Overview of Head & Neck cancer

Dr.Vinin.N.V Assistant Professor Radiation Oncology Malabar Cancer Centre

Head & neck cancer refers to cancers of the UADT (Upper aero digestive tract)

Oral Cavity Pharynx Larynx Nasal cavity & Paranasal sinuses Salivary glands

Epidemiology  

Overall, head and neck cancer accounts for more than 550,000 cases annually worldwide

Males are affected significantly more than females with a ratio ranging from 2:1 to 4:1.

The incidence rate in males exceeds 20 per 100,000 in India.

Head and neck cancers are common in India and account for about 30% of cancers in males and about 13% in females.

Oral cavity cancers are more common in the India

HEAD AND NECK CANCER CLASSIFICATION 

Head and neck cancers arise from a variety of locations and structures within the head and neck region.

This region is divided into five sites by which cancers are classified

1. Oral cavity, which includes the lips, buccal mucosa, anterior tongue, floor of the mouth, hard palate, upper gingiva, lower gingiva, and retromolar trigone .

2. Pharynx, which is divided into the nasopharynx, the oropharynx, and the hypopharynx.

The nasopharynx, the narrow tubular passage behind the nasal cavity, is the upper part of the pharynx.

The oropharynx, the middle part of the pharynx, includes the tonsillar area, the tongue base, the soft palate, and the posterior pharyngeal wall.

The hypopharynx, which is the lower part of the pharynx, includes the pyriform sinuses, the posterior surface of the larynx (postcricoid area) and the inferoposterior, and inferolateral pharyngeal walls.

3. Larynx is divided into three anatomic regions: the supraglottic larynx, the glottic larynx (true vocal cords and the anterior and posterior commissures) and the subglottic larynx.

4.Nasal cavity and the paranasal sinuses, which include the maxillary, ethmoid, sphenoid, and frontal sinuses.

5. Major salivary glands (parotid, submandibular, and sublingual) and the minor salivary glands, which are located throughout the submucosa of the mouth and upper aerodigestive tract.

PATHOLOGY

Squamous cell carcinomas account for 90 to 95 percent of the lesions in the head and neck.

They can be categorized as well differentiated (greater than 75 percent keratinization), moderately differentiated (25 to 75 percent keratinization), and poorly differentiated (less than 25 percent keratinization) tumors.

Less common histologies include verrucous carcinoma (a variant of squamous cell carcinoma), adenocarcinoma, adenoid cystic carcinoma, and mucoepidermoid carcinomas.

Etiology & Risk Factors

Smoking : In heavy cigarette smokers, there is a 5- to 25-fold increased risk of cancer compared with nonsmokers.

Alcohol : Alcohol consumption independently increases the risk of cancer in the upper aerodigestive tract.

Viral infection Epstein-Barr virus : A large body of

evidence supports the role of EBV as the primary etiologic agent in the pathogenesis of nasopharyngeal carcinoma.

Human papillomavirus   Epidemiologic and molecular evidence has

established a causal role for HPV, primarily type 16, in patients with head and neck cancer, particularly those arising in the base of the tongue and the tonsils.

HPV associated oropharyngeal cancers are typically seen in younger men who are nonusers of tobacco and alcohol.

Human immunodeficiency virus — There is an approximately two- to three fold increase in the incidence of squamous cell carcinoma of the head and neck in HIV-infected patients.

Betel nut chewing — Betel nut chewing, is an independent risk factor for the development of squamous cell head and neck cancer. The effects appear to be synergistic with tobacco and alcohol.

Occupational exposure — Multiple occupational or environmental toxins have been

studied for potential relationship with head and neck cancer. These include the dry cleaning agent perchloroethylene ,

asbestos, pesticides, polycyclic aromatic hydrocarbons , textile workers, wood workers .

Formaldehyde is associated with nasopharyngeal cancer and possibly cancers of the nasal cavity and paranasal sinuses.

Squamous cell carcinoma of the larynx and base of tongue has also been associated with exposure to Agent Orange.

Field Cancerization Field cancerization is an important concept related to

the natural history of head and neck cancer. This term describes the diffuse epithelial injury

throughout the head and neck, lungs, and esophagus that results from chronic exposure to carcinogens.

Clinically, field cancerization is manifested by the frequent occurrence of (1) mucosal abnormalities, beyond the margins of a head and neck cancer, and (2) second primary tumors within this exposed field.

The lifetime risk of a patient with head and neck cancer developing a new cancer is 20% to 40%.

Genetic factors — Multiple genetic factors and pathways may contribute to an increase in risk of head and neck cancer, and these factors may interact with other known risk factors.

Two inherited genetic syndromes, Fanconi anemia and Dyskeratosis congenita, may greatly increase the likelihood of developing throat and mouth cancers in people at an early age.

Radiation — Prior irradiation for either malignant or benign disease has been linked to thyroid cancer, salivary gland tumors, squamous cell cancers, and sarcomas.

Diet  Several studies have shown a protective effect

associated with increased consumption of fruits and vegetables.

Studies suggest that the risk of nasopharyngeal carcinoma is increased in frequent consumers of preserved meats that contain high levels of added nitrites.

