title: Hypothyroidism in patients with renal cell carcinoma: blessing or curse?
abstract: BACKGROUND
  Sunitinib and sorafenib are tyrosine kinase inhibitors that have important antitumor activity in metastatic renal cell carcinoma (mRCC). Hypothyroidism constitutes a commonly reported side effect of both drugs, and particularly of sunitinib. The objective of this analysis was to investigate whether the occurrence of hypothyroidism during treatment with sunitinib and sorafenib affects the outcome of patients with mRCC.
  
  
  METHODS
  Eighty-seven consecutive patients with mRCC who were to receive treatment with sunitinib or sorafenib were included in a prospective analysis. Thyroid function was assessed in each patient every 4 weeks during the first 2 months of treatment and every 2 to 4 months thereafter. Assessment included serum levels of thyroid-stimulating hormone (TSH), tri-iodthyronine (T3), and thyroxine (T4). Subclinical hypothyroidism was defined as an increase in TSH above the upper limit of normal (>3.77 μM/mL) with normal T3 and T4 levels.
  
  
  RESULTS
  Subclinical hypothyroidism was evident in 5 patients at baseline and occurred in 30 patients (36.1%) within the first 2 months after treatment initiation. There was a statistically significant correlation between the occurrence of subclinical hypothyroidism during treatment and the rate of objective remission (hypothyroid patients vs euthyroid patients: 28.3% vs 3.3%, respectively; P < .001) and the median duration of survival (not reached vs 13.9 months, respectively; hazard ratio, 0.35; 95% confidence interval, 0.14-0.85; P = .016). In multivariate analysis, the development of subclinical hypothyroidism was identified as an independent predictor of survival (hazard ratio, 0.31; P = .014).
  
  
  CONCLUSIONS
  The current results indicated that hypothyroidism may serve as a predictive marker of treatment outcome in patients with mRCC. Thus, the interpretation of hypothyroidism during treatment with sunitinib and sorafenib as an unwanted side effect should be reconsidered.
authors.affiliation: Clinical Division of Oncology, Department of Medicine I and Cancer Center, Medical University of Vienna, Vienna, Austria. manuela.schmidinger@meduniwien.ac.at
authors.forename: Manuela
authors.initials: M
authors.lastname: Schmidinger
authors.forename: Ursula M
authors.initials: UM
authors.lastname: Vogl
authors.forename: Marija
authors.initials: M
authors.lastname: Bojic
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Lamm
authors.forename: Harald
authors.initials: H
authors.lastname: Heinzl
authors.forename: Andrea
authors.initials: A
authors.lastname: Haitel
authors.forename: Martin
authors.initials: M
authors.lastname: Clodi
authors.forename: Gero
authors.initials: G
authors.lastname: Kramer
authors.forename: Christoph C
authors.initials: CC
authors.lastname: Zielinski
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001557:Benzenesulfonates / Q000009:adverse effects / Q000627:therapeutic use*; D002292:Carcinoma, Renal Cell / Q000150:complications* / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000139:chemically induced; D007211:Indoles / Q000009:adverse effects / Q000627:therapeutic use*; D007680:Kidney Neoplasms / Q000150:complications* / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009536:Niacinamide / Q000031:analogs & derivatives; D010671:Phenylurea Compounds; D011379:Prognosis; D011725:Pyridines / Q000009:adverse effects / Q000627:therapeutic use*; D011758:Pyrroles / Q000009:adverse effects / Q000627:therapeutic use*; D000077157:Sorafenib; D000077210:Sunitinib; D013972:Thyrotropin / Q000097:blood; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D001557:Benzenesulfonates; D007211:Indoles; D010671:Phenylurea Compounds; D011725:Pyridines; D011758:Pyrroles; D009536:Niacinamide; D013972:Thyrotropin; D000077157:Sorafenib; D000077210:Sunitinib