Introduction/Background Endometrial Stromal Sarcoma (ESS), both Low-Grade (LG-ESS) or High-Grade (HG-ESS), are rare uterine tumours, accounting for less than 1% of all uterine neoplasms. Our aim was to describe a single centre experience and to evaluate which variables affected survival in our cohort.

Methodology All patients with a histopathological diagnosis of LG-ESS or HG-ESS treated at our centre from January 1995 until February 2018 were included in the study. Data were collected from electronic medical records. Survival analysis was done using Kaplan Meier method and log-rank test for univariate analysis, and Cox proportional hazards method for multivariate analysis.

Results A total of 44 patients were included, of which 27 (61.4%) had a diagnosis of LG-ESS and 17 (38.6%) HG-ESS. Median age at diagnosis was 57.5 years (interquartile range, IQR: 47.5–76.5). Most women presented vaginal bleeding as initial symptom (54.8%), were surgically treated (93.2%), and underwent laparotomy (73.2%). Pelvic lymphadenectomy was performed in most patients (56.1%). More than one-half of the patients were diagnosed at initial stages of the disease (Stage I 53.7%), while most patients recurred after surgical treatment (51.2%). HG-ESS patients were older (median age 64.5 vs 51.5 years, p=0.040), presented bigger tumours (Maximum tumour diameter 115 vs 38 mm, p=0.014), and recurred more frequently (81.3% vs 32.0%, p=0.002) than LG-ESS patients.

The median follow-up of the global cohort was 8.15 years (IQR: 1.47–12.85). 5-year overall survival (OS) for the entire cohort was 59.9%, and was significantly better for LG-ESS patients (78.6% vs 31.3%, p=0.001). For LG-ESS patients, only stage remained significantly correlated with survival after multivariant analysis, while for HG-ESS patients, optimal surgery, stage, adjuvant chemotherapy and radiotherapy remained significantly correlated with survival.

Conclusion HG-ESS patients have worse prognosis than those affected by LG-ESS; proper surgical management and adjuvant therapies are key in order to achieve better survival in this group.

Disclosure Nothing to disclose.

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Abstract P101 Figure 1

Overall survival (OS) comparison by groups