Regarding nasopharyngeal carcinoma (NPC), all of the following are true EXCEPT:

Explanation

## Nasopharyngeal Carcinoma — Epidemiology and Aetiology ### Geographic Distribution and Risk Factors **Key Point:** Nasopharyngeal carcinoma shows striking geographic variation, with highest incidence in Southeast Asia (particularly Southern China, Hong Kong, Malaysia, and Vietnam) and North Africa. However, this clustering is NOT due to genetic predisposition alone. **High-Yield:** The high incidence in endemic regions results from a **multifactorial model** combining: - Genetic susceptibility (HLA-A2, HLA-B17 associations) - **EBV infection** (particularly undifferentiated histology) - Environmental factors: salt-cured foods, preserved meats (nitrosamines), smoking, occupational exposures - Viral cofactors (HPV in some cases) ### Histopathology **Key Point:** Squamous cell carcinoma (SCC) is the predominant histological type worldwide, accounting for >95% of cases. EBV is strongly linked to undifferentiated SCC (WHO Type III), which is the most common type in endemic regions. ### Clinical Presentation and Staging **Clinical Pearl:** Cervical lymph node metastasis is present in approximately 80% of patients at initial presentation, reflecting the rich lymphatic drainage of the nasopharynx and often late diagnosis. | Feature | Details | |---------|----------| | Most common presenting symptom | Cervical lymphadenopathy (often first sign) | | Nasal/otologic symptoms | Epistaxis, unilateral serous otitis media | | Advanced disease | Cranial nerve palsies (CN II–VI), trismus | | Metastatic disease at presentation | ~20% have distant metastases | ### Why Option 3 Is Incorrect Option 3 states that higher incidence is due to "genetic predisposition **alone**" — this is an oversimplification and factually incorrect. While genetic factors (HLA polymorphisms) do contribute, the endemic pattern is driven by a **combination** of genetic susceptibility, EBV infection, dietary carcinogens, and environmental exposures. Genetic predisposition alone cannot explain the disease — EBV serology and environmental factors are equally critical. **High-Yield:** This is a classic NEET PG trap: recognizing that multifactorial diseases are never explained by a single factor, even when that factor is partially correct.