CLINICAL PRESENTATION

The clinical presentation of head and neck cancer varies widely depending upon the primary site

Oral cavity tumors – Patients may present with nonhealing mouth

ulcers, loosening of teeth, dysphagia, odynophagia, weight loss, bleeding, or referred otalgia.

Up to 66 percent of patients with primary tongue lesions have cervical nodal involvement, while the incidence is substantially lower in patients with hard palate and lip cancers.

Oropharyngeal tumors – Presenting complaints can include pain, odynophagia, bleeding, or a neck mass.

Nasopharyngeal carcinoma – The most frequent presenting complaint is a neck

mass due to regional lymph node metastasis, which occurs in nearly 90 percent of patients.

Symptoms due to the primary tumor may include hearing loss (associated with serous otitis media), tinnitus, nasal obstruction and pain, and its associated growth into adjacent anatomical structures, which can lead to muscle involvement and impaired function of cranial nerves II to VI.

Hypopharyngeal tumors – Patients with these tumors often

remain asymptomatic for a longer period and are therefore more likely to be seen in the later stages of the disease.

Dysphagia, odynophagia, otalgia, weight loss, and neck mass are common presenting symptoms.

Laryngeal cancer – The symptoms associated with cancer of the larynx depend upon location.

Persistent hoarseness may be the initial complaint in glottic cancers; later symptoms may include dysphagia, referred otalgia, chronic cough, hemoptysis, and stridor.

Supraglottic cancers are often discovered later and may present with airway obstruction or palpable metastatic lymph nodes.

Primary subglottic tumors are rare. Affected patients typically present with stridor or complaints of dyspnea on exertion.

Sinus tumors – Common presenting symptoms of

sinus tumors include epistaxis and unilateral nasal obstruction.

Facial and/or head pain may be seen in later stages, due to pressure or tumor infiltration into nerves or periosteum.

Diagnosis and staging 

Initial evaluation — The initial assessment of the primary tumor is based upon a combination of inspection, palpation, indirect mirror examination, and direct endoscopy.

Physical examination should include careful assessment of the nasal cavity and oral cavity with visual examination and palpation of mucous membranes, the floor of the mouth, the anterior two-thirds of the tongue, tonsillar fossae and tongue base, palate, tonsillar fossae, buccal and gingival mucosa

Visualization of lesions outside the mouth is best accomplished by mirror examination and/or the use of a flexible fiberoptic endoscope with the goal of examining all of the mucosa in the nasopharynx, oropharynx, hypopharynx, and larynx.

Other abnormalities that should be specifically searched for are impairment of vocal cord mobility, pooling of secretions, asymmetries, and bleeding.

The appropriate nodal drainage areas are examined by careful palpation of the neck.

Examination of the neck for pathologic adenopathy or other masses is best done according to neck levels.

Biopsy should be taken from lesions and sent for HPE.

LYMPH NODE LEVELS

An examination under anesthesia often is performed to best characterize the extent of the tumor, to look for synchronous second primary tumors, and to take biopsies for a tissue diagnosis. This exam is particularly useful for patients with laryngeal and hypopharyngeal malignancies.

Symptom-directed panendoscopy (laryngoscopy, bronchoscopy and esophagoscopy) reveals a 2.4 to 4.5 percent incidence of second primary tumors of the upper aerodigestive tract.

In general, patients with a history of heavy alcohol or tobacco use should undergo panendoscopy.

Imaging studies may augment the physical exam and evaluation of squamous cell carcinoma of the head and neck, particularly for assessing the degree of local invasion, involvement of regional lymph nodes, and presence of distant metastases or second primary malignancies.

The most common metastatic sites are the lungs, liver, and bone.

The most common sites of second primary malignancies are the head and neck, followed by the lungs and esophagus.

Fine needle aspiration cytology — Fine needle aspiration cytology (FNA) is frequently used to make an initial tissue diagnosis of a head and neck cancer when a patient presents with a neck mass (metastatic cervical lymph node) without an obvious primary mucosal/upper aerodigestive tract site.

This technique has high sensitivity and specificity and a diagnostic accuracy that ranges from 89 to 98 percent .

Imaging studies — Imaging studies (computed tomography [CT], magnetic resonance imaging [MRI], positron emission tomography [PET], and integrated PET/CT) are important for assessing the degree of local infiltration, involvement of regional lymph nodes, and presence of distant metastases or second primary tumors.

CT is particularly useful in upstaging cancers that have deeper local invasion or infiltration into adjacent structures that is difficult to detect on physical examination.

CT can provide information on invasion of the preepiglottic space, laryngeal cartilage, paraglottic space and subglottic extension, and can evaluate retropharyngeal, parapharyngeal, upper mediastinal, and paratracheal nodes.

In addition, bone and cartilage invasion, a criterion for stage T4 disease, can be more readily detected.

CT scan showing thyroid cartilage erosion

Magnetic resonance imaging   MRI provides superior soft tissue

definition compared with CT . MRI can provide more accurate

definition of tumors of the tongue and is more sensitive for superficial tumors.

