Nasopharyngeal carcinoma with skull base invasion: a necessity of staging subdivision

Diagnosis of skull-base invasion by nasopharyngeal tumors on CT with a deep-learning approach

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.

Headache Attributed to Disorder of the Cranium and Base of the Skull

The article describes the approach to imaging that clinicians should adopt in cases of headaches suspected to be secondary to cranial vault or skull-base disorder. As a rule, computed tomography (CT) is superior to MRI for most of the osseous lesions, and lesions of the middle and external ear. MRI provides a complimentary role to CT and is the modality of choice in a few conditions such as extraosseous neoplasms of the skull base.

Skull Base Regeneration During Treatment With Chemoradiation for Nasopharyngeal Carcinoma: A Case Report

BACKGROUND

Advanced cases of nasopharyngal carcinoma can present with skull base invasion. Treatment of these advanced cases with radiotherapy poses a challenge given proximity of tumor to critical neural structures as well as concern that a skull base defect and associated complications could develop with tumor regression.

CASE PRESENTATION

A 34-year-old male patient presented with a 7-cm nasopharyngeal tumor invading the skull base with destruction of the clivus and intracranial extension. He underwent a course of definitive chemoradiation, requiring use of adaptive radiotherapy, that resulted in complete tumor regression and is free of disease 5 years posttreatment. Imaging done during treatment demonstrated that significant regeneration of bone occurred simultaneously with tumor regression.

CONCLUSIONS

This case demonstrates that it is possible for bony regeneration to occur simultaneously with tumor regression in a patient with skull base invasion by tumor, precluding the need for neurosurgical intervention.

MiR196a-5p in extracellular vesicles released from human nasopharyngeal carcinoma enhance the phagocytosis and secretion of microglia by targeting ROCK1

The microenvironment of the brain has become increasingly recognized as an essential regulator in metastatic and primary brain tumors. Recent studies demonstrate that circulating tumor-derived exosomes are critical for the brain tumor microenvironment. Nasopharyngeal carcinoma (NPC), a malignant tumor of the head and neck, often invades the skull base but infrequently extends to brain parenchyma. Neurobiological communication between microglia and tumor-derived extracellular vesicles (EVs) has been extensively studied, but how NPC cells regulate the immune microenvironment in the brain remains unknown. Here, we report that NPC derived EVs lead to increased microglial phagocytosis and proliferation, and heightened levels of IL-6, IL-8, CXCL1 and TGF-β1. Analysis of microRNAs in EVs reveal that miR196a-5p is the major effector microRNA. Moreover, we demonstrate an enrichment of miR196a-5p in the plasmatic EVs of NPC patients. Further investigation demonstrated that miR196a-5p was transferred to microglia and regulated microglial structure and functions by downregulating the expression of ROCK1. Therefore, these data indicate that NPC-derived EVs are potent modulators of microglial functions in brain microenvironment. Regardless of brain colonization, EVs-mediated functional changes in microglia may be a universal phenomenon that results in the alteration of the tumor host's microenvironment in the brain.

CT Evaluation of Squamous Cell Carcinoma of the Nasopharynx

Squamous cell carcinoma is the most common type of neoplasia which affects the mucosa of the upper aero-digestive tract. Nasopharyngeal carcinoma is a unique disease with clinical behavior, epidemiology, and histopathology that is different from that of squamous cell carcinomas of the head and neck. For malignant tumors such as SCC, rapid growth may occur even though there are no previous clinical signs. Enlargement of a cervical lymph node, as the first presenting feature of neoplasia, is not uncommon, particularly with certain “silent” site, such as nasopharynx. Therefore, clinical examination must be complemented by radiological examination for the assessment of size, thickness and depth of the tumor, the degree of bone tissue invasion, and to detect the presence of enlarged lymph nodes. A total of 16 cases of patients were studied using CT, all diagnosed and operated with squamous cancer with localization in the nasopharynx.

