A registry-based analysis of survival outcomes in mast cell leukemia

Mast cell leukemia (MCL) is rare and carries a poor prognosis. No standard-of-care has been established. No USA registry-based analyses have examined clinical correlates of overall survival (OS) in MCL patients, thus we aimed to do this using the Surveillance, Epidemiology, and End Results (SEER) database, and the National Cancer Database (NCDB).

We included 25 patients from SEER, and 50 patients from NCDB diagnosed with MCL through 2015. Kaplan-Meier and multivariable regression analyses were used to assess the impact of clinical characteristics on OS in each dataset, and on a pooled cohort of both datasets.

Median age at diagnosis for the pooled cohort was 63 years, and median OS was 9.4 months. The proportion of patients surviving 12, 36, and 60 months was 42.9%, 23.2%, and 16.6%, respectively. Males (n = 44, 58.7%) outnumbered females (n = 31, 41.3%). Caucasians formed a majority (n = 66, 88%). With Cox regression accounting for database of origin, age at and year of diagnosis, sex, race, sequence number, and receipt of chemotherapy, no variable was significantly associated with OS. However, in the same analysis, when stratified by sex, receipt of chemotherapy was associated with improved OS in males (HR = 0.41, 95% CI 0.14-0.89, p < 0.03), and poorer OS in females (HR = 3.64, 95% CI 1.07-12.44, p = 0.04).

Our study reaffirms that MCL carries a poor prognosis. Chemotherapy may improve survival in subsets of patients, though generalizability is limited by biases inherent in registry-based datasets. Due to poor outcomes for MCL patients, more study is needed to determine optimal care.