MRI is superior to CT for evaluation of perineural spread, skull base invasion, and intracranial extension of head and neck cancer.

Regional nodes 

Imaging by CT or MRI is complementary to the clinical examination for the staging of the neck lymph nodes.

In most studies, CT scanning outperforms MRI for the detection of pathologic nodal metastases.

Extracapsular spread of nodal metastasis is an important prognostic factor that should be assessed on imaging.

PET and integrated PET/CT — With PET, injected positron-emitting radionuclides, such as fluorine-18, are taken up by metabolically or functionally active tissues. PET images are created by detecting these emissions by an array of detectors and then using reconstruction techniques to create a three dimensional image.

The most commonly used agent is 18F-flourodeoxyglucose (FDG), which is taken up into cells in different concentrations depending on the relative metabolism of different tissues. It is fairly specific for tumors because metabolic rates are very high in many tumors.

PET/CT is accurate for detecting occult cervical nodal metastases.

Its main utility is in finding occult distant metastases, unknown primary lesions, and synchronous second primary tumors

Helps in altering radiation fields and doses for patients who are not undergoing neck dissection.

PET CT of a 70yr old man with right sided neck mass

Evaluation for distant metastases  A component of the initial staging

evaluation for patients with new or recurrent head and neck cancer is the search for distant metastases.

The reported incidence is between 2 and 26 percent and varies based on locoregional control, nodal involvement (number and presence of extracapsular extension), primary site (particularly hypopharynx), histologic grade, and T stage .

Distant metastases are usually asymptomatic; the most common sites are the lungs followed by the liver and bone.

CT scan is the most sensitive method to screen for distant metastases in patients with head and neck cancer, identifying malignant findings in between 4 and 19 percent of cases.

Incidence of second and multiple primaries — At-risk patients (ie, those with strong tobacco and alcohol use or family history) are prone to develop second primary cancers of the upper aerodigestive tract. Such tumors may be present at presentation or develop subsequently.

TNM STAGING SYSTEM

The tumor node metastases (TNM) staging system of the American Joint Committee on Cancer (AJCC) and the International Union for Cancer Control (UICC) is used to classify cancers of the head and neck.

T classifications indicate the extent of the primary tumor and are site specific; there is considerable overlap in the cervical node (N) classifications.

TNM Staging : Carcinoma Oral Cavity

Tis : Carcinoma in situ T1: Tumor is 2cm or less in greatest

dimension T2: Tumor is > 2cm ≤ 4cm in greatest

dimension T3: Tumor is > 4cm in greatest dimension T4a: Tumor invades adjacent structures

(cortical bone , deep extrinsic muscles of tongue, skin of face)

T4b: Tumor invades masticator space, pterygoid plates, or skull base or ICA.

N0 : No regional nodal metastasis N1 : Metastasis in single ipsilateral LN,<3 cm in

greatest dimension. N2a: Metastasis in single ipsilateral LN > 3 cm

≤ 6 cm in greatest dimension. N2b : Metastasis in multiple ipsilateral LNs,

none more than 6 cm in greatest dimension. N2c: Metastasis in bilateral or contralateral

LNs, none more than 6 cm in greatest dimension.

N3 : Metastasis in LN > 6 cm in greatest dimension.

Mx : Distant metastasis cannot be assessed

M0 : No evidence of distant

metastasis

M1 : Distant metastasis

Stage Grouping

STAGE

O TisN0M0

I T1N0M0

II T2N0M0

III T3N0M0, T1-T3N1M0

IVA T4aN0-N1M0,T1-T4aN2M0

IVB AnyTN3M0,T4b AnyNM0

IVC AnyT Any N M1

Treatment, rehabilitation, and prognosis

Treatment for head and neck cancer is complex• Variety of tumor subsites.• Anatomic constraints of the head and neck.• Importance of maintaining organ function. A multidisciplinary approach including Surgeons Medical oncologists Radiation oncologists Dentists Dieticians Rehabilitation therapists

Treatment

EARLY STAGE  Approximately 30 to 40 percent of

patients with head and neck squamous cell carcinomas (HNSCCs) present with early (stage I and II) disease.

In general, these patients are treated with either primary surgery or definitive radiation therapy (RT).

Five-year overall survival in patients with stage I or stage II disease is typically 70 to 90 percent.

Both modalities result in similar rates of local control and survival, the choice is typically based upon surgical accessibility of the tumor and the functional outcomes and morbidity associated with each modality.

In general, surgery is used as the main modality of treatment in the oral cavity, whereas RT is more commonly used in the other mucosal sites.

ADVANCED STAGE  Historically, local therapy alone, ie,

primary surgery or definitive radiation therapy (RT), for locoregionally advanced (stage III, IVA, and IVB) head and neck squamous cell carcinomas resulted in high rates of locoregional recurrence and considerable morbidity, including loss of tongue and larynx function (speech and swallowing).

Effective approaches for locoregionally advanced head and neck squamous cell carcinomas include

Primary surgery followed by either postoperative RT or concurrent chemoradiation

Concurrent chemoradiation Sequential therapy (induction

chemotherapy followed by concurrent chemoradiotherapy).

THANK YOU