Ziel/Aim: The advent of immune-check-point inhibitors (ICI) in routine clinical care has caused
profound improvement in the therapy of advanced-staged malignancies with poor outcome.
This approach is, however, associated with adverse effects due to immune-mediated
acute inflammation briefly after initiation of ICI-therapy. ICI-thyroiditis represents
the most common adverse effect with an overall incidence of up to 11.1%, mostly presenting
with thyrotoxicosis. Given the multimorbidity and undergoing immunotherapy, this entity
needs a timely and accurate discrimination from other etiologies of thyroid dysfunction.
This retrospective study sought to analyze the clinical impact of thyroid scan in
the diagnostic work-up of thyroid dysfunction in patients undergoing immune therapy.
Methodik/Methods: A total of 16 patients (6 males and 10 females) undergoing immunotherapy for advanced
malignancies were enrolled in this retrospective study between October 2022 and October
2024. These patients had clinical signs of thyroid disorder or abnormalities in thyroid
function tests (TFT). Following the initial endocrinological evaluation including
ultrasonography, serial TFTs and urinary iodine, we performed thyroid scan with [99mTc]Pertechnetate and evaluated the tracer uptake pattern of the suspected cases. The
reporting results were confirmed in the further follow-up period with a median of
6 months (1 – 15).
Ergebnisse/Results: The median time elapsed between the first signs of thyroid disorder and initiation
of immunotherapy was 74 days (17 – 163). The majority of patients exhibited only abnormal
TFTs, while a 71-years-old-patient demonstrated clinical symptoms such as fatigue,
hair and weight loss. The thyroid scan aided in conclusive clarification of 14 (88%)
out of 16 patients. ICI-thyroiditis was confirmed in 10 (63%) patients. All cases
with ICI-thyroiditis showed a tracer uptake of≤0,50% with no accompanying elevation
of anti-thyroid antibody titers. The urinary iodine levels were normal. Four patients
needed an anti-thyroid drug in combination with steroid therapy.
Schlussfolgerungen/Conclusions: Our results underscore the pivotal impact of thyroid scan in the multidisciplinary
approach on clinical management of patients with thyroid dysfunction undergoing immunotherapy.
