Low Psoas Muscle/BMI Ratio Is a Bad Prognostic Index Of Non-Relapse Survival After Allogeneic Stem Cell Transplantation

Physical and functional status affect the survival after allogeneic stem cell transplantation. There are several indices to measure risk of complication and non-relapse mortality after stem cell transplantation. Karnofsky score and ECOG score are the mostly used indices for measuring functional status. However they are measured subjectively by observer and can be changed in brief time. Recently a few reports documented relationship between the mortality and sarcopenia in various malignant or non-malignant diseases. Therefore we tried to measure the patient’s functional status by measuring psoas area in abdominal CT scan which was taken before allogeneic stem cell transplantation.

The medical records of total 83 patients from August 2010 to April 2012 were retrospectively reviewed. Every patients took abdominal CT scan 2 weeks to 1 month before transplantation according to the protocol for pre-transplant workup of Severance Hospital (Seoul, Korea). The area of bilateral psoas muscle at the level of upper margin of L4 vertebral body was manually measured by one trained observer using polygon tool of CENTRICITY Radiology RA1000 program (GE Healthcare Integrated IT Solutions, IL, USA).

Male patients were 49 and female patients were 34. Median age was 37.0 years (range 15-60). Underlying diagnosis was AML (n=31), ALL (n=24), SAA (n=7), MDS (n=5), lymphoma (n=7), CML (n=6) and others (n=3). Myeloablative conditioning was applied in 54 patients. Stem cell source was mostly peripheral blood (n=68). 8 patients received HLA-mismatched transplantation. The total non-relapse mortality was 20.4%. 32.5% of patients had higher BMI than 25 kg/m². In whole patients, psoas muscle area didn’t affect non-relapse survival. However, when low psoas area/BMI ratio show significant correlation with non-relapse survival (median 733 days vs. 966 days, P=0.009). In univariate analysis for non-relapse survival, age, pre-transplant disease status, and psoas/BMI ratio showed statistical correlation. And in multivariate analysis psoas/BMI ratio was the sole prognostic index.

Low psoas/BMI ratio is related to increased treatment related mortality in obese patients. This index can be used in part to estimate risk of transplant in obese patients.

No relevant conflicts of interest to declare.