Changes in quality of life after thyroidectomy in subjects with thyroid cancer in relation to the dose of levothyroxine.

Purpose: Previous studies demonstrated decreased quality of life (QoL) in differentiated thyroid cancer (DTC) survivors and suggested QoL variability related to time from thyroidectomy and levothyroxine dosage. The aims of this study were to evaluate QoL in thyroidectomized subjects in different levothyroxine states and to evaluate the association between TSH and thyroid hormones and QoL.

Methods: Prospective 5-year study enrolling 208 patients thyroidectomized for DTC, studied in one to four times according to levothyroxine dosage: withdrawal (WITHD), complete (C-SUPP) and mild TSH-suppression (M-SUPP), replacement (REPL). Each patient was allowed to participate into the study more than one time. A total of 300 evaluations were collected, consisting of detailed thyroid hormone profile and QoL assessment through the ThyPRO questionnaire.

Results: Comparing the four groups, significant differences were found for anxiety, impaired social and daily life and item 12 (overall impact of thyroid disease) domains (p < 0.05). Interestingly, C-SUPP subjects reported the best scores in almost all ThyPRO scales. Significant correlations were found between QoL and pituitary-thyroid axis function, as well as between QoL and gender, being females more affected. At multiple regression analyses fT3 demonstrated to be the best explanatory factor for overall impact of thyroid disease on the patient's life, followed by gender.

Conclusions: TSH-suppressive doses of levothyroxine are more effective in improving QoL in DTC patients after thyroidectomy. These results confirm the urgent need of further studies aimed to define the best treatment of hypothyroidism, effective on well-being and harmless for patients.