[Statistical analysis on the cases of thyroid papillary carcinoma]

Statistical analysis was performed on the postoperative recurrence of forty four patients with thyroid papillary adenocarcinoma, who underwent radical surgery in the Department of Otolaryngology, Hamamatsu University Hospital from January 1978 to March 1991. In this study, we defined a new factor called "Operative Radicality index (OR index)" and analyzed the data with a multivariate analysis (Cox model). The result showed that the risk of postoperative recurrence was significantly affected by the age, the size of tumor and the OR index. The postoperative five-year cumulative recurrence rate was approximately 10% in the group of patients whose lateral neck regions were systematically dissected only when any metastatic lymph nodes were clinically detected within the region, in addition to the routine anterior neck dissection, and 70% in the group of patients whose metastatic lymph nodes in the lateral neck region were partially removed, but 6% in the group of N0 patients who did not undergo lateral neck dissection because no nodal metastases were detected even in the operative findings. Considering the quality of postoperative life, we concluded that in the primary surgery for the thyroid papillary adenocarcinoma, the lateral neck dissection should be applied to only the regions with metastatic nodes detected preoperatively or during operation, in addition to the routine anterior neck dissection. And the OR index was useful for the statistical analysis with regard to the policies of treatment and the prognosis.