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

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.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.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.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.