Clinical Oncology - Head and Neck Cancer

Is head and neck cancer more common in females or males?

Incident rates for men are more than twice as high than for women

Which head and neck cancer is more common in females?

Post-cricoid cancer

What is the most common site for distant metastasis?

Lungs

What are the other sites of distant metastasis?

Bones, brain, mediastinal lymph nodes, liver

The incidence of distant metastasis is greatest with tumour of the:

Nasopharynx and hypo-pharynx

A direct correlation appears to exist between __________ and the development of of distant metastasis

the bulk of cervical lymph node disease

What are high grade parotid tumours known for?

To involve facial nerves and cause paralysis

What is the leading cause of death in early stage tumours of the head and neck? What research has come out regarding this cause?

Secondary primary tumours; research on adjuvant chemotherapy to prevent secondary primary tumours is ongoing

What cancer of the head and neck is increasing in incidence in white men and women?

Oropharyngeal cancer associated with HPV infection

What is included in the oropharynx?

Tonsils, base of tongue, soft palate, oropharyngeal walls and the uvula

Which cancer is uncommon in US but common in Asia (Hong Kong, China, southeast Asia)?

Nasopharyngeal cancer

Why is nasopharyngeal cancer more common in Asia?

It may be due to environmental factors, as there is a decreased incidence of nasopharyngeal cancer in generations of Chinese born Americans

What head and neck cancer is more common in India?

Tumours of the base of tongue and oral cavity, which indicates environmental and cultural factors

What are the etiological factors for head and neck cancer?

Tobacco and alcohol use

Viral infections

Ultraviolet light

Radiation exposure

Diet

Marijuana

Dentures, fillings, and poor oral hygiene

Genetics

Consumption of alcohol and tobacco incur the highest risk for cancers of the:

Oral cavity, oropharynx, hypopharynx, larynx

What are oropharynx tumours close to the esophagus associated with?

Pooling of saliva carrying carcinogens related to tobacco

Alcohol consumption is a risk factor for the development of:

Pharyngeal and laryngeal cancer

Etiology - Occupational Exposures

Nickel refining

Furniture and woodworking: larynx, nasal cavity, paranasal sinuses

Steel and textile work: oral cancer

Exposure to dust, fumes, formaldehyde: NPC

Carpenters and sawmill workers: adenocarinoma of nasal cavity and ethmoid sinuses

Etiology - Radiation Exposure

Exposure to radiation, especially in childhood, may be associated with thyroid and salivary gland tumours

What viruses are associated with the development of head and neck cancer?

Epstein-Barr virus, Herpes simplex virus (HSV-1), HPV

Carcinomas of the ___ have been found to have a high prevalence of HPV DNA

tonsil, tongue, and floor of mouth

Etiology - Diet

Nutritional deficiencies (A and E) may be associated with hypopharyngeal cancer, especially in alcoholics and females. Nasopharyngeal cancer has been associated with salted fish.

Etiology - Genetics

Bloom syndrome and Li-Fraumeni syndrome

Morbidity of treatment increases and prognosis decreases as affected area progresses from _____ to ______

back of lips to hypopharynx, excluding the larynx

What indicates poor prognosis?

Vascular invasion, non-SCCs, extent of lymph node involvement, presence of cervical metastases, endophytic growth (invasion of lamina propria and submucosa),

What can result from enlargement of adenoid/pharyngeal tonsil?

Obstruction of upper air passage and allows breathing only through the mouth

What is the function of tonsils?

1. Lymphoid tissue that provide protection against airway infections

2. Form barrier between respiratory tubes (nasopharynx) and digestive tubes (oropharynx, hypopharynx)

Where is the first cervical vertebrae (C1)?

Inferior margin of nasopharynx

What does C2 contain?

Oropharynx

What is C4 in line with?

True vocal cords

What can salivary gland tumours involve?

Facial nerves, major cranial nerves, arterial neck blood flow, several lymph node groups

Lymphatic drainage is mainly _____

ipsilateral

Which structures have bilateral drainage?

Soft palate, tonsils, base of tongue, posterior pharyngeal walls, nasopharynx

Which structures have few or no lymphatic vessels?

True vocal cord, paranasal sinuses, middle ear

What are endophytic tumours?

More aggressive in spread and harder to control locally

What are exophytic tumours?