Bone Subtraction Iodine Imaging Using Area Detector CT for Evaluation of Skull Base Invasion by Nasopharyngeal Carcinoma

BACKGROUND AND PURPOSE

Conventional CT has generally lower detectability of bone marrow invasion than MR imaging due to lower tissue contrast. The purpose of this study was to compare the diagnostic performance of conventional CT alone or in combination with bone subtraction iodine imaging using area detector CT for the evaluation of skull base invasion in patients with nasopharyngeal carcinoma.

MATERIALS AND METHODS

Forty-four consecutive patients who underwent contrast-enhanced CT using 320-row area detector CT and contrast-enhanced MR imaging for nasopharyngeal carcinoma staging between April 2012 and November 2017 were enrolled in this retrospective study. Bone subtraction iodine images were generated by subtracting pre- and postcontrast volume scans using a high-resolution deformable registration algorithm. Two blinded observers evaluated skull base invasion at multiple sites (sphenoid body, clivus, bilateral base of the pterygoid process, and petrous bone) using conventional CT images alone or in combination with bone subtraction iodine images. Examination of MR and CT images by an experienced neuroradiologist was the reference standard for evaluating sensitivity, specificity, and area under the receiver operating characteristic curve.

RESULTS

Twenty-six patients (59%) showed skull base invasion at 84 sites on the reference standard. Conventional CT plus bone subtraction iodine images showed higher sensitivity (92.9% versus 78.6%, P = .02) and specificity (95.6% versus 86.1%, P = .01) than conventional CT images alone for evaluating skull base invasion. The area under the receiver operating characteristic curve for conventional CT plus bone subtraction iodine (0.98) was significantly larger (P < .001) than the area under the receiver operating characteristic curve for conventional CT alone (0.90).

CONCLUSIONS

Conventional CT plus bone subtraction iodine performs more closely to the accuracy of combining CT and MR imaging compared with conventional CT alone.

A Case of Squamous Cell Carcinoma of the Oropharynx Invading Skull Base

Squamous cell carcinoma is the most common type of neoplasia which affects the mucosa of the upper aero-digestive tract. We present the case of a male patient that at the clinical exam showed a tumor mass at the rhinopharynx. The CT examination showed a tumor mass developed from the upper portion of the oropharynx, from the soft palate. The tumor was invasive into the nasopharynx, and into the structures of skull base the skull base, and with bilateral lymphnodes metastasis. At histopathological examination, the fragments of tumor biopsy revealed the aspect of a moderately differentiated keratinised squamous cell carcinoma, with lymph node metastasis, and with invasion in the adjacent fibro-muscular tissue.

Sellar and Parasellar Imaging

The skull base is a complex anatomical region that harbors many important neurovascular structures in a relatively confined space. The pathology that can develop at this site is varied, and many disease processes may present with similar clinical and neuroimaging findings. While computed tomography maintains a role in the evaluation of many entities and can, for instance, delineate osseous erosion with great detail and characterize calcified tumor matrices, magnetic resonance imaging (MRI) is the mainstay in the neuroimaging assessment of most pathology occurring at the skull base. Various MRI sequences have proven to be robust tools for tissue characterization and can provide information on the presence of lipids, paramagnetic and diamagnetic elements, and tumor cellularity, among others. In addition, currently available MRI techniques are able to generate high spatial resolution images that allow visualization of cranial nerves and their involvement by adjacent pathology. The information obtained from such examinations may aid in the distinction of these disease processes and in the accurate delineation of their extent prior to biopsy or treatment planning.

Nasopharyngeal carcinoma

Nasopharyngeal carcinoma is uncommon in the United States, with only 0.2 to 0.5 cases per 100,00 people; this is in contrast to southern China and Hong Kong, where the incidence is 25 to 50 per 100,000 people. There is a potential link between Epstein-Barr virus and the development of nasopharyngeal carcinoma. Radiotherapy alone as a single modality leads to similar 10-year survival rates in United States, Denmark, and Hong Kong (34%, 37%, and 43%, respectively). Multiple studies have shown an advantage to concurrent chemoradiation in the treatment of advanced disease. Radiation therapy remains the mainstay of salvage therapy, and modern techniques have allowed clinicians to achieve adequate local control without excessive toxicity.

