Chapter 45 Oropharynx Flashcards
What is the etiology of oropharyngeal cancer in non smoker and non drinker?
HPV
What is the prognosis of HPV associated oropharyngeal cancers?
Favorable
What is the HPV type most common in oropharyngeal cancer?
HPV 16
Infection with HPV 16 confers how many fold increase in risk of oropharyngeal cancer?
14 fold
Oropharyngeal oncogenesis is primarily mediated by which HPV genome oncoproteins?
E6 and E7 oncoproteins
Name different technique used to detect HPV in oropharyngeal cancer?
- PCR of HPV DNA High sensitivity but low specificity
- ISH uses oligonucleotide probe designed to anneal to complementary HPV DNA in tumor specimen.
- IHC staining for p16INK4A used as surrogate for HPV status
HPV associated oropharyngeal cancer are more likely to occur among men or women?
Men
Name mutations demonstrated by HPV associated oropharyngeal cancer?
wild-type p53
p16 expression
Infrequent expression of Cyclin D
Name mutations demonstrated by HPV associated oropharyngeal cancer with more extensive smoking history?
TP53 mutation
Higher EGFR
Bcl-xl expression
RTOG 0129 HPV associated vs unassociated oropharyngeal cancer what was the conclusion?
HPV+ HPV- 3 year OS 82%. 54% LRP 13.6% 24.8% (LocoRegional Progression) PFS 71.8% 50.4%
Describe boundaries of oropharynx
Superior Nasopharynx
Posteroinferior Larynx and Hypopharynx
Anterior Oral cavity
What are subregions of oropharynx
Tonsil
Base of tongue
Soft palate
Describe tonsillar region
Contains anterior(palatoglossal)and posterior(palatopharyngeal) tonsillar pillar, palatine tonsil
Describe boundary of base of tongue
Anterior circumvallate papillae
Posteroinferior hyoid and epiglottis
Lateral glossopharyngeal sulci
Describe boundary of soft palate
Anterior hard palate
Lateral anterior tonsillar pillar
Posteroinferior forms free edge and midline uvula
Soft palate are composed of which 5 different muscles?
Levator veli palatini Tensor veli palatini Palatoglossus Palatopharyngeus Musculus uvulae
What are the sensory innervation of base of tongue?
CN IX and X(Internal Laryngeal Nerve)
What are nerve supply of soft palate?
Motor supply all muscles are supplied by CN IX and X except tensor veli palatini supplied by CN V2
Sensory supply CN IX
What are the functions of oropharynx?
Degustation
Respiration
Speech
What are the primary route of spread of oropharyngeal cancer?
Direct extension and lymphatic spread
What is the most common location of lymph node metastasis in oropharyngeal cancer?
Level II
What are high risk nodal metastasis in oropharyngeal cancer?
Level II, III, IV
What are the indications of Level I and V nodes involvement in oropharyngeal cancer?
When other levels are involved
What are the indications of bilateral node involvement in oropharyngeal cancer?
When tumor encroaches or crosses midline or involve posterior pharyngeal wall
What is the craniocaudal extension of RetroPharyngeal(RP) lymph nodes?
Base of skull to Cranial edge of body of hyoid bone
What is the most common location of distant metastatic spread of oropharyngeal cancer?
Lung followed by
Bone and Liver
What factors are responsible for distant metastatic spread of oropharyngeal cancer?
Locoregionally advanced or recurrent tumor Primary tumor stage N-stage Extranodal extension Lower cervical lymphadenopathy(level IV) LVSI
How to differentiate pulmonary metastasis and primary pulmonary malignancy radiographically?
Pulmonary mets : well circumscribed peripherally located nodules
Primary pulmonary malignancy : spiculated irregularly shaped mass commonly associated with hilar and mediastinal lymphadenopathy
What should be the treatment approach when it is difficult to distinguish between primary and metastatic lesion in oropharyngeal cancer?
Physically fit patient should be given benefit of doubt and treated as if they are seperate primary tumors.
What is the treatment approach for physically fit patient with known oropharyngeal cancer with pulmonary mets?
Resection of pulmonary metastasis may improve survival
What is the treatment approach for nonsurgical patient with known oropharyngeal cancer with limited pulmonary mets?
Hypofractionated IGRT to all known metastatic sites
What is the cause of deep seated otalgia located within auditory canal in oropharyngeal cancer?
Pain mediated by irritation of CN IX with referral via petrosal ganglion to tympanic nerve of Jacobson
What is the sensitivity and specificity of PET scan in oropharyngeal cancer?
High sensitivity of 100%
Specificity 60%for pathologically proven tumor