Thyroid dysfunction in patients undergoing allogeneic stem cell transplantation in childhood and adolescence, thirty years follow-up
Abstract
Radiotherapy and high-dose chemotherapy can cause a lot of early and late effects. Thyroid dysfunction is a known late complication following HSCT (hematopoietic stem cell transplantation).
The objective of this study was to analyze the occurrence and characteristics of thyroid dysfunction in patients who have undergone HSCT in childhood and adolescence at our center (HSCT Unit, Department of Pediatric Hematology and Oncology, University Hospital Motol, Prague). Patients and methods: A retrospective review of clinical records was conducted for patients who had undergone allogeneic HSCT in childhood and adolescence, and subsequently were diagnosed with thyroid involvement.
Thyroid gland function was evaluated in regular terms (pre-HSCT, six months, one year and then annually after HSCT). Ultrasound examination was performed in patients with thyroid gland involvement and as a screening.
We have evaluated data in 463 patients (295 male, 168 female) who underwent allogeneic transplantation at a median age of 7.8 years (range: 0.1–20.5) from 1989 till 2018 and were alive more than one year after transplantation at the time of evaluation. Three hundred one patient (65%) were treated for malignant disease.
In one‑third of patients who underwent HSCT, total body irradiation (TBI) conditioning regimen was used, almost 50% of patients underwent Busulphan based condition regimen. Three hundred twenty-seven transplantations (66.6%) were performed from an unrelated donor, 33.4% from a matched sibling or other family donor.
Results: One hundred sixty-nine patients (36.5%) were diagnosed with thyroid gland involvement at a median of 2.0 (range: 0.4–21.3) years after HSCT. Primary hypothyroidism was the most common type of thyroid dysfunction (110 patients – 65.1%), only nine of them were with clinical signs.
Thyroid anti-bodies (aTPO, aTG) were detected in 95 patients. Thyroid nodules were found during ultrasound examination in 29 patients at a median of 11.5 (range 5.1–23.4) years after HSCT, fifteen patients were treated due to thyroid dysfunction (hypo = 8, AITD = 7).
Thyroid carcinoma was diagnosed in 8 patients (in 1.7% of all patients, 27.6% of patients with nodules) at a median of 10.8 (range 5.4–21.5) years after HSCT. All but one had received TBI based conditioning regimen.
Conclusions: Allogeneic hematopoietic stem cell transplantation is a potentially curative therapy for a variety of malignant and non-malignant disorders. With the improved outcome, increasing attention has been drawn to late complications in long-term survivors.
Thyroid dysfunction is one of the most frequent complications. Regular evaluation of thyroid gland function (every 6–12 months) including laboratory parameters is highly recommended.
The risk of secondary malignancies after HSCT is increasing within time. Careful follow-up of thyroid status including annual ultrasound examination every 1–3 years, is very important for early detection of tumor, namely in all patients exposed to TBI.