title: A comparison of lobectomy and total thyroidectomy in patients with papillary thyroid microcarcinoma: a retrospective individual risk factor-matched cohort study.
abstract: OBJECTIVE
  Papillary thyroid microcarcinoma (PTMC) accounts for most of the increase in thyroid cancer in recent decades. We compared clinical outcomes and surgical complications of lobectomy and total thyroidectomy (TT) in PTMC patients.
  
  
  METHODS
  In this retrospective individual risk factor-matched cohort study, 2031 patients with PTMC were initially included. Patients who underwent lobectomy or TT were one-to-one matched according to individual risk factors, including age, sex, primary tumor size, extrathyroidal extension, multifocality and cervical lymph node (LN) metastasis.
  
  
  RESULTS
  In total, 688 patients were assigned to each group. During the median 8.5 years of follow-up, 26 patients (3.8%) in the lobectomy group and 11 patients (1.6%) in the TT group had recurrences. The relative risk of recurrence was significantly less in the TT than that in the lobectomy group (hazard ratio (HR) 0.41; 95% confidence interval (CI) 0.21-0.81; P = 0.01). Most recurrences (84.6%) in the lobectomy group occurred in the contralateral lobe, and all patients were disease-free after completion of thyroidectomy. There were no significant differences in recurrence-free survival between the two groups after exclusion of contralateral lobe recurrences (HR, 2.75; 95% CI, 0.08-8.79; P = 0.08). There were significantly more patients with transient and permanent hypoparathyroidism in the TT than that in the lobectomy group (P < 0.001).
  
  
  CONCLUSIONS
  Lobectomy could be appropriate for most patients with PTMC when there is no evidence of extrathyroidal disease in the preoperative work-up. Preoperative and postoperative imaging studies are important for patients who undergo lobectomy for PTMC, because most recurrences are in the contralateral lobe.
authors.affiliation: Departments of Internal Medicine.
authors.forename: Hyemi
authors.initials: H
authors.lastname: Kwon
authors.affiliation: Departments of Internal Medicine.
authors.forename: Min Ji
authors.initials: MJ
authors.lastname: Jeon
authors.affiliation: Departments of Internal Medicine.
authors.forename: Won Gu
authors.initials: WG
authors.lastname: Kim
authors.affiliation: Departments of Internal Medicine.
authors.forename: Suyeon
authors.initials: S
authors.lastname: Park
authors.affiliation: Departments of Internal Medicine.
authors.forename: Mijin
authors.initials: M
authors.lastname: Kim
authors.affiliation: Pathology.
authors.forename: Dong Eun
authors.initials: DE
authors.lastname: Song
authors.affiliation: SurgeryAsan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Tae-Yon
authors.initials: TY
authors.lastname: Sung
authors.affiliation: SurgeryAsan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Jong Ho
authors.initials: JH
authors.lastname: Yoon
authors.affiliation: SurgeryAsan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Suck Joon
authors.initials: SJ
authors.lastname: Hong
authors.affiliation: Departments of Internal Medicine.
authors.forename: Tae Yong
authors.initials: TY
authors.lastname: Kim
authors.affiliation: Departments of Internal Medicine.
authors.forename: Young Kee
authors.initials: YK
authors.lastname: Shong
authors.affiliation: Departments of Internal Medicine.
authors.forename: Won Bae
authors.initials: WB
authors.lastname: Kim
mesh_terms: D000328:Adult; D002291:Carcinoma, Papillary / Q000601:surgery*; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007011:Hypoparathyroidism / Q000453:epidemiology / Q000209:etiology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology; D011183:Postoperative Complications / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D013964:Thyroid Neoplasms / Q000601:surgery*; D013965:Thyroidectomy / Q000009:adverse effects / Q000379:methods*; D016896:Treatment Outcome