Endocrine Abstracts

Introduction: With the increasing survival rates from cancer the focus has been shifting towards the adverse sequelae, occurring both acutely, or developing as late effects, deriving from its multimodality treatment.

Aim: We investigated the occurrence of thyroid complications in patients with haematological malignancies treated with chemotherapy, radiotherapy involving the neck and/or haematopoietic stem cell transplantation (HSCT), referred to our endocrine sequelae clinic over the course of 20 years.

Patients and Methods: We prospectively enrolled 343 patients (172 females, 50.1%), with median age at diagnosis of 17 years (range: 1-76), and median follow-up of 12.4 years. Diagnoses were similarly distributed across: acute myeloid leukaemia, acute lymphoblastic leukaemia, chronic myeloid leukaemia, Hodgkin’s lymphoma, non-Hodgkin’s lymphomas, myelodysplastic syndromes and multiple myeloma. All patients underwent systemic chemotherapy, radiotherapy involving the neck was needed in 103 patients and 208 subjects received HSCT. We investigated the occurrence of: overall thyroid complications, transient and permanent thyroid dysfunction, low T3 syndrome, thyroid autoimmunity, benign and malignant thyroid nodules using Kaplan-Meier survival analyses and Cox proportional hazards models with bootstrapping.

Results: Overall 58.7% of patients experienced thyroid complications, with a median latency time of 3.7 years. Primary hypothyroidism was encountered in 15.6% and transient hypothyroidism in 6.3% of patients; Cox regression revealed female sex (P=0.008), adult age (P=0.035) and radiotherapy (P< 0.001) as independent predictors. Low T3 syndrome was diagnosed in 10.1% of patients, and female sex and radiotherapy were independent predictors (P=0.027 and 0.009, respectively). Transient hyperthyroidism was found in 2.1%, mostly after neck radiotherapy. Thyroid autoimmunity was encountered in 32%, and adult age at diagnosis (>18 years) was the only independent predictor (P=0.028). Thyroid nodules were encountered in 41.1%, with adult age at diagnosis as the only independent predictor (P=0.032); 5 patients were diagnosed with papillary thyroid carcinomas. With regards to overall thyroid complications, female sex and adult age at diagnosis were associated with the highest risk (P< 0.001 and 0.001, respectively). Neck radiotherapy was associated with an increased risk of complications after a median of 18 years, whereas HSCT was not, after multiple adjustments.

Conclusions: Thyroid comorbidities are highly prevalent among patients treated for haematological malignancies, with specific associations with treatment modality, requiring long-term endocrine follow-up.