Head and Neck Cancers and Associated Dental Management Guidelines
Cancers of the mouth, salivary glands, sinuses, nose, throat, and lymph nodes in the neck are designated head and neck cancers. Difficulty swallowing, hoarseness, lesions in the oral cavity, and lymph node enlargements in the neck are frequently how head and neck cancers present.
The dentist plays a very important role in the detection of head and neck cancers because oral cancer screening is a routine part of patient examination, and patients visit dentists more frequently than physicians.
Cancer care is multifaceted and multidisciplinary. This chapter discusses cancer terminology, cancer staging, cancer treatment principles and goals, cancer treatment options, and treatment response definitions. This information will enable the reader to understand and participate in the cancer patient’s care.
HEAD AND NECK CANCER DETECTION AND THE DENTIST
The dentist might be the first provider to track and follow through with a patient experiencing difficulty swallowing. The dentist can also identify hoarseness that is of concern and request further evaluation; the dentist can identify suspicious oral lesions because of their color, shape, or size, and refer the patient for biopsy.
The dentist can focus on lesions associated with poor healing and triage the patient to a physician for further assessment. The dentist can find lymph node enlargements that do not fit the picture of infection-associated enlargements, but rather have cancer-associated features. Thus, the dentist is often the first provider to refer the patient to the medical side for further evaluation.
A dentist can also aid in the diagnosis of leukemias and lymphomas by detecting the following:
NEOPLASMS OF THE ORAL CAVITY
To understand cancer growth one has to understand tumor biology. One malignant cell creates 109 cells. These cancer cells grow faster than normal cells and have unstable DNA that cannot be repaired.
Head and neck cancers account for 6% of all cancers, and of these, 30% of the cancers occur in the oral cavity. Males are more often affected than females. The patients are usually in their 40s or 50s. The most common tumor of the oral cavity is a squamous cell carcinoma in the upper aero digestive tract.
NEOPLASMS OF THE NASAL CAVITY
Neoplasms of the nasal cavity are rare. There are two types of neoplasms:
HEAD AND NECK CANCER SYMPTOMS AND SIGNS
Symptoms and signs frequently experienced are localized pain, odynophagia (pain on swallowing), dysphagia (difficulty swallowing), hoarseness, dyspnea (shortness of breath), coughing up blood, and referred pain to the ear from the upper digestive tract, especially in patients with alcohol and tobacco use.
LYMPH NODES OF THE HEAD AND NECK
A dentist needs to know about cancers of the head and neck region and the associated lymphatic drainage so the two can be correlated to assist in the diagnosis, treatment, and follow-up of benign or malignant tumors. The lymph nodes surrounding the base of the skull and the cervical chains of lymph nodes are the nodes of great importance for head and neck tumors. A dentist should have a clear understanding of what specific areas each set of nodes drains. Thus, when a lesion is detected during physical examination, the appropriate lymph nodes should be palpated to determine the extent of involvement.
Lymph Nodes Surrounding the Base of the Skull
These nodes include the following:
- The preauricular or superficial parotid node
- The postauricular nodes
- The occipital nodes
- The deep parotid nodes
- The retropharyngeal nodes
- The submandibular nodes
- The submental nodes
- The tonsilar/jugulodigastric node
- The juguloomohyoid node
- The para-tracheal and pre-tracheal nodes
The Cervical Chain of Lymph Nodes
These nodes include the following:
- The superficial cervical chains
- The deep cervical chains
The Superficial Cervical Chains
The superficial cervical chains receive drainage from the preauricular, postauricular, and occipital nodes. The superficial cervical chains, in turn, drain into the deep cervical chains.
