Nasopharyngeal carcinoma (NPC) is a tumour of the
nasopharynx which is situated at the deep end of the nose. It has the highest
incidence amongst the Chinese of Southeastern region and Hong Kong. It is one of the top 5 cancers affecting both
male and female in Malaysia apart from breast, colorectal (bowel), lung and
cervical cancer. The Malaysian National Cancer Registry in 2006 noted an
incidence of 7.5 per 100,000 for males and 2.4 per 100,000 for females. Chinese
men had the highest incidence rate of 15.9 per 100,000. The age specific
incidence increased after 30 years old.
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| The nasopharynx is situated at the deep end of the nose which makes it a blind spot to normal clinical examination. Tumors or the nasopharynx also often present late because of this anatomical position. |
This disease has a multifactorial origin and is a result of
interplay between genetic susceptibility, environmental factors and Epstein
Barr virus. There is evidence to suggest that abnormalities in specific
chromosomes may play a role in the pathogenesis. Cultural factors linked to NPC
which have been observed include consumption of dried salted fish in childhood.
CLINICAL FEATURES
The symptoms of NPC are usually non obvious and only
apparent when the tumor has spread, due to the anatomical location of the
nasopharynx. More commonly patients present with neck swelling in 50-70% of
cases followed by unilateral ear block or tinnitus and nasal obstruction. Other
less common symptoms include blood stained nasal discharge or saliva and
headache. Advanced disease may present with cranial nerve palsies, altered
conscious level or distant tumour spread.
DIAGNOSIS
The diagnosis of NPC requires visualization of the nasopharynx
region using nasal endoscopy. This endoscopic facility is readily available as
an outpatient procedure in ENT clinics. The neck is also palpated to assess for
enlarged lymph nodes. Patients with neck swelling and unilateral ear symptoms
coupled with high risk ethnicity should always be examined with nasal
endoscopy. Endoscopic examination findings in NPC would show as a growth/mass,
swelling or obliteration of the Fossa of Rosenmuller. The diagnosis of NPC is
confirmed by biopsy and examination of the tissue in the histopathological
laboratory. In rare instances, nasal endoscopy may be normal. In these highly
suspicious cases the ENT surgeon may suggest examination under general
anaesthesia with deep multiple biopsies.
TUMOR STAGING
When diagnosis is confirmed, the tumour is then staged by
imaging studies. The rationale for tumour staging is to give a true picture of the tumour extension and its related prognosis. Imaging studies include computed tomography
(CT) scan of the head and neck area, chest radiograph, abdominal ultrasound and
bone scan.
TREATMENT
The mainstay of treatment for NPC is radiotherapy with
without concurrent chemotherapy. Early
small tumours will do well with radiotherapy alone. Often the radiotherapy is
combined with chemotherapy. The oncologist will devise the treatment plan after
discussing with the patient.
Nowadays advanced forms of radiotherapy such as intensity
modulated radiation therapy (IMRT) can better target the tumour volume thus
reducing radiation exposure to normal tissues. The side effects that patients may
experience with radiotherapy include skin pigmentation and desquamation, oral
ulcers and dryness, tiredness, restricted mouth movements, taste disturbance
and hearing changes. These side effects would gradually occur during the course
of the treatment and will slowly get better. However some of the side effects
such as dry mouth and hearing changes are long term.
FOLLOW UP AFTER TREATMENT
After completing the treatment for NPC, the patient is
reassessed to ensure good response to the treatment given. Patient is again
reviewed by medical history, physical examination along with nasal endoscopy
and imaging studies are performed to make sure that the tumour has been
eradicated. These clinic reviews are also important to assess for tumour
recurrence (return of the tumour), metastasis (distant spread of the disease)
and any ongoing problems that the patient may have following treatment. The
follow up consultation may be frequent, 3-4 monthly, in the first 2 years and
then becomes a 6-12 monthly visit after that.
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