Incorporation of Immunophenotyping in the Risk Stratification of Patients with Philadelphia Chromosome Negative B Cell Acute Lymphoblastic Leukemia
Yan Chen, Kenneth Craddock, Joesph Brandwein, Hong Chang. University Health Network, Toronto, ON, Canada
Background: In adults with precursor-B lymphoblastic leukemia (BCP-ALL) a number of factors have been identified as being of prognostic value, including age, baseline white blood count (WBC) and cytogenetics, but there remain a majority of patients who fall in an intermediate cytogenetics risk category, with a wide range of outcomes. This group needs improved prognostication.
Design: Immunophenotypic and cytogenetic factors were analyzed retrospectively in 126 consecutive adults with BCR-ABL negative BCP-ALL who were treated with a pediatric-based protocol at a single institution over a ten year period.
Results: In addition to age, WCC and cytogenetic findings, CD13 positivity was an independent poor prognostic indicator for all 3 endpoints: overall survival (OS, p=0.049), event-free survival (EFS, p=0.013), and relapse-free survival (RFS, p<0.001). The prognostic value of CD13 was primarily seen in patients with normal or intermediate risk cytogenetics. A risk model that includes 4 high-risk factors: age > 60 years, WBC > 30x109/ L, SWOG high/very high risk cytogenetics and CD13 positivity, performs better than a risk model of cytogenetics alone for stratifying patients by OS (p=0.001), EFS (p=7x10-4) and RFS (p=8x10-4).
Conclusions: Our findings indicate that CD13 expression is an independent prognostic factor for survival in adults with BCR-ABL negative BCP-ALL. Incorporating this into a scoring system which also includes age, WBC and cytogenetics provides high discrimination for relapse risk and survival.
Wednesday, March 6, 2013 9:30 AM
Poster Session V # 240, Wednesday Morning