title: The effect of Ginkgo biloba extract on genotoxic damage in patients with differentiated thyroid carcinoma receiving thyroid remnant ablation with iodine-131.
abstract: BACKGROUND
  Radioiodine ((131)I) therapy is usually performed in patients with differentiated thyroid cancer (DTC). Although (131)I is generally considered safe, genotoxic damage has been demonstrated both in vivo and in vitro. The aim of the current study was to evaluate the effect of Ginkgo biloba extract (GBE) on the time-course of appearance, after (131)I therapy for DTC, of plasma factors with chromosome-damaging properties (so-called "clastogenic" factors [CFs]) and of micronuclei (MN) in lymphocytes.
  
  
  METHODS
  Twenty-three patients (median age 42 years, range 18-73) with DTC receiving (131)I activity (3.7 GBq) for thyroid remnant ablation were randomly assigned to receive GBE (120 mg/day for one month; n=10) or placebo (n=13) in a double-blind manner. Blood samples were taken at various intervals (from baseline to 90 days) after (131)I therapy. The frequency of MN in blood lymphocytes was determined, and CFs were assayed in plasma by a method that used MN increase in lymphocytes from an healthy donor as the endpoint of the assay.
  
  
  RESULTS
  MN in blood lymphocytes increased significantly after (131)I treatment in the placebo group, peaking at the 7th day (p=0.002) and slowly declining thereafter. In contrast, in similarly treated patients who were also treated with GBE both before and after (131)I treatment, a significant increase of blood lymphocyte MN level was not observed. In addition, only the placebo group showed a significant, progressive increase in CFs activity. This peaked at the 14th day (p=0.003 vs. baseline) and was still noted for the last plasma sample. The differences in the change in lymphocyte MN and CFs activity between the placebo and GBE-treated groups were significant (p<0.01 and p<0.05, respectively). Thyroid function tests, including serum thyroglobulin (Tg) and anti-Tg antibody levels, were never significantly different.
  
  
  CONCLUSIONS
  GBE may protect from possible oxidative and genotoxic damage associated with (131)I treatment in patients requiring (131)I therapy for thyroid cancer, without affecting the clinical outcome. Further studies with larger cohorts of patients are needed to confirm this report and verify the beneficial effect of GBE in patients requiring (131)I therapy, particularly for those in whom repeated treatments and high activities of (131)I are required.
authors.affiliation: Geriatrics and Gerontology Section, Department of Internal Medicine, University of Pisa, Pisa, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Dardano
authors.forename: Michela
authors.initials: M
authors.lastname: Ballardin
authors.forename: Nadia
authors.initials: N
authors.lastname: Caraccio
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Boni
authors.forename: Claudio
authors.initials: C
authors.lastname: Traino
authors.forename: Giuliano
authors.initials: G
authors.lastname: Mariani
authors.forename: Marco
authors.initials: M
authors.lastname: Ferdeghini
authors.forename: Roberto
authors.initials: R
authors.lastname: Barale
authors.forename: Fabio
authors.initials: F
authors.lastname: Monzani
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004311:Double-Blind Method; D005260:Female; D020441:Ginkgo biloba; D041743:Herb-Drug Interactions; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects* / Q000627:therapeutic use; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects; D008297:Male; D048629:Micronuclei, Chromosome-Defective / Q000139:chemically induced; D008875:Middle Aged; D009153:Mutagens / Q000032:analysis; D010936:Plant Extracts / Q000627:therapeutic use*; D011832:Radiation Injuries / Q000517:prevention & control*; D019275:Radiopharmaceuticals / Q000009:adverse effects* / Q000627:therapeutic use; D013960:Thyroid Function Tests; D013964:Thyroid Neoplasms / Q000188:drug therapy*
chemical_list: D007457:Iodine Radioisotopes; D009153:Mutagens; D010936:Plant Extracts; D019275:Radiopharmaceuticals