Chronic Myeloid Leukemia Survival in Older Population in Pre- and Post- Imatinib Era in the United States

Median age at diagnosis for CML is 64 years of age. CML survival in elderly population is not well studied. This study was conducted to evaluate the relative survival rates among CML patients older than 50 years in pre- (1991–2000) and post- (2001– 2009) imatinib era.

We analyzed the Surveillance, Epidemiology, and End Results (SEER*Stat) 18 registry database to compare 3-year and 5-year relative survival rates among CML patients by gender and age groups (50–69, ≥70) from the pre- (1991–2000) to post- imatinib eras (2001–2009). We used Z-test in the SEER*Stat program to calculate the differences in relative survival rates among different cohorts.

The 3-year and 5-year relative survival rates for CML patients age ≥50 years in pre- (n=3,848) vs post- (n=6,501) imatinib era were: 44.1±0.9% vs 55.9±0.8%, p=<0.0001, Z-value=10.179 at 3-years and 31.4±0.9% vs 46.9±0.9%, p=<0.0001, Z-value=12.361 at 5-years. The 3-year and 5-year relative survival rates for old (50–69) patients in pre- (n=1,723) vs post- (n=3011) imatinib era were: 57.7 ± 1.2% vs 72.3 ±1.0%, p=<0.0001, Z-value=9.454 at 3 years and 44.8±1.3% vs 64.3±1.2%, P=<0.0001, Z-value= 11.365 at 5 years. The survival rates for elderly (≥70) patients in pre (n= 2,125) and post (n=3,490) imatinib era were: 32.4±1.2% and 41.3±1.1%, p=<0.0001, Z-value=5.806 at 3 years and 19.3±1.1% and 31.2±1.2%, P=<0.0001, Z-value=7.135 at 5 years respectively. Table 1 shows CML survival rates by age and sex in patients older than 50 years of age.

This study showed significant increase in 3 year and 5 year relative survival rates in post- imatinib era among CML patients older than 50 in all cohorts examined. However, the improvement in survival rates is modest compared to published data from randomized clinical trials.

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No relevant conflicts of interest to declare.