Noninvasive neoplasms characterized by raised, elevated borders

What is a common symptom that head and neck patients report?

60% of patients report otalgia (ear pain)

What is a common symptom in oral cavity tumours?

Swelling or ulcer that fails to heal. Localized pain is considered a symptom of advanced disease.

What are common symptoms in oropharynx tumours?

Painful swallowing, sore throat and referred otalgia

What are common symptoms of nasopharynx tumours?

Bloody discharge, difficulty with hearing, neck mass from metastatic adenopathy

What are common symptoms of laryngeal tumours?

Persistent sore throat, hoarseness and stridor

What are common symptoms of hypoharynx tumours?

Sore throat, odynophagia, and painful neck nodes. Up to 25% of cases present with a neck mass only. Dysphagia and weight loss are common symptoms of advanced disease.

What are common symptoms of tumours of nose/sinuses?

Obstruction, discharge, facial pain, diplopia, local swelling

What is a common site of metastases from the oral cavity, oropharynx or hypopharynx?

Subdigastric nodes

What nodes frequently arise from tumours found in the salivary glands?

Preauricular nodes

What is associated with tumours of the hypopharynx, base of tongue, and larynx?

Midcervical neck mass

During a physical examination, what are characteristics of metastasis?

Nodes that are hard, greater than 1 cm, nontender, nonmobile, and raised

What is the most common pathology of head and neck cancer?

Squamous cell carcinoma

What is stage IVA, IVB, IVC?

Advanced resectable disease

Advanced unresectable disease

Advanced metastatic disease

What are contrast enhanced CT and MRI scans for?

To determine size and shape of tumour, better than a clinical evaluation

Why is the volume of irradiated fields large?

Due to risk of nodal spread

How common is recurrence in head and neck cancers?

High. More than 75% of all head and neck cancers recur locally or regionally.

How common is hematogenous spread?

Hematogenous spread below neck is rare, except in nasopharyngeal or parotid gland cancer

In nasopharyngeal cancer, which nodes are commonly positive?

Inferior cervical nodes are clinically positive in 6% to 23% of cases

How does metastatic spread occur in nasopharyngeal cancer?

Nasopharyngeal cancer with bilateral cervical node involvement has a 25% chance of spreading via blood to bone then lung

What are the goals of treatment?

Eradication of disease, maintenance of physiologic function, preservation of cosmetics

What are the major curative modalities for head and neck cancer?

Radiation therapy and surgery, with adjuvant chemotherapy for advanced stages

What treatment modality is typically indicated?

Radiation therapy, as tumours in the head and neck area are often inaccessible via surgery

What is the treatment modality for small lesions with negative nodes?

One modality - surgery or radiation therapy

What is the treatment modality for small lesions with involved nodes?

Surgery and radiation therapy for control

What is the treatment modality for large lesions (T3/4), extensive cervical node disease, or both?

Surgery, radiation therapy and chemotherapy

What is the use of surgery as treatment correlated to?

Possibility of en bloc resection, as partial resections involve high risk of recurrence. Wide margins (>2 cm) are usually needed.

What is also performed during surgery?

Biopsy of cervical nodes and lesions

When would surgery be the modality of choice?

Early stage oral cavity or floor mouth cancers with no clinically positive nodes or if risk of deep cervical node involvement is low

What are conventional curative surgeries?

Laser therapy, cryotherapy, electrocautery

What is an ideal case for surgery as palliative salvage therapy in the event of failure after radiation therapy?

If conventional treatment was done, as accelerated treatments result in severe acute toxic effects that often require feeding tube and mucosal healing that take months

What is the modality of choice for disease that has invaded bone? Why?

Surgery, as radiation therapy doses have high risk of necrosis

What is a radical neck dissection?

Removes lymph nodes from level I to V, sternocleidomastoid muscle, internal jugular vein, spinal accessory and 11th cranial nerve

What is the modified radical neck dissection?

Decreases morbidity by sparing sternocleidomastoid muscle, internal jugular vein, and 11th cranial nerve, depending on location of metastatic spread

What is wound healing impacted by?

Diminished blood supply, impaired collagen formation and increased risk of infection due to decreased leukocyte function

Why is there more caution with radiation and neck dissections?

High doses from radiation can cause decreased vascularity and fibrosis, and may likely result in healing complications

What is the role of chemotherapy in head and neck cancer?

