Reduced Intensity Conditioning Followed by Allogeneic Hematopoietic Stem Cell Transplantation Is a Good Choice for Acute Myeloid Leukemia and Myelodysplastic Syndrome: A Meta-Analysis of Randomized Controlled Trials

Is oligometastatic disease an applicable and useful concept in haematologic malignancies? A narrative review of radiation therapy standards, modern techniques, and innovations

PURPOSE

Haematologic malignancies are particular in that they can generally be cured, even when distant metastases are present at diagnosis, unlike solid malignancies. Systemic treatments, including chemotherapy, targeted therapies, and immunotherapy, are the standard of care with excellent results. The considerable progress made in the management of these diseases in the last 20years has redefined the role of radiation therapy as minor in many clinical situations. We propose a literature review of data, showing that radiation therapy still has a role in curative, salvage, and palliative therapy situations.

MATERIAL AND METHODS

A document and literature search was carried out in the following databases: Medline and ClinicalTrial.gov, for the terms "radiotherapy", "haematologic malignancies", "Hodgkin lymphoma", "non-Hodgkin lymphoma", "CAR T cells", "multiple myeloma", "solitary plasmocytoma", "intensity-modulated radiotherapy", "extracranial stereotactic body radiation therapy" and "proton therapy references".

RESULTS

Haemopathological malignancies include a wide range of diseases and radiation therapy indications have been assessed over the past 20years. Currently, radiation therapy is indicated for localized disease (solitary plasmocytoma), as an adjuvant (Hodgkin lymphoma), in palliative settings, or after systemic treatment in relapsed patients (chimeric antigen receptor [CAR] T-cells) with a low recurrence burden, which can therefore be considered "oligorecurrence". Radiation therapy, through total body irradiation, has important indications, thanks to its immunomodulatory and/or myeloablative effects. Moreover, recent technological developments have made possible significant improvement in safety, contributing to radiation therapy being positioned in the treatment strategy of several indications.

CONCLUSIONS

Given the effectiveness of systemic treatments in hematologic malignancies, the oligometastasis stage is of little importance. A curative intent after local radiation therapy, even advanced stage, is possible, both with residual disease for advanced Hodgkin lymphoma, aggressive non-Hodgkin lymphoma, or solitary plasmocytoma, and even without evidence of disease after chemotherapy for Hodgkin or non-Hodgkin lymphoma. The role of new treatments, such as CAR T cells, allows us to consider radiation therapy after systemic treatment of relapsed diseases with low volume recurrence, which can be considered oligorecurrence.

The Simplified Comorbidity Index predicts non-relapse mortality in reduced-intensity conditioning allogeneic haematopoietic cell transplantation

Comorbidity assessment before allogeneic haematopoietic cell transplantation (allo-HCT) is essential for estimating non-relapse mortality (NRM) risk. We previously developed the Simplified Comorbidity Index (SCI), which captures a small number of 'high-yield' comorbidities and older age. The SCI was predictive of NRM in myeloablative CD34-selected allo-HCT. Here, we evaluated the SCI in a single-centre cohort of 327 patients receiving reduced-intensity conditioning followed by unmanipulated allografts from HLA-matched donors. Among the SCI factors, age above 60, mild renal impairment, moderate pulmonary disease and cardiac disease were most frequent. SCI scores ranged from 0 to 8, with 39%, 20%, 20% and 21% having scores of 0-1, 2, 3 and ≥4 respectively. Corresponding cumulative incidences of 3-year NRM were 11%, 16%, 22% and 27%; p = 0.03. In multivariable models, higher SCI scores were associated with incremental risks of all-cause mortality and NRM. The SCI had an area under the receiver operating characteristic curve of 65.9%, 64.1% and 62.9% for predicting 1-, 2- and 3-year NRM versus 58.4%, 60.4% and 59.3% with the haematopoietic cell transplantation comorbidity index. These results demonstrate for the first time that the SCI is predictive of NRM in patients receiving allo-HCT from HLA-matched donors after reduced-intensity conditioning.

