title: Alternative surgical strategies and favorable outcomes in patients with medullary thyroid carcinoma in Japan: experience of a single institution.
abstract: BACKGROUND
  Medullary thyroid carcinoma (MTC) accounts only for 1.4% of all thyroid malignancies in Japan. Since 1996, we have performed hemithyroidectomy, instead of total thyroidectomy, for sporadic nonhereditary MTC when the primary lesion is located in only one lobe. Regarding lymph node dissection, modified radical neck dissection (MND) at least ipsilateral to the tumor has been routinely performed, even if there is no clinically apparent metastasis. We investigated the clinical outcomes of MTC patients in our department.
  
  
  METHODS
  A series of 118 patients with MTC who underwent initial surgery between 1975 and 2005 were enrolled in this study. The RET gene mutations were analyzed for all patients and 46 had germline RET gene mutations. Of those 46 patients, 26 were diagnosed as MEN 2A and 2 were diagnosed as MEN 2B. Postoperative follow-up periods averaged 141 months.
  
  
  RESULTS
  Of 115 patients who did not have distant metastasis at surgery and who underwent locally curative surgery, 78 (67.8%) were biochemically cured. All patients without pathological lymph node metastasis were biochemically cured, and 44.8% of patients with node metastasis were also biochemically cured. The 10-year and 20-year disease-free survival rates were 89.0% and 82.5%, respectively. None of the patients who did not show lymph node metastasis and only 2 (2.6%) of 78 patients who were biochemically cured showed clinically apparent carcinoma recurrence. The 10-year and 20-year cause-specific survival rates were 96.6% and 91.7%, respectively. Lymph node metastasis, tumor size>4 cm, extrathyroid and extranodal tumor extensions significantly affected cause-specific survival of patients.
  
  
  CONCLUSIONS
  Clinical outcomes of MTC patients in our series were better than those in Western countries, a result that might have resulted in part because of our routine MND regardless of whether clinically apparent node metastasis was detected.
authors.affiliation: Department of Surgery, Kuma Hospital, 8-2-35, Shimoyamate-dori, Chuo-ku, Kobe, 650-0011, Japan. ito01@kuma-h.or.jp
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ito
authors.forename: Akira
authors.initials: A
authors.lastname: Miyauchi
authors.forename: Tomonori
authors.initials: T
authors.lastname: Yabuta
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Fukushima
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Inoue
authors.forename: Chisato
authors.initials: C
authors.lastname: Tomoda
authors.forename: Takashi
authors.initials: T
authors.lastname: Uruno
authors.forename: Minoru
authors.initials: M
authors.lastname: Kihara
authors.forename: Takuya
authors.initials: T
authors.lastname: Higashiyama
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Takamura
authors.forename: Akihiro
authors.initials: A
authors.lastname: Miya
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Fumio
authors.initials: F
authors.lastname: Matsuzuka
mesh_terms: D002116:Calcitonin / Q000097:blood; D018276:Carcinoma, Medullary / Q000453:epidemiology / Q000235:genetics / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008137:Longitudinal Studies; D008198:Lymph Nodes / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D037981:Neck Dissection; D009364:Neoplasm Recurrence, Local; D051096:Proto-Oncogene Proteins c-ret / Q000235:genetics; D011956:Receptors, Cell Surface / Q000097:blood; D015996:Survival Rate; D013964:Thyroid Neoplasms / Q000453:epidemiology / Q000235:genetics / Q000601:surgery*; D013965:Thyroidectomy / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D011956:Receptors, Cell Surface; C065686:carcinoembryonic antigen binding protein, human; D002116:Calcitonin; D051096:Proto-Oncogene Proteins c-ret; C099282:RET protein, human