General Information About Nasopharyngeal Cancer
Anatomy
Risk Factors
Signs and Symptoms
Diagnostic Tests
Prognosis
Follow-up
Anatomy
The nasopharynx has a cuboidal shape. The lateral walls are formed by the
eustachian tube and the fossa of Rosenmuller. The roof, sloping downward from
anterior to posterior, is bordered by the pharyngeal hypophysis, pharyngeal
tonsil, and pharyngeal bursa with the base of the skull above. Anteriorly, the
nasopharynx abuts the posterior choanae and nasal cavity, and the posterior
boundary is formed by the muscles of the posterior pharyngeal wall.
Inferiorly, the nasopharynx ends at an imaginary horizontal line formed by the
upper surface of the soft palate and the posterior pharyngeal wall.
Risk Factors
Unlike other squamous cell cancers of the head and neck, nasopharyngeal cancer
does not appear to be linked to excess use of tobacco and alcohol. Factors
thought to predispose to this tumor include:
- Chinese (or Asian) ancestry.[1]
- Epstein-Barr virus (EBV) exposure.
- Unknown factors that result in
very rare familial clusters.[2]
Signs and Symptoms
Symptoms and signs at presentation include:
- Painless, enlarged lymph nodes in
the neck (present in approximately 75% of patients and often bilateral and
posterior).
- Nasal obstruction.
- Epistaxis.
- Diminished hearing.
- Tinnitus.
- Recurrent otitis media.
- Cranial nerve dysfunction (usually II–VI or IX–XII).
- Sore throat.
- Headache.
In the patient who presents with only cervical
adenopathy, the finding of EBV genomic material in the tissue after
amplification of DNA with the polymerase chain reaction lends strong evidence
for a nasopharyngeal primary tumor, and a concerted search should be conducted
in that area.[3]
Diagnostic Tests
Diagnosis is made by biopsy of the nasopharyngeal mass. Workup includes:
[4]
- Careful visual examination (by mirror or endoscopic examination).
- Documentation
of the size and location of the tumor and neck nodes.
- Evaluation of cranial
nerve function and hearing.
- Skull films (especially base-of-skull views)
evaluating neural foramina.
- Complete computed tomographic (CT) scan or magnetic
resonance imaging (MRI) with views delineating the upper and lower extent of
the lesion.
- Chest x-ray.
- Hemogram.
- Chemistry panel.
Any clinical or
laboratory suggestion of distant metastasis may prompt further evaluation of
other sites. Careful dental and oral hygiene evaluation and therapy is
particularly important prior to initiation of radiation treatment. MRI is
often more helpful than CT scans in detecting abnormalities and in defining
their extent.[4-6]
Prognosis
Major prognostic factors adversely influencing outcome of treatment include:[7]
- Large tumor size.
- A higher tumor (T) stage.
- The presence of involved neck
nodes.
Other factors linked to diminished survival that were present in some, but not all,
studies include:
- Age.
- Nonlymphoepithelial histology.
- Long interval between
biopsy and initiation of radiation therapy.
- Diminished immune function at
diagnosis.
- Incomplete excision of involved neck nodes.
- Pregnancy during
treatment.
- Locoregional relapse.
- Certain EBV antibody titer patterns.
Small cancers of the nasopharynx are highly curable by radiation therapy, and patients with these small cancers have shown
survival rates of 80% to 90%.[8]
Moderately advanced lesions without clinical evidence of spread to cervical
lymph nodes are often curable, and patients with these lesions have shown survival rates of 50% to 70%.
Patients with advanced lesions, especially those associated with clinically
positive cervical lymph nodes, cranial nerve involvement, and bone destruction have disease that is poorly controlled locally by radiation therapy with or without surgery, and
the lesions often develop distant metastases despite local control.[9,10]
Follow-up
Follow-up for patients includes:
- Routine periodic examination of the original
tumor site and neck.
- Chest x-ray.
- MRI or CT scan.
- Blood work.
Positron emission tomography scans may be useful in planning treatment for patients with suspected recurrence.[11] Monitoring
of patients should include:
- Surveillance of thyroid and pituitary function.
- Dental and oral hygiene.
- Jaw exercises to avoid trismus.
- Evaluation of cranial
nerve function, especially as it relates to vision and hearing.
