Mild Decreases in White Blood Cell and Platelet Counts Are Present One Year After Radioactive Iodine Remnant Ablation
ABSTRACT Bone marrow suppression after multiple, high-dose radioactive iodine (RAI) therapies is well described. However, changes in the peripheral complete blood count (CBC) that may occur after a single treatment of RAI such as that commonly used for routine remnant ablation is much less well studied. In this retrospective trial, we examined the rate of persistent anemia, leukopenia, and thrombocytopenia 1 year after a single RAI administration.
Peripheral blood counts at baseline were compared to those obtained 1 year after RAI remnant ablation in 206 consecutive thyroid cancer patients. Analyses were performed to determine the potential impact of both the method of preparation (recombinant human thyroid stimulating hormone [rhTSH] vs. thyroid hormone withdrawal) and administered activity of (131)I on hemoglobin, white blood cell (WBC), and platelet counts.
Comparison of the baseline CBC before RAI ablation (median administered activity of approximately 3700 MBq or 100 mCi) with the follow-up CBC done 1 year later demonstrated a statistically significant decline in total WBC (6.7 +/- 2.1 x 10(9) vs. 6.0 +/- 1.8 x 10(9)/L, p < 0.001; 9.7% below the reference range at 1-year follow-up) and platelet (272 +/- 67 vs. 250 +/- 65 x 10(9)/L, p < 0.001; 5.8% below the reference range at 1-year follow-up) with no significant change in hemoglobin (1.40 +/- 0.14 vs. 1.40 +/- 0.14 g/L or 14.0 +/- 1.4 vs. 14.0 +/- 1.4 g/dL; 1.5% below the reference range at 1-year follow-up). There were no significant clinical complications observed during the 1-year follow-up period. The changes in total WBC and platelets were not related to the method of preparation or the administered activity of RAI.
A single RAI treatment of approximately 3700 MBq (100 mCi) after thyroidectomy is associated with a statistically significant, mild decline in WBC and platelet counts that persists for at least 1 year after ablation. Given the small magnitude of the changes and the lack of clinically significant adverse events, these observations should not decrease the use of RAI ablation in moderate to high-risk patients in whom the benefits of ablation are likely to outweigh these minor risks.
- Future Oncology 07/2013; 9(7):921-3. DOI:10.2217/fon.13.80 · 2.61 Impact Factor
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ABSTRACT: Objective: Radioactive iodine (RAI) has been associated with hematologic abnormalities. Previous research has shown that even a single dose of RAI can cause changes in the peripheral complete blood count (CBC). It is unclear if the use of dosimetry guidance would prevent the effects of high doses of RAI on bone marrow suppression.Methods: CBC at baseline was compared to a CBC obtained one year after the last RAI treatment in 50 thyroid cancer patients that received 250mCi of RAI or more during the course of their disease. Cumulative dose, number of treatments, patients' age, and the use of external beam radiation therapy (EBRT) were considered in the analysis.Results: We observed a small, but statistically significant decrease in hemoglobin (Hb) / hematocrit (Hct) and platelet (Plts) count at one year in 50 patients who had received ≥ 250mCi of RAI. We did not find a significant change in white blood cell count (WBC). Sixty percent of patients who developed anemia had concomitant WBC and Plt abnormalities. RAI dose, number of treatments, and age at diagnosis did not confer a higher risk of bone marrow suppression.Conclusion: High cumulative activities of RAI administered under dosimetric guidance are associated with a small but statistically significant decrease in Hb/Hct and platelet counts. The clinical implications of these changes, if any, are unclear. The benefits obtained with high doses of RAI, when indicated, are likely to outweigh the minimal hematologic risks observed.Endocrine Practice 10/2013; 20(3):1-26. DOI:10.4158/EP13172.OR · 2.49 Impact Factor
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ABSTRACT: The ACR Head and Neck Cancer Appropriateness Criteria Committee reviewed relevant medical literature to provide guidance for those managing patients with thyroid carcinoma. The American College of Radiology Appropriateness Criteriaare evidence-based guidelines for specific clinical conditions that are reviewed every 2years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment. Thyroid cancer is the most common endocrine malignancy in the United States, most often presenting as a localized palpable nodule. Surgery is the mainstay of treatment for WDTC, with most patients undergoing complete resection of their disease having good outcomes. Following surgery thyroxine supplementation should begin to suppress TSH, which unchecked can stimulate residual disease and/or metastatic progression, Adjuvant treatment with radioactive iodine (RAI) using iodine-131 ((131)I) is frequently used for diagnostic and therapeutic purposes. The use of EBRT for thyroid cancer has not been tested in well-designed, randomized, controlled trials and should, therefore, be considered on a case-by-case basis. Chemotherapy plays a minimal role in the management of WDTC. Novel biologic agents, such as systemic therapy options, are being actively investigated, and patients with metastatic thyroid cancer that is not iodine avid should be encouraged to enroll in clinical trials exploring novel systemic agents.Oral Oncology 06/2014; 50(6):577-586. DOI:10.1016/j.oraloncology.2013.12.004 · 3.03 Impact Factor