Although the incidence of thyroid cancer has increased, the mortality rate of it has remained stable (Pellegriti, Frasca, Regalbuto, Squatrito, & Vigneri, 2013). As the result of the great progress in diagnostic and therapeutic methods, the number of survived patients from thyroid cancer has increased (van Nagell et al., 2013); so, with the rise of its incidence and decreasing in mortality, we now see the increase in the population of thyroid cancer survival. Differentiated thyroid cancer has a very good prognosis, specially when it is diagnosed and treated soon. The average rate of survival up to 5-years is up to 98% and it is really close to the healthy population (SEER
[1], 2018). Patients with thyroid cancer have a good prognosis. Thus, physicians assume that their quality of life is similar to healthy population. However, quality of life is not directly dependent to the severity of prognosis of cancer (Singer et al., 2012).
The rapid increase in thyroid cancer’s incidence has made some worries and attention to health-related quality of life in thyroid cancer survivors (Lee et al., 2010). The importance of evaluation of health-related quality of life in the survivors is being known rapidly (Goldfarb & Casillas, 2016)and it is shown in new guidelines of the American Thyroid Association (Haugen et al., 2016). The therapeutic strategies should include evaluation of quality of life and also evaluation of long-term side effects of the treatments; so that we can choose the best treatment for this growing population of patients (Vega-Vázquez et al., 2015).
In sensitive periods of the course of DTC and its treatment, some research has shown that the quality of life had decreased: Time to diagnose cancer and inform the individual about having thyroid cancer (Bãrbuş, Peştean, Larg, & Piciu, 2017; Stanton, Rowland, & Ganz, 2015); surgery time and removing all or part of the thyroid gland (Thyroidectomy); timing and hospitalization; and temporary withdrawal of thyroid hormones (Chow et al., 2006; Dow, Ferrell, & Anello, 1997; Luster, Felbinger, Dietlein, & Reiners, 2005; Schroeder et al., 2006).
The aim of this study is to see whether the temporary withdrawal of levothyroxine affects the health-related quality of life in patients with DTC or not. In detail, we want to figure out which domains of HRQOL were affected more and why. Through considering the quality of life before and after the withdrawal of levothyroxine, we hope better therapeutic decisions and with our patients to improve their quality of life.