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11. Tumors of the Head and the Neck


Malignant tumors of the head and neck represent about 10% of all statistically recorded tumors of malignant nature. At least 40% of them appear inside the oral cavity and on the lips. Oral cavity tumors are located on the mucous membrane of cheeks and the alveolar ridge, on the movable portion of the tongue (two frontal thirds), on the oral base and on the palate. Anatomical relationship of such tumors to the oropharynx (the tongue base, soft palate, palatal arches and tonsils) is very tight. Contribution of stomatology, oral, maxillar, and facial surgery to diagnostics and therapy of this group of tumors is thus more than obvious. The majority of orofacial tumors are epidermoid carcinomas derived from the mucous membrane of the mouth and oropharynx, as well as tumors originating from the lymphoid tissue of the Waldeyer’s ring. Lymphatic supply of these areas is achieved via the neck lymphatic system, consisting of regional submental and submandibular nodes, and nodes jugular, paravertebral and supraclavicular. Nearly one half of carcinomas of the oral cavity and oropharynx exhibit a presence of local metastases already at the time of diagnosis. This fact tells us about late recognition of the head and neck tumors. Non-characteristic initial signs, underestimation of the condition by a patient or even a physician, contribute to late diagnoses. Timely diagnosis of oral and oropharyngeal tumors plays an essential role for a prognosis. The presence of metastases decreases chances of patient’s survival for the next five years down to mere 25-30%.

11.1 Epidemiology


The oral cavity is a gateway to the upper airway-digestive tract. It comes into a close contact with carcinogens received in food and products of smoking and exhalations. The most significant risk factors for origination of oral carcinomas are tobacco and alcohol, whose carcinogenic potentiation effects have been proven. Currently, the peroral use of drugs, especially marihuana, is considered as an etiological factor.

Oral precancerous conditions (pre-neoplasias) cannot be overlooked here. The most characteristic among those are leukoplakia and erythroplakia of oral and lip mucosas. Leukoplakia may have either a benign form, with a typical parakeratosis or even acanthosis, and a malignant form with apparent signs of dysplasia or already as a carcinoma in situ. The origin of a malignant process may also be benign epithelial tumors of mucous papilloma type, if they get permanently irritated chemically or mechanically. During each examination of the mouth, especially by a dentist, it is reasonable to consider possibilities of chronic irritation or traumatization of mucosa by dental materials and fault intra-oral prosthetic constructions. An early elimination of carcinogenic causes is the most efficient prevention of a malignant process initiation (a secondary prevention). Every suspicious skin lesion that persists longer than 3 weeks has to be evaluated by a specialist. Histology testing of an excised tissue sample is then usually indicated.


Pathology

Absolute majority (up to 9/10) of oral and peri-oral tumors are epidermoid carcinomas at various stages of differentiation. Carcinomas of the lips, the tongue base and palate are usually well differentiated. Carcinomas of the oral base are partially differentiated, and carcinomas of the movable part of tongue are not very well differentiated at most cases. Low degree of differentiation has been proven to influence a disease prognosis unfavorably. Other tumors of non-epidermal origin occur at salivary glands (mixed tumors, adenoid cystic carcinomas), at the maxillary sinus (adenocarcinomas). Sarcomas penetrate the mouth mostly from jawbones and maxillary sinuses. Lymphomas affect lymphatic components of the Waldeyer’s circle - nodes at the upper part of the neck (a regional lymphatic system).



11.2 Diagnosis and Staging


The majority of head and neck tumors affects men older than 50 years. Although, the lower age boundary has shifted to earlier decades which supports again theories on participation of genetic and immunologic basis in the process of carcinogenesis. Patients with early stages of a carcinoma at the oral cavity sense vague, non-characteristic symptoms of discomfort inside the mouth; and a physical findings are usually not very convincing, either. It is this phase of a malignant disease development that has to be immediately predicted and carefully dealt with by dentists, general physicians and oral surgeons. General signs of the oral cavity carcinoma are a local pain, non-healing mucous ulcerations and changes in position and adhesion of dentures. Oropharyngeal tumors manifest themselves later and that is why they get diagnosed only at progressive stages. Later phases of tumors of the above discussed locations exhibit more distinct symptomatology. It includes an increasing pain, contracture of jaws, difficulties to swallow, restricted movability of the tongue and its base, formation of inner and outer fistulas and cervical node reaction. Failures of a neurologic sensitivity and motility of facial areas are also significant (branches of n. trigemini, n. facialis).

Oncologically oriented examination of the mouth and upper parts of neck should be a routine part of every periodical check at a dentist’s or a general physician’s office. Besides a careful aspection of visible parts of mucosa it is necessary to palpate bimanually the oral base, the whole tongue and the neck lymphatic nodes. Suspicious areas and the above mentioned precancerous states have to be clarified by biopsies. A diagnostic excision is the most exact diagnostic method of a malignant process and the most weighty foundation for determination of a course of therapy.

A clinical check should be complemented with sonography and modern methods of X-ray examinations. Computer tomography (CT) and magnetic resonance (MR) specify an extent and nature of a tumor and determine its relationship to surrounding organs (bones, blood vessels, nerves), as well as these methods point out at an infiltration of regional nodes. The classification system TNM (tumor, nodi lymphatici, metastases) integrates all clinical information according to the international rules (UICC) for purposes of staging (determination of a stage) of a malignant disease.

The following classification scheme is valid for carcinomas of the lips and oral cavity:

T1 = 2 cm

T2 2 - 4 cm

T3 4 cm

T4 infiltration of adjacent structures (the bone)


N1 ipsilateral solitary = 3 cm

N2 ipsilateral solitary 3 - 6 cm

ipsilateral solitary 6 cm

bilateral, contralateral = 6 cm

N3 6 cm
M0 remote nodes negative

M1 remote nodes positive


The 1st to the 4th stages of a malignant disease (staging) are determined by combination of the above elements of classification. Staging is a respected groundwork for choosing an optimum therapy and a guideline for a disease prognosis.

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