Cancer of Oral Cavity & Oropharynx
Introduction:
Every year in
India, approximately 650,000 patients develop cancer. Of these,
10% (65,000) of patients develop cancer in the oral cavity (ICMR
Report 1992). More than half of these patients die of the disease,
because they present late.
By contrast,
early diagnosis and treatment is associated with a good outcome.
Late detection makes more radical treatment necessary, leading to
increased morbidity associated with loss of function, aesthetics
and psychological problems. Since oral cancers are readily detectable
and identifiable at an early stage it should be possible to improve
detection and hence the prognosis.
Oral cavity
includes the: Oropharynx includes the
- Lipsv Front
two-thirds of the tongue
- Upper and
lower gums (the gingiva)
- Lining of
the inside of the cheeks and lips (the buccal mucosa)
- Floor of
the mouth under the tonguev Bony top of the mouth (hard palate)
- Small area
behind the wisdom teeth(the retromolar trigone)
- Back one-third
of the tonguev Soft palatev Tonsils
- Part of
the throat behind the mouth.
Oral cavity
and oropharynx are made up of many types of cells. When cells divide
in an abnormal, uncontrolled way, they can form a non-cancerous
(Benign) or cancerous (Malignant) tumours. Oral cancer typically
spreads through the lymphatic system that produces, stores and carries
infection and disease fighting cells. When it spreads, oral cancer
usually travels to the lymph nodes in the neck.
Causes:
Although the
aetiology of oral cancer is complex, most Western studies have implicated
tobacco smoking and alcohol drinking as the major cause of this
disease. But in South Asia, in addition to the above factors chewing
of tobacco, betel nut and “pan masala” seems to be the
main cause of this problem. Repeated trauma from a sharp tooth or
ill-fitting denture may promote neoplastic change over a long period
of time.
Clinical
Presentation:
If a patient
has any of the following symptoms for more than 2 weeks, they should
see a doctor. Pain is not an early symptom. A tiny spot , ulcer
or small lump should not be ignored, especially if a person is a
smoker or drinker.
Patients may
have one or more of the following symptoms:
- Non-healing
ulcer, painless/painful
- Swellings
in the gums, palate, tongue etc.
- Loose teeth
- Inability
to wear the denture properly
- Difficulty
in chewing or swallowing
- Blood in
spit
- Lumps in
the neck
- Pain in
the ear
- A white
patch (Leukoplakia) or a red patch
Pre-cancerous
conditions:
While the majority
of oral cancers arise from a clinically normal mucosal lining, some
oral cancers are preceded by pre-malignant changes. They may appear
as white patches (Leukoplakia) or red patches (Erythroplakia). These
may be caused by chronic trauma from sharp tooth or ill-fitting
dentures or chemical irritants (tobacco, betel nut etc).
Another condition
very common among Indians is known as sub mucous fibrosis. This
is caused by chronic irritation from tobacco juice and pan masala.
The lining of whole of mouth and throat are exposed to this irritation,
resulting in fibrosis (scarring) underneath the mucosa. The mouth
looks pale and the mouth slowly closes due to scar contracture.
They are unable to open the mouth, always have a burning sensation
in the mouth and have a tendency to develop cancer in multiple areas.
Response to radiation therapy is also poor because of poor blood
supply in the scarred areas.
Types
of Cancer:
Over 90% of
oral cancers arise from the cells that line the mouth and are known
as squamous cell carcinoma. Another source of cancer in the mouth
is the minor salivary glands that are found just underneath the
surface. These are much less common. There are a few other cancers
of the oral cavity that are very uncommon, such as lymphoma, sarcoma
and melanoma.
Detection:
Early detection
is more important because treatment is most effective before the
disease has spread. After complete clinical examination, the doctor
may recommend CT scan or MRI scan or an endoscopic procedure to
know the extent of the growth and the structures it is involving.
The endoscopic procedure may be done under general anaesthetic and
local anaesthetic.
If the physical
examination shows an abnormal area, the doctor will advise for a
biopsy. A biopsy is the only way for a doctor to know for sure whether
or not the suspicious area is cancerous. The biopsy specimen is
examined by a pathologist for the presence of cancer cells. Incisional
or punch biopsies are done under local or general anesthesia using
special instruments. Doing open biopsy of glands in the neck can
lead to spreading of disease to skin. Therefore, the surgeon does
Fine Needle Aspiration Cytology (FNAC) in which the surgeon uses
a thin needle to remove cells from the mass.
If cancer is
found the doctor needs to know the extent of the disease. In most
cases, the most important factors in considering treatment options
is the stage of the disease. The stage of the disease is based on
the size of the tumour, as well as whether and where the cancer
has spread.
