Clinical characteristics of papillary thyroid microcarcinoma less than or equal to 5 mm / 中国医师进修杂志

ABSTRACT

Objective To summarize the clinical characteristics of papillary thyroid microcarcinoma with diameter ≤ 5 mm. Methods The clinical data of 259 papillary thyroid microcarcinoma patients who had underwent radical thyroidectomy from January 2015 to December 2017 were retrospectively analyzed. The patients were divided into 2 groups according to the preoperative tumor diameter ＞5 mm group (88 cases) and ≤ 5 mm group (171 cases); then according to the lymph node metastasis, the 2 groups were divided into non-lymph node metastasis sub-group and lymph node metastasis sub-group. The reason of lymph node metastasis was analyzed. Results There were no statistical difference in gender composition, age and combined Hashimoto thyroiditis rate between ＞5 mm group and≤5 mm group (P＞0.05). The rates of T3-4 stage, N1a-1b stage and multifocal tumors in＞5 mm group were significantly higher than those in ≤ 5 mm group 34.1% (30/88) vs. 18.7% (32/171), 45.5% (40/88) vs. 22.8% (39/171) and 39.8% (35/88) vs. 22.8% (39/171), and there were statistical differences (P＜0.05 or＜0.01). In＞5 mm group, lymph node metastasis sub-group had 40 cases, non-lymph node metastasis sub-group had 48 cases; the rate of T3-4 stage in lymph node metastasis sub-group was significantly higher than that in non-lymph node metastasis sub-group 55.0% (22/40) vs. 16.7% (8/48), and there was statistical difference (P＜0.01). In≤5 mm group, lymph node metastasis sub-group had 39 cases, and non-lymph node metastasis sub-group had 132 cases; the rate of T3-4 stage in lymph node metastasis sub-group was significantly higher than that in non-lymph node metastasis sub-group51.3% (20/39) vs. 9.1% (12/132), and there was statistical difference (P＜0.01). In＞5 mm group and≤5 mm group, there were no statistical difference in gender composition, age, combined Hashimoto thyroiditis rate and multifocal tumors rate between 2 sub-groups (P＞0.05). Conclusions The clinical behavior of papillary thyroid microcarcinoma with diameter ≤ 5 mm has a less aggressive nature compared to that＞5 mm. Tumor capsular invasion or extra thyroidal extension has a great influence on lymph node metastasis in thyroid papillary microcarcinoma of different diameter.