Clinical significance of cranial nerve deficit in the therapy of nasopharyngeal carcinoma

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Abstract
The results of radiation treatment of nasopharyngeal carcinoma (NPC) have recently been improved, but the prognosis remains relatively poor in cases with cranial nerve (CN) involvement. A total of 109 cases with histologically-proven NPC and cranial nerve involvement treated during 1979-1985 were reviewed and analyzed. Definitive radiotherapy (RT) was given to patients with a high upper margin of the RT field at 2.5 cm above the base of the skull to a total dose of 70.2 Gy/39 fractions/8 weeks, with two applications of intranasopharyngeal brachytherapy. There were 37 cases (34%) in Group I (upward invasion only) and 72 cases (66%) in Group II (bidirectional invasion). Abducens, trigeminal, occulomotor and facial were the commonly involved nerves. Headache was the major symptom at diagnosis and was present in 82.6% of the patients, significantly higher than in general NPC cases (p < 0.005). Fifty percent (31/62) achieved complete response to definitive RT, but it did not correlate well with survival rate. The residual neurological deficit of each CN ranged from 31 to 57%. The actuarial 5-year survival rates of Groups I and II were similar in spite of neck lymph node metastasis in Group II (33% (I) compared with 24% (II); p > 0.05). Cases with single CN deficit did not show better results than those with multiple CN involvements. Five-year survivors were seen only in those who received a complete course of definitive RT.