Oral cavity 2

Dr.Hussein Surgery Lec.2

III. Benign swellings of the oral cavity:
B. Inflammatory swellings: most of the inflammatory swellings are associated
with the teeth, dental caries and gingivitis are predisposing factors. These
cysts may lead to destruction of the enamel and dentine and dental abscess
formation leading to chronic inflammatory disease of the gum. Treatment is by
removal of the swelling and treatment of the causative infection.
IV. Tumors of the oral cavity:
A. Benign tumors:
1. Odontogenic tumours and cysts.
2. Papilloma: squamous papilloma arise from the stratified squamous epithelia of
the oral cavity.
3. Pleomorphic adenoma: it’s the most common benign salivary gland tumor in
the oral cavity, the majority occur in the hard palate, also the tongue, floor
of the mouth. It’s soft, irregular, bluish or purple in color. Treatment is by
complete excision which should be as conservative as possible.
4. Neurogenic tumors: neurilemmoma is rarely seen in the oral cavity (usually in
the tongue). Neurofibroma is sometimes seen as part of Von-Recklinghausen’s
disease.
5. Connective tissue tumors: rarely seen as leiomyoma, rhabdomyoma, and lipoma.
6. Granular cell myoplastoma: it’s not a true neoplasm but shows
pseudoepitheliomatous hyperplasia, its firm non ulcerated nodule composed of a
mass of large cells with granular eosinophilic cytoplasm.
B. Malignant tumors of the oral cavity:
Whilst the term oral cancer encompasses a range of malignant tumors
arising within the lip, oral cavity and oropharynx, over 90% of oral cancers are
primary squamous cell carcinomas arising from the oral mucous membrane.
Worldwide, the incidence of oral cancer varies, with India and parts of Asia
having the highest rates (40% of all cancers), while in western countries the
incidence is about 3% of all new cancers. However this incidence is rising
particularly in younger patients and women, and oral cancer is a particularly
lethal disease.
Approximately 3400 new cases of oral cancer occur each year in the UK and
there are about 1600 deaths. Overall the 5 year survival rate for patients with
oral cancer is only 50%, although small, slow-growing lesions, tumors detected
early and those presenting at the front of the mouth tend to do better.
Posteriorly sited, rapidly growing tumours invading bone and with demonstrable
lymph node metastases at presentation have the worst prognosis.
Aetiology and risk factors
The principal aetiological factors involve the use of tobacco and alcohol, which
are known mucosal irritants and mutagenic agents. There is an important
synergistic relationship between the two, which significantly increases the risk
of cancer for those who both smoke and drink. Patients who have had oral cancer
previously or those who have had lung throat or esophageal tumours, are also at
high risk of developing new oral tumors or recurrence of their original cancers.
Immuncompromized patients, such as those with AIDS or post-transplant patients
on long term immunosuppressive agents, are also at risk. Other postulated
aetiological agents include viruses, chronic candidal infections, anaemias,
nutritional and vitamin deficiencies, and for lip cancer exposure to
ultra-violet radiation.


Clinical presentation
The most frequent clinical presentation is an indurated area of ulceration,
often
Surrounded by leukoplakic or erythroplakic patches , while the commonest sites
involved are the floor of the mouth, ventro-lateral tongue and the soft palate
complex (soft palate, retromolar trigone and anterior tonsilar pillar).
Oral cancer is usually a symptomatic in the early stages. late presentation is
common although patients report non-specific symptoms over several months prior
to their seeking attention.
Symptoms of early lesions: Asymptomatic, Irritation, Discomfort
Symptoms of late lesions: Pain and swelling, Parasthesia, Dysarthia, Dysphagia.
Signs of oral cancer: Non-healing ulcer, Induration and fixation of tissues,
Exophytic growth, White/red mucosal patches, Unexplained localized tooth
mobility, Non-healing tooth socket.

Spread of oral cancer

The most significant behavioral feature of oral cancers is their ability
to invade and destroy local structures and to spread via lymphatics into the
neck. An appreciation of the pattern of spread is essential for effective
treatment in order to control the disease within the mouth and neck.
Local invasion:
Cancers can infiltrate widely into adjacent connective tissue, within muscle
bundles, perineural spaces, or local blood vessels. Direct extension via odontal
membrane or cortical deficiencies in edentulous ridges allows invasion of
alveolar bone.
Lymph node metastasis:
The likelihood of lymphatic spread increases with the size of the primary tumor.
While the precise group of cervical lymph nodes affected depends on the location
of the primary, intraoral cancers tend to spread initially to the ipsilateral
submandibular, upper, middle and lower deep cervical nodes (levels I to IV).
Tumors of the tongue, lip and floor of mouth close to the midline can
metastasize to nodes on both sides of the neck, while the posterior triangle
(Level V ) may be involved in aggressive tongue and posterior oral tumours. The
more lymph nodes involved, the presence of metastases in lower cervical nodes
and the extension of tumour beyond the node capsule( extra-capsular spread) all
indicate a worse prognosis.
Distant spread
Distant spread tends to be more frequent in the later stages of the
disease and may not be clinically apparent, although metastatic deposits have
been found in the lungs, liver and bones in approximately 50% of post-mortem
examinations carried out in patients dying with oral cancer.


Surgery
Surgical access:
Good surgical access is fundamental to the effective exposure and complete
removal of oral tumors. The approach adopted should be easy to repair and
produce minimal scarring and deformity. While an intraoral technique may be
sufficient for small anteriorly sited tumours, splitting of the lip, division of
the mandible (mandibulotomy) and resultant mandibular swing fully displays the
posterior tongue, retromolar and soft palate regions and facilitates tumour
excision in three dimensions under direct vision. Facial cheek flaps and
maxillary osteotomies allow similar access to the posterior palate and retro
maxillary regions.

