Effects of Dosimetrically Guided I-131 Therapy on Hematopoiesis in Patients With Differentiated Thyroid Cancer

Objective: The objective of the study was to evaluate the effects of dosimetrically guided I-131 prescribed activities on hematopoiesis reflected by changes in complete blood counts (CBCs). Design: This was a retrospective analysis. Setting: The study was conducted at an academic center. Patients: A total of 152 patients with differentiated thyroid cancer who had 185 dosimetrically guided I-131 treatments. Interventions: There were no interventions. Main Outcome Measures: Repeated-measure ANOVA was used for the analysis of the differences in the averages of CBCs that were documented at baseline and 1, 6, 12, 24–36, and 48–60 months after I-131 treatment. Results: All parameters decreased to their respective nadir at 1 month and then gradually returned toward baseline values. White blood cells (WBCs) and platelets (PLTs) were the most significantly affected cells. At 1 month, the decrease was 29.6% (P < .0001) for WBCs and 25% (P < .0001) for PLTs, whereas at 12 months, the decrease was 15.5% (P < .0001) a...