-year follow-up was carried out. The skull base invasion was related to their tumor (T) staging and prognosis at the 5-year follow-up after treatment with definitive radiation therapy. In addition, a survival health-related quality of life (QOL), overall survival (OS), local relapse-free survival (LRFS) and distant metastasis-free survival (DMFS) were also assessed among the three groups. Results: The total incidence of skull-base invasion was 65.51% (549/838). The differences in T-stage distribution, and the total survival health-related QOL, among the three groups were statistically significant (χ 2 =160.45, p <0.005; χ 2 =38.43, p <0.005, respectively). The differences between any two of the three groups were also significant, except when the medium grade was compared to the low grade. Significant differences were observed with regard to 5-year OS (83.2%, 74.7%, 59.2%, p =0.000) and DMFS (95.0%, 88.0%, 88.0%, p =0.016); no significant difference was observed in LRFS (95.3%, 95.6%, 91.23%, p =0.450). Conclusions: The results indicate that medium and low group displayed similar findings of skull base invasion, and survival status. We, therefore, propose that patients in these two groups be grouped under T4 in the TNM classification that might have a bearing in implementing optimum treatment. [Copyright &y& Elsevier]