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ABSTRACT Objective: Our aim was to assess the ability of serum magnesium (Mg), measured on the first postoperative day (Mg1PO), to predict the need for calcium (Ca) replacement in patients undergoing total thyroidectomy (TT). Subjects and methods: Eighty patients undergoing TT, with Mg1PO and PTH dosage in the first (PTH1h) and eighth (PTH8h) hours after TT, were evaluated for the need for Ca replacement. Data were evaluated by uni/multivariate logistic regression and Receiver Operating Characteristic (ROC) curve. Results: 32 patients (40%) required Ca replacement. Median PTH1h, PTH8h and Mg1PO were higher in the no replacement group: 17 versus (vs) 3 pg/mL (p < 0.001), 18.2 vs 3.0 pg/mL (p < 0.001) and 2 vs 1.6 mg/dL (p < 0.001), respectively. Mg1PO was the isolated predictor for this replacement (odds ratio = 0.0004, 95% confidence interval: 0.000003-0.04; p = 0.001), with the cut-off value of 1.8 mg/dL showing sensitivity and specificity of 78.1% and 87.5%, respectively. Conclusions: In this group of patients, serum Mg1PO was the isolated predictor for the need for Ca replacement.
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ABSTRACT Objective: Cytological analysis and Bethesda classification of thyroid nodules is the standard method of diagnosing differentiated thyroid carcinoma (DTC). However, even for nodules with a non-malignant cytological diagnosis, there is a not insignificant risk of cancer. There are doubts whether this lack of certainty would influence patient prognosis. Our aim was to compare patients with DTC, classified according to the preoperative cytological diagnosis, regarding their evolution. Subjects and methods: A retrospective study was carried out with 108 DTC patients submitted to total thyroidectomy (TT) between 2009 and 2015, divided into three groups according to preoperative cytological diagnosis (Bethesda classification): classes I/II, III/IV, and V/VI. Groups were compared for evolution considering response to treatment at last evaluation as well as time disease free. Statistical analysis used ANOVA, chi squared, and Kaplan-Meier curves with p<0.05 considered significant. Results: Groups differed for time between nodule puncture and TT [in months; V/VI (2.35 ± 2.48) < III/IV (7.32 ± 6.34) < I/II (13.36 ± 8.9); p < 0.0001]. There was no significant difference between groups for evolution at final evaluation (disease free status; classes I/II: 71.4%; classes III/IV: 60%; classes V/VI: 66.6%; p = 0.7433), as well as time disease free (in months; classes I/II: 34.57 ± 25.82; classes III/IV: 38.04 ± 26.66; classes V/VI: 30.84 ± 26.34; p = 0.3841). Conclusions: DTC patients classified according to preoperative cytological diagnosis did not differ for evolution. Although patients with non-malignant cytological diagnoses were submitted to TT later, this did not affect the evolution of the cases.
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ABSTRACT Objective: Thyrotropin-stimulated thyroglobulin (STg) after total thyroidectomy is a prognosis marker for differentiated thyroid carcinoma (DTC). As Tg level is influenced by thyrotropin (TSH), perhaps the STg/TSH ratio is also a prognosis marker for these tumours. We aimed to compare STg/TSH ratio and first STg level in differentiated thyroid carcinoma patients for their ability to predict the long-term response to initial treatment. Subjects and methods: This retrospective study evaluated data from 181 DTC patients for first (1st) STg and STg/TSH ratio, at 1-3 months post-total thyroidectomy and before iodine-131 therapy, according to response to initial therapy [Excellent/Indeterminate or Incomplete (Biochemical/Structural)] observed at final evaluation, and with the survival time with excellent/indeterminate response. Results: Cases with incomplete response presented higher STg level [225.13 ± 585.26 ng/mL versus (vs) 20.4 ± 192.9 ng/mL; p < 0.001] and STg/TSH ratio (3.01 ± 7.8 vs 0.27 ± 2.58; p < 0.001). Cutoffs of 5 ng/mL for STg and 0.085 for STg/TSH displayed sensitivities of 76.7% and 76.9%, and specificities of 79.2% and 82.6%, respectively, in predicting response to therapy. Values below these cutoffs were associated with longer survival time in excellent/indeterminate response (140.4 vs 15.9 and 144.6 vs 15.9 months, respectively). Conclusion: STg/TSH ratio has a similar performance to the 1st STg in predicting long-term response to initial therapy.