Updated: May 2003
General Information
The majority of tumours are carcinomas. Classical Nasopharyngeal carcinoma has been classified into three types by the WHO:
Type 1: Keratinizing squamous cell carcinoma
Type 2 Nonkeratinizing /poorly differentiated carcinoma
Type 3 Undifferentiated/anaplastic carcinoma.
Type 1 may have an association with cigarette and alcohol consumption and accounts for up to 30% of cases in non-endemic areas and < 5% in endemic areas.
Other less common tumour types include minor salivary gland tumours, sarcomas, lymphomas, plasmocytomas and angiofibromas. The management of these tumours is individualized.
Common presenting symptoms include unilateral hearing loss, a mass in the neck, nasal stuffiness/bleeding, headache and cranial nerve palsies.
Nasopharyngeal carcinoma may spread by direct extension into neighbouring structures. Superior spread into the foramen lacerum or foramen ovale often results damage to cranial nerves VI, V and occasionally III. Posterolateral spread into the parapharyngeal space is common and may lead to lower cranial nerve palsies.
The nasopharynx has a rich supply of lymphatics and lymph node metastases are common at presentation. Nodes that are commonly involved include the jugulodigastric, the posterior cervical and retropharyngeal lymph nodes.
Systemic dissemination (15 – 20%) is more common at presentation than other head and neck cancers. It is more common when there is extensive nodal disease and consideration should be given to a metastatic workup at presentation if there is a high index of suspicion of distant disease.
The staging system employed is the UICC 1997 System.
Nasopharynx (T)
T1 Tumour confined to the nasopharynx
T2 Extension to the oropharynx or nasal cavity
T2a without parapharyngeal extension
T2b with parapharyngeal extension
T3 Bone invasion and/or paranasal sinuses
T4 Cranial nerve palsies, extension to the infratemporal fossa , intracranial extension etc
Lymph nodes (N)
N1 Unilateral lymph node (s)< 6 cm above supraclavicular fossa
N2 Bilateral lymph nodes < 6 cm above supraclavicular fossa
N3 Unilateral or bilateral node(s) > 6 cm or nodes in the supraclavicular fossa
Distant Metastasis
M0 No evidence of distant metastasis
M1 Distant metastasis
Patient Assessment
The assessment of the tumour and regional lymph nodes is based on physical examination, endoscopy and appropriate radiological investigation.
Imaging of the nasopharynx and its environs is best carried out with either CT scan and/or an MRI. In both cases axial and coronal images are required for optimal evaluation. CT is better for determining the presence or absence of bone invasion. MRI is particularly helpful in differentiating between inflammatory change and tumour and for evaluating intracranial extension.
Other radiological investigations include a chest X-ray, liver ultrasound if liver function tests are abnormal or there is advanced nodal disease and, a bone scan if there is bone pain, elevation of alkaline phosphatase or advanced nodal disease. Other imaging modalities such as PET may be cost effective in detecting systemic metastatic disease for those at high risk.
Treatment
Radiotherapy
Radiotherapy is the primary treatment modality for carcinoma of the nasopharynx. The precise volume to be irradiated will be defined for each patient. In general it will consist of the tumour with a margin, involved lymph nodes and lymph nodes at risk of disease. The nasopharynx is a midline structure and there is a high incidence of bilateral nodal involvement hence both sides of the neck are usually irradiated. Because of the juxtaposition of the tumour volume to a number of critical number structures (optic nerve, chiasm, temporal lobe, brain stem, spinal cord etc), meticulous treatment planning is essential. The tumour and nodal chains are irradiated en-bloc usually through opposed lateral fields although the precise field arrangement will depend on the configuration of disease. A shrinking field is used and shielding is introduced so that the dose to critical structures dose not exceed organ tolerance.
Reference:
Lee et al Nasopharyngeal carcinoma: Local control by megavoltage irradiation. The British Journal of Radiology 1993;66:528-536.
There is no evidence to support the use of altered fractionation schemes (accelerated/hyperfractionated radiotherapy) outside a randomized trial.
Escalation in dose with the use of either stereotactic radiotherapy or brachytherapy is not recommended routinely but may be considered in selected instances.
Chemotherapy
Nasopharyngeal cancer is much more sensitive to chemotherapy than other cancers arising in the upper aerodigestive tract. It has been used in a number of settings. These will be discussed individually below.
Neoadjuvant (prior to definitive treatment)
There have been several Phase 2/3 studies evaluating chemotherapy given prior to and/or following radiotherapy The majority of the regimes were cisplatin based. Other active agents include 5-flurouracil,bleomycin, cyclophosphamide and adriamycin. In general these have shown increased toxicity, encouraging response rates but no increase in overall survival. this is not a recommended standard treatment at this time.
Concurrent/Adjuvant
A randomized trial comparing radiotherapy alone versus radiotherapy and concurrent cisplatin followed by adjuvant cisplatin/5-FU demonstrated in increase in 3 year relapse-free survival (24% versus 69%) and overall survival at 3 years (47% versus78%). The radiotherapy (70 Gy in 35 fractions) was identical in both arms. These differences are significant. Concerns expressed about this study include the poor results in the radiotherapy alone arm and the high proportion of patients with type 1 (well differentiated squamous cell carcinoma) who are not well represented in populations where this disease is endemic. In addition the treatment delivery was limited /problematic in the patients in the combined arm. In the light of these concerns this treatment strategy has not as yet been adopted as a standard at BCCA. The BCCA is currently participating in a multicenter international trial in an effort to evaluate this treatment strategy further.
Reference:
Al-Sarraf M et al. Chemo-radiotherapy versus radiotherapy in patients with advanced nasopharyngeal cancer: phase III randomized intergroup study 0099 .Journal of Clinical Oncology 1998;16:1310-1317
Adjuvant (following definitive treatment).
This has not been widely studied. One randomized trial using non-cisplatin based therapy did not show any benefit.
Reference:
Rossi et al Adjuvant chemotherapy with vincristine, cyclophosphamide, and doxorubicin after radiotherapy in local-regional nasopharyngeal cancer:results of a 4-year multicenter randomized study. Journal of Clinical Oncology 1988;61401-1410.
Chemotherapy for metastatic disease
There have been several phase 2 studies employing a variety of active agents (cisplatin, bleomycin,methotrexate, 5-flurouracil, gemcitabine) encouraging response rates are encountered. Median survival is between 10 = 16 months. Occasional long-term survivors are encountered.
References:
Siu et al Phase I/II study of the CAPABLE regimen for patients with poorly differentiated carcinoma of the nasopharynx. Journal of Clinical Oncology 1998;16:2514-2522.
Boussen et al chemotherapy of Metastatic and/or recurrent Undifferentiated nasopharyngeal Carcinoma with Cisplatin, bleomycin and Fluorouracil. Journal of Clinical oncology 1991;9:1675-1681.
Treatment of recurrence
Patients with local recurrence should be considered for salvage radiotherapy which may be curative. This may take the form of a gold seed implant or repeat external beam radiotherapy. Patients with a regional nodal recurrence should be considered for a neck dissection.
Reference:
A Lee et al Retrospective analysis of patients with nasopharyngeal carcinoma treated during 1976-1985:survival after local recurrence. IJORP;1993:773-782.
