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The following is a summary of “Splenic irradiation for myelofibrosis prior to hematopoietic cell transplantation: A global collaborative analysis,” published in the February 2024 issue of Hematology by Gagelmann et al. 

Splenomegaly, a key sign of myelofibrosis, during allogeneic hematopoietic cell transplantation (HCT), is linked to graft failure and suboptimal graft function, highlighting the need for strategies to decrease spleen size post-failed Janus kinase (JAK) inhibition.

Researchers performed a retrospective study to utilize a worldwide collaboration to examine the safety and effectiveness of splenic irradiation within the HCT framework for myelofibrosis patients.

They enrolled 59 patients, undergoing irradiation approximately 2 weeks(range, 0.9–12 weeks) before HCT, with a median spleen size of 23 cm (ranging from 14 to 35 cm) before the procedure.

The results showed that splenic irradiation led to a notable and rapid reduction in spleen size in 97% of patients (57/59), with a median decrease of 5.0 cm (95% CI, 4.1–6.3 cm). Thrombocytopenia was the most common AE, and there was no observed correlation between irradiation dose and hematological toxicities. The 3-year overall survival rate was 62% (95% CI, 48%–76%), while the 1-year non-relapse mortality rate was 26% (95% CI, 14%–38%). Independent predictors for survival included severe thrombocytopenia and anemia before irradiation, transplant-specific risk score, higher-intensity conditioning, and the presence of portal vein thrombosis. In propensity score matching adjusted for common confounders, splenic irradiation was linked to a significantly reduced relapse rate (P=.01), with a 3-year incidence of 12% compared to 29% for immediate HCT and 38% for patients undergoing splenectomy.

They concluded that for JAK inhibitor-resistant patients, immediate pre-HCT splenic irradiation proves effective with low relapse risk.

Source: onlinelibrary.wiley.com/doi/full/10.1002/ajh.27252