Background

Question 1

What is the incidence of nasopharyngeal cancer (NPC) in the United States vs. in Asian countries?

Answer 1

NPC is rare in the United States (0.2–0.5 in 100,000) but endemic in Asia (25–50 in 100,000).

Question 2

What are the environmental risk factors associated with NPC?

Answer 2

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

Question 3

What is the median age at Dx for NPC?

Answer 3

∼50 yrs

Question 4

Is there a sex predilection for NPC?

Answer 4

Yes. Males > Females (3:1)

Question 5

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

Answer 5

Superior: sphenoid bone

Inferior: soft palate

Posterior: clivus/C1–2

Anterior: post edge of choanae

Question 6

From what anatomic location do most NPCs arise?

Answer 6

Fossa of Rosenmuller (pharyngeal recess)

Question 7

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

Answer 7

Superiorly: invades (via the foramen lacerum) the cavernous sinus with initial CN VI involvement

Inferiorly/posteriorly: OPX

Laterally: parapharyngeal space

Anteriorly: nasal cavity

Question 8

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

Answer 8

Petrosphenoidal syndrome: CNs III–IV and VI involvement (oculomotor signs/Sx)

Retroparotidian syndrome: CN IX–XII involvement

Question 9

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

Answer 9

Cavernous sinus: CNs III–IV, V1 and V2, and VI

Foramen rotundum: V2

Foramen ovale: V3

Foramen lacerum: cartilage of the eustachian tube

Jugular foramen: CNs IX–XI

Hypoglossal canal: CN XII

Question 10

What are the histologic subtypes of NPC and corresponding WHO classifications?

Answer 10

Keratinizing SCC (WHO type I, 25%). Sporadic form

Nonkeratinizing carcinoma: Differentiated (WHO type II, 12%). Undifferentiated (WHO type III 63% vs. 95% in Asia)

Question 11

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

Answer 11

Nonkeratinizing undifferentiated (WHO type III) is endemic (better LC but higher metastatic risk).

Question 12

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

Answer 12

Keratinizing SCC (WHO type I) is associated with smoking, poorer LC, and less distant spread.

Question 13

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

Answer 13

Nonkeratinizing undifferentiated (WHO type III)

Question 14

With what autoimmune condition can NPC be associated?

Answer 14

Dermatomyositis

Question 15

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

Answer 15

Presence of keratin (WHO type I)

Question 16

What role does p53 play in the pathogenesis of NPC?

Answer 16

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

Question 17

What is a commonality b/t NPX and OPX cancers?

Answer 17

Viral-associated tumors (EBV-NPX: HPV-OPX) have better LC but higher propensity for distant spread compared to nonviral-associated tumors in these regions.