Rosh Internal Medicine Boost Practice Exam

In a patient with a history of differentiated papillary thyroid carcinoma, what is the recommended range for serum TSH levels?

1. Less than 0.1 mU/L

2. 0.1-0.5 mU/L

3. 0.1-2.0 mU/L

4. 0.5-5.0 mU/L

The correct answer is: 0.1-2.0 mU/L

In patients with a history of differentiated papillary thyroid carcinoma, the recommended range for serum Thyroid-Stimulating Hormone (TSH) levels is typically set to a lower target, specifically less than 0.1 mU/L, especially for those at higher risk of recurrence. However, the ideal range for many patients in a post-treatment setting is often specified between 0.1 and 2.0 mU/L. This target effectively suppresses TSH because elevated TSH levels can stimulate any residual thyroid cancer cells, thus potentially increasing the risk of recurrence. Maintaining TSH levels within this range is crucial, as it helps balance the need to minimize the risk of cancer recurrence while avoiding overtreatment and the accompanying side effects of excessive thyroid hormone replacement. Additionally, regular monitoring and adjustments of TSH are often necessary based on individual patient response and risk factors, particularly after ablation therapy or thyroidectomy for differentiated thyroid cancers. While lower ranges (like less than 0.1 mU/L) can be recommended in specific high-risk cases, the broader target range of 0.1 to 2.0 mU/L provides a safe margin for long-term management in many patients, which is why this range is commonly