Objective : There are three major stragies in the treatment of patients with a stage N0 neck with squamous cell carcinoma of mobile tongue : elective neck dissection(END), elective neck irradiation(ENI), and observation. To establish the incidence of node metastases and to assess the prevalence of occult nodes in cancer of the mobile tongue with clinically N0 neck, and to assess the meanings of elective neck dissection(END), elective neck irradiation(ENI), and observation in cancer of the mobile tongue with N0 neck, this study was undertaken.


Materials and Method
: Retrospective study with review of records and CT or MRI of a total of 48 patients of mobile tongue cancers with clinically N0 neck treated primarily with surgery at Department of Otolaryngology-Head and Neck Surgery, Korea Cancer Canter Hospital, from Jan 1989 to Dec. 1994.


Results
: With clinically N0 neck, the rate of occult matastasis was 27.3% in T1, 30.4% in T2, and 80% in advanced mobile tongue cancer(T3, T4). In T1 lesion, recurrence rate of neck node was 29% in observation group, but recurrence of neck node was none in END and ENI group. In T2 lesion, recurrence rate of neck node was 38% in observation group, 20% in END group, 25% in ENI group. Although duration of follow-up period is short, success rate of salvage treatment for recurrent neck node was higher in observation group than in elective treatment group.


Conclusion
: In tongue cancers with clinically N0 stage & any T stage, elective neck treatment is necessary because the rate of occult metastasis with any T stage over 27%. It is reasonable to delay neck treatment in N0 cases when regular followup is available.