**1. Introduction**

132 Carcinogenesis, Diagnosis, and Molecular Targeted Treatment for Nasopharyngeal Carcinoma

[10] Neel HB. Nasopharyngeal carcinoma: clinical presentation, diagnosis, treatment and

[11] Feasel AM, Brown TJ, Bogle MA, Tschen JA, Nelson BR. Perineural invasion of

[12] Fagan JJ, Collins B, Barnes L, D'Amico F, Myers EN, Johnson JT. Perineural invasion in

[13] Lawrence N, Cottel WI. Squamous cell carcinoma of skin with perineural invasion. J

[14] McCord MW, Mendenhall WM, Parsons JT, Flowers FP. Skin cancer of the head and

[15] Xie GF, Cao KJ, Li Y, Huang PY. Impact of dose boost in skull base on recurrence of

[16] Ma J, Mai HQ, Hong MH, et al. Results of a prospective randomized trial comparing

[17] Ballantyne AJ, McCarten AB, Ibanez ML. The extension of cancer of the head and neck

[18] Byers RM, O'Brien J, Waxler J. The therapeutic and prognostic implications of nerve invasion in cancer of the lower lip. Int J Radiat Oncol Biol Phys. 1978;4:215-217. [19] Batsakis JG. Nerves and neurotropic carcinomas. Ann Otol Rhinol Laryngol.

[20] Chang JT, Lin CY, Chen TM, et al. Nasopharyngeal carcinoma with cranial nerve palsy:

[21] Kam MK, Teo PM, Chau RM, et al. Treatment of nasopharyngeal carcinoma with

the importance of MRI for radiotherapy. Int J Radiat Oncol Biol Phys. 2005;63:1354-

intensity modulated radiotherapy: the Hong Kong experience. Int J Radiat Oncol

stage T4 nasopharyngeal carcinoma. Ai Zheng. 2005;24:1246-1248.

through peripheral nerves. Am J Surg. 1963;106:651-667.

squamous cell carcinoma of the head and neck. Arch Otolaryngol Head Neck Surg.

neck with incidental microscopic perineural invasion. Int J Radiat Oncol Biol Phys.

neoadjuvant chemotherapy plus radiotherapy with radiotherapy alone in patients with locoregionally advanced nasopharyngeal carcinoma. J Clin Oncol.

prognosis. Otolaryngol Clin North Am. 1985;18:479-490.

cutaneous malignancies. Dermatol Surg. 2001;27:531-542.

1998;124:637-640.

1999;43:591-595.

2001;19:1350-1357.

1985;94:426-427.

Biol Phys. 2004;60:1440-1450.

1360.

Am Acad Dermatol. 1994;31:30- 33.

Long-term endocrine disorders are the most frequent complications in survivors of adult and paediatric nasopharyngeal carcinoma (NPC). The hypothalamic-pituitary (h-p) axis lies within the field of radiation therapy for NPC. Consequently, neuro-endocrine abnormalities due to radiation-induced damage of the h-p occur in the majority of patients followed long term. Similarly, radiation injury to the thyroid gland can result in primary thyroid dysfunction, particularly hypothyroidism as well as benign and malignant thyroid nodule. Chemotherapy-induced gonadal damage is another frequently seen complication in patients treated with chemotherapy.

Most of the endocrine complications are irreversible and progressive in nature. They may be of sufficient severity to have adverse impact on growth and pubertal development (in children), body image, sexual function, fertility, muscular and skeletal health and ultimately quality of life. It is mandatory that survivors of NPC undergo regular clinical, radiological and/or hormonal surveillance to ensure early diagnosis of these complications and appropriate and timely introduction of hormone replacement therapy and other therapeutic interventions.
