EVALUATION OF THE TREATMENT PATTERN OF EWING SARCOMA IN ADULT PATIENTS: RETROSPECTIVE, SINGLE-CENTER STUDY

Introduction: These are rare high grade tumors and there is a lack of survival data and prognostic factors in adults (>18 years) because the population of randomized trials is mostly pediatric. Objective: describe the overall survival in adult patients with Ewing Family Tumors (localized and metastatic) in a retrospective cohort. Secondary objectives include event-free survival and prognostic factors. Method: Data was anonymously collected from adult patients treated from 1991 to 2021. A total of 131 cases were included. Variables used were age, gender, location, size, metastases if present, type of chemotherapy, grade 3-4 toxicities, local treatment and pathological response. Kaplan-Meier method and log-rank test were used for survival analysis and Cox method for uni/multivariate analysis. Results: The 5-year Overall Survival for localizeded tumors (91 cases) was 70% (median not reached) and 32% (median 39 months) for the 40 metastatic cases. The median Event-Free Survival for localized and metastatis cases was 12 and 9 months respectively. Significant prognostic factors for survival at univariate analysis were: metastasis at diagnosis (HR 3.09, 95%CI 1.77-5.39, p 0.001), size>8 cm (HR 1.91, 95%CI 1.07-3.38, p 0.024), age>45 years (HR 3.22, 95%CI 1.42-7.29, p 0.003). and complete pathological response (HR 0.27, 95%CI 0.14-0.48, p 0.027). Extra-skeletical origin, pelvic origin, ifosfamide/etoposide, adjuvant radiotherapy and high-dose chemotherapy with Autologous Stem Cell Transplantation were not significant. On multivariate analysis only metastasis and complete pathological response remained significant. 3 patients did not receive chemotherapy due to complications from local procedures. The most frequent grade 3-4 toxicity was neutropenia (64%), with 2 treatment-related deaths. From 40 years on, it was seen less cycling. Surgery was performed in 61 cases (47%), radiotherapy in 26 cases (20%) and the combination in 27 cases (21%), this last one showed a nonsignificant tendency to higher 5-year survival compared to surgery or radiotherapy. From 69 relapses, 28 cases had local recurrence (41%) and 25 cases pulmonary metastasis (36%). Other sites included bone, liver, CNS and meninges. Local recurrence at 5 years for surgery was 14%, for radiotherapy 15% and for combined approach was 0%, thus not significant (p-value 0.633). Conclusion: Adults could achieve similar outcomes as pediatric patients with adequate support to perform multimodal treatment.