The Deep Cervical Chains
The deep cervical nodes receive drainage from the salivary glands, thyroid gland, tongue, tonsils, nose, pharynx, and larynx (Table 51.1< ?anchor c51-tbl-0001 ?>). On the left side, the deep cervical chain drains into the thoracic duct. On the right side, the deep cervical chain drains into the right lymphatic duct, or the internal jugular, subclavian, or brachiocephalic veins.
|Lymph Nodes||Areas Drained||Drainage|
|Pre-auricular or Superficial Parotid Nodes:||Drain the external ear canal, front of auricle, and the adjacent scalp||Indirect drainage from Superficial Cervical to Deep Cervical nodes|
|Post-auricular Nodes:||Drain the external ear canal, back of the auricle and the adjacent scalp||Indirect drainage from Superficial Cervical to Deep Cervical nodes|
|Occipital Nodes:||Drain the posterior part of scalp and adjacent region of neck||Indirect drainage from Superficial Cervical to Deep Cervical nodes|
|Deep Parotid Nodes:||Drain the anterior half of scalp, infra-temporal region, orbit, lateral eyelids, maxillary molar teeth, external ear canal, and the parotid gland||Direct drainage: Deep Parotid nodes directly drain into the Deep Cervical nodes|
|Retropharyngeal Nodes:||Drain the upper part of the pharynx and adjoining structures||Direct drainage: These nodes drain directly into the Deep Cervical nodes|
|Submandibular nodes:||Drain the anterior nasal cavities, tongue, teeth, gums, submandibular and sublingual glands, and all of the face except the lateral eyelids and medial lower lip and chin||Direct drainage: These nodes drain directly into the Deep Cervical nodes|
|Submental nodes:||Drain the tip of the tongue, floor of the mouth, and the lower lip and chin||Direct drainage: These nodes drain directly into the Deep Cervical nodes|
|Tonsilar/Jugulo-digastric Nodes:||Drain the tonsils and lateral part of the tongue||Direct drainage: These nodes drain directly into the Deep Cervical nodes|
|Jugulo-Omohyoid Nodes:||Drain the tongue via the submental and submandibular nodes||Direct drainage: These nodes drain directly into the Deep Cervical nodes|
|Para Tracheal and Pretracheal Nodes:||Drain the trachea and thyroid gland. These nodes drain into the tracheo-bronchial nodes in the mediastinum||Direct drainage: These nodes drain directly into the Deep Cervical nodes|
GENERAL CANCER RISK FACTORS AND PREVENTION
The general risk factors for cancer are smoking tobacco, alcohol consumption, and miscellaneous other causes.
Smoking as a Cancer Factor
Smoking tobacco accounts for 170,000 deaths each year. Of all cancers, 30% are due to tobacco and 80% of all lung cancers are due to smoking.
Examples of Tobacco-Related Cancers
Tobacco-associated cancers include lung, mouth, and pharynx cancers; esophageal cancers; pancreatic cancer; uterus, cervix, kidney, and bladder cancers; oral cancer from chewing tobacco; and lung, oral, larynx, and esophageal cancers from cigar smoking.
Alcohol as a Cancer Factor
Alcohol accounts for 19,000 deaths per year and alcohol is an important etiological factor for many cancers, especially cancers of the head and neck. Oral cancer risk is highest in patients using both alcohol and tobacco, compared with those using just one or the other.
Miscellaneous Risk Factors
Other risk factors for head and neck cancers are obesity, viruses, exposure to ultraviolet light, and immune conditions.
The risk of cancer can be lowered with smoking cessation, screening tests, sunscreen use, diet modification, and healthy lifestyle.
SCREENING TESTS FOR CANCER DETECTION AT SPECIFIC BODY SITES
A dentist has to be very familiar with oral cancer screening, and as a health-care provider, the responsibility extends to knowing other forms of cancer screenings too. Your patient may provide information about having had specific tests or may question you about other screening methods or tests, so it is important to be knowledgeable. Common cancer screening tests are:
Cancer management is multi-tiered and consists of the following:
CANCER DIAGNOSTIC AIDS
To confirm cancer pathology, tissue samples can be obtained using any of the following options; biopsy of suspect tissue, bone marrow aspiration, blood sample, assessment of cell surface markers, and cytogenics or DNA analysis.
Tumor staging can be done using the Broder’s classification and/or the TNM staging system.
Tumor grading using the Broder’s classification (Tumor Grade [G]), is as follows:
The TNM Staging System
The TNM staging system is a clinical staging system that helps estimate the extent of disease prior to treatment. The staging process helps determine the treatment choice, the predictive treatment response, and survival. The tumor and nodes are assessed by inspection and palpation when possible. The status of the tumor must be confirmed histopathologically before treatment options are explored. Additional tests that help with the staging process are biopsy, x-ray, CT scan, MRI, nuclear study, or surgery.
