10. Radiotherapy

8. Treatment

120 Hematology - Latest Research and Clinical Advances

with concurrent AML [38].

contrary to this observation.

9. Chemotherapy

cytarabine to be an essential drug in this regard [37].

Given the scarcity of positively diagnosed MS and randomized prospective trials, there is at present no consensus MS specific therapeutic regimen. The current routine includes conventional AML-type chemotherapy and radiotherapy for both isolated and MS or MS with concomitant AML. Studies led by different groups have shown that standard AML therapy exhibits better overall survival in case of isolated MS incidents [10]. Nevertheless, there is a lack of data addressing a particular chemotherapeutic regimen for MS. Existing data indicates

The use of radiotherapy is also not well studied as a prospective means of treatment of MS. Although, in some instances, radiation is used in combination with chemotherapy to treat MS. However, no added advantage was observed in those cases [11, 38]. In addition, hematopoietic stem cell transplantation is also used, albeit retrospectively, in MS patients [1]. Reported data does suggest an advantage of auto- or allo-HSCT in MS patients with or without concomitant AML irrespective of age, gender, anatomic location, clinical presentation or cytogenic status [1, 3, 11]. In addition, retrospective chemotherapy trials conducted by the Children's Cancer Group demonstrated a better event-free survival for children with isolated MS than patients

Taken together, however, no studies ever compared the different prognostic factors in MS patients with or without AML and consequently, their effects on the treatment regimens. The published data, nevertheless, do suggest a difference in prognosis between patients with isolated MS and with concurrent or relapsed AML. Traditionally, the simultaneous expression of MS at diagnosis of AML is considered as poor prognosis. However, there is evidence

As stated above, till now there is no specific treatment for MS. Consequently, to a large extent the treatment of MS depends on the site, volume as well as the timing of diagnosis of the extramedullary tumor. Based on these factors, the clinicians determine the treatment plan by employing singly chemotherapy, radiation therapy or bone marrow transplantation or in combination. A detailed discussion of these different therapeutic regimens is discussed below.

Systemic chemotherapy is the primary choice of treatment for both isolated MS and MS with simultaneous bone marrow involvement. This is largely due to the fact that even if there is no primary bone marrow involvement, isolated or primary MS ultimately gives rise to AML in majority of the cases [3, 39]. Consequently, the chemotherapy regimens for MS generally follow the same protocol as AML. All these regimens mainly include cytarabine with fludarabine, idarubicin, or both. In some instances, granulocyte colony-stimulating factor (G-CSF), daunorubicin and cyclophosphamide are also used [32, 37, 40]. In particular, combination therapy with cytarabine and daunorubicin has been demonstrated to achieve complete In some instance, radiation is also used as a part of the treatment plan for MS. However, existing data does suggest that radiation alone may not be sufficient enough to completely eradicate MS. Study conducted by Bakst et al. has demonstrated that patients with isolated MS generally respond better to systemic chemotherapy compared to radiotherapy [39]. In addition, there is also no conclusive data demonstrating that radiotherapy in MS alone can prevent the development of systemic leukemia involving bone marrow (40%). Consequently, in most cases radiation is used in combination with chemotherapy in treating MS [42].
