Objective:To investigate the BRAF(V600E)gene mutation of pediatric papillary thyroid carcinoma (PTC) and refine their clinicopathological correlates. Methods:Tumor tissue samples of pediatric PTCs (≤18 years old) were collected from tumor tissue bank of Tianjin Medical University Cancer Institute and Hospital from January 2012 to December 2016.The medical records of 22 patients with pediatric PTC were reviewed retrospectively.The frequencies of BRAF(V600E) mutation were evaluated and the correlation between BRAF(V600E) mutation and clinical characteristics were analyzed. Results:BRAF(V600E) mutations were present in 45.5% of cases (10 cases). BRAF(V600E) mutation in pediatric PTC was obviously lower than that in adults PTC(77.7%) ( &chi;2=11.250, P=0.001). BRAF(V600E) mutation in>12-year-old group (66.7%) was remarkably higher than that in ≤12-year-old group (20.0%) ( P<0.05). BRAF(V600E) mutation in female (69.2%) was greatly higher than that in male (11.1%) ( P<0.05). There was no significant correlation with BRAF(V600E) mutation and multiple tumor, tumor size, highly invasive subtype, extrathyroidal extension, lymph node metastasis and radiological history of infants (all P>0.05). The median follow-up time was 45 months.No patients died and BRAF(V600E) mutation was not associated with the increase of recurrence rate ( P>0.05). Conclusions:BRAF(V600E)gene mutation in pediatric PTC is lower than that in adults. BRAF(V600E) mutation does not portend a more aggressive clinical biological behavior in pediatric PTC.

Objective:To evaluate the role of Tg in diagnosis of lateral cervical lymph node recurrence in papillary thyoid cancer(PTC)after radioactive iodine(RAI) therapy.Methods:From Jan 2012 to Aug 2018, 22 PTC patients who received RAI therapy after operation were reoperated for lateral cervical lymph node recurrence. The clinical data was retrospectively analyzed.Results:The median recurrence time was 30.5 (5-86) months. All 22 patients received RAI therapy after the first operation, and the median dose of RAI was 250mCi(100-700 mCi) and the episode of RAI therapy ranged from 1 to 4. All 22 PTC patients underwent neck reoperation, among which 20 cases were identified to have lymph node metastasis. The median number of lymph nodes dissected was 31 (8-83) and median number of metastatic lymph nodes was 4 (1-19) . The diagnostic accuracy of ultrasonography in detecting lymph node metastasis was 90.9%. Before reoperation, the median Tg was 1.305 (0.10-99.51) μg/L, with the cutoff value of Tg being 0.2 μg/L, and its sensitivity and specificity were 80.0% and 100%, respectively. The median stimulated Tg was 5.89 (0.14-255.80) μg/L in the 10 patients, with the cutoff value of stimulated Tg of 2 μg/L, and its sensitivity and specificity were 88.9% and 100%, respectively.Conclusions:The serum Tg level is helpful for monitoring the recurence of PTC, but recurrence cannot be completely ruled out for those with low Tg.

Objective:To discuss the causes and effective measures of prevention and treatment of chylous fistula after central lymph node dissection (CLND) of thyroid cancer. Methods:A total of 6 127 patients who underwent CLND of thyroid cancer in the Tianjin Medical University Cancer Institute and Hospital between July 2013 and June 2015 were analyzed;of which, 14 patients acquired the complication of postoperative chylous fistula. The following conservative treatments were initially performed:systemic therapy, local pressure bandaging, normal pressure drainage, 50%glucose injection, or pingyangmycin injection through a drainage tube. Surgical op-eration was then conducted when the efficacy of the treatment was poor. Results:After the conservative treatment of the 14 patients, the drainage volume gradually decreased in 12 patients, and surgery was performed on the remaining two patients. Conclusion:The CLND of thyroid cancer must be carefully conducted to prevent postoperative chylous fistula. An active conservative treatment must be the first option when chylous fistula occurs. Surgery must only be performed if the treatment is invalid.

Objective:To evaluate postoperative calcitonin level as a prognostic marker in long-term follow-up of medullary thyroid carcinoma(MTC).Methods:Clinical data of 146 MTC cases treated at Tianjin Medical University Cancer Institute and Hospital from Jan 2011 to Dec 2019 were reviewed retrospectively. The relationship between postoperative calcitonin and disease-free survival was analyzed. According to the level of calcitonin six months after operation, patients were divided into normal level group and elevated group.Results:The median tumor size in those 146 cases was (1.78±1.22)cm, and 81 cases had lymph node metastasis. After 6 months of follow-up, 89 cases had normal calcitonin, with median tumor size of (1.63±1.20)cm, and 35 cases had lymph node metastasis . After a median follow-up of 56 months, 78 patients had normal calcitonin, 11 patients had biochemical relapse, 3 patients had structural relapse, and no patients died. 57 cases had a higher calcitonin ,median tumor size (1.97±1.22)cm, 46 cases had lymph node metastasis, 5 cases had distant metastasis, 18 cases had structural recurrence, and 7 patients died. Univariate analysis showed that lymph node metastasis, TNM stage, preoperative calcitonin, lymph node dissection and postoperative calcitonin were correlated with long-term disease-free survival (all P < 0.05). Multivariate analysis showed that postoperative calcitonin and TNM stage were an independent prognosis factor for disease-free survival in MTC patients (all P < 0.05). Conclusion:Postoperative calcitonin is a independent prognostic marker for long-term disease-free survival in MTC patients.