Nasopharyngeal Carcinoma — Diagnosis and Treatment

Nasopharyngeal carcinoma represents a distinct entity from other head and neck cancers, arising from the epithelial lining of the nasopharynx, particularly the fossa of Rosenmüller. WHO histologic classification distinguishes three types: keratinizing squamous cell carcinoma (WHO type I, similar to other head/neck SCC, less EBV association), non-keratinizing differentiated (WHO type II, intermediate features), and non-keratinizing undifferentiated/lymphoepithelioma (WHO type III, strong EBV association, most common in endemic populations).

The disease shows striking geographic and ethnic variation: incidence is approximately 25-30 per 100,000 in southern Chinese populations (Cantonese), 5-15 in Southeast Asia and northern Africa, but only 0.5-1 in Caucasian populations. This pattern reflects complex interactions between EBV infection (essentially universal in undifferentiated NPC), dietary factors (salted fish containing nitrosamines, particularly during weaning), and genetic susceptibility (HLA-A2, HLA-B14, HLA-Bw46).

Diagnosis is established through nasopharyngoscopic biopsy with histopathologic evaluation including in situ hybridization for EBV-encoded RNA (EBER) confirming undifferentiated subtype. Imaging utilizes MRI for primary tumor and skull base evaluation, neck CT/MRI for nodal staging, and PET-CT or chest/abdominal imaging for distant metastases. Plasma EBV DNA quantitation by PCR has emerged as both prognostic biomarker and surveillance tool. Treatment paradigms involve definitive radiation therapy with intensity-modulated technique sparing normal structures, concurrent platinum-based chemotherapy for stage II-IV disease, and increasingly induction chemotherapy followed by chemoradiation for advanced disease. Adjuvant chemotherapy and immune checkpoint inhibitors are emerging for high-risk and recurrent/metastatic disease.