Oropharynx Flashcards
epidemiology & aetiology
50-70
rare
<1% of all cancer deaths
2.9: 1 [m:f]
poor oral hygiene
smoking: inhalation, risk increases as number and tar content increases
HPV: affects young people and non smokers, improves prognosis
mouthwash, high alcohol content
heavy consumption of alcohol
pathology
SCC [75%]
lymphomas
seen to protrude the throat
types of spread
direct
lymphatic
direct spread
early
affects pillars of forces and soft palate
later invasion of tongue and post pharyngeal wall
lymphatic spread
tonsils and pillars: jugulodigastric -> DCC
soft palate: retropharyngeal -> DCC
base of tongue: retropharyngeal -> DCC
what is the investigations
full medical history
physical exam: cervical lymphdenopathy, visible signs of primary
radiography: CT/MRI, soft tissue laterals
EUA: under GA for visualisation of the tumour and biopsy
staging
T1 = < 2cm
T2 = 2<x< 4cm
T3 = >4cm
T4 = invasion of surrounding structures (pterygoid muscles, mandible, hard palate, deep tongue muscles, larynx)
presentation
dysphagia
enlarged lymph nodes (20% are bi)
early
trismus: infiltration deep into para-pharyngeal space
what tumours is surgery for
T1/T2
what surgery takes place
radical tonsilectomy with partial mandibularectomy with ipsilateral node dissection
tissue deficit made up with a flap repair
what types of tumour have RT
SCC and lymphomas
what is the dose for SCC
66Gy in 33
55Gy in 20
what is the non lateral technique
IMRT
contralateral parotid and spinal cord are OAR
66Gy in 33
54Gy in 33
what is the CTV volumes for N0
CTV 1 = ipsilateral level II, bilateral retropharyngeal nodes @ oropharynx
CTV 2 = ipsilateral level III + IV, ipsilateral IB if ant pillar/ oral tongue is involved), contralateral level II-IV
what is the CTV volumes for N1-N3
CTV 1 = ipsi level II + involved nodes, bi retropharyngeal nodes at level of oropharynx
CTV 2 = ipsi uninvolved nodes at IB-V, ipsi supraclavicular nodes [selective], con level II-IV, con level IB [selective]
describe RT for lymphomas
PTV = waldeyers ring, LN both sides of the neck and base of skull
2 lat fields, covering nasopharynx, ant and post can be used
40Gy in 20
soft palate EBRT for T1/T2
TV = GTV + 2cm
small lat parallel opposed fields
primary only
60-66Gy in 30-33
soft palate EBRT for T3/T4
bi lateral neck irradiation
same technique as advanced tonsillar
side effects
erythema
MDS
mucositis
sore throat
dysphagia
xerostomia
loss of taste
trismus
prognosis for T1
60-80
prognosis for T2,3,4
30-50
why is PET/CT used
early identification of recurrence allow for better outcome and imporved survival
what is the PET/CT protocol
MRI/PET-CT = 3 months
PET/CT = 6 months for oropharyngeal, hypopharyngeal and oral SCCs
what is PET
it creates 3D images by radiotracers via IV, these are made up of carrier molecules which bond to a radioisotope. Cancerous tissue uptakes glucose, the isotope produces positrons which interact with electrons cause complete annhiliation, which releases two photons. PET detectors measure the photons and the information creates images
what radioisotope is used
FDG = modified type of glucose