- Evaluation
of systemic complaints to identify distant metastasis.
Although most recurrences occur within 5 years of diagnosis, relapse can be
seen at longer intervals. The incidence of second primary malignancies is
less than after treatment of tumors at other head and neck sites.[12]
Poorly differentiated squamous cell cancer has been associated with EBV
antibodies.[3,13] High-titer antibodies to virus capsid antigen and early
antigen, especially of high IgA class, or high titers that persist after
therapy, have been associated with a poorer prognosis.[14] This finding remains
under evaluation.
Tumors of many histologies can occur in the nasopharynx, but this discussion,
like the American Joint Committee on Cancer nasopharynx staging, refers
exclusively to squamous cell types of tumors.
References
-
Chien YC, Chen JY, Liu MY, et al.: Serologic markers of Epstein-Barr virus infection and nasopharyngeal carcinoma in Taiwanese men. N Engl J Med 345 (26): 1877-82, 2001.
[PUBMED Abstract]
-
Decker J, Goldstein JC: Risk factors in head and neck cancer. N Engl J Med 306 (19): 1151-5, 1982.
[PUBMED Abstract]
-
Feinmesser R, Miyazaki I, Cheung R, et al.: Diagnosis of nasopharyngeal carcinoma by DNA amplification of tissue obtained by fine-needle aspiration. N Engl J Med 326 (1): 17-21, 1992.
[PUBMED Abstract]
-
Cummings CW, Fredrickson JM, Harker LA, et al.: Otolaryngology - Head and Neck Surgery. Saint Louis, Mo: Mosby-Year Book, Inc., 1998.
-
Mendenhall WM, Riggs CE Jr, Cassisi NJ: Treatment of head and neck cancers. In: DeVita VT Jr, Hellman S, Rosenberg SA, eds.: Cancer: Principles and Practice of Oncology. 7th ed. Philadelphia, Pa: Lippincott Williams & Wilkins, 2005, pp 662-732.
-
Laramore GE, ed.: Radiation Therapy of Head and Neck Cancer. Berlin: Springer-Verlag, 1989.
-
Sanguineti G, Geara FB, Garden AS, et al.: Carcinoma of the nasopharynx treated by radiotherapy alone: determinants of local and regional control. Int J Radiat Oncol Biol Phys 37 (5): 985-96, 1997.
[PUBMED Abstract]
-
Bailet JW, Mark RJ, Abemayor E, et al.: Nasopharyngeal carcinoma: treatment results with primary radiation therapy. Laryngoscope 102 (9): 965-72, 1992.
[PUBMED Abstract]
-
Fandi A, Altun M, Azli N, et al.: Nasopharyngeal cancer: epidemiology, staging, and treatment. Semin Oncol 21 (3): 382-97, 1994.
[PUBMED Abstract]
-
Teo PM, Chan AT, Lee WY, et al.: Enhancement of local control in locally advanced node-positive nasopharyngeal carcinoma by adjunctive chemotherapy. Int J Radiat Oncol Biol Phys 43 (2): 261-71, 1999.
[PUBMED Abstract]
-
Zheng XK, Chen LH, Wang QS, et al.: Influence of [18F] fluorodeoxyglucose positron emission tomography on salvage treatment decision making for locally persistent nasopharyngeal carcinoma. Int J Radiat Oncol Biol Phys 65 (4): 1020-5, 2006.
[PUBMED Abstract]
-
Cooper JS, Scott C, Marcial V, et al.: The relationship of nasopharyngeal carcinomas and second independent malignancies based on the Radiation Therapy Oncology Group experience. Cancer 67 (6): 1673-7, 1991.
[PUBMED Abstract]
-
Neel HB 3rd, Pearson GR, Taylor WF: Antibodies to Epstein-Barr virus in patients with nasopharyngeal carcinoma and in comparison groups. Ann Otol Rhinol Laryngol 93 (5 Pt 1): 477-82, 1984 Sep-Oct.
[PUBMED Abstract]
-
Lin JC, Chen KY, Wang WY, et al.: Detection of Epstein-Barr virus DNA the peripheral-blood cells of patients with nasopharyngeal carcinoma: relationship to distant metastasis and survival. J Clin Oncol 19 (10): 2607-15, 2001.
[PUBMED Abstract]
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