title: Metformin Attenuates 131I-Induced Decrease in Peripheral Blood Cells in Patients with Differentiated Thyroid Cancer.
abstract: BACKGROUND
  131I treatment (tx) of differentiated thyroid cancer (DTC) is associated with hematopoietic toxicity. It was hypothesized that metformin could have radioprotective effects on bone-marrow function. The objective was to determine whether metformin prevents 131I-induced changes in complete blood counts (CBC) in patients with DTC.
  
  
  METHODS
  A retrospective analysis was performed of CBC values in DTC patients who were (40 patients: metformin group) or were not taking metformin (39 patients: control group) at the time of administration of 131I. Repeated measures analysis of variance was used for the analysis of the differences in the averages of CBC that were documented at baseline and at 1, 6, and 12 months post 131I tx.
  
  
  RESULTS
  The groups were comparable in terms of age, sex, stage of DTC, 131I dose administered, and baseline CBC values. In the control group, the decrease in white blood cells (WBC) was 35.8% (p < 0.0001) at one month, 21.8% (p < 0.0001) at six months, and 19.4% (p < 0.0001) at 12 months. In the metformin group, the decrease in WBC was 17.1% (p < 0.0001) at one month, and 8.6% at six months (p = 0.01), while at 12 months WBC had returned to baseline values (p = 0.9). Differences between the two groups were highly statistically significant at all time points (p < 0.0001, p = 0.0027, and p < 0.0001, respectively). Lymphocytes were more sensitive to 131I, but metformin's radioprotective properties were more prominent in neutrophils. At 12 months, the decrease in platelets in the control group was 15.5% (p < 0.0001) versus 5.6% (p = 0.056) in the metformin group, while at one and six months the reductions in the two groups were comparable. No statistically significant differences were observed between the two groups in the change from baseline values for hemoglobin.
  
  
  CONCLUSIONS
  Metformin attenuated the 131I-induced decrease in CBC parameters, and its radioprotective properties were more prominent in WBC. Patients who were taking metformin during 131I tx also experienced a faster recovery in their blood counts, when compared to the control group. Further study is warranted in order to examine if the radioprotective properties of metformin observed in the current study for 131I tx can also apply to other forms of therapeutic chemo- and radiotherapy.
authors.affiliation: 1 Division of Endocrinology, Department of Medicine, MedStar Washington Hospital Center , Washington, DC.|2 MedStar Health Research Institute , Washington, DC.
authors.forename: Athanasios
authors.initials: A
authors.lastname: Bikas
authors.affiliation: 3 Department of Nuclear Medicine, MedStar Washington Hospital Center , Washington, DC.
authors.forename: Douglas
authors.initials: D
authors.lastname: Van Nostrand
authors.affiliation: 4 Department of Pediatrics, Uniformed Services University of the Health Sciences , Bethesda, Maryland.
authors.forename: Kirk
authors.initials: K
authors.lastname: Jensen
authors.affiliation: 2 MedStar Health Research Institute , Washington, DC.
authors.forename: Sameer
authors.initials: S
authors.lastname: Desale
authors.affiliation: 2 MedStar Health Research Institute , Washington, DC.
authors.forename: Mihriye
authors.initials: M
authors.lastname: Mete
authors.affiliation: 4 Department of Pediatrics, Uniformed Services University of the Health Sciences , Bethesda, Maryland.
authors.forename: Aneeta
authors.initials: A
authors.lastname: Patel
authors.affiliation: 1 Division of Endocrinology, Department of Medicine, MedStar Washington Hospital Center , Washington, DC.
authors.forename: Leonard
authors.initials: L
authors.lastname: Wartofsky
authors.affiliation: 4 Department of Pediatrics, Uniformed Services University of the Health Sciences , Bethesda, Maryland.
authors.forename: Vasyl
authors.initials: V
authors.lastname: Vasko
authors.affiliation: 1 Division of Endocrinology, Department of Medicine, MedStar Washington Hospital Center , Washington, DC.
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Burman
mesh_terms: D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000378:metabolism; D001854:Bone Marrow Cells / Q000528:radiation effects; D004906:Erythrocyte Count; D005260:Female; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D007457:Iodine Radioisotopes / Q000009:adverse effects* / Q000627:therapeutic use*; D007958:Leukocyte Count; D008297:Male; D008687:Metformin / Q000627:therapeutic use*; D008875:Middle Aged; D011837:Radiation-Protective Agents / Q000627:therapeutic use*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000097:blood* / Q000188:drug therapy*; D013965:Thyroidectomy
chemical_list: D006454:Hemoglobins; D007004:Hypoglycemic Agents; D007457:Iodine Radioisotopes; D011837:Radiation-Protective Agents; D008687:Metformin