Researchers have developed a novel risk stratification system to help interpret and analyze studies of heterogeneous cohorts of patients undergoing allogeneic hematopoietic stem-cell transplantation (HSCT), according to a study published in The Lancet Haematology.

The system, called the disease-risk stratification system (DRSS) model, incorporates features related to histology, genetic profile, and treatment response. Researchers developed it and tested it using data from 47,265 adult patients (18 years or older) who received allogeneic HSCT from January 2012 to December 2016 for diseases including acute leukemia, lymphoma, multiple myeloma, and myeloproliferative and myelodysplastic disorders. Patients were divided into derivation, tuning, and geographic validation cohorts.

In the derivation cohort, patients were stratified into 5 risk groups with increasing mortality risk: low risk (reference), intermediate-1 (hazard ratio [HR] for overall survival=1.26), intermediate-2 (HR=1.53), high (HR=2.03), and very high (HR=2.87). In addition, DRSS levels were associated with a stepwise increase in risk across the tuning and validation cohorts, the researchers reported.

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An independent cohort of 660 patients in the United States was used to externally validate the findings. In this group, the DRSS model separated patients into 4 risk groups associated with increasing risk of mortality: intermediate-2 (HR=1.34), high (HR=2.03), and very high (HR=2.26) compared with low and intermediate-1 groups.

According to the researchers, “The new system reclassifies patients previously considered to have intermediate-risk disease by the [Disease Risk Index (DRI)] into finer, potentially actionable, prognostic categories.”

Using DRI, 64% to 65% of patients would have been categorized as intermediate risk. Using DRSS, these patients were reclassified as low risk (6%), intermediate-1 (51%), intermediate-2 (41%), and high or very high (3%).

Projected 2-year overall survival was also more refined using these adjusted risk categories, the researchers noted.

“Our system reflects an up-to-date approach for risk stratification in patients with haematological malignancies undergoing allogeneic haemopoietic stem cell transplantation…. The system should also serve the medical community as a benchmark for transplantation outcomes in the coming years,” the researchers concluded.

Disclosures: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ affiliations.


Shouval R, Fein JA, Labopin M, et al. Development and validation of a disease risk stratification system for patients with haematological malignancies: a retrospective cohort study of the European Society for Blood and Marrow Transplantation registry. Lancet Haematol. Published online March 8, 2021. doi:10.1016/S2352-3026(20)30394-X