Background and objective: The prognostic value of myeloid antigen expression in adult acute lymphoblastic leukemia (ALL) is controversial. The objective of this study was to evaluate the frequency and prognostic significance of myeloid antigen expression in adults with high risk ALL.
Patients and method: Between June 1993 and July 2002, 222 adults patients with high-risk ALL were treated according to the PETHEMA LAL 93 protocol. The frequency of myeloid antigen expression, its association with other clinical and biologic variables and the prognostic significance in terms of complete remission (CR) rate, event free survival (EFS) and overall survival (OS) were analyzed.
Results: Myeloid antigen expression was present in 96 out of 222 patients (43%). No association was observed between myeloid antigen expression and the main clinical and biologic characteristics of ALL. Response to treatment was slower in patients expressing myeloid antigens, but no differences were found in CR achievement, EFS or OS. The probability of EFS at 10 years for ALL patients without and with myeloid antigen expression was 35% and 34%, respectively, while the probability of OS at 10 years was 30% and 33%, respectively. This absence of differences in EFS and OS probabilities was also observed when only slow responding patients were analyzed.
Conclusions: In this study, myeloid antigen expression did not have prognostic influence in adult patients with high risk ALL.