[Clinical pathological characteristics of resectable papillary thyroid microcarcinoma]

Objective: To investigate the difference of prognostic factors and recurrence rates between papillary thyroid microcarcinoma (PTMC) and lager papillary thyroid carcinoma (PTC) and analyze the clinical pathological characteristics of PTMC suitable for surgery. Methods: A retrospective analysis on the clinicopathological features, expression level of of v-raf murine sarcoma viral oncogene homolog B1 (BRAF) V600E gene mutation and pigment epithelium-derived factor (PEDF), and postoperative follow-up results of the 251 PTC patients who underwent surgical treatment from October 2011 to October 2013, including 169 cases with PTMC and 82 with lager PTC (Tumor diameter>1 cm). Results: The BRAF V600E mutation rates of PTMC and lager PTC patients are 65.1%(110/169)and 78.0% (64/82) respectively, and the difference is statistically significant (P<0.05). The prevalence of extrathyroidal invasion (7.1%) and lymph nodes metastasis (27.2%) of the patients with PTMC were significantly lower than those of the patients with larger PTC (15.9% and 46.3%, respectively)(P<0.01). The follow-up durations for PTMC and lager PTC were (45.6±3.6) months and (45.0±3.4) months, respectively (P>0.05). There was no statistic significance for the difference in age, gender, coexistent hashimoto's thyroiditis, PEDF expression, and recurrence rate between the patients with PTMC and with larger PTC (P>0.05). The recurrence rate of the patients who have the high risk factors of PTMC was 1.6%(2/122)and that of larger PTC was 4.9% (4/82). Conclusions: Extrathyroid invasion, lymph node metastases and BRAF V600E gene mutation are the high risk factors of recurrent PTMC. The same treatment strategy should be considered for PTMC with coexistent high risk factors as that for larger PTC. For PTMC with BRAF V600E gene mutation, earlier surgical treatment is suggested. PTMC patients with BRAF V600E gene mutation and high cell subtype are suggested to undergo total thyroidectomy for the first operation in order to reduce the potential risk of recurrence.