title: Intra-operative parathyroid hormone monitoring in patients with parathyroid cancer.
abstract: BACKGROUND
  Intra-operative parathyroid hormone (PTH) monitoring (IPM) is 97% accurate in predicting postoperative eucalcemia in sporadic primary hyperparathyroidism (SPHPT). However, its usefulness in parathyroid cancer has not been demonstrated. This study reports IPM accuracy during surgical resections for parathyroid cancer.
  
  
  METHODS
  Eight of 556 consecutive patients with SPHPT underwent parathyroidectomy using IPM and had parathyroid cancer. Operative success was defined as eucalcemia > six months and operative failure/persistent cancer as hypercalcemia within six months of parathyroidectomy. The IPM criterion for operative success was defined as a >50% decrease of peripheral PTH levels from the highest either pre-incision or pre-excision values, 10 minutes after resection.
  
  
  RESULTS
  In eight patients, 11 operations were performed. Ten operations (91%) resulted in >50% intra-operative PTH decrease. However, in only seven (70%) of these resections, eucalcemia was achieved for >6 months with five of these seven (71%) procedures being initial en bloc resections. The remaining 3/10 (30%) operations with >50% intra-operative PTH decrease resulted in operative failures. In the last operation, intraoperative parathormone monitoring (IPM) correctly predicted operative failure. IPM sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy in predicting outcome were 100, 40, 70, 100, and 75%, respectively.
  
  
  CONCLUSIONS
  IPM with the criterion of >50% PTH drop from the highest level is less accurate in predicting operative success in parathyroid cancer when compared to SPHPT. A >50% intra-operative PTH level decrease in patients with parathyroid cancer, particularly in reoperative cases, is less predictive of complete resection. The initial recognition of this disease followed by proper resection remains essential in the treatment of parathyroid cancer.
authors.affiliation: Division of Endocrine Surgery, University of Miami Miller School of Medicine, 1475 NW 12th Ave, Room 3550, Miami, FL 33136, USA. csolorzano@med.miami.edu
authors.forename: C C
authors.initials: CC
authors.lastname: Solórzano
authors.forename: D M
authors.initials: DM
authors.lastname: Carneiro-Pla
authors.forename: J I
authors.initials: JI
authors.lastname: Lew
authors.forename: S E
authors.initials: SE
authors.lastname: Rodgers
authors.forename: R
authors.initials: R
authors.lastname: Montano
authors.forename: G L
authors.initials: GL
authors.lastname: Irvin
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D005260:Female; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010281:Parathyroid Hormone / Q000097:blood*; D010282:Parathyroid Neoplasms / Q000097:blood* / Q000601:surgery; D016105:Parathyroidectomy / Q000379:methods; D011379:Prognosis; D011877:Radionuclide Imaging; D012680:Sensitivity and Specificity