Myelofibrosis is a rare bone marrow disease in which the marrow gradually changes into connective tissue and ceases to function properly. The body then often “transfers” blood production to other organs – most often to the spleen, which becomes significantly enlarged (this is called splenomegaly). An enlarged spleen can cause pain, pressure in the abdomen, impair blood production, and complicate future treatment.
Myelofibrosis can occur on its own, but it can also be a consequence of other blood diseases. It typically affects middle-aged and older adult patients. In many cases, the disease can be slowed down with modern medications (e.g., JAK inhibitors). However, in some patients, these medications stop working and the disease progresses. In such situations, the most effective treatment option is bone marrow transplantation (allogeneic stem cell transplantation).
If the spleen is too enlarged, transplantation can be risky for the patient – donated cells are less likely to “take hold” and there is a higher probability of the disease returning. Therefore, it is sometimes necessary to reduce the size of the spleen before transplantation. In the past, this was done by surgically removing the spleen (splenectomy), but this is a major and stressful procedure. Today, low-dose radiation of the spleen is increasingly used, which is gentler and less risky.
International studies and pilot projects show that even low doses of radiation can visibly shrink the spleen and facilitate the transplant process.
Proton irradiation of the spleen helps to:
