title: Individually-tailored thyroxine requirement in the same patients before and after thyroidectomy: a longitudinal study.
abstract: OBJECTIVE
  Thyroxine (T4) requirement after total thyroidectomy for differentiated thyroid carcinoma (DTC) is a debated issue. As most of the studies in the area have been retrospective and/or performed with heterogeneous therapeutic approaches, we designed our study to determine T4 requirement in the same patients and treatment settings, before and after total thyroidectomy.
  
  
  METHODS
  This was a longitudinal study including 23 goitrous patients treated with T4 in an individually tailored fashion. All patients exhibited a stable TSH (median TSH = 0.28 mU/l) at a stable T4 dose for at least 1 year before surgery (median T4 dose = 1.50 μg/kg per day). The patients underwent total thyroidectomy based on cancer suspicion or compressive symptoms. Eventually diagnosed as having DTC (pT1b-pT2N0) and following surgical and radiometabolic treatment, they were treated with the same pre-surgical doses of T4.
  
  
  RESULTS
  Three months after surgery,using the same pre-surgical dose, median TSH increased up to 5.38 mU/l (P<0.0001) and so the T4 dose had to be increased (median T4 dose = 1.95 μg/kg per day; +30%; P < 0.0001). Once divided by patients' age, we observed that, after thyroidectomy and maintaining the same pre-surgical dose, serum TSH significantly increased both in younger and in older patients (median TSH = 4.57 and 6.11 mU/l respectively). Serum TSH was restored to the pre-surgical level by increasing the dose up to 1.95 and 1.77 μg/kg per day (+25 and +21%) respectively.
  
  
  CONCLUSIONS
  Following the same treatment regimen, a thyroidectomized patient requires one-third higher therapeutic T4 dose than before surgery. Despite this increase, the dose of T4 needed in our patients remains significantly lower than that previously described in athyreotic patients.
authors.affiliation: Department of Medico-Surgical Sciences and Biotechnologies'Sapienza' University of Rome, Corso della Repubblica 79, 04100 Latina, ItalyDepartment of Surgical Specialties and Organ Transplantation 'P. Stefanini'Policlinico Umberto I, 'Sapienza' University of Rome, Rome, ItalyEndocrinology UnitAUSL Latina, Latina, Italy.
authors.forename: S C
authors.initials: SC
authors.lastname: Del Duca
authors.affiliation: Department of Medico-Surgical Sciences and Biotechnologies'Sapienza' University of Rome, Corso della Repubblica 79, 04100 Latina, ItalyDepartment of Surgical Specialties and Organ Transplantation 'P. Stefanini'Policlinico Umberto I, 'Sapienza' University of Rome, Rome, ItalyEndocrinology UnitAUSL Latina, Latina, Italy.
authors.forename: M G
authors.initials: MG
authors.lastname: Santaguida
authors.affiliation: Department of Medico-Surgical Sciences and Biotechnologies'Sapienza' University of Rome, Corso della Repubblica 79, 04100 Latina, ItalyDepartment of Surgical Specialties and Organ Transplantation 'P. Stefanini'Policlinico Umberto I, 'Sapienza' University of Rome, Rome, ItalyEndocrinology UnitAUSL Latina, Latina, Italy.
authors.forename: N
authors.initials: N
authors.lastname: Brusca
authors.affiliation: Department of Medico-Surgical Sciences and Biotechnologies'Sapienza' University of Rome, Corso della Repubblica 79, 04100 Latina, ItalyDepartment of Surgical Specialties and Organ Transplantation 'P. Stefanini'Policlinico Umberto I, 'Sapienza' University of Rome, Rome, ItalyEndocrinology UnitAUSL Latina, Latina, Italy.
authors.forename: I
authors.initials: I
authors.lastname: Gatto
authors.affiliation: Department of Medico-Surgical Sciences and Biotechnologies'Sapienza' University of Rome, Corso della Repubblica 79, 04100 Latina, ItalyDepartment of Surgical Specialties and Organ Transplantation 'P. Stefanini'Policlinico Umberto I, 'Sapienza' University of Rome, Rome, ItalyEndocrinology UnitAUSL Latina, Latina, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Cellini
authors.affiliation: Department of Medico-Surgical Sciences and Biotechnologies'Sapienza' University of Rome, Corso della Repubblica 79, 04100 Latina, ItalyDepartment of Surgical Specialties and Organ Transplantation 'P. Stefanini'Policlinico Umberto I, 'Sapienza' University of Rome, Rome, ItalyEndocrinology UnitAUSL Latina, Latina, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Gargano
authors.affiliation: Department of Medico-Surgical Sciences and Biotechnologies'Sapienza' University of Rome, Corso della Repubblica 79, 04100 Latina, ItalyDepartment of Surgical Specialties and Organ Transplantation 'P. Stefanini'Policlinico Umberto I, 'Sapienza' University of Rome, Rome, ItalyEndocrinology UnitAUSL Latina, Latina, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Verga Falzacappa
authors.affiliation: Department of Medico-Surgical Sciences and Biotechnologies'Sapienza' University of Rome, Corso della Repubblica 79, 04100 Latina, ItalyDepartment of Surgical Specialties and Organ Transplantation 'P. Stefanini'Policlinico Umberto I, 'Sapienza' University of Rome, Rome, ItalyEndocrinology UnitAUSL Latina, Latina, Italy.
authors.forename: F M
authors.initials: FM
authors.lastname: Frattaroli
authors.affiliation: Department of Medico-Surgical Sciences and Biotechnologies'Sapienza' University of Rome, Corso della Repubblica 79, 04100 Latina, ItalyDepartment of Surgical Specialties and Organ Transplantation 'P. Stefanini'Policlinico Umberto I, 'Sapienza' University of Rome, Rome, ItalyEndocrinology UnitAUSL Latina, Latina, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Virili
authors.affiliation: Department of Medico-Surgical Sciences and Biotechnologies'Sapienza' University of Rome, Corso della Repubblica 79, 04100 Latina, ItalyDepartment of Surgical Specialties and Organ Transplantation 'P. Stefanini'Policlinico Umberto I, 'Sapienza' University of Rome, Rome, ItalyEndocrinology UnitAUSL Latina, Latina, Italy Department of Medico-Surgical Sciences and Biotechnologies'Sapienza' University of Rome, Corso della Repubblica 79, 04100 Latina, ItalyDepartment of Surgical Specialties and Organ Transplantation 'P. Stefanini'Policlinico Umberto I, 'Sapienza' University of Rome, Rome, ItalyEndocrinology UnitAUSL Latina, Latina, Italy marco.centanni@uniroma1.it.
authors.forename: M
authors.initials: M
authors.lastname: Centanni
mesh_terms: D002277:Carcinoma / Q000601:surgery*; D004305:Dose-Response Relationship, Drug; D005260:Female; D020249:Hormone Replacement Therapy / Q000379:methods; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000188:drug therapy* / Q000209:etiology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D057285:Precision Medicine; D057234:Preoperative Period; D013964:Thyroid Neoplasms / Q000601:surgery*; D013965:Thyroidectomy / Q000009:adverse effects; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000008:administration & dosage*
chemical_list: D013972:Thyrotropin; D013974:Thyroxine