ABSTRACT
Background
The impact of disease and treatment on patients’ overall well-being and functioning is a topic of growing interest in clinical research and practice. Multiple myeloma (MM) is the second most prevalent haematologic malignancy, representing 1% of all cancers, with an increasing incidence due to longer life expectancy and increasing prevalence due to improved treatments. Significant progress has been achieved in the treatment of multiple myeloma in recent decades. However, the treatment is accompanied by numerous symptoms and a decrease in health-related quality of life (HrQoL).
Aim
The aim of our study was to obtain reference data on the quality of life in Croatia in a representative sample of the general population older than 40 years, to measure the HrQoL scores in the cohort of newly diagnosed multiple myeloma patients in Croatia and to assess the impact of disease and its systemic treatment on the patients’ HrQoL.
Hypotheses
1. Age, gender and place of residence have significant impact on the HrQoL in Croatian general population older than 40 years.
2. The MM patients at diagnosis have lower QLQ-C30 scores on global quality of life, all functional and symptoms scales as well as all single items (excluding financial difficulties) compared to the general population older than 40 years even if the sample is adjusted to age, gender and place of residence.
3. The mean scores for the subscales symptoms, side effects and body image of QLQ-MY20 are significantly reduced three months after the stem cell transplantation (ASCT) in MM patients.
Methods
For the first part of the study, respondents were randomly selected individuals in the Croatian population, 310 of them, older than 40 years. In the clinical part of the study, MM patients, 51 of them, were included as prospectively diagnosed within two years in two major Croatian haematological centres. The EORTC QLQ-C30 in both trials and EORTC QLQ-MY20 in MM patients were applied for HrQoL assessment. The statistical difference between groups was determined using the Kruskal-Wallis test, Mann-Whitney U test and Wilcoxon signed rank test.
Results
In the general population there is a statistically significant difference in age for many dimensions of the EORTC QLQ-C30. The scores for general quality of life are highest for respondents aged 50-59 and lowest for respondents aged 70 and older. Furthermore, scores for physical functioning, emotional functioning and social functioning are lower for respondents aged 70 and older. The largest number of respondents in Croatian population was in the age group 50-59, and the smallest in the age group 70 and more. Men reported better quality of life, as well as physical and emotional functioning and better functioning for all items on the symptom scale. In our population sample, there is half as many men as women.
There is a statistically significant difference for global HrQoL, physical, role and social functioning, fatigue, pain, appetite loss and financial difficulties when comparing the general population and MM patients. However, we could not adjust the general population to the MM population by age, gender and place of residence due to the inadequately adjusted sample in the general population. The values for global HrQoL, physical functioning, role functioning and social functioning are higher for the general population while values for fatigue, pain, appetite loss and financial difficulties are higher in MM patients.
Among MM patients, there is a statistically significant difference in physical functioning, cognitive functioning, social functioning, fatigue, pain, insomnia and financial difficulties in the measurements before and after conventional therapy, and results were worse in measurements after conventional therapy. Furthermore, there is a statistically significant difference for global HrQoL role functioning, social functioning, nausea and vomiting, diarrhoea and financial difficulties when measured after ASCT.
When analysing QLQ-MY20 questionnaire, there is a statistically significant difference for body image and disease symptoms in measurements before and after conventional therapy. In post-testing, the results were worse. There is a statistically significant difference for future perspective in measurements before and after ASCT.
For MM patients on conventional therapy, the results showed that in comparison to the general population and transplant patients, their functional scale was worse in the initial testing and further deteriorated in post-testing. For transplant patients, the results were worse in comparison to the general population but better when compared to patients on conventional therapy. In post-testing, the results improved. ASCT is the most effective treatment modality for MM patients, while conventional therapy is frequently in delivered lower dosages in elderly patients who, in addition to the symptoms of the disease, have also age-related symptoms related to a specific organic system. Patients who were treated only with conventional therapy were older patients with a worse prognosis. Withdrawal of symptoms depends on the patient's response to therapy and varies from patient to patient. Therefore, the therapy may change during treatment.
Overall, the disease followed by the choice of therapeutical approach may influence HrQoL determinants.
Conclusion
The normal values will help to interpret HrQoL for clinicians and will aid in planning cancer care interventions. Elderly patients on conventional therapy have lower overall quality of life outcomes along with present symptoms and the condition progresses over time, while younger patients on ASCT have better outcomes and withdrawal symptoms after treatment for a period of time. However, it should be noted that there was a small number of MM respondents in our study.
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