Nasopharyngeal Cancer

John P. Christodouleas and Giuseppe Sanguineti

Background

What is the prevalence of nasopharyngeal cancer (NPC) in the U.S. vs. in Asian countries?

NPC is rare in the U.S. (0.2–0.5 in 100,000 cases) but endemic in Asia (25–50 in 100,000 cases).

What are the environ-mental risk factors associated with NPC?

Consumption of salted fish and preserved meats, EBV infection, and smoking for keratizing squamous cell type (no alcohol association)

What is the median age at Dx for NPC?

The median age at Dx is ~50 yrs for NPC.

What are the anatomic boundaries that make up the nasopharynx (NPX)?

Superior: sphenoid bone
Inferior: soft palate
Posterior: clivus/C1-2
Anterior: post edge of choanae

From what anatomic location does most NPC arise?

Fossa of Rossenmuller (fossa post to the torus tubarius, which is the cartilaginous prominence in the lat wall of the NPX that forms the opening of the eustachian tube)

What is the local pattern of spread for NPC superiorly, inferiorly, posteriorly, laterally, and anteriorly?

Superiorly: invades the cavernous sinus with predominantly CN VI involvement
Inferiorly/posteriorly: oropharyngeal structures
Laterally: parapharyngeal space
Anteriorly: nasal cavity

How does NPC reach and invade the cavernous sinus?

NPC can track to the cavernous sinus through the foramen lacerum.

What 2 CN syndromes are commonly associated with NPC, and what CNs are involved in each?

Petrosphenoidal syndrome: CN III–IV and VI involvement (oculomotor signs/Sx)
Retroparotidian syndrome: CN IX–XII involvement

What CNs or structures traverse through the base of skull sinuses/foramina (e.g., cavernous sinus, foramen rotundum, ovale, lacerum, jugular, hypoglossal)?

Cavernous sinus: CNs III–IV, V1-2, and VI
Foramen rotundum: V2
Foramen ovale: V3
Foramen lacerum: cartilage of the eustachian tube
Jugular foramen: CNs IX–XI
Hypoglossal canal: CN XII

What are the 3 WHO histologic subtypes of NPC, and what is the prevalence of each type?

WHO I: keratizing squamous cell carcinoma (SCC) (20%)
WHO IIa: nonkeratinizing SCC (nondifferentiated) (30%–40%)
WHO IIb: undifferentiated or lymphoepithelial (40%–50%)

Which WHO type of NPC is endemic and prone to distant recurrence?

WHO IIb (undifferentiated or lymphoepithelial) is endemic (better LC but more distant spread).

Which WHO type of NPC is associated with smoking and has poor LC but a lower propensity for DM?

WHO I (keratizing SCC) is associated with smoking, poor LC, and less distant spread.

Which WHO type of NPC is most strongly associated with EBV exposure?

WHO IIb (undifferentiated or lymphoepithelial) NPC is most strongly associated with EBV.

With what autoimmune condition can NPC be associated?

NPC may be associated with dermatomyositis.

What histologic feature of NPC is an adverse prognostic factor in terms of LC and OS?

The presence of keratin is an adverse prognostic feature.

What role does p53 play in the pathogenesis of NPC?

p53 alteration is seen in the minority of cases (unlike other H&N cancers).

Workup/Staging

What are some common presenting Sx in pts with NPC?

Neck mass (>60%); epistaxis, otalgia, and nasal congestion; and trismus. CN deficits are seen with more advanced Dz.

What is the general workup for a pt who presents with a neck node and a suspicious mass in the NPX?

Neck node and suspicious mass workup: H&P, CBC/CMP, direct nasopharyngolaryngoscopy and Bx of the lesion, CT head/neck/chest, MRI head/neck, and PET scan

What is the DDx for a pt with a nasopharyngeal mass?

Carcinoma, lymphoma, melanoma, plasmacytoma, angiofibroma, rhabdomyosarcoma (children), and mets

What % of NPC pts present with palpable LAD?

60%–90% of NPC pts present with palpable LAD.

What % of NPC pts present with bilat LAD?

Up to 50% of NPC pts present with bilat LAD.

Adenopathy near the mastoid tip is indicative of involvement of which nodal group?

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