Background: Survivors of Hodgkin lymphoma and other patients who receive neck irradiation are at increased risk of thyroid cancer. Ultrasonography provides an inexpensive and non-invasive method of thyroid screening, but the clinical significance of thyroid nodules detected by ultrasound screening is uncertain.
Procedure: We reviewed the demographics, clinical characteristics, method of detection, and outcome of patients who developed thyroid nodules after treatment for pediatric Hodgkin lymphoma at our institution. One radiologist reviewed all imaging studies.
Results: Sixty-seven children treated for Hodgkin lymphoma from 1962 to 2001 developed thyroid nodules. The study group represented 9,024 person-years of follow-up after the diagnosis of Hodgkin lymphoma and 581 person-years after diagnosis of a thyroid nodule. A median of 10.5 years (range, 0.2-24.8 years) elapsed between the diagnoses of Hodgkin lymphoma and thyroid nodule(s). All but one patient had received neck irradiation for Hodgkin lymphoma, with a median thyroid radiation dose of 35 Gy (range, 12-45 Gy). Thyroid nodules were found to be malignant in seven patients (10%), at a median of 16.2 years (range, 8.4-23.7 years) after diagnosis of Hodgkin lymphoma. Only one malignancy was found through screening ultrasonography. All patients with thyroid cancer remained disease-free at 0.4-16.2 years of follow-up.
Conclusions: Thyroid nodules are common in Hodgkin lymphoma survivors treated with neck irradiation, but the majority of these lesions have an indolent clinical course and do not undergo malignant transformation. Only patients with a palpable mass or clinical symptoms need more extensive evaluation, including Doppler-flow ultrasonography and fine-needle aspiration.