title: Serum Thyroglobulin Doubling Time in Progressive Thyroid Cancer.
abstract: Tumor marker doubling time (DT) has been proposed as a prognostic marker for various types of cancer. The present study analyzed the DT of the thyroid-specific tumor marker thyroglobulin (Tg), focusing on patients with progressive differentiated thyroid cancer (DTC).
  
  
  
  A total of 144 Tg courses of 99 patients with progressive or recurrent DTC were included (median observation period 19 months, 3-11 Tg measurements per course) in this retrospective study. The distribution of Tg-DT was determined for both a highly sensitive assay (functional working range 0.03-3 ng/mL) and a routine assay. Tg-DT and other prognostic markers were used to perform uni- and multivariate statistical analyses for survival predictors.
  
  
  
  The median Tg-DT was 212 days (95% percentile: 49-961 days). No significant differences were observed between DT derived from Tg values in the very low range using a highly sensitive assay and DT calculated from Tg values measured by a conventional Tg assay. Multivariate analysis yielded no simple correlation between Tg-DT and survival rate, but the mortality risk of patients with a Tg-DT <5 months was more than twice as high as compared with a Tg-DT of >14 months. Highly significant differences on survival rates were only observed in patients with a high tumor load (Tg >100 ng/mL).
  
  
  
  Tg-DT alone is not an independent survival predictor in all patients with progressive DTC; however, analyzing only patients with a high tumor load, we found highly significant differences in survival rates.
authors.affiliation: 1 Klinik für Nuklearmedizin, Universitätsklinikum Essen , Essen, Germany .
authors.forename: Ronja Maria
authors.initials: RM
authors.lastname: Rössing
authors.affiliation: 1 Klinik für Nuklearmedizin, Universitätsklinikum Essen , Essen, Germany .
authors.forename: Walter
authors.initials: W
authors.lastname: Jentzen
authors.affiliation: 2 Human Oncology and Pathogenesis Program, Molecular Imaging and Therapy Service, Memorial Sloan-Kettering Cancer Center , New York, New York.
authors.forename: James
authors.initials: J
authors.lastname: Nagarajah
authors.affiliation: 1 Klinik für Nuklearmedizin, Universitätsklinikum Essen , Essen, Germany .
authors.forename: Andreas
authors.initials: A
authors.lastname: Bockisch
authors.affiliation: 1 Klinik für Nuklearmedizin, Universitätsklinikum Essen , Essen, Germany .
authors.forename: Rainer
authors.initials: R
authors.lastname: Görges
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013954:Thyroglobulin / Q000097:blood*; D013960:Thyroid Function Tests; D013964:Thyroid Neoplasms / Q000097:blood* / Q000401:mortality / Q000473:pathology; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D013954:Thyroglobulin
keywords: differentiated thyroid carcinoma; highly sensitive Tg assay; thyroglobulin; tumor marker doubling time; tumor progression