Resection of the primary tumor

The principal objective of surgical treatment is to excise the
entire primary tumor with a margin (ideally about 1cm) of adjacent normal tissue
in anticipation of microscopic spread, and to remove potential channels of
metastasis such as nerves, vessels and lymphatics. Lower lip cancers may be
treated by wedge excision alone or combined with a lip shave procedure (removal
of the entire vermilion) where there is extensive ultra-violet damage Anterior
tongue tumors may require partial, hemi or subtotal glossectomy depending on the
size and position.
While small buccal mucosal cancers can be excised intraorally, more
advanced lesions may require excision of buccinator muscle and overlying skin.
Tumors of the floor of mouth, retromolar region and lower alveolus usually
involve the underlying mandible and require mandibular resection. As bony
invasion usually occurs from the superior aspect, a marginal resection may be
possible preserving the mandibular lower border. The inferior dental nerve
canal, extending from lingula to mental foramen, should be included in
mandibular body resections owing to the likelihood of perineural spread. Mucosal
excision, alveolar resection, palatal fenestration or maxillectomy may be
required for tumours arising from the palatal mucosa and maxillary alveolus
depending on their size and position.
Management of the neck
Dissection of cervical lymph nodes containing metastatic disease is essential
for the effective management of oral cancer, and is indicated whenever clinical
examination or imaging techniques confirm enlarged, draining lymph nodes. FNA
may be carried out to confirm cytologically the presence of carcinoma deposits
within enlarged nodes.
Neck dissection operations may be classified according to the various levels at
which nodes are removed and the key anatomical structures which are either
excised or preserved. In oral cancer management. Levels I to III or IV are the
most often dissected with post-operative radiotherapy advised if multiple nodes
prove positive or there is extra capsular tumor spread' Neck dissection may be
contraindicated; however, in extensive disease where involved lymph nodes may be
fixed by tumour extension into vital structures such as the carotid artery or
skull base. A complete surgical excision is either not possible or may produce
significant morbidity or even mortality.
Reconstruction
Following ablative tumor surgery, reconstruction is essential to prevent facial
deformity, maintain bone continuity and facilitate masticatory, swallowing and
speech functions. Reduction of psychological morbidity and an acceptable quality
of life outcome are equally important aims. Extensive removal of orofacial soft
tissues and underlying mandibular or maxillary bone is often necessary for
effective tumour resection and a range of reconstructive techniques are
available.
The use of free tissue transfer and micro vascular surgery, in which free flaps
(often comprising skin, muscle and bone) are transferred from distant sites and
their dependent arteries and veins connected to vessels in the neck. Enables
reconstruction of complex defects with vascularised tissue at the time of tumor
excision. The radial forearm osseofasciocutaneous flap, a groin flap based on
the deep circumflex iliac artery (DCIA), or the fibula flap, may be used to
reconstruct the mandible. Maxillary defects result in direct communications
between oral and nasal cavities or the paranasal sinuses, with the inevitable
production of nasal speech and swallowing difficulties. The principal aim is
thus to re-establish palatal continuity either with flap reconstruction or a
prosthetic appliance and obturator which fills the defect. Initially, such
appliances may be secured with intraosseous screws to adjacent palatal bone
holding skin grafts in position to reline mucosal defects. Later, they are
replaced with specially designed removable appliances.
Radiotherapy
Radiotherapy is the treatment of tumors with ionizing radiation and is
potentially curative in oral cancer treatment. X-ray, gamma ray and less
commonly particulate radiation is delivered as external beams from outside the
patient (teletherapy) or radioactive materials such as iridium wires can be
implanted within or in close proximity to the tumor (brachytherapy). External
beams of super voltage radiation converge on the tumor, so the latter receives a
very much high dose than the surrounding tissues. The total therapeutic dose of
external beam therapy, usually 60 Grays (Gy), is fractionated into a number of
smaller doses over 4 to 6 weeks. This increases the differential effect on tumor
cells which are less able to repair themselves compared with normal tissue.
Brachytherapy treatment requires an intense radiation dose within the tumour and
immediate vicinity, usually delivering a total of 65 to 70 Gy over 8 days.
Radiation may be given palliatively to incurable patients with a short life
expectancy to relieve disease symptoms such as pain, bleeding or swelling.
A cure is not attempted and the risk of acute reaction lessened by using a
smaller dose, for example, 20Gy over 5 days.
Chemotherapy
Chemotherapy has provided a major advance in the management of certain
malignancies. As the primary form of treatment for lymphomas and leukaemias, for
example, chemotherapeutic agents have markedly improved the long-term survival
rates of patients. In general, however, chemotherapy is less effective in
treating solid tumours in adults and is rarely of curative value in oral cancer
treatment, but may have a role in trying to prevent secondary tumours developing
from metastatic deposits.
Chemotherapy targets actively dividing cells to eliminate tumours while allowing
normal cells to recover and repair. Drugs are thus usually administered in high
doses intermittently and often in combination to aid synergy and overcome
potential resistance Many types of drugs are now available and a number of
different therapeutic regimes may be applied. The major side effects of
chemotherapy are nausea and vomiting, bone marrow suppression, alopecia and oral
mucositis. To reduce the severity of mucositis, a high standard of oral hygiene
and careful attention to preventive and restorative dental care is essential.


Saif AlDeen Adil