2.2. Data Collection

The following data were collected: age at the time of treatment; sex; tumor size and histology; tumor-node-metastasis (TNM) stage according to the American Joint Committee on Cancer (AJCC) staging manual eighth edition^[31]; current RAI activity; cumulative RAI activity; renal function (e.g., blood creatinine, urea level and the estimated glomerular filtration rate [eGFR]); and CBC before and after RAI treatment, including red blood cell (RBC), hemoglobin (Hb), platelet (PLT), white blood cell (WBC), neutrophil (NEUT), lymphocyte (LYMPH). Additional data were collected for hospitalizations, acute infections, blood transfusions, or treatment with granulocyte colony-stimulating factor within 1 year following RAI treatment. Bone marrow suppression was defined as the suppression of bone marrow function as a result of significant reduction in the number of RBC, Hb, PLT, WBC, NEUT, and LYMPH according to Common Terminology Criteria for Adverse Events (CTCAE) version 5.0.^[32]

Whole-blood samples were processed by the Sysmex XE-5000 analyzer (Sysmex Corp., Kobe, Japan). Intervals assessed for bone marrow function were as follows: baseline values (within 3 months before RAI), 1.5–3 months, 3–6 months, 6–12 months after RAI treatment.