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

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 analysed. 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 per cent (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.