Childhood Nasopharyngeal Carcinoma (NPC): A Review of Clinical-Imaging Features and Recent Trends in Management
Mark Yoi Sun Soo
Clinical Senior Lecturer and VMO Radiologist, Department of Radiology, Westmead Hospital Campus, Centre for Biomedical Imaging Research and Development (CBIRD), and University of Sydney, NSW, Australia 2145
Abstract: Introduction: Nasopharyngeal carcinoma (NPC) in children and adolescents is a relatively rare yet highly malignant disease. Clinical presentation of NPC in this age group is non-specific and varied leading to a predominantly late diagnosis. The objective of this paper is to explore and clarify the tumour’s ambiguity and assess the precision of imaging in mapping its morphology and loco-regional extension and possible distant metastases. Treatment regimes that minimize adverse radio-therapeutic effects on surrounding structures will be highlighted.
Method: Retrospective analysis and observations of literature (in English) between 2004 to December 2017 was performed. A search was performed using the Medline data-base. The following are the search terms: “children”, “nasopharyngeal carcinoma”, “symptoms’, “imaging” and “therapy”.
Material: Of the 43 papers found on the primary search only 36 satisfied the search criteria. Four review papers of the primary search were retained as sources of reference. The core material comprised 22 papers on NPC’s clinical presentation and the role of imaging in diagnosis and prognostication. There were three papers on advanced imaging in adults. The rest of the seven comprised selected articles on chemo-radiation, radiotherapy and related late toxicities.
Results: The clinical presentations range from nasal stuffiness, otalgia to unilateral or bilateral neck masses. Symptoms can last from a few weeks to 6 months; by then disease can be advanced. A WHO high-grade undifferentiated squamous cell carcinoma is the commonest lesion in clinical practice. Data from magnetic resonance imaging (MRI) focusing on tumour extensions and tumour volume are markers of long-term prognosis. Diffusion weighted MRI by assessing microscopic changes of NPC can determine the ultimate outlook of adults afflicted with NPC. Treatment of paediatric NPC consists of induction chemotherapy followed by radiotherapy with dosage up to 65-70 Gy.
Morphologically, the main mimicker of childhood NPC is an embryonic parameningeal rhabdomyosarcoma arising from the pharyngeal and nasal space. Both have inclination to invade the skull base.
Conclusion: Despite NPC’s varied and nonspecific presentations, the clinician must be vigilant because treatment of the disease in different stages of severity has a higher response rate than its adult counterpart. Contrast MRI and computed tomography (CT) are precise in showing skull base invasion, loco-regional and distant metastases. The application of diffusion weighted MRI has a role in determining the tumour’s microscopic contents and long-term prognosis. Use of intensity modulated radiation therapy (IMRT) in addition to induction chemotherapy and irradiation treatment regime has decreased the incidence of the dreaded late sequelae.
Keywords: Nasopharyngeal carcinoma, childhood, symptoms, Imaging, therapy.