ÇOCUKLUK ÇAĞI HODGKİN LENFOMALI HASTALARDA TEDAVİNİN UZUN DÖNEMDE TİROİD ÜZERİNE ETKİLERİ

Abstract

Deveci, E.I. Long-Term Effects of Treatment on the Thyroid in Patients with Childhood Hodgkin Lymphoma. Hacettepe University Faculty of Medicine, Department of Pediatrics, Thesis in Pediatrics, Ankara, 2026. High survival rates in childhood Hodgkin lymphoma (HL) have increased the importance of treatment-related late effects. This study aimed to evaluate the frequency and timing of long-term thyroid function and structural abnormalities after childhood HL treatment and their associated factors. In this single-center retrospective study, records of 370 patients diagnosed with HL before age 18 between February 1, 1999, and February 1, 2024, were reviewed; 175 patients with post-treatment thyroid function test (TFT) abnormalities and/or pathological thyroid ultrasonography (US) findings who met the study criteria were evaluated. The most common first thyroid laboratory abnormality was subclinical hypothyroidism (61.1%); primary hypothyroidism was detected in 46.9% during follow-up. Median times to the first thyroid laboratory and US abnormalities were 2.22 and 5.40 years after treatment, respectively. Among patients who underwent US, thyroid parenchymal heterogeneity, decreased thyroid volume, and thyroid nodules were detected in 18.3%, 40.5%, and 42.5%, respectively. Secondary thyroid malignancy developed in 10 patients (5.7%), all of whom had the neck included in the radiotherapy (RT) field. In multivariable analysis, higher neck–supraclavicular fossa (SCF) RT dose was associated with higher odds of primary hypothyroidism (aOR per 1 Gy, 1.084; 95% CI 1.015–1.159; p=0.017), while longer total follow-up was associated with higher odds of thyroid nodules (aOR per year, 1.159; 95% CI 1.085–1.238; p<0.001). Inclusion of the neck in the RT field increased the hazard of thyroid disorders (aHR 1.886; 95% CI 1.118–3.182; p=0.017). Thyroid disorders were found to occur from the early post-treatment period and continue to emerge over many years, with thyroid function abnormalities detected earlier than structural abnormalities. The findings indicate that direct thyroid irradiation and increasing RT dose are associated with hypothyroidism, while the timing of thyroid late effects is associated with treatment and follow-up characteristics. Long-term monitoring of thyroid function and structural findings in childhood HL survivors is important, considering treatment exposures. Keywords: Hodgkin disease; long term adverse effects; radiotherapy; survivors of childhood cancer; thyroid diseases.