Potential to Improve Therapy of Chronic Myeloid Leukemia (CML), Especially for Patients with Older Age: Incidence, Mortality, and Survival Rates of Patients with CML in Switzerland from 1995 to 2017

Simple Summary In a population-based study of chronic myeloid leukemia (CML) patients in Switzerland, we confirmed an increase in relative survival for all age groups over the last decades. This was primarily based on the stable age-adjusted rate of incidence and a substantial decrease of the age-adjusted mortality rate. Investigating data from four different study periods, before and after introduction of tyrosine kinase inhibitors and their more potent second- and third-generation compounds, we found higher increases in relative survival for older patients at later time periods compared to younger CML patients. However, for the last study period (2013–2017), the five-year relative survival (RS) in the elderly population reached only 53% compared to 89% in younger patients, implicating additional potential to improve CML therapy, especially in the elderly population. Abstract Background: Tyrosine kinase inhibitors (TKI) substantially improved chronic myeloid leukemia (CML) prognosis. We aimed to describe time period- and age-dependent outcomes by reporting real-world data of CML patients from Switzerland. Methods: Population-based incidence, mortality, and survival were assessed for four different study periods and age groups on the basis of aggregated data from Swiss Cantonal Cancer Registries. Results: A total of 1552 new CML cases were reported from 1995 to 2017. The age-standardized rate (ASR) for the incidence remained stable, while the ASR for mortality decreased by 50–80%, resulting in a five-year RS from 36% to 74% over all four age groups. Importantly, for patients <60 years (yrs), the five-year RS increased only in earlier time periods up to 92%, whereas for older patients (+80 yrs), the five-year RS continued to increase later, however, reaching only 53% until 2017. Conclusions: This is the first population-based study of CML patients in Switzerland confirming similar data compared to other population-based registries in Europe. The RS increased significantly in all age groups over the last decades after the establishment of TKI therapy. Interestingly, we found a more prominent increase in RS of patients with older age at later observation periods (45%) compared to patients at younger age (10%), implicating a greater benefit from TKI treatment for elderly occurring with delay since the establishment of TKI therapy. Our findings suggest more potential to improve CML therapy, especially for older patients.