Longitudinal analysis of quality of life in patients treated for differentiated thyroid cancer.

Objective: Earlier cross-sectional studies showed that patients with differentiated thyroid cancer (DTC) have a significant reduction of quality of life (QoL) compared to controls. However, recent longitudinal studies showed mixed results and had relative short follow-up or lacked knowledge about QoL before initial surgery. Therefore, we initiated a longitudinal study to assess changes of QoL in patients undergoing treatment for DTC.

Methods: We prospectively included patients, aged 18-80 years, who were treated for DTC at a Dutch university hospital. Using questionnaires, QoL was assessed before surgery, just before radioiodine (RAI) therapy, and regularly during follow-up. Repeated measurement analysis was used to assess changes of QoL over time, and we explored the influence of different characteristics on QoL.

Results: Longitudinal QoL assessments were available in 185 patients (mean age 47 years; 71% women). All patients were treated according to the Dutch guidelines with total thyroidectomy followed by RAI (83% after thyroid hormone withdrawal). Median time between baseline and final questionnaire was 31 months, and patients completed a median of three questionnaires. QoL at baseline was lower than that in the general population, developed non-linear over time, was lowest around RAI therapy, and recovered over time. Females, younger patients, and patients with persistent hypoparathyroidism had lower QoL scores.

Conclusions: In a population of DTC patients, QoL before initial therapy is already lower than that in the general population. Thereafter, QoL develops non-linearly over time in general, with the lowest QoL around RAI therapy, while 2 to 3 years later, it approximates baseline values.