title: Utility of serum thyroglobulin measurements after prophylactic thyroidectomy in patients with hereditary medullary thyroid cancer.
abstract: BACKGROUND
  Prophylactic thyroidectomy can be curative for patients with hereditary medullary thyroid cancer (MTC) caused by RET proto-oncogene mutations. Calcitonin is a sensitive tumor marker used to follow patients. We suggest that thyroglobulin (Tg) levels should also be monitored postoperatively in these patients.
  
  
  METHODS
  We reviewed patients with RET mutations who underwent prophylactic thyroidectomy between 1981 and 2011 at an academic endocrine surgery center. Patients were excluded if they had no postoperative Tg levels recorded.
  
  
  RESULTS
  Of the 22 patients who underwent prophylactic thyroidectomy, 14 were included in the final analysis. The average age at thyroidectomy was 9.8 years (range, 4-29). Tg levels were detectable 1.5 months to 31 years postoperatively in 11 patients (79%), all of whom were <15 years old at thyroidectomy. Median thyroid-stimulating hormone (TSH) was 2.5 mIU/L and 13.4 mIU/L in patients with undetectable and detectable Tg, respectively. Of those with detectable Tg, 5 had cervical ultrasonographic examination: Two showed no residual tissue in the thyroid bed, and 3 showed remnant thyroid tissue.
  
  
  CONCLUSIONS
  Tg levels can identify patients with remnant thyroid tissue after prophylactic thyroidectomy. Ultrasonography can determine whether thyroid tissue remains posterolaterally that is at risk of MTC recurrence. Maintaining normal TSH may prevent growth of remaining thyroid follicular cells.
authors.affiliation: Department of Surgery, University of California, San Francisco, San Francisco, CA. Electronic address: Carolyn.Seib@ucsfmedctr.org.
authors.forename: Carolyn D
authors.initials: CD
authors.lastname: Seib
authors.affiliation: Department of Surgery, University of California, Los Angeles, Los Angeles, CA.
authors.forename: Avital
authors.initials: A
authors.lastname: Harari
authors.affiliation: Department of Surgery, University of California, San Francisco, San Francisco, CA.
authors.forename: Felix A
authors.initials: FA
authors.lastname: Conte
authors.affiliation: Department of Surgery, University of California, San Francisco, San Francisco, CA.
authors.forename: Quan-Yang
authors.initials: QY
authors.lastname: Duh
authors.affiliation: Department of Surgery, University of California, San Francisco, San Francisco, CA.
authors.forename: Orlo H
authors.initials: OH
authors.lastname: Clark
authors.affiliation: Department of Surgery, University of California, San Francisco, San Francisco, CA.
authors.forename: Jessica E
authors.initials: JE
authors.lastname: Gosnell
mesh_terms: D000293:Adolescent; D000328:Adult; D018276:Carcinoma, Medullary / Q000097:blood* / Q000235:genetics / Q000601:surgery*; D018278:Carcinoma, Neuroendocrine; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D018813:Multiple Endocrine Neoplasia Type 2a / Q000097:blood / Q000235:genetics / Q000601:surgery; D009154:Mutation; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control; D000090063:Proto-Oncogene Mas; D051096:Proto-Oncogene Proteins c-ret / Q000235:genetics; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood* / Q000235:genetics / Q000601:surgery*; D013965:Thyroidectomy; D013972:Thyrotropin / Q000097:blood
chemical_list: C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D013972:Thyrotropin; D013954:Thyroglobulin; D051096:Proto-Oncogene Proteins c-ret; C099282:RET protein, human