Treatment
options:
Nearly half
of all head and neck cancers are found in the mouth and throat.
Treatment for head and neck cancers may change the way person looks,
breathes, talks, eats or swallows. Therefore multidisciplinary approach
to patient care is so important. The team includes:
- ENT –
Head and neck surgeon
- Plastic surgeon
- Radiation
oncologist
- Medical
oncologist
- Dental surgeon
- Prosthodontist
- Speech therapist
- Swallowing
therapist
- Dietician
The treatment
options are surgery, radiation therapy and chemotherapy either alone
or in combination depending on the stage of tumour. In choosing
a treatment plan, factors to consider include overall physical health,
the type and stage of cancer, the probability of curing the disease,
and the impact of treatment on functions like speech, chewing and
swallowing. Surgery or radiotherapy or both modalities combined
is usually the most appropriate treatment form for curative intent.
Chemotherapy is mostly reserved for patients with very advanced
cancers.
If the patient
undergoes surgery for oral cancer, the surgeon may remove the cancer
and some of the healthy, adjoining tissue. Complete surgical clearance
of the tumour is achieved with the help of the pathologist who examines
the removed tissue at the time of surgery itself (Frozen Section)
and says whether the removal was complete or needs further removal.
Small tumours
of the oral cavity can be quickly and successfully treated by surgical
excision, leaving behind little cosmetic or functional change. Among
the advantages for treating early stage cancer with surgery is that
it is completed quickly usually requiring a few days of hospital
care, instead of 6 weeks of daily Radiotherapy. Dryness of mouth
and radiation induced damage to teeth can be avoided. Most importantly,
if the patient subsequently develops another cancer in the mouth,
throat or voice box, radiotherapy would still be available as treatment
option. This will avoid a more significant and disfiguring operation.
Very early cases
of oral cancers can be treated with removal of the primary tumour
alone. But as the size of the tumour increases, the possibility
of some cancer cells spreading through the lymphatic to the lymph
nodes in the neck is high. When the index of suspicion is high that
there may be cancer cells present in the lymph nodes, an operation
called a neck dissection is performed. For large primary tumour
the surgeon may need to remove part of the palate, tongue or jaw.
Tumours in the
back one third of the tongue are treated with radiotherapy as surgery
can affect the swallowing and speech. Surgery is reserved for radioresistent
tumour and the tumours that are not cured by radiotherapy.
Whenever total
glossectomy (complete removal of tongue) is performed, aspiration
of food into the voice box resulting in recurrent lung infection
is common. In the past, to avoid this problem, voice box was also
removed at the same time. But, the current technique in reconstruction
has reduced the aspiration and therefore the need for the removal
of voice box.
Such operations
are likely to change the patient’s ability to chew, swallow
or talk. Newer techniques in reconstruction using micro vascular
free flaps provide the patient with better function of the oral
cavity by providing lining with sensation or restoring the jaw with
bone. After the surgery the patient’s face may be swollen.
This swelling usually goes away within a few weeks. However, removing
the lymph nodes slow the flow of lymph, which may collect in the
tissue. This swelling may last for a long time. Until the wound
heals and swallowing improves, the patient will be fed through a
tube passing through the nose into the stomach. Rehabilitation may
include speech and swallowing therapy.
Follow-up
care:
Regular follow-up
examinations are very important for anyone who has been treated
for oral cancer. The doctor will watch the patient closely to check
the healing process and to look for signs that the cancer may have
returned. Patients with dryness of mouth from radiotherapy should
have regular dental examination. The patient may need to see a dietitian
if weight loss or eating problem continues. Oral cancer patients
are strongly advised to stop using tobacco and limit alcohol intake
to reduce the risk of developing another cancer.
Case
Studies:
1.Tongue I
(Partial Glossectomy)
2. Tongue II (Total Glossectomy)
3. Lower Jaw
4. Buccal mucosa
5. Palate
Questions
patients should ask before deciding about the treatment:
1. What are
my treatment options?
2. What are the risks and benefits for each of my treatment options?
3. How will treatment affect my everyday activity? How long?
4. How often will I need to return?
5. Has my doctor explained various surgical options to my satisfaction?
6. Have I been seen by a surgeon who has expertise with removal
of cancer, as well as, with reconstruction? Have I seen by a surgeon,
radiation oncologist, prosthodontist and dentist?
7. Do I know all I need to know about prostheses and prosthetic
techniques?
8. How often has the surgeon performed the kind of surgery he
is recommending?
9. What will the surgical site look like after healing?
10. Will my appearance and physical capabilities be affected?
If so how?
11. Should I consider combination therapy (both surgery and radiation
therapy)?
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