Bone Marrow Function After (131)I Therapy in Patients With Differentiated Thyroid Carcinoma

Area of Science:

• Endocrinology
• Oncology
• Hematology

Background:

• Differentiated thyroid carcinoma (DTC) is often treated with radioactive iodine ((131)I).
• Bone marrow function can be affected by (131)I therapy, necessitating evaluation of its short- and long-term toxic effects.

Purpose of the Study:

• To assess the short- and long-term impact of (131)I therapy on bone marrow function in DTC patients.
• To identify patient characteristics associated with impaired bone marrow function post-(131)I treatment.

Main Methods:

• Retrospective analysis of 331 DTC patients treated with (131)I between 1989 and 2013.
• Comparison of baseline blood counts (platelets, leukocytes, hemoglobin) with post-treatment values at 3, 6 months, 1, and 5 years.
• Logistic multivariate regression to identify risk factors for thrombocytopenia.

Main Results:

• Platelet and leukocyte counts significantly decreased at 6 months and 1 year post-treatment, normalizing by 5 years.
• No significant decrease in hemoglobin was observed.
• Fourteen patients (4.2%) experienced transient thrombocytopenia; risk factors included older age, T4 stage, male gender, and cumulative (131)I dose.
• Cumulative (131)I dose was independently associated with thrombocytopenia.

Conclusions:

• (131)I therapy causes transient reductions in platelets and leukocytes in DTC patients.
• Cumulative (131)I dose is a key factor for thrombocytopenia.
• Bone marrow toxicity from (131)I therapy is generally limited and reversible within five years for most DTC patients.