Radiation Therapy in Paediatric Orbital Granulocytic Sarcomas: Experience from a Tertiary Cancer Center

Orbital Granulocytic Sarcoma (OGS) is an uncommon manifestation associated with haematological malignancies. Chemotherapy remains the cornerstone of the treatment. The role of radiation is not well-defined.

To evaluate the effect of radiation in OGS and to define an optimal dose for achieving adequate local control.

This was a retrospective analysis of 11 patients who received radiation therapy to orbit for Granulocytic Sarcoma (GS) between 2007 and 2014 at a tertiary cancer center in India. Radiotherapy was planned by three dimensional conformal (3DCRT) techniques. Demographic and disease characteristics, including clinical, imaging, histopathology and treatment details in this patient cohort were recorded and their response to therapy was assessed.

The median age was 7 years (Range: 2-16 years). There were 3 female and 8 male patients. Eight patients were diagnosed as Acute Myelogenous Leukemia (AML), two patients had Primary Orbital Granulocytic Sarcoma (POGS) and one had bi-phenotypic leukemia. Median dose was 24.5Gy (Range-15-45 Gy). Two anterior oblique field design were used most commonly. Out of 11 patients, 5 (45.4%) had complete response, 3 (27.27%) had partial response, 1 patient had stable disease (9%) and 2 developed progressive disease (18%). Median follow-up was 24 months (Range 24-84 months). At last follow-up, 7 (63.6%) patients were alive and 4 patients (37.4%) were dead due to progressive disease.

In patients with residual orbital disease after chemotherapy, low dose radiation can be used to improve local disease control and improve quality of life. Local conformal radiotherapy of 24-30 Gy in conventional fractionation appears optimal with excellent local control and minimal morbidity.