Nasopharyngeal carcinoma presenting with rapidly progressive severe visual disturbance: a case report

INTRODUCTION

Nasopharyngeal carcinoma is one of the most difficult tumors to diagnose correctly at the initial phase because of the occasional lack of nasal symptoms. The perineural spread of the trigeminal nerve is one of the most common and important routes in the intracranial paracavernous extension of nasopharyngeal carcinoma, but visual loss is very rare.

CASE PRESENTATION

We report the case of a 54-year-old Japanese man with nasopharyngeal carcinoma, who presented with rapid and severe disturbance of left monocular visual acuity and eye movement with a 10-month history of ipsilateral otitis media and facial pain. Magnetic resonance imaging revealed a lesion in the left fossa of Rosenmüller, pterygopalatine fossa, sphenoid and ethmoid sinus, and the left cavernous sinus extending to the orbital apex through the superior orbital fissure. The histopathological diagnosis was nonkeratinizing undifferentiated nasopharyngeal carcinoma. Epstein-Barr virus was detected by in situ hybridization. Although focal radiotherapy induced remarkable tumor shrinkage and relieved ocular motor disturbance and facial pain, his visual acuity did not improve.

CONCLUSION

The awareness of cranial nerves in addition to intracranial and orbital apex involvement, as in this case, is important for appropriate diagnosis and treatment planning of nasopharyngeal carcinoma.

T4-locally advanced nasopharyngeal carcinoma: prognostic influence of cranial nerve involvement in different radiotherapy techniques

BACKGROUND

Cranial nerve involvement at disease presentation of nasopharyngeal carcinoma was not uncommon. We investigated the prognosis of patients with T4-locally advanced NPC, with or without cranial nerve involvement, and compared the outcome of patients treated using different radiotherapy techniques.

METHODS

In this retrospective study, 83 T4-locally advanced NPC patients were diagnosed according to the seventh edition of the American Joint Committee on Cancer staging system. All patients were treated using three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiation therapy (IMRT). The survival rate was analyzed using the Kaplan-Meier method.

RESULTS

The 5-year overall, locoregional-free, and disease-free survival rates of patients treated using IMRT were 88.9%, 75.2%, and 69.2%, respectively. The outcome in these patients was significantly better than that in patients treated using 3D-CRT, with survival rates of 58.2%, 54.4%, and 47.2%, respectively. There was no significant difference in the 5-year overall, locoregional-free, and disease-free survival rates of the patients with (64.2%, 60.5%, and 53.5%, resp.) and without (76.9%, 63.6%, and 57.6%, resp.) cranial nerve involvement.

CONCLUSION

Locally advanced NPC patients treated using IMRT had significantly better outcomes than patients treated using 3D-CRT. Our results showed that the outcome of T4 NPC patients with or without cranial nerve involvement was not different.

Long-term survival of a patient with leptomeningeal involvement by nasopharyngeal carcinoma after treatment with high-dose intravenous methotrexate

BACKGROUND

Nasopharyngeal carcinoma with leptomeningeal involvement is rare and typically has poor prognosis.

METHODS AND RESULTS

We present a case report of a patient with nasopharyngeal carcinoma who was treated with high-dose intravenous methotrexate and remains asymptomatic and without clinical evidence of disease 6 years later.

CONCLUSIONS

Systemic high-dose methotrexate should be evaluated in the treatment of advanced nasopharyngeal carcinoma with central nervous involvement.

Impact of intracranial extension on survival in stage IV nasopharyngeal carcinoma: identification of a subset of patients with better prognosis

OBJECTIVE

T-stage is an imperfect prognostic indicator for patients with nasopharyngeal carcinoma. We evaluated the effect of extent of intracranial involvement on survival after conventional radiotherapy in patients with Stage T4 nasopharyngeal carcinoma.

