Use of drugs and chronic conditions after thyroid cancer
In Norway, approximately 500 new cases of thyroid cancer are diagnosed annually. About half of those diagnosed are less than 50 years old, and females constitute two thirds of the patients. The incidence of thyroid cancer is on the rise both in Norway and worldwide. Fortunately, the prognosis is quite good, and most patients are cured by surgery alone. Because the surgical treatment often necessitates the complete removal of the thyroid gland, permanent hypothyroidism is a common consequence of thyroid cancer.
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Even though thyroid cancer affects younger individuals, and the prognosis is good, there is little knowledge on how the patients fare after treatment. We therefore conducted a cohort study using Norwegian mandatory nationwide registers1. We evaluated whether adults diagnosed with thyroid cancer between 2005 and 2019 had higher use of prescribed drugs for a set of chronic conditions following thyroid cancer diagnosis, as compared to the cancer-free population. The total study population included 3.52 million individuals, of which 3486 were diagnosed with thyroid cancer and followed for up to 15 years after diagnosis.
More than 80% of the individuals diagnosed with thyroid cancer used thyroid hormone supplements following diagnosis, indicating that most were treated with complete removal of the thyroid gland. Approximately 9% of the male patients and 6% of the female patients used drugs that indicated that their parathyroid glands had been removed or damaged during the treatment. Furthermore, both male and female thyroid cancer patients had increased drug use for high blood pressure, gastroesophageal reflux disease, pain and anxiety, and this increased use could persist throughout the follow-up period. However, we also found an increased use of these drugs prior to the cancer diagnosis. Consequently, one could imagine that it was not the thyroid cancer itself that caused these conditions, but rather that there may be factors that could lead to both thyroid cancer and e.g., high blood pressure. One such factor could be high body-mass index (BMI).
1. Hegvik TA, Zhou Y, Brauckhoff K, Furu K, Hjellvik V, Bjørge T, Engeland A. Prevalence of drugs used for chronic conditions after diagnosis of thyroid cancer: a register-based cohort study. Eur J Endocrinol 2024; 191: 166-174.