Health-Related Quality of Life In Patients with Chronic Myeloid Leukemia Undergoing First Line Treatment with Imatinib for at Least Three Years Compared with the General Population. A Multicenter Study Including 448 Patients.

Background: While Imatinib (IM) has revolutionized treatment for chronic myeloid leukemia (CML), demonstrating outstanding survival figures, currently no data exist on mid to long term impact of disease burden and therapy from the patients’ perspective. Aim: The main objective of this study is to identify specific limitations of quality of life (QoL) in CML survivors who are undergoing first line treatment with IM in comparison with controls from the general population. Patient-reported symptom prevalence was also investigated. Patients and methods: Patients were recruited in 26 centers, randomly selected to geographically represent the whole study country. Patients selection criteria included: being in treatment with IM for at least three years and being in complete cytogenetic response at the time of study entry. All patients were invited by their treating physicians in the hospital to participate and all consenting patients were requested to complete a Health Survey Packet at home. Pre-paid reply envelopes were also provided with the request to send back completed Surveys to an independent National coordinating Data Center. Generic QoL was assessed with the SF-36 that consists of 36 items covering eight generic health status/QoL domains: physical functioning (PF), role limitations due to physical health (RP), bodily pain (BP), general health perceptions (GH), vitality (VT), social functioning (SF), role limitations due to emotional problems (RE), and mental health (MH). All scales ranging between 0 and 100 with higher scores representing better outcomes. A previously devised patient-reported CML Symptom Checklist was used to investigate 9 symptoms of possible major concern in these patients. Mean SF-36 scores were compared to available national general population reference values and all analyses were adjusted for age and gender. Statistical comparisons were all adjusted for multiple testing. Differences in mean scores were expressed in Cohen effect sizes (ES; with 0.2, 0.5, and 0.8 indicating small, medium, and large ES, respectively) and clinical significance. Results: Between March and December 2009, 448 patients were recruited in a large national-based survivorship project. Patients’ compliance was optimal with 94% of patients (N=421) returning a valid Health Survey Packet to the National coordinating Data center. At study participation, mean age of patients was 56 years (59% male and 41% female) and median time of IM therapy was 5 years. Seventy-seven percent of patients were receiving standard dose of 400 mg and 43% had at least one comorbidity. Age and gender adjusted comparisons with general population norms revealed worse outcomes for the following scales: RP (P<.001; ES=0.3), GH (P<.001; ES=0.4) and RE (P=.01; ES=0.2). The largest clinically meaningful difference (Δ=12.3 points) was found for the RP domain with mean scores of 61.4 vs. 73.7 respectively for the CML and the general population. Age specific comparisons, adjusted by gender, (55-64; 65-74 and >75 years) suggested an almost uniform pattern in all scales with worse outcomes between CML patients and population controls among the youngest groups. GH was significantly worse in younger patients (55-64) (P=.03; ES=0.4) and no differences were found in the older age groups compared with population norms. Prevalence of reported symptoms (with any level of concern) was: fatigue (82%); problems with muscular cramps (78%); problems with musculoskeletal pain (72%); problems with edema (70%); skin problems (47%); diarrhea (43%); headache (39%); abdominal discomfort and nausea (28%). Conclusion: This study suggests that while still being on treatment with IM for years, CML patients might expect to have a QoL profile broadly similar to that of general population in many areas. However, role limitations (i.e., in work or other regular daily activities) due to physical health seem the major constraint faced by these patients; there is also an indication that younger patients might be those experiencing major limitations. Additional analyses will be undertaken to ascertain the impact of symptoms and other laboratory and clinical data on specific QoL domains. Such unique patient-reported data supplements conventional information on clinical efficacy of IM and may support both clinicians and patients in making more informed treatment decisions in this area.