Real-world outcomes and prognostic factors among patients with acute myeloid leukemia treated with allogeneic hematopoietic stem cell transplantation

Acute myeloid leukemia (AML) is a malignant lymphohematopoietic tumor that ranks among the most frequent indications for allogeneic hematopoietic stem cell transplantation (allo-HSCT). This article aims to provide a comprehensive analysis of the application of allo-HSCT for AML and identify prognostic factors to enhance future treatment effect. This retrospective study collected data from 323 patients diagnosed with AML at Peking University First Hospital who underwent allo-HSCT between September 2003 and July 2022. The annual number of transplantations has steadily increased. Our center has observed a rise in the proportion of cytogenetic high-risk and measurable residual disease (MRD) positive patients since 2013, as well as an increase in the number of haploidentical transplantations. The overall leukocyte engraftment time has decreased over the past 20 years. Furthermore, both overall survival (OS) and disease-free survival (DFS) have significantly improved, while non-relapse mortality (NRM) has significantly decreased since 2013. Multivariate analysis identified transplantation before 2013, patients in complete remission (CR) 2 or non-CR, and recipients older than 50 years as risk factors for NRM, while patients in non-CR and patients with positive MRD are risk factors for recurrence. These findings offer insights into AML treatment outcomes in China, highlighting changes in transplantation practices and the need to reduce post-transplant relapse. Effective interventions, such as MRD monitoring and risk stratification schemes, are crucial for further enhancing transplant outcomes.

Lower intensity regimens for acute myeloid leukemia: opportunities and challenges

Acute myeloid leukemia (AML) is an aggressive hematological malignancy for whom most patients a hematopoietic stem cell transplant (HSCT) is the only curative treatment modality. Intensive chemotherapy has been the first-line treatment for AML for many years but has significant morbidity and mortality in elderly patients and those with comorbidities, who constitute the majority of patients with this disease. Since 2017, multiple new lower intensity therapies have been approved for the treatment of AML. Their advantages include decreased hematological and non-hematological side effects, lower rates of infections and the ability to be given in an outpatient setting. For HSCT, reduced intensity conditioning (RIC) regimens have improved for older and comorbid patients, allowing potent graft vs. tumor effects with lower toxicity profiles, resulting in the expansion of this therapy to more patients. More studies are required to improve and refine lower intensity regimens as well as RIC, as they are increasingly utilized in AML treatment.

Post-transplant cyclophosphamide for GVHD prophylaxis in pediatrics with chronic active Epstein-Barr virus infection after haplo-HSCT

BACKGROUND

Chronic active Epstein-Barr virus infection (CAEBV) is a rare but life-threatening progressive disease. Human leukocyte antigen (HLA)-haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is the best choice as sometimes HLA-matched donor is not accessible. However, graft-versus-host-disease (GVHD) following transplantation remains a major cause of treatment failure and elevated mortality. Post-transplant cyclophosphamide (PTCy) has recently emerged for effective GVHD prophylaxis in a haploidentical setting in many hematologic malignancies. Here, we report the performance of PTCy for GVHD prophylaxis in a series of CEABV patients treated with haplo-HSCT.

METHODS

Consecutive pediatric CAEBV patients who were treated with haplo-HSCT and give PTCy for GVHD prophylaxis were analyzed. 1-year GVHD and relapse-free survival (GRFS), overall survival (OS) and cumulative incidence of moderate-to-severe chronic GVHD (cGVHD) were estimated.

RESULTS

A total of 8 patients ranging from 2 to 15 years old were included. Among them, 4 patients had early complications after haplo-HSCT. Counts of T-cell subsets increased within 6 months post transplantation, indicating an immune reconstitution. Only 1 patient developed grade II acute GVHD, and 2 patients had moderate cGVHD. One patient died from diffuse alveolar hemorrhage within the first year after transplantation. The 1-year GRFS rate, OS rate and cumulative incidence of moderate-to-severe cGVHD were 62.5%, 87.5% and 25.0%, respectively.

CONCLUSION

Our findings suggest that, among CAEBV patients treated with haplo-HSCT, PTCy may be an alternative choice for the prevention of GVHD.