For detection and localization of head and neck tumors, magnetic resonance imaging (MRI) is a better option compared with CT scans. MRIs are also better than CT scans in distinguishing lymph nodes from blood vessels in the assessment of head and neck cancers. In the event of a relapse, restaging of the cancer is done to determine appropriate additional treatment that will be required.
American Joint Committee on Cancer (AJCC) TNM Classification
TNM staging is done using these definitions for tumor, lymph nodes, and metastasis:
- Primary tumor (T) represents the extent of the primary tumor
- TX: Primary tumor cannot be assessed
- T0 (T zero): No evidence of primary tumor
- TIS: Carcinoma in situ
- T1: Tumor ≤2cm in its greatest dimension
- T2: Tumor >2cm but ≤4cm in its greatest dimension
- T3: Tumor >4cm in its greatest dimension
- T4: Invasive tumor
- N represents the degree of lymph node involvement
- NX: Regional lymph nodes cannot be assessed
- N0 (N zero): No regional lymph node metastasis present
- N1: Metastasis present in a single ipsilateral (same side) lymph node, ≤3cm in its greatest dimension
- N2a: Metastasis in a single ipsilateral (same side) lymph node >3cm but ≤6cm in dimension
- N2b: Metastasis in multiple ipsilateral lymph nodes, ≤6cm in greatest dimension
- N2c: Metastasis in bilateral or contralateral (on the opposite side) lymph nodes, ≤6cm in greatest dimension
- N3: Metastasis in a lymph node >6cm in greatest dimension
- M represents the presence of metastasis
- MX: Distant metastasis cannot be assessed
- M0 (M zero): No distant metastasis present
- M1: Distant metastasis present
The TNM Stages
The TNM stages are as follows:
American Joint Committee on Cancer (AJCC) Stage Groupings
The stage groupings indicate the TNM definitions associated with each of the TNM stages:
The Eastern Cooperative Oncology Group Scale
The Eastern cooperative oncology scale helps decide which patients can receive treatment. It does so by classifying the patient’s level of activity with the associated cancer. According to the scale, it is appropriate to treat only Stage 2 or better because the patient loses one level during treatment. The following are the stages according to the Eastern Cooperative Oncology Scale:
Cancer treatment entails establishment of the following:
Treatment Options and Goals
Cancer treatment options and their respective goals are as follows:
Cancer treatment options depend on the invasiveness of the cancer; the options offered are:
Treatment Response Definitions
The dentist plays a very important role in managing and maintaining the oral health status of the cancer patient during chemotherapy and/or radiotherapy. The treating oncologist can sometimes forward the patient’s records to the dental provider to assist with the care. Familiarity with the treatment response definitions often used by the treating oncologists is thus helpful in evaluating the records and assessing the patient’s status. Common treatment response definitions used are:
Head and Neck Cancer Treatment Options
The treatment options for cancer care are:
Stage I and Stage II cancers are highly curable by surgery or radiation therapy. Stage III or Stage IV cancer patients are candidates for treatment by a combination of surgery and radiation therapy. They should also be considered for a combination of chemotherapy with surgery and/or radiation therapy to improve local control and to decrease the frequency of distant metastases.
HEAD AND NECK CANCER TREATMENT
Advantages of Surgical Therapy
Surgical therapy is curative and ideal for early-stage cancer with limited involvement.
Risks of Surgical Therapy
Risks are limited to what can be removed, the microscopic disease status, and the operating room risks. Surgery is not a useful choice in widespread disease.
Advantages of Radiation Therapy
Radiation works differently in different cancers but is a good choice for tumors that cannot be removed. The mechanism of action of radiotherapy is different than that for chemotherapy. The response is fast and with minimal side effects.
Risks of Radiotherapy
Radiotherapy damages the surrounding normal tissues and it is useless in widespread cancers.
