Endocrine Abstracts

Introduction: The use of immunotherapy in oncology patients is increasing and is likely to continue to increase in the future. It is widely known that therapies have endocrinological side effects which can be serious, but maybe are also useful indicators to judge a response to the treatment. Presently, we do have not enough information regarding these side effects and their evolution.

Materials and methods: Observational and retrospective study of 162 oncology patients treated with immunotherapy in a third level hospital since 2014. Patients taking part in a double blind trial were excluded. The results were analysed with SPSS 24 package.

Results: Results from 162 patients were analysed (78% men, mean age of cancer diagnosis: 64±11 years). 43% were treated with Nivolumab, 27% Pembrolizumab, 18% Atezolizumab, 3% Ipilimumab. 20 patients (12%) developed endocrine toxicity, with the thyroid being the most affected gland (11% of total patients). There was just 1 case of Hypophysitis, which occurred in a patient treated with Ipilimumab. 13% of patients treated with anti-PD1 had a thyroid disorder (60% hypothyroidism and 40% hyperthyroidism). Most side effects where reported with Nivolumab (55%), however, this was also the most frequently used drug and so it was deemed to be not statistically significant. The mean time between the first dose of the drug and the detection of the toxicity was 104±129 days, separated by toxicities; hypothyroidism was developed in 80±65 days (median 60 days) and hyperthyroidism in 142±212 days (median 52 days). The evolution of these side effects in the thyroid gland, 88% of hypothyroidism and 29% of hyperthyroidism respectively, are persist. The case of hypophysitis persists.

Conclusions: Endocrine toxicity is a frequently observed side effect of immunotherapy with thyroid disorders being the most commonly reported, predominantly hypothyroidism. The incidence of our series is similar to other published series. The time to onset is variable, with a median of 2 months in the case of hypothyroidism. If hypothyroidism appears, it seems to be persistent but further long term studies are required.