title: Central compartment reoperation for recurrent/persistent differentiated thyroid cancer: patterns of recurrence, morbidity, and prediction of postoperative hypocalcemia.
abstract: BACKGROUND
  Incidence rates of hypoparathyroidism and vocal cord paralysis are high following central compartment reoperation, but few prospective studies have assessed morbidities and factors predictive of hypocalcemia after reoperation. We investigated recurrence patterns, morbidity, and factors predictive of postoperative hypocalcemia in patients undergoing central compartment reoperation for recurrent/persistent differentiated thyroid cancer (DTC).
  
  
  METHODS
  We prospectively evaluated 45 consecutive patients with recurrent/persistent DTC. Thyroid remnants or recurrent cancers were removed in 16 patients, the unilateral or bilateral central compartment was cleared in all patients, and the lateral compartment on the diseased side was comprehensively removed from 24 patients. Recurrence patterns were assessed histopathologically, morbidities were monitored, and serum concentrations of calcium and intact parathyroid hormone (iPTH) were measured in all patients.
  
  
  RESULTS
  Eleven patients (24.4%) had tumor invasion into the recurrent laryngeal nerve and/or the tracheoesophagus. Central nodal involvement occurred frequently (86.7%), and the ipsilateral jugular nodes of the lateral compartment were frequently involved. Temporary and permanent vocal cord paralysis developed in 10 (22.2%) and 8 (17.8%) patients, respectively, due primarily to intentional nerve resection following tumor invasion. Of 41 patients without preoperative hypoparathyroidism, 21 (46.3%) had temporary and 2 (4.9%) had permanent hypocalcemia. Multivariate analysis showed that bilateral central compartment dissection and low iPTH levels (<12.0 pg/ml) were independent predictors of postoperative hypocalcemia.
  
  
  CONCLUSIONS
  Most patients with recurrent/persistent DTC harbor lesions in the central compartment. Central compartment reoperation may lead to high rates of morbidity, including hypoparathyroidism, which can be predicted by surgical extent and low serum iPTH levels.
authors.affiliation: Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. rohjl@amc.seoul.kr
authors.forename: Jong-Lyel
authors.initials: JL
authors.lastname: Roh
authors.forename: Jin-Man
authors.initials: JM
authors.lastname: Kim
authors.forename: Chan Il
authors.initials: CI
authors.lastname: Park
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000150:complications / Q000601:surgery; D000328:Adult; D000368:Aged; D002118:Calcium / Q000097:blood; D002291:Carcinoma, Papillary / Q000150:complications / Q000601:surgery; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000209:etiology*; D007011:Hypoparathyroidism / Q000209:etiology; D008297:Male; D008875:Middle Aged; D009017:Morbidity; D009364:Neoplasm Recurrence, Local; D010281:Parathyroid Hormone / Q000097:blood; D011183:Postoperative Complications; D011446:Prospective Studies; D012086:Reoperation; D015996:Survival Rate; D013964:Thyroid Neoplasms / Q000150:complications* / Q000601:surgery*; D013965:Thyroidectomy / Q000009:adverse effects*; D016896:Treatment Outcome; D014826:Vocal Cord Paralysis / Q000209:etiology; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone; D002118:Calcium