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.
|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.
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.
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.
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.
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.