People living after thyroid cancer who are stable on hormone replacement therapy can experience severe and unpredictable fatigue and poor exercise tolerance. Exercise reduces fatigue and other side-effects and improves quality of life in other cancer populations, but these benefits have scarcely been explored in rare cancers, such as thyroid cancer. At the same time, responses to exercise in this population may differ due to disease- and treatment- related physiological changes. These mechanisms are still poorly understood.

The objective of the T-REX study is to understand how thyroid hormone levels, inflammatory markers and lactate respond to different types of exercise. Furthermore, we will evaluate the outcomes of a 12-week personalized but self-directed exercise program on several patient-relevant outcomes, including self-reported fatigue, health-related quality of life (HRQOL) and perceived exercise tolerance. Overall, the explorative T-REX study will provide preliminary insights that may guide the development of future exercise interventions aiming at reducing fatigue and improving quality of life of people living after thyroid cancer.