Newer Cancer Drugs May Cause Thyroid to Function Abnormally || NCI Cancer Bulletin for October 18, 2011 - National Cancer Institute

Newer Cancer Drugs May Cause Thyroid to Function Abnormally

Over the last decade, many patients with cancer have benefited from the development of new targeted therapies and immunotherapies. But a common side effect of these agents may be unintended effects on the thyroid gland, according to a report published online today in the Journal of the National Cancer Institute.

Ole-Petter R. Hamnvik of Brigham and Women’s Hospital and his colleagues reviewed the scientific literature on thyroid dysfunction and newer anticancer therapies. They found that thyroid dysfunction occurred in an estimated 20 percent to 50 percent of patients who received the newer therapies, which include tyrosine kinase inhibitors and immunotherapies such as ipilimumab.

A common side effect of the newer cancer therapies is hypothyroidism, which causes symptoms such as fatigue and constipation. These conditions are common among cancer patients and may therefore be difficult to distinguish from symptoms caused by the underlying malignancy or by medications used for symptom control. Symptoms of thyroid dysfunction can also be confused with other treatment-related toxic effects, which may lead doctors to reduce treatment dosages or frequency.

Hamnvik and his colleagues recommended that doctors closely monitor patients receiving these treatments for signs of thyroid dysfunction. “This may allow early recognition and treatment of thyroid disease, allowing continued treatment of the underlying cancer, as well as improving the quality of life of the patient,” they wrote.

The report’s authors also recommended that doctors monitor thyroid function in all clinical trials involving new anticancer agents.

More research is needed to understand the mechanisms of the thyroid abnormalities associated with these treatments and to explore the many unanswered questions in the field, the authors added, noting that most of the published data are from small or preliminary studies.

“Treatment for thyroid diseases is safe and likely to enhance patient quality of life, as well as potentially allow effective treatments for the underlying cancer to continue,” the authors concluded.
NCI Cancer Bulletin for October 18, 2011 - National Cancer Institute