[Characteristics of occult cervical lymph node metastasis in squamous cell carcinoma of tongue and their influence on prognosis].

BACKGROUND & OBJECTIVE: Occult cervical lymph node metastasis in squamous cell carcinoma of tongue has regularity and influence on the prognosis of patients. This study was designed to investigate the characteristics of occult cervical lymph node metastasis in squamous cell carcinoma of tongue and their influence on the prognosis to provide clinical bases for elective supraomohyoid neck dissection. METHODS: The data of 164 patients with squamous cell carcinoma of tongue who were treated in cancer center, Sun Yat-sen University, from 1990 to 1996 were reviewed. The characteristics of occult cervical lymph node metastasis in squamous cell carcinoma of tongue and their influence on the prognosis were analyzed. RESULTS: The rate of occult cervical lymph node metastasis of squamous cell carcinoma of tongue was 25.71%. The most common site of occult cervical lymph node metastasis was ipsilateral level II, and followed by ipsilateral level I and III. 82.98% of the lymph nodes of occult metastasis occurred in the above three levels. Most cervical lymph nodes of occult metastasis were found within two years after the first operation (33/36). There was significant difference of the prognosis between the group of dominant or occult cervical lymph node metastasis and the group of without cervical lymph node metastasis in squamous cell carcinoma of tongue (log-rank,P< 0.01); whereas there was no significant difference of the prognosis between the group of dominant cervical lymph node metastasis and the group of occult cervical lymph node metastasis according to log-rank test (P >0.05). CONCLUSION: The ipsilateral level I to level III were the common regions where occult cervical lymph node metastasis occurred. The authors suggest that elective supraomohyoid neck dissection may be applied to clinically negative neck of the patients with squamous cell carcinoma of tongue who were prone to metastasize latently. Occult cervical lymph node metastasis influences the prognosis of patients with squamous cell carcinoma of tongue significantly.