title: Success of the postoperative 131I therapy in young Belarusian patients with differentiated thyroid cancer after Chernobyl depends on the radiation absorbed dose to the blood and the thyroglobulin level.
abstract: OBJECTIVE
  Differentiated thyroid carcinoma (DTC) in children and young adults is rare but often aggressive and in an advanced stage at diagnosis. In a cohort of young Belarusian patients with advanced DTC after Chernobyl we retrospectively studied parameters influencing the success of the postoperative (131)I therapy.
  
  
  METHODS
  Included in the study were 136 patients (83 female, 53 male; median age 14.3 years, range 9.4-22.8 years) who had had total thyroidectomy in Belarus and subsequent (131)I therapy and follow-up in Germany. Of the 136 patients, 34 were classified as M1 and 102 as M0 (N0 1, N1 101). The median weight-adjusted (131)I activity administered after thyroid hormone withdrawal was 52 MBq/kg (range 24-74 MBq/kg). TNM stage, gender, administered activity, whole-body residence time and blood dose during ablation, Tg and TSH levels, date, and age at time of treatment were tested for their effect on the rate of complete remission (CR). CR was defined as a negative scan and a stimulated Tg level of <1 ng/ml at follow-up.
  
  
  RESULTS
  CR was observed in 1 of 34 M1 and in 51 of 102 M0 patients after the first treatment. Multivariate analysis in the M0 group identified the Tg level (P < 0.0001 for log(Tg)) and the radiation absorbed dose to the blood (P < 0.001) as independent determinants; all other parameters were unimportant (P > 0.3). The regression model was able to correctly predict CR in 82 of 102 patients (80.4%).
  
  
  CONCLUSIONS
  In children and young adults with advanced DTC, the rate of CR after postoperative (131)I therapy is dependent on the preablative Tg level and the radiation absorbed dose to the blood. Though the present results must be confirmed in a prospective study, they imply that preablative dosimetry may improve rates of CR.
authors: Department of Nuclear Medicine, University of Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany. Haenscheid_h@klinik.uni-wuerzburg.de
authors: Heribert
authors: H
authors: Hänscheid
authors: Frederik Anton
authors: FA
authors: Verburg
authors: Johannes
authors: J
authors: Biko
authors: Stefanie
authors: S
authors: Diessl
authors: Yuri E
authors: YE
authors: Demidchik
authors: Valentina
authors: V
authors: Drozd
authors: Christoph
authors: C
authors: Reiners
mesh_terms: D000293:Adolescent; D000328:Adult; D047852:Chernobyl Nuclear Accident; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D009367:Neoplasm Staging; D009381:Neoplasms, Radiation-Induced / Q000097:blood* / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D011184:Postoperative Period; D011829:Radiation Dosage; D002094:Republic of Belarus; D013954:Thyroglobulin / Q000378:metabolism*; D013964:Thyroid Neoplasms / Q000097:blood* / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D007457:Iodine Radioisotopes; D013954:Thyroglobulin