title: Postoperative biochemical remission of serum calcitonin is the best predictive factor for recurrence-free survival of medullary thyroid cancer: a large-scale retrospective analysis over 30 years.
abstract: The increase in thyroid screening in the general population may lead to earlier detection of medullary thyroid carcinoma (MTC).
  
  
  
  We aimed to evaluate secular trends in clinicopathological characteristics and long-term prognosis of MTC and its prognostic factors.
  
  
  
  This was a retrospective analysis from 1982 to 2012.
  
  
  
  Three hundred and thirty-one patients with MTC were included and grouped based on the year of diagnosis (1982-2000, 2001-2005, 2006-2010 and 2011-2012).
  
  
  
  These included recurrence and mortality as well as biochemical remission (BCR) of serum calcitonin.
  
  
  
  Mean tumour size (from 2·5 cm to 1·7 cm, P < 0·001) and percentage of extrathyroidal extension (from 52·0% to 26·0%, P = 0·026) decreased. The percentage of patients achieving BCR within six postoperative months (po-BCR) increased with time (from 39·6% to 76·1%, P < 0·001). The 5-year overall recurrence rate significantly decreased in 2006-2012 compared to 1982-2005 (10% vs 18%, respectively, P = 0·031), although the 5-year survival rate did not improve (92% vs 92%, P = 0·929). Failure to achieve po-BCR was the strongest predictive factor associated with recurrence (hazard ratio [HR] = 58·04, 95% CI 7·14-472·11; P < 0·001). Male gender (HR = 3·18, 95% CI 1·18-8·56; P = 0·022), tumour size >2 cm (HR = 18·33, 95% CI 2·35-143·06; P = 0·006) and distant metastasis (HR = 4·00, 95% CI 1·31-12·21; P = 0·015) were significant prognostic factors for mortality.
  
  
  
  Clinicopathological characteristics and recurrence of MTC improved with time. Po-BCR was the best predictive factor for recurrence-free survival.
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Kyong Yeun
authors.initials: KY
authors.lastname: Jung
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Seok-Mo
authors.initials: SM
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Department of Internal Medicine, Dankook University College of Medicine, Cheonan, Korea.
authors.forename: Won Sang
authors.initials: WS
authors.lastname: Yoo
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Bup-Woo
authors.initials: BW
authors.lastname: Kim
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Yong Sang
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Kyung Won
authors.initials: KW
authors.lastname: Kim
authors.affiliation: Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Kyu Eun
authors.initials: KE
authors.lastname: Lee
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jong Ju
authors.initials: JJ
authors.lastname: Jeong
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Kee-Hyun
authors.initials: KH
authors.lastname: Nam
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Se Hoon
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Jeong Hun
authors.initials: JH
authors.lastname: Hah
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Woong Youn
authors.initials: WY
authors.lastname: Chung
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul, Korea.
authors.forename: Ka Hee
authors.initials: KH
authors.lastname: Yi
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Do Joon
authors.initials: DJ
authors.lastname: Park
authors.affiliation: Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Yeo-Kyu
authors.initials: YK
authors.lastname: Youn
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Myung-Whun
authors.initials: MW
authors.lastname: Sung
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea.
authors.forename: Bo Youn
authors.initials: BY
authors.lastname: Cho
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Cheong Soo
authors.initials: CS
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.|Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Young Joo
authors.initials: YJ
authors.lastname: Park
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hang-Seok
authors.initials: HS
authors.lastname: Chang
mesh_terms: D000328:Adult; D000368:Aged; D002116:Calcitonin / Q000097:blood*; D018278:Carcinoma, Neuroendocrine / Q000097:blood* / Q000473:pathology / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local; D017063:Outcome Assessment, Health Care / Q000379:methods / Q000706:statistics & numerical data; D011184:Postoperative Period; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012074:Remission Induction; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D013964:Thyroid Neoplasms / Q000097:blood* / Q000473:pathology / Q000601:surgery*; D047368:Tumor Burden
chemical_list: D002116:Calcitonin