(P 074) EWING SARCOMA AND RHABDOMYOSARCOMA PATIENT OUTCOME VARIATIONS BASED ON TREATMENT CENTRE VOLUME

Objective: Due to the complexity of Ewing Sarcoma (EWS) and rhabdomyosarcoma (RMS), studies demonstrate improved patient outcomes when managed at high volume centres (HVCs) with multidisciplinary tumour board discussions (MTDs). This is reflected in guideline recommendations for patients to be treated at reference centres or HVCs. However, frequent travel to HVCs is less feasible in larger geographical areas such as British Columbia (BC), Canada. Our study aims to explore the difference in outcomes of EWS and RMS patients based on location of diagnosis and treatment in BC.

Methods: This analysis includes a multi-center retrospective chart review of adults diagnosed with EWS and RMS between Jan 1st 2000, to Dec 31st 2020 undergoing curative intent therapy in one of six cancer centers contributing to the BC Cancer Sarcoma Outcomes Database. Fisher’s exact and chi-squared tests were used to evaluate associations. Cox proportional hazards model was used to assess for predictors of better survival outcomes by treatment centre. HVCs was defined as those that saw ≥15 patients.

Results: 77 patients were included in this analysis. 46 and 31 respectively were treated at high vs low volume centers (Table 1). Compared to patients treated at low volume centres (LVCs), those treated at HVCs were more likely to receive curative intent radiation 34 (89%) vs 13 (59%) respectively, p = 0.006, more likely to be presented at MTDs, 42 (91%) vs 23 (74%) respectively, p = 0.042, and less likely to experience disease progression (p = 0.044). The average days from diagnosis to receipt of chemotherapy was 13 days sooner at HVCs vs LVCs (34 vs 47 days respectively, p = 0.12). Chemotherapy regimen (p = 0.25) and receipt of surgery (p = 0.75) were not significantly different between HVCs vs LVCs. Age, ECOG, stage, and Charlson Comorbidities Index (CCI) were all significant contributors to overall survival. There was no statistically significant difference in overall survival by treatment center (HR 0.684, 95% CI 0.364 – 1.287).

Conclusion: Variations in care exist for both treatment and outcomes amongst EWS and RMS patients treated at high vs low volume centers in BC. Patients treated at HVCs were more likely to be presented at MTDs, to receive curative intent radiation, and less likely to experience disease progression. This may reflect differences in access to resources, clinical specialists, and potentially higher comfort levels with upfront aggressive treatment. This study can be used to better inform decisions regarding triaging and centralization of curable EWS and RMS patients.

CTOS 2022 abstract_table1.pdf