Perioperative Parathyroid Function Monitoring Of Differentiated Thyroid Carcinoma And Study On Prophylactic Calcium Strategies Based On Risk Stratifications

Objective:To conform the roles of the potential risk factors thay may cause postoperative hypocalcemia on the change of PTH and serum calcium levels during the perioperative period of differentiated thyroid carcinoma and to study on effective prophylactic calcium supplement strategies for patients with DTC according to different risk stratifications in order to providing clinical evidences for individualized prophylactic calcium supplement theory.Methods:A retrospective study lasted from March 2015 to February 2016 with a sample of 117 patients with DTC was carried on in head and neck surgery department, Sichuan Cancer Hospital. Divided all patients into three groups according to the scores of risk stratification:group A (group of low risk), group B and group C(groups of high risk). Managed group B with intravenous calcium 2 g per day, group C with intravenous calcium 2 g twice a day, group A without calcium supplement, for each group hypocalcemia both with and without symptom were observed and analyzed.Results:PTH reduced to the lowest level in phase 1, and then gradually rise in the following phases.PTH in phase 4 is lower than the preoperative level. No statistical difference in serum calcium levels was found between random two phases even though phase2 revealed the lowest levels. PTH of female was higher than that of male in phase0 (46.75±117.3 pg/ml VS 38.08±14.78 pg/ml χ2=5.518, P=0.02). Patients underwent unilateral lobectomy plus isthmectomy (ULI) revealed higher PTH and serum calcium levels than who underwent total thyroidectomy (TT). Differences were significant in phase 1 to 3 (P<0.01). Patients underwent bilateral central lymph node dissection revealed higher levels only on PTH than the ones who underwent unilateral central lymph node dissection and differences were significant in phase 1 to 3 (P<0.05). Patients underwent two parathyroid glands autotransplantation (PAT) revealed lower PTH and serum calcium levels than who treated with one and without PAT. Group A revealed higher PTH level than group B and group C in each postoperative phase, but statistical difference was not found between group B and group C (P=0.28). Group B demonstrated the highest and group A the lowest incidence of hypocalcemia (47.9%;31.2%; 17.2%P< 0.05). Symptomatic hypocalcemia showed most frenquantly in group B(25.5%) while there was no statistical difference between the rest two groups(4.1%; 5.2%, P= 0.65). Serum calcium values 95% confidence interval of symptomatic group was CI [1.74, 1.80].Conclusions:①Perioperative PTH level firstly reduced to a lowest level in day 1 to 3 after operations then gradually rise in the following phases. It requires longer than two weeks for PTH to recovers to preoperative level. ￤omen possess higher PTH basal levels than men.③TT and BCND are more likely to result in lower PTH in compare with ULI and UCND.④TT is more likely to lead to hypocalcemia. ⑤Autotransplantation of less than two parathyroid reveals no significant effects on reducing postoperative PTH and serum calcium levels. ⑥Managing high-risk patients with intravenous calcium 2 g twice a day could reduce the incidence of symptomatic hypocalcemia and maintain appropriate serum calcium levels.⑦Doctors should be vigilant about symptomatic hypocalcemia when serum calcium level<1.8mmol/L.