METHODS

We conducted a retrospective analysis of the results of computed tomography, magnetic resonance imaging and treatment outcomes in 84 consecutive patients with Stage T4 nasopharyngeal carcinoma during the period September 1993 to December 2002 in Taiwan. The patients were subcategorized into those who had limited intracranial involvement (primary nasopharyngeal tumors with involvement of the unilateral cavernous sinus or the parasellar region only) or extensive involvement (extension of the tumors to the bilateral cavernous sinus or the parasellar region, into the orbit and the ethmoid sinus anteriorly, or to the prepontine region and the posterior cranial fossa).

RESULTS

Extensive intracranial involvement was found in 51.2% of the patients. Among these patients, the 5-year rate of overall survival after conventional radiotherapy was only 3.4%. In contrast, the 5-year survival among patients with limited intracranial involvement was 42.9%. This difference was significant (P < 0.001). In the multivariate analysis, extensive intracranial involvement, advanced age and a nodal status of N3 correlated with poor overall survival (all P < 0.05).

CONCLUSIONS

Among patients with T4 nasopharyngeal carcinoma, better treatment outcomes were associated with limited intracranial involvement. We conclude that a subdivision of Stage T4 nasopharyngeal carcinoma disease based on the extent of intracranial involvement would provide better prognostic information.

Radiologic Findings after Successful Chemoradiation for Nasopharyngeal cancer with Skull Base Erosion

Nonoperative management is generally accepted as a treatment strategy for nasopharyngeal cancer characterized by destruction of the skull base. Chemoradiotherapy is considered the standard of care in these cases. We report a case in which imaging studies documented the successful treatment of the patient's locally extensive nasopharyngeal carcinoma with this nonsurgical approach.

Extension patterns of nasopharyngeal carcinoma

The nasopharynx represents an intersection between the nasal choanae, the oropharynx, the deep facial spaces, the skull base and the intracranial cavity. Most nasopharyngeal neoplasms are malignant tumors showing aggressive local infiltration along well-defined routes. The primary role of imaging is accurate tumor mapping and detection of possible tumor extension, especially to the skull base and the deep facial spaces. The aim of this paper is to illustrate these extension patterns of nasopharyngeal carcinomas on imaging and to show the particular implication of imaging in the correct staging of the lesion.

The relationship between nasopharyngeal carcinoma tumor volume and TNM T-classification: a quantitative analysis

Recent findings show that tumor volume is a significant prognostic factor for the treatment of nasopharyngeal carcinoma (NPC). The inclusion of tumor volume as an additional prognostic factor in the UICC TNM classification system was suggested; however, how tumor volume could possibly be incorporated is still unexplored. In this paper, we report a quantitative analysis on the relationship between NPC tumor volume and T-classification, using the data from 206 NPC patients. By T-classification and semi-automatic tumor volume measurement, the difference in tumor volumes among the various TNM T-classification groups was examined. In addition, a statistics-based analysis scheme, which used the T-classification as the "gold standard", was proposed to classify NPC tumors into volume-based groups to explore the possible links. The results show that NPC tumor volume has positive correlation with advancing T-classification groups and significant difference existed in the distribution of T-classification among various volume-based groups (P < 0.001). By the proposed statistical scheme, tumor volume could be included as an additional prognostic factor in the TNM framework, following validation studies.

Cranial nerve involvement in nasopharyngeal carcinoma: response to radiotherapy and its clinical impact

OBJECTIVES

To evaluate the cranial nerve (CN) palsy associated with nasopharyngeal carcinoma (NPC), we studied factors that influenced the neurologic outcome of radiotherapy (RT), and the patterns and time course of neurologic recovery of CN palsy.

METHODS

Between July 1987 and July 1989, 93 patients who presented with CN palsy at the time of diagnosis of NPC were studied. All patients underwent external-beam RT with either cobalt-60 or 6-MV photon beams to a dose of 69 to 84 Gy at 2 Gy per fraction. The time course and pattern of neurologic recovery (complete, partial, or none) from CN palsy were evaluated. Age, sex, stage, histology, incidence and distribution of types of CNs involved, duration of CN palsy, and time course of tumor response during RT were correlated with the patterns and the time course of neurologic CN recovery by univariate and multivariate analyses.

