1959P - Clinicopathological features and survival analysis of orbital rhabdomyosarcoma

Background

Orbital rhabdomyosarcoma is a very rare childhood malignancy and the most common primary orbital malignancy in children, with incidence of 250 new cases per year. Due to its scarcity, there is not enough data available in the literature regarding its etiology and risk factors. The aim of this study is to explore the clinicopathological features of the disease and to evaluate the overall survival to add new updated evidence to the literature.

Methods

Data of 152 patients was extracted from The Surveillance, Epidemiology and End Results (SEER) database from 17 registries and diagnosed from 2000 to 2020. The following International Classification of Diseases for Oncology was adopted, Third Edition (ICD-O-3), histology code: 8,900, 8,901, 8,902, 8,910, 8,912, and 8,920; and the ICD-O-3/ WHO 2008 site code (eye and orbit). SPSS version 23 was used for data analysis, Kaplan-Meier Curve and Log rank test for survival analysis.

Results

the 1-year and 5-year relative survival for orbital rhabdomyosarcoma was 98.8% and 90.0%. performing COX-regression model for age, race, gender, year of diagnosis and stage showed age (HR=1.031, 95% CI: 1.062- 1.001; P=0.04) and stage (HR=0.03, 95% CI: 0.290- 0.005; P=0.02) were significantly associated with survival outcome while gender (HR= 2.487, 95% CI: 12.370- 0.500; P= 0.226) and race (HR= 0.902, 95% CI= 6.465-0.126; -P= 0.919) had no statistical significance. However, 93.7% of the sample were white and only 3.1% had distant metastasis. Regarding histological types; we found 114 patients (70.8%) had embryonal rhabdomyosarcoma, 18 patients (11.8%) had the alveolar type and four patients (2.5%) had the spindle type.

Conclusions

The results of this study showed promising survival outcome for orbital rhabdomyosarcoma with increased incidence in the white race and increased risk with age and stage. The most common histological subtype was embryonal rhabdomyosarcoma. These results give clear updated data about orbital rhabdomyosarcoma to understand the nature of this disease better which help in designing a plan of management putting into consideration the age and stage for better outcome.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.