Assessment Of The Hematopoietic Cell Transplantation Comorbidity Index In Older Patients Receiving Reduced-Intensity Allogeneic Hematopoietic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (HSCT) is an established therapy for malignant and nonmalignant hematologic disorders. Reduced-intensity conditioning (RIC) regimens have expanded the use of HSCT to elderly and higher risk patients. However, HSCT still remains associated with a significant mortality and morbidity and the careful assessment of risks and benefits before transplantation is essential. Major factors which influence non-relapse mortality (NRM) and overall survival (OS) after HSCT are diagnosis, type of transplant, remission status and the patient's risk profile, which includes age and presence of comorbidities. The use of the hematopoietic cell transplantation-specific comorbidity index (HCT-CI) has been proposed to predict the probability of NRM and OS following HSCT. However, the HCT-CI usefulness for older patients receiving a reduced intensity allogeneic HSCT remains unclear.

A retrospective medical record review was performed to collect data from patients who underwent an allogeneic HSCT at a large, urban, NCI Comprehensive Cancer Center during a five year period (January 2005 to December 2010). Patients 55 years and older who were transplanted using RIC for a hematologic malignancy were selected to be analyzed. Comorbidities and test results were collected to determine the HCT-CI score and other clinical data collected included disease and remission status at time of transplant.

85 patients aged >55 years old who received a RIC HSCT for hematologic malignancies between January 2005 to December 2010 were analyzed. The median patient age at the time of transplantation was 63 years (range: 55-75 years). The patient diagnoses included AML (39%), NHL (29%), MM (9%), MDS (11%), CLL (8%), ALL (4%). The median pre-transplantation HSCT-CI score was 2 (range: 0-9). Among 85 patients, OS at 2 years was 44%. The 2 yr OS was 31%, 37% and 44% in the low-, intermediate-, and high-risk HSCT-CI groups (p = 0.61), respectively. The corresponding NRM at 2 years was 25%, 17% and 18% (p = 0.91). We found no predictive value of HSCT-CI for either OS or NRM in older patients having an allogeneic HSCT with reduced-intensity condition. Stratification of age (55-59, 60-64, and 65+) showed no significant impact on 2 yr OS or NRM. However, there was a trend towards a better 2 yr OS for patients who had achieved a CR versus no CR at time of transplant (48% vs 41%).

Older patients with hematologic malignancies represent a highly selected cohort, with the prospect of an allogeneic HSCT often considered too high-risk. A method to reliably stratify these older HSCT candidates is greatly needed. However, the HCT-CI score in this retrospective analysis did not help predict their NRM or 2 year OS for patients 55 years and older with hematologic malignancies receiving a reduced intensity HSCT. Further research is warranted into what combination of factors may provide a reliable predictive score for older patients with hematologic malignancies.

Mehta: Millennium: Speakers Bureau; Celgene: Speakers Bureau.