Radiation Therapy Options
A dentist should be familiar with all forms of radiation therapy to the head and neck region and know the amount of radiation the patient has received during cancer care. Radiation options available are:
Knowledge of the following chemotherapy-associated topics is important for optimal patient care:
For provision of dental care during chemotherapy, it is always important to know the patient’s chemotherapy schedule and the terms used to describe the schedules. Some of the terms used are:
Chemotherapy Vascular Access
Multiple (four in all) vascular accesses are established prior to the start of chemotherapy. The reason multiple accesses are established is that if one line gets infected, it has to be removed and another line gets inserted. To create a new access during chemotherapy is not possible because of tissue scarring. Two jugulars and two subclavial vascular lines are needed for blood draws. Presence of a vascular access requires the dentist to premedicate the patient prior to dental treatment.
Chemotherapeutic choices are determined by identifying the cycle specificity and the phase specificity:
BONE MARROW TRANSPLANT
Bone marrow transplant (BMT) is another option available for cancer care. High-dose chemotherapy, usually ten times the normal dose, is needed for BMT. Stem cells used are taken from the patient or from a donor. In donor cells BMT, one can get a host-graft in which the donor cells see the cancer cells as bad and attack it. Post-transplant immune suppression is always needed to prevent rejection.
Bone Marrow Transplant Complications
Significant complications associated with bone marrow transplantation are: xerostomia; mucositis; fungal, viral, or bacterial infections; and graft versus host disease.
Graft versus host disease is an adverse reaction wherein donor cells attack the healthy cells of the host. The right thing to happen with BMT is for donor cells to see tumor cells as bad and attack them. This is the graft versus tumor attack.
IMPORTANT HEAD AND NECK CANCER FACTS
Most head and neck cancers are of the squamous cell variety. Patient factors and local expertise influence the choice of treatment. When the tumor invades the vasculature, the prognosis is bad. Leukoplakia is a descriptive term that indicates a white patch that does not rub off. Early cancers of the buccal mucosa are equally curable by radiation therapy or by adequate excision. The treatment options for lip and oral cavity cancer may be surgery alone, radiation therapy alone, or a combination of surgery, radiation, and chemotherapy.
Larger cancers require composite resection with reconstruction of the defect by pedicle flaps. Moderate excisions of tongue, even hemiglossectomy, often results in little speech disability. With extensive tongue resection there can be problems with aspiration, difficulty swallowing, and speech difficulties.
Patients who smoke while on radiation therapy have lower response and survival rates, and such patients should be counseled to stop smoking before starting radiation therapy. Additionally, poor oral hygiene and tobacco or alcohol use during radiation can accelerate the onset of osteoradionecrosis (ORN). Be aware that patients with head and neck cancers have an increased incidence of developing a second primary tumor of the upper aerodigestive tract.
Surgery for parotid tumor can lead to facial paralysis because the facial nerve goes through the gland. Dental status evaluation should be performed prior to radiation or chemotherapy. Prosthodontic rehabilitation post treatment is implemented for better quality of life.
Localized and Systemic Complications Associated with Head and Neck Cancer Therapy
Localized and systemic complications associated with head and neck cancer therapy are mucositis, xerostomia, xerostomia-associated rampant caries and periodontal disease, infection (viral, fungal, and bacterial), pain, nausea and vomiting, malnutrition, deformity, trismus, microvascular injury, osteoradionecrosis (ORN), bone marrow suppression, and death.
HEAD AND NECK CANCERS AND DENTISTRY
Dentistry in a patient with a current or past history of head and neck cancer has to be a well-thought-out, planned process. Several aspects associated with the cancer care have to be evaluated prior to implementation of dentistry. Head and neck radiation therapy causes short-term and long-term side effects. Short-term side effects associated with radiation therapy are:
Mucositis usually begins by the third week of radiation and it presents as an inflammation or ulceration of the oral mucosa. Patients suffering from mucositis often benefit from using a mouthwash prepared as follows: Mix 2tsp salt and 2tsp baking soda in 8oz cold water. The patient should gargle and expectorate the mixture.
Altered salivary gland function causes xerostomia, and xerostomia in turn leads to oral candidiasis and caries. It is absolutely necessary to avoid alcohol-based mouth rinses at this time because further drying of the oral mucosa can occur.
The long-term side effects of radiation occur because of progressive vascular and cellular changes in the bones and soft tissue. There is slow remodeling of the bone and soft tissue, and this leads to necrosis and an increased rate of infection. Salivary gland damage and increased fibrosis also occurs. The hallmark features of long-term radiation-associated />