Is there a “gold” standard treatment for patients with isolated myeloid sarcoma?

Isolated myeloid sarcoma is an extramedullary tumor of immature myeloid cells defined by the absence of leukemia history, myelodisplastic syndrome, or myeloproliferative neoplasma with a negative bone marrow biopsy. Myeloid sarcoma is a very rare condition, and few cases have been reported. We reviewed data of 12 patients with isolated myeloid sarcoma managed at a single center to determine the possible prognostic factors affecting patient survival, such as age, sex, type, localization, and treatment options. Patients were mostly men (n=8), with a median age of 39 years. Patients were initially treated with chemotherapy (n=7) or surgery (n=5). In three patients, hematopoietic stem cell transplantation was performed. During the follow-up period, nine patients died. The median overall survival was 13 months, while event-free survival was 8 months. Regarding initial treatment strategy, no significant difference in overall survival was observed. Both chemotherapy and hematopoietic stem cell transplantation independently improved event-free survival. In addition, patients who received chemotherapy combined with hematopoietic stem cell transplantation had significantly longer event-free survival than those treated with chemotherapy alone. Age<40 years together with chemotherapy/hematopoietic stem cell transplantation significant affected event-free survival. Based on our results, the treatment of myeloid sarcoma requires a systemic rather than a localized approach with surgery or radiotherapy. While prospective evaluations are needed, chemotherapy with allogenic hematopoietic stem cell transplantation should be considered as the optimal therapy for isolated myeloid sarcoma.