Molecular profile & clinical outcome in 121 cases - experience from a tertiary referral centre in South India

Abstract

Ewing sarcoma is the second most common sarcoma involving the bones in children and adolescents. Published data on the clinical features, morphology, translocation and follow-up of patients with Ewing sarcoma from India, is sparse. Objectives of this study were to analyse the clinico-pathologic features of Ewing sarcoma and compare with translocation status, BCoR immunohistochemistry, treatment and survival. 406 cases of Ewing sarcoma were diagnosed in the Department of Pathology, Christian Medical College, Vellore during the period 2008-2015. 135 patients underwent molecular testing for common translocations by RT-PCR and were included in this study.Mean age of patients at diagnosis was 22 years. Most common location of tumour was appendicular skeleton (31.4%) and 19% had solid organ involvement. Distant metastasis was present in 21.5% patients. Translocation was seen in 63 (46.7%) cases, EWS-FLI1 type I (87%), EWS-FLI1 type II(11%) and one patient had EWS-ERG translocation. Seven out of 30 patients were classified as “Sarcoma with BCOR genetic alteration”. Patients who underwent 6 cycles of chemotherapy had a better mean survival. Mean follow-up was 13.72 months and 3 year event free survival of patients was 93.8%.Percentage of viable tumour <10% was the only significant histologic parameter predicting survival. Age at diagnosis ≤15yrs, female sex, size ≤12cm, extra-osseous site, chemotherapy and translocation positivity predicted an improved survival. This study has analysed the type of mutations/translocations seen in a subset of Indian patients with Ewing sarcoma and correlated the clinical and pathological factors affecting survival.