Short-term bone marrow suppression in differentiated thyroid cancer patients after radioactive iodine treatment

• Published in: ENDOCRINE JOURNAL Vol. 67; no. 12; pp. 1193 - 1198
• Main Authors: Yi, Wook, Kim, Bo Hyun, Kim, Mijin, Ryang, So Ree, Jang, Min Hee, Kim, Jeong Mi, Kim, Eun Heui, Jeon, Yun Kyung, Kim, Sang Soo, Kim, In Joo
• Format: Journal Article
• Language: English; Japanese
• Published: Japan The Japan Endocrine Society 01.01.2020; Japan Science and Technology Agency
• Subjects: Blood; Bone marrow; Differentiated thyroid cancer; Hemoglobin; Iodine; Leukopenia; Lymphocyte; Lymphocytes; Myelosuppression; Peripheral blood; Platelets; Radioactive iodine; Statistical analysis; Thrombocytopenia; Thyroid cancer; Thyroidectomy; White blood cell; Bone marrow; Radioactive iodine; Lymphocyte; Differentiated thyroid cancer; White blood cell
• ISSN: 0918-8959; 1348-4540
• DOI: 10.1507/endocrj.EJ20-0242

After thyroidectomy in differentiated thyroid cancer (DTC), radioactive iodine (RAI) treatment is often used for remnant ablation. However, RAI treatment has been associated with bone marrow suppression, and leukopenia, anemia, and thrombocytopenia may occur after a single RAI administration. In this study, we examined the change in complete blood counts at 1 week after RAI administration; this is less well studied. A group of 189 DTC patients who received RAI treatment and underwent blood tests before and after treatment, were included. Peripheral blood counts at baseline were compared to those obtained at 1 week, 1–6 months, and 6–12 months after RAI treatment in order to test for bone marrow suppression. At 1 week after RAI treatment, there was a significant decrease in the white blood cell count (WBC, 5.8 ± 1.6 × 109/L vs. 5.4 ± 1.5 × 109/L, p < 0.001) and hemoglobin level (Hb, 13.5 ± 1.7 g/dL vs. 13.3 ± 1.4 g/dL, p = 0.001). The WBC decrease was mostly due to lymphocyte counts (2.2 ± 0.6 × 109/L vs. 1.6 ± 0.5 × 109/L, p < 0.001), with no decrease in the neutrophil count. Although not significantly changed at 1 week, platelets counts were altered within 6 months (265 ± 69 × 109/L vs. 239 ± 53 × 109/L, p < 0.001). The decline in the WBC count recovered within 6 months; lymphocyte and platelet counts recovered within 12 months. In conclusion, RAI treatment after a thyroidectomy was associated with a statistically significant but temporary decline in WBC counts and Hb levels at 1 week. Physicians treating DTC patients should not decrease usage of moderate dose RAI treatments.