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Determining When HSCT Is Indicated: Comparison of HSCT and Chemotherapy Outcomes
Source: Pediatric Hematopoietic Stem Cell Transplant and Cellular Therapy for Cancer (PDQ®)–Health Professional Version, National Cancer Institute.
Source updated: June 13, 2024 · Captured 2026-09-09.
Selected source text with whitespace normalised. This Triangle page is not an NCI PDQ summary. Independent clinical review is pending.
Context: General Information About Hematopoietic Stem Cell Transplant (HSCT)
Because the outcomes using chemotherapy and HSCT treatments have been changing over time, these approaches should be compared regularly to continually redefine optimal therapy for a given patient. For some diseases, randomized trials or intent-to-treat trials using an HLA-matched sibling donor have established the benefit of HSCT by direct comparison.[1,2] However, for very high-risk patients, such as those with early relapse of acute lymphoblastic leukemia, randomized trials have not been feasible because of investigator bias.[3,4]
In general, HSCT typically benefits only children at high risk of relapse with standard chemotherapy approaches. Accordingly, treatment schemas that accurately identify these high-risk patients and offer HSCT if appropriate allogeneic donors are available are the preferred approach for many diseases.[5] Less well-established, higher-risk approaches to HSCT, such as haploidentical transplant, are sometimes reserved for only the very highest-risk patients. However, these higher-risk approaches are becoming safer and more efficacious and are increasingly used interchangeably with fully matched allogeneic approaches.[6-9] For more information, see the Haploidentical HSCT section in Pediatric Allogeneic Hematopoietic Stem Cell Transplant.
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When comparisons of similar patients treated with HSCT or chemotherapy are made in the setting where randomized or intent-to-treat studies are not feasible, the following issues should be considered:
Remission/disease status: Comparisons of HSCT and chemotherapy should include only patients who obtain remission, preferably after similar approaches to salvage therapy, because patients who fail to obtain remission have poor outcomes with any therapy.[10] To account for time-to-transplant bias, the chemotherapy comparator arm should include only patients who maintained remission until the median time to HSCT. The HSCT comparator arm should also include only patients who achieved the initial remission mentioned above and maintained that remission until the time of HSCT.[10]High-risk and intermediate-risk patient groups should not be combined because benefit or lack of benefit of HSCT in the high-risk group can be masked by different levels of benefit in the intermediate-risk group.[10]
Therapy approaches used for comparison: Comparisons should be made with the best or most used chemotherapy/immunotherapy or HSCT approaches used during the time frame under study.
HSCT approach: HSCT approaches that are very high risk or have documented lower rates of survival should not be combined for analysis with standard-risk HSCT approaches.
Criteria for relapse: Risk factors for relapse should be carefully defined, and analysis should be based on the most current knowledge of risk.
Selection bias: Attempts should be made to understand and eliminate or correct for selection bias. Examples include the following:
Selection bias: Attempts should be made to understand and eliminate or correct for selection bias. Examples include the following:
Higher-risk patients preferentially undergoing HSCT (i.e., patients who take several rounds to achieve remission or have disease relapse after obtaining remission and go back into a subsequent remission before HSCT).
Selection bias: Attempts should be made to understand and eliminate or correct for selection bias. Examples include the following:
Sicker patients deferred from HSCT because of comorbidities.
Selection bias: Attempts should be made to understand and eliminate or correct for selection bias. Examples include the following:
Related to the time-to-transplant bias noted above, patients who undergo HSCT after relapse or recurrence are a subset of all patients with a disease recurrence and will be selected from those who are able to obtain a remission and remain healthy enough to undergo HSCT.
Selection bias: Attempts should be made to understand and eliminate or correct for selection bias. Examples include the following:
Patient or parent refusal.
Selection bias: Attempts should be made to understand and eliminate or correct for selection bias. Examples include the following:
Lack of or inability to obtain insurance approval for HSCT.
Selection bias: Attempts should be made to understand and eliminate or correct for selection bias. Examples include the following:
Lack of access to HSCT because of distance or inability to travel.
Physician bias, for or against HSCT, is difficult to control for or detect. The effects of access to HSCT and therapeutic bias on outcomes of pediatric malignancies for which HSCT may be indicated have been poorly studied.
For more information about pediatric HSCT, see the following summaries:
Pediatric Autologous Hematopoietic Stem Cell Transplant.
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Pediatric Allogeneic Hematopoietic Stem Cell Transplant.
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Pediatric Chimeric Antigen Receptor (CAR) T-Cell Therapy.
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Complications, Graft-Versus-Host Disease, and Late Effects after Pediatric Hematopoietic Stem Cell Transplant.
Publication references
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Preserved source evidence · Independent clinical review pending · Not medical advice