Decision analysis and treatment threshold in a management for the N0 neck of the oral cavity carcinoma.

The optimal method of management of clinical N0 neck in squamous cell carcinoma of the oral cavity remains controversial. We used decision analysis to determine the current optimal strategy in comparison with observation of the neck and elective neck dissection. A total of 165 previously untreated patients with N0 classification were investigated. Probabilities of each recurrence were calculated and probabilities of being cured in each event were substituted with the 5-year overall survival calculation with Kaplan-Meier method. A sensitivity analysis was performed to determine the optimal threshold for treatment of the N0 neck. The threshold of N0 neck was calculated using the formula with putting the three probabilities of being cured. In this study the threshold was estimated at 44.4%. N0 neck of squamous cell carcinoma of the oral cavity should be observed if the probability of occult metastasis is less than 44.4%. Proper calculation of three probabilities of being cured in each institution will make a decision of the optimal method of clinical N0 neck by using the threshold formula.