A modified EBMT risk score and the hematopoietic cell transplantation-specific comorbidity index for pre-transplant risk assessment in adult acute lymphoblastic leukemia.

BACKGROUND: Disease stage is the most important prognostic parameter in allogeneic hematopoietic cell transplantation (HCT) for acute lymphoblastic leukemia, but other factors such as donor/host histocompatibility and gender combination, recipient age, performance status and comorbidities need to be considered. Several scoring systems are available to predict outcome in HCT recipients; however, their prognostic relevance in acute lymphoblastic leukemia is not well defined.

DESIGN AND METHODS: In the present study we evaluated a modified EBMT risk score (mEBMT) and the HCT-specific comorbidity index (HCT-CI) in 151 adult acute lymphoblastic leukemia patients who received allogeneic HCT from 1995 until 2007 at our center.

RESULTS: Disease status was first complete remission (CR1) (47%), CR>1 (21%) or no CR (32%). Overall survival (OS) at one, two and five years was 62%, 51% and 40% and non-relapse mortality (NRM) was 21%, 24% and 32%. Median mEBMT was 3 (0-6). Higher mEBMT was associated with inferior OS (hazard ratio per score unit (HR): 1.50, P<0.001), higher NRM (HR: 1.36, P=0.042) and higher relapse mortality (HR: 1.68, P<0.001). Disease stage was the predominant prognostic factor in this score. Comorbidities were present in 71% of patients with mild hepatic disease (29%), moderate pulmonary disease (28%) and infections (23%) being the most common. Median HCT-CI was 1 (0-9). In univariate analysis a trend for inferior OS (HR: 1.08, P=0.20) and higher NRM (HR: 1.14, P=0.11) with increasing HCT-CI was observed but the level of significance was not reached. In additional analyses we found that reduced Karnofsky Performance Status (KPS) was associated with inferior OS (HR: 1.34, P=0.023) and higher relapse mortality (HR: 1.71, P=0.001) when analyzed univariately. However, KPS was associated with disease stage and significance was lost in multivariate analysis.

CONCLUSIONS: The mEBMT was prognostic in our patient cohort with predominant influence of disease stage, whereas a trend but no significant prognostic value was observed for the HCT-CI.