Quality of life in patients with thyroid cancer

Abstract

Background: The prevalence of differentiated thyroid cancer (DTC) is increasing as a consequence of rising incidence, young age at diagnosis and excellent survival. The established treatment is surgery, followed by radioiodine as well as levothyroxine substitution. Because of the longevity of DTC patients, health-related quality of life (HRQoL) has become important. Previous studies have shown decreased HRQoL in DTC, nevertheless, changes of HRQoL over time and factors affecting HRQoL are scarcely described. The aims of this thesis were to investigate long-term HRQoL, how HRQoL changes over time and how anxiety and fear of recurrence affect patients with thyroid cancer.

Patients, methods and results: In Studies I-III, SF-36 and a study-specific questionnaire were used. In Studies I-II, long-term HRQoL was measured by including patients 14-17 years after diagnosis. HRQoL was shown to be lower in DTC patients compared with the Swedish general population. Half of the patients had fear of recurrence, and those with fear had significantly lower HRQoL. Thyroid-related symptoms, such as fatigue, sleeping problems, irritability and sweating were measured, and the majority (88%) had at least one of these symptoms. Those with major or moderate symptom intensity had significantly lower HRQoL in eight and four SF-36 domains, respectively. These differences remained after adjustment for age, sex, comorbidities and education.

In study III, DTC patients were included at diagnosis and followed-up. After one year, HRQoL was higher compared with baseline in six of eight SF-36 domains. As the majority of the patients were treated with levothyroxine in TSH suppressive doses, this might have affected HRQoL. Surprisingly, those on moderate TSH suppression had lower HRQoL compared with those on complete suppression. In addition, more than half of the patients had a fear of recurrence, with significantly lower HRQoL. Predictive factors of HRQoL at follow-up were studied and in bivariate models, e.g. comorbidities and HRQoL at diagnosis were associated with lower HRQoL at one year. In regression models, poor HRQoL at diagnosis was the only predictive factor for poor HRQoL at one-year of follow-up, after adjustment for comorbidities, age, sex, stage of disease and fear of recurrence.

To broaden the understanding about anxiety and fear of recurrence, semi-structured interviews were performed with 21 patients in Study IV. Anxiety was present both in patients with and without recurrence and regardless of sociodemographic factors. Fear of recurrence, follow-up routines, distrust in the healthcare system and lack of information were all sources of anxiety. In some patients, hidden anxiety not mentioned in the beginning became apparent later during the interviews. Everyday life and routines were used as protective strategies against frightening thoughts. Avoiding contact with healthcare helped them gather energy to cope with their disease.

Discussion: HRQoL was decreased in DTC patients compared with a general population and was negatively associated with thyroid-related symptoms and fear of recurrence. Interestingly, TSH suppression was not associated to lower HRQoL. The patients’ perception of having a “good cancer” might have discouraged them from discussing anxiety with healthcare. As HRQoL at diagnosis was the only independent predictive factor of HRQoL at one year of follow-up, the evaluation of HRQoL early in the disease trajectory is important. Individualised follow-up routines and evaluation of fears and anxiety during consultations might be helpful, and instead of using the term “good cancer”, “low-risk cancer” can be recommended.