Used for metastatic disease, locally recurrent disease, or salvage therapy when surgery and radiation therapy can no longer be used

What is the role of chemotherapy in nasopharyngeal cancer?

For advanced NPC, neoadjuvant chemotherapy can be used as a radio-sensitizer, or used adjuvantly after treatment

Which chemotherapy drug has the highest overall and complete remission rates?

Cisplatin containing drug combinations

What is the most common chemotherapy drug combination?

Cisplatin and 5-FU

What is a reason why chemotherapy may not be used?

When used concurrently with RT, it can increase severity of toxicities and complication rates - which is why it may not be used

How do we determine whether a patient receives concurrent or adjuvant chemotherapy?

For a fit patient, concurrent chemoradiation may be offered to maximize the chance to skip surgery and neoadjuvant chemotherapy may be used for borderline fit patients, as acute toxicity during RT is lower

How does proton beam radiation therapy minimize dose to surrounding tissues?

Protons deposit low energy when they enter the body and then there is a rapid increase in the deposit of energy (Bragg Peak), followed by a steep decrease in energy

How is PBRT beneficial for head and neck cancer?

It can spare OARs, contralateral areas, such as salivary glands, and can be used to irradiate recurrent disease

What is the standard course of treatment in the event of recurrence?

Surgery or chemotherapy. Radiation therapy is not used due to the higher rate of toxicities.

Can electron beams be used for head and neck cancers?

May be used to boost doses to superficial regions

What fractionation is used for SCCs with longer doubling times?

Standard fractionation (200 cGy, 5 days/week)

What fractionation is used for SCCs with shorter doubling times?

Accelerated hyperfractionation (120 cGy, twice daily)

What would the patient position be for treatment of the maxillary sinus/antrum?

Chin is extended to include the anterior aspect of maxillary sinus/antrum in the anterior field, without including the eyes

What techniques and immobilization would be used for post-operative patients? Why?

An electron boost field or bolus may be used, as tumour cells in surgical beds are less oxygenated and more radioresistant. Hence, higher doses are necessary.

What is the purpose of a tongue blade as an immobilization device?

Tongue blade may be inserted between incisor teeth to depress tongue if tumour invasion includes tongue to reduce superior border, displace tongue from treatment field (lesion is at anterior floor of mouth), or displace palate

What are the subdivisions of the oral cavity?

Anterior two-thirds of tongue, lips, buccal mucosa, lower and upper alveolar ridge, retromolar trigone, floor of mouth, hard palate

How is the clinical target volume defined in oral cavity cancer?

Pre-op diagnostic images, surgical and pathological findings, post-op changes on post-op CT scan

Is nodal and metastatic spread common in oral cavity cancer?

No, cervical lymph node involvement at time of presentation is uncommon and oral cavity cancers have the lowest incidence of nodal metastasis. Hematogenous spread occurs in fewer than 20% of patients.

What is the treatment for early stage and pre-malignant lesions in oral cavity cancer?

Surgery alone

When is surgery and radiation therapy indicated in oral cavity cancer?

Inadequate surgical margins and neck nodal involvement

In oral cavity cancer, is irradiation of the neck nodes involved?

If lesion has high rate of spread or history of bilateral spread via lymphatics

When do lesions of the oral cavity typically recur?

Most sites typically recur within 2 years and rarely after 5 years

What dose does gross disease of the oral cavity receive?

70 Gy

What volumes receive 64 Gy in oral cavity irradiation?

High risk of microscopic disease

High risk lymph nodes

What volumes receive 60 Gy in oral cavity irradiation?

Contralateral neck or low neck

What is included in the low-risk CTV in oral cavity irradiation?

Contralateral neck or low neck

How much dose does each volume receive if the patient is receiving 72 Gy in oral cavity irradiation?

72 Gy to primary lesion

66 Gy to high risk CTV

60 Gy to low risk CTV

Final 6 Gy delivered via electron beam

For patients who had neo-adjuvant chemotherapy for oral cavity cancer, what are the target volumes for radiation therapy?

Target volumes are defined from the original extent of the tumour

Describe the lymphatic drainage of the upper lips

Drain into buccal, parotid, upper cervical and submandibular nodes. It may cross midline to the submental and submandibular nodes of contralateral side.