Endocrine Abstracts

Introduction: The development of immunotherapy has opened up a new approach in the management of different types of tumors that previously had not treatment, and its use is becoming increasingly widespread. Immunotherapy is based on blocking immune checkpoints involved in activating the immune response to malignant neoplasms. Since its introduction into clinical practice, several adverse effects related to the immune system have been reported. Among the endocrinological adverse effects, hypophysitis and thyroid dysfunction are the most frequent. Adrenal insufficiency, DM1 and hypoparathyroidism have also been documented.

Case Series: We present the cases of 5 patients who developed hypothyroidism during immunotherapy treatment at the General La Mancha Centro Hospital and General Hospital in Tomelloso (Ciudad Real, Spain). All patients were male, aged between 56-72 years, and none of them had thyroid disorders prior to the use of immunotherapy. After the diagnosis of advanced oncological disease (melanoma, lung cancer, kidney cancer, and multiple myeloma), it was decided to start immunotherapy treatment, 3 patients with nivolumab (anti PD-1), 1 patient with durvalumab (anti PD-L1), and 1 patient with velcade (proteosomal inhibitor) plus daratumumab (AcMo anti CD38). Several months after starting treatment, patients were diagnosed with hypothyroidism (3 subclinical and 2 central), with asthenia being the main symptom. Antithyroid antibodies were present in 2 patients. In those patients with suspected hypophysitis, an MRI was performed to rule out this pathology, and no cases were observed. After ruling out adrenal insufficiency, which was only documented in the patient treated with velcade plus daratumumab, replacement therapy was initiated, without requiring suspension of immunotherapy in any case.

Discussion: Endocrine disorders related to immunotherapy are increasingly recognized as one of the most common adverse effects. Its diagnosis is sometimes complicated, as symptoms are nonspecific and may overlap with symptoms due to tumor progression. In most cases, the management of these endocrinopathies does not require discontinuation of immunotherapy, although they are usually irreversible and require long-term treatment.

Conclusion: Thyroid dysfunction is a relatively common adverse effect in patients treated with immunotherapy. The risk of developing endocrinopathy is greater at the beginning of treatment, hence the need to monitor thyroid function both at the beginning and during treatment with immunotherapy, in order to carry out an early diagnosis and treatment.