Heterogeneity in endocrine monitoring and timing of endocrinology involvement during immune checkpoint inhibitor therapy: A Real-World Single-Center study

Endocrine immune-related adverse events (irAEs) are increasingly encountered with immune checkpoint inhibitors (ICIs), yet patterns of screening, referral, and emergency outcomes remain underexplored. This study evaluated the adequacy of endocrine monitoring, iming of endocrinology involvement, and determinants of endocrine emergencies in ICI-treated patients. We retrospectively reviewed 103 patients (67 men, 36 women; mean age 60.8 ± 12.1 years) referred to the Endocrinology Department between 2016 and 2025. Clinical data, cancer types, immunotherapy regimens, hormonal assessments, and causes and timing of referral were analyzed. Most patients (93.3%) were referred due to newly developed endocrine irAEs, with endocrinology involvement occurring at a median of 7.4 months (≈ 10th therapy cycle) after ICI initiation. The predominant ICI regimen involved PD-1 inhibitors (66%). Thyroid dysfunction (n = 64), secondary adrenal insufficiency (n = 28), and hyperglycemia (n = 4) were the leading endocrinopathies; hypophysitis was detected in 7 cases. Before ICI treatment, endocrine evaluation was absent in 22.3% and incomplete in 38.2%, while 9.7% received no endocrine follow-up during ICI therapy. Emergency admissions occurred in 17.4%, mainly due to adrenal crisis (n = 12), followed by thyrotoxicosis (n = 3). Although baseline screening status and timing of endocrinology involvement were not associated with emergency risk, phenotype strongly influenced outcomes: central adrenal insufficiency increased risk (RR = 3.29; 95% CI 1.33–8.08; p = 0.0197). Endocrine irAEs are frequent and may be recognized only after clinical deterioration, exposing patients to preventable endocrine emergencies, particularly adrenal crisis. These findings highlight heterogeneity and gaps in endocrine surveillance during ICI therapy and support early, structured oncologist–endocrinologist collaboration with standardized baseline and follow-up assessments to improve patient safety and continuity of immunotherapy.