title: Treatment with tyrosine kinase inhibitors in patients with metastatic renal cell carcinoma is associated with drug-induced hyperparathyroidism: a single center experience in 59 patients.
abstract: OBJECTIVE
  Multi-targeted tyrosine kinase inhibitors (MTKIs) are the standard in the treatment of metastatic renal cell carcinoma (mRCC). In spite their clinical activity, interaction with physiological functions has been shown. Here, we report on alterations of the bone mineral metabolism in patients with mRCC treated with MTKIs.
  
  
  METHODS
  Fifty-nine patients with mRCC treated during April 2005 and September 2009 at our center were evaluated. Demographics, chemistry, parathyroid and renal function, bone metastasis and clinics were assessed, retrospectively. Parathyroid hormone (PTH), calcium and phosphate were either determined prior to, during or after cessation of MTKI therapy.
  
  
  RESULTS
  From evaluable patients, 90% (N = 53) received at least one MTKI treatment, 10% (N = 8) had evaluations without MTKI exposure. The mean PTH value prior to MTKI treatment was 49.4 (range (r):2.5-115), increased during the therapy to 121.2 (r:5-302) (P = 0.003) and returned to its basic values after MTKI cessation. In parallel, mean phosphate significantly decreased during the treatment from 1.10 (r = 0.66-1.59) to 0.87 (r = 0.48-1.45) (P < 0.001) and calcium showed a slight decrease (P = 0.039). PTH alterations were associated with clinical signs in some patients but not with bone metastasis or renal function. Univariate logistic regression analysis of pathologically elevated PTH levels revealed an association with MTKI treatment duration.
  
  
  CONCLUSIONS
  Even though the mechanism of bone mineral alteration remains elusive, the MTKI treatment is associated with a dysregulated parathyroid axis, which may have clinical implications in a number of patients. Furthermore, prospective trials are mandatory, and PTH monitoring should be considered in selected patients during MTKI treatment.
authors.affiliation: Clinic of Hematology, Hemostasis, Oncology and Stem Cell Transplantation, Medizinische Hochschule Hannover, Carl-Neuberg Str. 1, 30625, Hannover, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Ivanyi
authors.forename: Thomas
authors.initials: T
authors.lastname: Winkler
authors.forename: Anika
authors.initials: A
authors.lastname: Grosshennig
authors.forename: Christoph
authors.initials: C
authors.lastname: Reuter
authors.forename: Axel S
authors.initials: AS
authors.lastname: Merseburger
authors.forename: Arnold
authors.initials: A
authors.lastname: Ganser
authors.forename: Viktor
authors.initials: V
authors.lastname: Grünwald
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015519:Bone Density / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D002292:Carcinoma, Renal Cell / Q000188:drug therapy* / Q000401:mortality / Q000556:secondary*; D015331:Cohort Studies; D016001:Confidence Intervals; D016503:Drug Delivery Systems; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006961:Hyperparathyroidism / Q000139:chemically induced* / Q000175:diagnosis / Q000453:epidemiology; D015994:Incidence; D007677:Kidney Function Tests; D007680:Kidney Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D016017:Odds Ratio; D010281:Parathyroid Hormone / Q000378:metabolism; D011336:Probability; D011379:Prognosis; D047428:Protein Kinase Inhibitors / Q000009:adverse effects* / Q000627:therapeutic use; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D012042:Registries; D012189:Retrospective Studies; D018570:Risk Assessment; D016019:Survival Analysis
chemical_list: D010281:Parathyroid Hormone; D047428:Protein Kinase Inhibitors; D011505:Protein-Tyrosine Kinases; D002118:Calcium