title: Is thymectomy worthwhile in central lymph node dissection for differentiated thyroid cancer?
abstract: BACKGROUND
  Clinical guidelines edited in 2006 by the American Thyroid Association (ATA) and stated in the European Thyroid Association Consensus (ETA) recommend routine central lymph node dissection (level VI neck dissection) in addition to thyroidectomy for the surgical treatment of differentiated thyroid cancer. This central dissection increases the incidence of postoperative hypocalcemia, which is related to the resection or devascularization of the inferior parathyroids together with bilateral thymectomy. Some authors perform unilateral thymectomy in order to minimize this complication. Our aim was to study the benefit/risk (incidence of thymic lymph node metastases versus postoperative hypocalcemia) of both procedures.
  
  
  METHODS
  We retrospectively reviewed the records of 138 patients who underwent total thyroidectomy with central neck lymph node dissection for differentiated thyroid cancer between 2004 and 2007. Bilateral thymectomy was performed in 45 patients (group 1, 15 males and 30 females) and unilateral thymectomy was performed in 93 patients (group 2, 27 males and 66 females). Forty-two papillary and 3 medullary cancers were found in group 1, and 75 papillary, 2 follicular, and 17 medullary cancers were found in group 2. The presence of thymic metastases at pathology and the occurrence of postoperative hypocalcemia were reviewed.
  
  
  RESULTS
  Two cases of papillary thymic metastases were found in group 1. These were lymph node micrometastases localized in the ipsilateral side of the primary tumor in both cases. Transient hypocalcemia was significantly more frequent (P < 0.001) in group 1 than in group 2: 16 patients (35.5%) versus 10 (10.7%). There was one case of permanent hypocalcemia in group 1 after the follow-up period.
  
  
  CONCLUSIONS
  Bilateral thymectomy risk outweighs any likely carcinologic benefit. We do not recommend routine bilateral thymectomy during central neck dissection for differentiated thyroid cancer.
authors.affiliation: Department of General and Endocrine Surgery, Hopital Huriez CHU, Lille Cedex, 59037, France.
authors.forename: Ziad
authors.initials: Z
authors.lastname: El Khatib
authors.forename: Julie
authors.initials: J
authors.lastname: Lamblin
authors.forename: Sebastien
authors.initials: S
authors.lastname: Aubert
authors.forename: Laurent
authors.initials: L
authors.lastname: Arnalsteen
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Leteurtre
authors.forename: Robert
authors.initials: R
authors.lastname: Caiazzo
authors.forename: Francois
authors.initials: F
authors.lastname: Pattou
authors.forename: Bruno
authors.initials: B
authors.lastname: Carnaille
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000209:etiology / Q000601:surgery*; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013934:Thymectomy; D013953:Thymus Neoplasms / Q000556:secondary* / Q000601:surgery*; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000601:surgery*; D013965:Thyroidectomy; D016896:Treatment Outcome