RESULTS

The cases of CN palsy most commonly involved CN V (38%), CN VI (26%), and CN XII (11%), which accounted for the majority of the cases (75%). The time course of CN recovery was variable and protracted. Most patients showed significant improvement upon completion of RT (51%, 19%, and 30% complete, partial, and no recovery, respectively) and further improvement 6 months after RT (58%, 17%, and 25%, respectively). Cranial nerves V, VI, and XII accounted for 75% of cases with no recovery. Recovery was best for CNs II, IX, and XI and the sympathetic nerve (100%, 87%, 100%, and 100%, respectively) and worst for CNs IV, VII, and XII (67%, 60%, and 40%, respectively, with no recovery). Neurologic CN recovery correlated significantly with the pretherapy duration (<3 months versus > or =3 months) of CN palsy (88% versus 62%; p = .002, multivariate analysis), the time course of clinical tumor regression, and neurologic symptom improvement during RT. Age, sex, T stage, N stage, histology, anterior versus posterior CN palsies, and base of skull involvement were not significant.

CONCLUSIONS

According to our limited data, most patients with CN palsy respond well to RT. That the time course of neurologic recovery is variable and can be protracted indicates a need for continuous and close neurologic surveillance. The poorer neurologic outcome associated with a longer duration of CN symptoms may be related to a more severe longterm CN compression that results in irreversible damage. Timely diagnosis of NPC and fast institution of therapy are therefore critical to improving the neurologic outcome.

Staging of nasopharyngeal carcinoma investigated by magnetic resonance imaging

BACKGROUND AND PURPOSE

To investigate the American Joint Commission on Cancer (AJCC) sixth edition staging system of nasopharyngeal carcinoma (NPC) by Magnetic Resonance Imaging (MRI).

PATIENTS AND METHODS

One hundred and fifty-nine non-disseminated biopsy-proven NPC patients were studied with MRI before treatment. Retrieval of MRI information enabled us to restage all patients accurately according to the sixth edition of the AJCC staging system. Splitting the respective T and N stages by the significant defining factors identified, the cancer death hazard ratios were modeled by the Cox model in SPSS 10.0 for windows (SPSS Inc, Chicago, IL).

RESULTS

Single site of skull base abnormality (HR = 3.91, 95% CI: 0.74-20.56) has a superior result to others involved in T3 (HR = 5.83, 95% CI: 1.24-27.29). Involvement of either anterior or posterior cranial nerves solely (HR = 6.02, 95% CI: 1.55-35.60) was not found to be as a poor prognostic indicator as others involved in T4 (HR = 7.81, 95% CI: 1.81-33.63). Less than or equal to 3 cm of N1 (HR = 4.01, 95% CI: 0.48-33.83) and N2 (HR = 4.72, 95% CI: 0.62-35.78) have a better result than >3 cm of N1 (HR = 8.09, 95% CI: 0.95-68.97) and N2 (HR = 10.58, 95% CI: 1.32-84.62), respectively.

CONCLUSIONS

Perhaps, it is better to down-stage single site of skull base abnormality from T3 to T2, and involvement of either anterior or posterior cranial nerves solely from T4 to T3, meanwhile, < or =3 cm of N2 down-stage to N1, >3 cm of N1 up-stage to N2.

[Imaging diagnostics of the pharynx and larynx]

The pharynx and larynx represent very sophisticated regions and may be involved in a diverse range of pathologic conditions. Evaluation of the head and neck has developed significantly with the establishment of CT and MRI as they provide true insights into the endoscopically blind areas as well as depth of tumor infiltration, its submucosal growth and contralateral involvement, cartilage invasion, bone marrow invasion, and nonpalpable adenopathy. Inflammations in the head and neck region are only exceptionally imaged with CT or MRI; indications are the diagnosis of retrotonsillar and parapharyngeal abscesses and ensuing complications. The different imaging modalities of malignant pharyngeal and laryngeal tumors and their differential diagnosis are presented in this paper.