77P Clinical characteristics and effects of treatment strategies for patients with orbital rhabdomyosarcoma: A retrospective study

Orbital rhabdomyosarcoma, more commonly known as RMS, is a malignant tumour that plagues the tissue surrounding the orbit. Relative to mesenchymal malignancies and tumours in general, it is quite rare. we analyzed data obtained from the SEER database to evaluate various therapeutic options on the survival outcomes for patients with RMS. We examined data from 217 patients diagnosed with orbital rhabdomyosarcoma between 1975 to 2020, sourced from the SEER database. Cox proportional hazards model assessed the relationships between the therapeutic procedure and survival outcomes. The results of the therapeutic procedures analysis (n=217, 44.2% females). The gender distribution showed 70% of patients were aged 9 years or younger. Tumor size varied, with 20.3% >3cm. Regarding the stage of cancer, 45.6% had an unknown stage, while 38.2% were localized. For therapeutic procedures, surgery, chemotherapy and RT were performed in 54.4%, 89.9%, 82.9% of cases, respectively. The histological types varied, with 73.3% classified as embryonal rhabdomyosarcoma. The ethnic distribution showed that 58.1% of patients were non-Hispanic White. Univariate analyses using a Cox proportional hazard model demonstrated significant associations with survival outcomes. Patients aged over 9 years demonstrated a significantly increased hazard, with an HR of 2.555 (95% CI: 1.302-5.015, p=0.006) compared to those aged 9 years or younger. Tumor size, stage and racial factors were all associated with varying hazards. For therapeutic procedures, surgery, chemotherapy and RT showed varied HRs 0.533 (95% CI: 0.269-1.056), 0.807 (95% CI: 0.308-2.118), 0.497 (95% CI: 0.238-1.040). Notably, the combined therapy of RT and surgery showed a trend towards a lower hazard compared to radiotherapy alone (HR=0.498, 95% CI: 0.221-1.123, p=0.093). Most patients were classified of embryonal rhabdomyosarcoma. Tumor size, stage and racial factors associated with better survival outcomes. There is no treatment of choice for orbital rhabdomyosarcoma in terms of survival. However, RT is a reasonable alternative treatment to surgery. The results require further validation by future prospective studies.