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Effective management of accelerated phase myelofibrosis with low-dose splenic radiotherapy
Abstract:
The main cause of hepatosplenomegaly in primary (PMF), post polycythemia vera (post-PV MF), and post essential thrombocythemia (post-ET MF) myelofibrosis (MF) is extramedullary hematopoiesis (EMH). Drug-refractory symptomatic splenomegaly in MF is usually managed by splenectomy or involved-field radiotherapy. The latter is most effective in the treatment of MF-associated bone pain and pulmonary hypertension.Our previous experience with hepatosplenic radiotherapy in MF showed efficacy in the majority of treated patients but its utility was limited by the transient nature of its benefit and the occurrence of treatment-related pancytopenia. In an effort to address these issues,we have adopted an induction-maintenance treatment strategy that utilizes lower radiation doses-induction with 100 cGy total in four daily doses of 25 cGy and maintenance with either the same or lower intensity regimen. Herein, we report our most recent experience using this treatment plan in two cases, who in addition to their expected response from the standpoint of splenomegaly, also unexpectedly showed a marked response of their underlying accelerated phase disease,including clearance of circulating blasts and basophilia.
Insights
This study explores a new low-dose radiation strategy for myelofibrosis (MF) patients with enlarged spleens. The treatment effectively reduced spleen size and unexpectedly improved accelerated phase disease, including blast clearance.
Area of Science:
- Hematology
- Oncology
- Radiation Oncology
Background:
- Hepatosplenomegaly in myelofibrosis (MF) is primarily caused by extramedullary hematopoiesis (EMH).
- Current treatments for drug-refractory symptomatic splenomegaly include splenectomy or radiotherapy, each with limitations.
- Previous radiotherapy approaches for MF-associated hepatosplenomegaly showed transient benefits and risk of pancytopenia.
Observation:
- A novel induction-maintenance radiotherapy strategy using lower doses (100 cGy total) was adopted.
- This approach aimed to mitigate the transient benefits and pancytopenia associated with higher-dose radiotherapy.
- Two cases of myelofibrosis (MF) were treated with this modified regimen.
Findings:
- The induction-maintenance radiotherapy effectively reduced splenomegaly in both patients.
- Unexpectedly, patients exhibited a marked response in their accelerated phase myelofibrosis.
- Observed improvements included clearance of circulating blasts and basophilia.
Implications:
- This low-dose induction-maintenance radiotherapy strategy shows promise for managing symptomatic splenomegaly in MF.
- The regimen may offer a beneficial effect on the underlying accelerated phase disease, warranting further investigation.
- This approach could represent a more tolerable and effective treatment option for select MF patients.
