Prospective Analysis: Relative Survival in Patients with Chronic Myeloid Leukemia in Chronic Phase in the Era of Tyrosine Kinase Inhibitors

Summary

Background

Tyrosine kinase inhibitors (TKIs) improved overall survival (OS) in patients with chronic myeloid leukemia in chronic phase (CML-CP). The purpose of this study was to compare OS in patients with newly diagnosed CML-CP to that of general population.

Methods

Response and survival data in six consecutive or parallel prospective clinical TKI trials were analyzed. Estimated OS rates in the general population matched by age, gender, ethnicity, and year at diagnosis were obtained from national vital statistics reports. Survival was also assessed by response and type of TKI.

Findings

Of the 483 patients, 271 patients received imatinib, 105 nilotinib and 107 dasatinib. The age grouping was as follows: 15–44 years, 197 patients; 45–64 years, 222; 65–84 years, 64. Five-year OS in CML-CP decreased with increasing age: 15–44 years, 96% (95% confidence interval[CI], 93·2–99·2); 45–64 years, 94% (95%CI, 89·9–97·1); and 65–84 years, 80% (95%CI, 69·5–90·7). Five-year relative OS was only slightly lower compared to the matched general population: 15–44 years, 97% (95%CI, 94·0–100·0); 45–64 years, 97% (95%CI, 92·9–100·3); and 65–84 years, 92% (95%CI, 79·5–103·8). Five-year relative OS in all ages with complete cytogenetic response (CCyR) or better was similar to that in the general population.

Interpretation

With TKI, the expected survival of patients diagnosed with CML-CP is only slightly lower to that of the general population, and for those patients who achieved CCyR or better it is similar to that of general population. Due to the relatively smaller number of patients followed for 10 years and the small number of older patients, the 10-year relative OS has a wider confidence interval and might vary with longer follow-up. However, 10-year relative OS derived from the imatinib cohort is favorable, and, considering the overall better results with dasatinib and nilotinib, it is reasonable to expect that the results will remain at least as favorable with additional follow-up observation with dasatinib or nilotinib. Thus with access to TKI, it is possible that most patients with CML can enjoy a near normal life expectancy.