HCT outcomes: a new tool?

Comment on Sorror et al, page 2912

Chronic disease comorbidities of patients undergoing hematopoietic cell allotransplantation are important prognostic determinants of survival and overall outcome.

The diversity of hematopoietic cell transplantation (HCT) options has never been greater, allowing a larger spectrum of patients to be treated while at the same time challenging transplantation physicians to more accurately assess the quality of HCT outcomes. As older patients with a variety of coexisting medical conditions (“comorbidities”) undergo nonmyeloablative HCT, it is important to assess the impact of these comorbidities on survival and cure. The Charlson Comorbidity Index (CCI) was developed to estimate mortality risk for patients with multiple chronic medical conditions¹  and is widely used in patients with solid tumors and other potentially fatal diseases. Sorror and colleagues tested the CCI in patients with hematologic malignancies undergoing allogeneic HCT.^2,3  They found that only 12% of Seattle patients had elevated scores prior to HCT, so the CCI lacked the discrimination necessary to separate groups with varying risk. In this issue of Blood, the same group describes the development and testing of an HCT-specific comorbidity index with higher discriminative capacity. The correlation of index scores with survival following transplantation was markedly superior to the CCI. Pretransplantation score assignment should be simple to accomplish using the new system, and be highly objective.FIG1 

This new comorbidity scoring system raises new questions and provides new opportunities. Is the index reproducible in multiple centers? Is it applicable to autotransplantations? Can the index be used to better direct patients to either myeloablative or nonmyeloablative allotransplant strategies? Can the index be added to other established prognostic variables to better predict patient outcome? As expectations from insurers, government agencies, and patients that transplantation outcomes become more quantifiable and predictable increase, this new index could add an important tool to assist in this effort. Finally, this index might allow refinement of our estimates of the outcomes of newly reported research treatments. Reporting comorbidity data of the type used in this index will likely become as important as defining cancer diagnosis, disease stage, remission status, and other, more familiar prognostic variables. ▪