High-dose radiation therapy with chemotherapy is the primary treatment of nasopharyngeal cancer, both for the primary tumor site and the neck. When feasible, surgery is usually reserved for nodes that fail to regress after radiation therapy or for nodal recurrence following clinical complete response. Radiation therapy dose and field margins are individually tailored to the location and size of the primary tumor and lymph nodes.[2,3,4,5] Although most tumors are treated with external-beam radiation therapy (EBRT) exclusively, in some tumors radiation therapy may be boosted with intracavitary or interstitial implants or by the use of stereotactic radiosurgery when clinical expertise is available, and the anatomy is suitable.[6,7,8,9,10] Intensity-modulated radiation therapy (IMRT) results in a lower incidence of xerostomia and may provide a better quality of life than conventional three-dimensional or two-dimensional radiation therapy.[11,12][Level of evidence: 1iiC] Results of a phase II RTOG study (RTOG-0225) showed the feasibility of IMRT in a multi-institutional setting and minimal grade III and IV xerostomia rates. The rate of grade 2 xerostomia at 1 year from start of IMRT was 13.5%. Only 2 of 68 patients were reported with grade 3 xerostomia, and none had grade 4 xerostomia.[Level of evidence: 2C]
Incidence and Mortality
Estimated new cases and deaths from thyroid cancer in the United States in 2014:
New cases: 62,980.
Carcinoma of the thyroid gland is an uncommon cancer but is the most common malignancy of the endocrine system. Differentiated tumors (papillary or follicular) are highly treatable and usually curable. Poorly differentiated tumors (medullary or anaplastic) are much less common, are aggressive, metastasize early, and have a much poorer prognosis...
Accumulating evidence has demonstrated a high incidence (>30%-40%) of hypothyroidism in patients who have received radiation therapy that delivered EBRT to the entire thyroid gland or to the pituitary gland. Thyroid-function testing of patients should be considered prior to therapy and as part of posttreatment follow-up.[14,15]
Treatments under clinical evaluation for patients with nasopharyngeal cancer include the following:
Dose escalation with new radiation therapy techniques such as stereotactic radiation therapy boost.[Level of evidence: 3iiiDiv]
Information about ongoing clinical trials is available from the NCI Web site.
Baujat B, Audry H, Bourhis J, et al.: Chemotherapy in locally advanced nasopharyngeal carcinoma: an individual patient data meta-analysis of eight randomized trials and 1753 patients. Int J Radiat Oncol Biol Phys 64 (1): 47-56, 2006.
Perez CA, Devineni VR, Marcial-Vega V, et al.: Carcinoma of the nasopharynx: factors affecting prognosis. Int J Radiat Oncol Biol Phys 23 (2): 271-80, 1992.
Lee AW, Law SC, Foo W, et al.: Nasopharyngeal carcinoma: local control by megavoltage irradiation. Br J Radiol 66 (786): 528-36, 1993.
Geara FB, Sanguineti G, Tucker SL, et al.: Carcinoma of the nasopharynx treated by radiotherapy alone: determinants of distant metastasis and survival. Radiother Oncol 43 (1): 53-61, 1997.
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.
Mendenhall WM, Werning JW, Pfister DG: Treatment of head and neck cancer. In: DeVita VT Jr, Lawrence TS, Rosenberg SA: Cancer: Principles and Practice of Oncology. 9th ed. Philadelphia, Pa: Lippincott Williams & Wilkins, 2011, pp 729-80.
Itami J, Anzai Y, Nemoto K, et al.: Prognostic factors for local control in nasopharyngeal cancer (NPC): analysis by multivariate proportional hazard models. Radiother Oncol 21 (4): 233-9, 1991.
Levendag PC, Schmitz PI, Jansen PP, et al.: Fractionated high-dose-rate brachytherapy in primary carcinoma of the nasopharynx. J Clin Oncol 16 (6): 2213-20, 1998.
Teo PM, Leung SF, Lee WY, et al.: Intracavitary brachytherapy significantly enhances local control of early T-stage nasopharyngeal carcinoma: the existence of a dose-tumor-control relationship above conventional tumoricidal dose. Int J Radiat Oncol Biol Phys 46 (2): 445-58, 2000.
Le QT, Tate D, Koong A, et al.: Improved local control with stereotactic radiosurgical boost in patients with nasopharyngeal carcinoma. Int J Radiat Oncol Biol Phys 56 (4): 1046-54, 2003.
Pow EH, Kwong DL, McMillan AS, et al.: Xerostomia and quality of life after intensity-modulated radiotherapy vs. conventional radiotherapy for early-stage nasopharyngeal carcinoma: initial report on a randomized controlled clinical trial. Int J Radiat Oncol Biol Phys 66 (4): 981-91, 2006.
Kam MK, Leung SF, Zee B, et al.: Prospective randomized study of intensity-modulated radiotherapy on salivary gland function in early-stage nasopharyngeal carcinoma patients. J Clin Oncol 25 (31): 4873-9, 2007.
Lee N, Harris J, Garden AS, et al.: Intensity-modulated radiation therapy with or without chemotherapy for nasopharyngeal carcinoma: radiation therapy oncology group phase II trial 0225. J Clin Oncol 27 (22): 3684-90, 2009.
Turner SL, Tiver KW, Boyages SC: Thyroid dysfunction following radiotherapy for head and neck cancer. Int J Radiat Oncol Biol Phys 31 (2): 279-83, 1995.
Constine LS: What else don't we know about the late effects of radiation in patients treated for head and neck cancer? Int J Radiat Oncol Biol Phys 31 (2): 427-9, 1995.
Tate DJ, Adler JR Jr, Chang SD, et al.: Stereotactic radiosurgical boost following radiotherapy in primary nasopharyngeal carcinoma: impact on local control. Int J Radiat Oncol Biol Phys 45 (4): 915-21, 1999.
Lu JJ, Shakespeare TP, Tan LK, et al.: Adjuvant fractionated high-dose-rate intracavitary brachytherapy after external beam radiotherapy in Tl and T2 nasopharyngeal carcinoma. Head Neck 26 (5): 389-95, 2004.
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