Oropharynx/Hypopharynx/nasopharynx/oralcavity Flashcards
Anatomy of the oral cavity (subdivisions)
Extends from the skin-vermilion junction of the lip to the posterior border of the hard palate.
Subdivisions include:
- anterior two/thirds of the tongue
- lip
- buccal mucosa
- retromolar trigone
- floor of the mouth
- hard palate
Clinical presentation of oral cancer
- poor oral/dental hygiene
- Plummer-Vinson syndrome (iron-deficiency anemia) is considered a risk factor in women
- leukoplakia and erythroplasia are considered serious pathologic problems.
- most oral cavity cancers present as non-healing lesions
- pain may be associated with advanced disease
Radiation therapy for oral cavity
Local regional control depends on highly accurate treatment with a sharp dose gradient to reduce the dose to surrounding healthy tissue.
The gross disease will receive a dose of approximately 70Gy
Volumes at high risk for microscopic disease and high-risk lymph nodes receive a dose of 64Gy
Volumes of low risk such as contralateral neck and elective lymph nodes should receive 60Gy
Electron treatment can be used for treatment areas such as lip or superficial tumours.
The natural history of oral cancer
- oral cavity cancers have the lowest incidence (except glottic tumours) of nodal spread for all head and neck cancers
Pharynx anatomy
Subdivided into three sections:
- oropharynx
- nasopharynx
- hypopharynx
Oropharynx anatomy
Consists of the base of the tongue, the tonsils, the soft palate and the oropharyngeal wall.
Situated between C3 and the axis
Located behind the mouth from the soft palate above to the hyoid bone
Anatomy of the hypopharynx
Composed of the pyriform sinuses, post-cricoid and lower posterior pharyngeal walls.
Anatomically situated between C3 and C6.
Cricoid cartilage represents the inferior border and the epiglottis the superior border.
Epidemiology for hypopharynx cancer
Male to female rate ranges from 5:1 to 7:1 for pyriform sinus cancer
Male to female rate ranges from 3:1 to 4:1 for pharyngeal wall cancer
Postcricoid cancers are typically female
Signs and symptoms of pharynx cancer
Sore throat and pain when swallowing is most common.
Otalagia (ear pain) can also occur
Enlargement of the cervical nodes
Common presenting symptoms of hypopharynx cancer
- sore throat
- odynophagia
- 25% present with a neck mass
Dysphagia and weight loss are more common in advanced diseases.
Etiology of oral cavity or oropharynx cancers
Growing subpopulation between 20 and 50 due to the rising incidence of HPV-related head and neck cancers.
50-60-year-old with a long history of smoke &/or alcohol consumption
- more than 20 cigs/day increase 6-fold risk
- 6oz liquor day increase 10-fold risk
Chewing betel nut, smokeless tobacco-related to buccal mucosa, lip and floor of mouth (more common in Asia)
Highest site of incidence for hypopharynx cancer
Pyriform sinus
Radiation therapy for the oropharynx region
Early T1 and T2 lesions are treatable with EBRT alone
Large volumes are required T3 and T4 lesions that encompass the cervical and supraclavicular nodes.
Stage III and IV cancers are treated with definitive radiation and concurrent chemotherapy
Treatment of hypopharynx cancer
Typically an advanced disease. With high rates of nodal metastasis for pyriform sinus cancers.
Rare T1 and T2 lesions can be treated with radiation therapy or surgery and are curable.
T2-T4 lesions are more common and are not candidates for laryngeal preservation surgery. Most patients receive combined radical surgery and radiation therapy. Large radiation therapy fields are needed to treat pyriform sinus as well as cervical lymph nodes.
Tumours of the posterior pharyngeal wall are unresectable and are treated with large field RT. That includes the entire pharynx, upper cervical esophagus, extending superiorly to the nasopharynx vault and local lymph nodes.
Radiation therapy for the pharynx region
Radiation therapy has become the standard of treatment for oropharynx cancer.
As cure rates increase the concern for treatment-related issues such as xerostomia and mandible necrosis has become important issues.
IMRT helps to reduce the dose to organs at risk and help with locoregional control
Pathology of pharynx cancers
Predominantly SCC (90%)
Lymphoepilioma may occur in the tonsil and the base of the tongue
