[Sunitinib and hypothyroidism]

Area of Science:

• Oncology
• Endocrinology
• Pharmacology

Background:

• Sunitinib is a multi-targeted tyrosine kinase inhibitor used for metastatic renal cell carcinoma and imatinib-resistant gastrointestinal stromal tumors.
• Clinical studies indicate a high incidence of hypothyroidism associated with sunitinib treatment, affecting over 50% of patients in some cohorts.
• Unusual cases of non-visualized thyroid tissue on ultrasonography have been reported in patients receiving sunitinib.

Purpose of the Study:

• To investigate the association between sunitinib use and thyroid dysfunction.
• To explore potential mechanisms underlying sunitinib-induced hypothyroidism.
• To highlight the clinical implications of this adverse effect and its potential connection to antitumor activity.

Main Methods:

• Review of prospective and retrospective studies examining sunitinib's side effect profile.
• Analysis of reported cases of thyroid abnormalities, including ultrasonography findings.
• Discussion of proposed pathogenetic mechanisms, including destructive thyroiditis and anti-angiogenic effects.

Main Results:

• Hypothyroidism is a common adverse effect of sunitinib, observed in a significant percentage of patients.
• In rare instances, sunitinib treatment has been associated with the non-visualisation of thyroid tissue on ultrasound.
• Evidence suggests sunitinib may possess anti-thyroperoxidase activity, contributing to hypothyroidism.

Conclusions:

• Regular screening for thyroid abnormalities (every three months) is crucial for patients on sunitinib to manage hypothyroidism and maintain quality of life.
• The unique thyroid-related side effects of sunitinib, including thyroid tissue non-visualisation, may suggest a potential antitumor effect in thyroid cancer.