[Clinical analysis of level V occult metastasis of papillary thyroid carcinoma]

To analyze the occurrence and frequency of level V occult metastasis of papillary thyroid carcinoma.

The clinicopathological data of 475 patients in our hospital from 1980 to 1996 were retrospectively analyzed. Pathological results of 275 cN + patients were analyzed and 200 cases with no lymph node metastasis were followed up to compare the recurrence rate of those two groups. The 275 cN + patients were divided into 3 subgroups according to the risk levels: high risk group 83 cases, moderate risk group 104 cases and low risk group 88 cases.

The occurrence rate of level V node occult metastasis in the 275 cases was 17.5%, among them, the results of low risk, moderate and high risk groups were 9.1%, 19.2% and 24.1%, respectively (Chi-Square value 7.041, P < 0.05). These 3 groups were divided according to the number of level II approximately IV positive lymph nodes 1, 2 - 10 and more than 10, and the rate was 0, 4.5% and 24.6%, respectively.

Careful prudence is needed to decide whether a patient of papillary thyroid carcinoma with clinically negative level V node metastasis should be operated for level V lymph node dissection or not. Patients of low risk group or with less positive lymph nodes could be kept under observation for level V node metastasis.