Nasopharynx

DPB presents a case of Nasopharynx for Resident Report this morning.

63 yo WF with history of R fullness. Biopsy of R level V positive for poorly differentiated carcinoma. CT of neck reveals bilaterally enlarged nodes. FOL reveals a mass in the R fossa of Rosenmeuller. EUA biopsy revealed poorly differentiated carcinoma and tested postive for EBV DNA. Staged as a T1N2.

Staging

• T1 - confined to nasopharynx
• T2 - extends to soft tissues
  • T2a - extends to oropharynx and/or nasal cavity
    
  • T2b - any tumor with parapharyngeal extension
• T3 - involves bony structures and/or paranasal sinuses
• T4 - intracranial extension and/or involvement of cranial nerves, infratemporal fossa, hypopharynx, orbit, or masticator space
  

• N1 - unilateral nodes, 6 cm or less, above the supraclavicular fossa
• N2 - bilateral nodes, 6 cm or less, above the supraclav fossa
• N3a - lymph node greater than 6 cm
• N3b - extension to the supraclav fossa
  

Special attention should be to the neurologic exam, as 20% have CN palsies.
Endemic to the Chinese population, and associated with EBV infection.
Obstruction of the Eustachion tube can cause a serous otitis media.
70-90% LN involvement, with 50% having bilateral involvement. Important to note that Level V is very frequently involved, and there is occaisional level IB involvement.

Teo IJROBP 1996 demonstrated that parapharyngeal invovlement was associated with worse DM and worse overall survival in the setting were other high risk factors were not present.

WHO classification of NP type 1 keratinizing squamous cell, type 2 non-keratinizing SCC, type 3 undifferentiated carcinoma. Lymphoepithelioma are carcinomas with a background of lymphocytes, and may have better outcomes.

For simulation, fusion of MRI with a planning CT with IV contrast is ideal.

Al-Sarraf Int 0099 stage III or IV, randomized to RT or RT+CT and adjuvant CT.
70Gy used to the primary at 1.8-2Gy day, 60Gy to nodes <2cm, 50Gy to elective nodal regions. CDDP 100mg/m2 x3 used during RT, adjuvant CDDP + FU (only 50% compliance however).
OS 78% vs 47% SS
Closed early due to survival benefit. PFS was also lower in the control arm than expected.

There are multiple other randomized trials from PMH and Asia which confirm benefit of RT. Metaanalysis in 2006 also showed a benefit to CT combined with RT, and suggests that concurrent may be the treatment of choice.

IMRT experience from UCSF from Lee IJROBP 2002, shows promising control rates, with dosimetric sparing of critical normal structures. There is also a randomized trial on this subject from Hong Kong (see link). This demonstrates significant improvement in objective measures of salivary flow, though the quality of life was no different amoung the arms.