(P 60) DIAGNOSIS AND MANAGEMENT OF PAEDIATRIC EWING SARCOMA PATIENTS IN ENGLAND 2014-2017: A COMPARISON OF NATIONAL DATA WITH THE EURO-EWING 2012 CLINICAL TRIAL

Objective: The National Disease Registration Service (NDRS) provides the population-based cancer registry for England and contributed data on a cohort of primary bone Ewing sarcoma (ES) patients to an international benchmarking study (BENCHISTA). We compared data from this cohort to the equivalent data from the Euro-Ewing 2012 (EE2012) clinical trial, established to compare two different standard chemotherapy regimens. Our objective was to assess the completeness of national data, determine the proportion recruited to EE2012 and compare management between national and trial cohorts.

Methods: Data on all ES patients diagnosed in England between 2014 and 2017, aged 3-17 years were compared with an equivalent data subset from EE2012, which opened in 2014 for patients with localised and pulmonary metastatic disease and included those with extrapulmonary metastases from May 2016. Patient demographics included age, gender, primary site and Toronto stage (distant metastasis or not), treatment given within 12 months of diagnosis included chemotherapy, radiotherapy (RT) — either photon or proton beam (PBT)— and surgery. Time intervals between systemic and local therapy were calculated where available. RT data were supplemented with overseas proton beam therapy (PBT) data from the Proton Clinical Outcome Unit. Results are reported with (%) or (range).

Results: A total of 129 patients aged 3-18 years were diagnosed with ES in England between 2014 and 2017, of which 70 (54%) were recruited to EE2012. The national and trial populations had similar demographics (median age 12 (3-17) vs 12 (3-17), gender split (51% vs 56% male respectively) and primary site mix; the most common being extremity with 52 (40%) of patients nationally and 30 (43%) in EE2012. A total of 43 (33%) of the national cohort were diagnosed as metastatic compared to 20 (29%) of the EE2012 patients.
In total, 126 (98%) patients nationally were documented as receiving chemotherapy vs 70 (100%) of those on EE2012; 74 (57%) patients nationally had surgery vs 50 (71%) of those on EE2012; 101 (78%) patients nationally had RT (photons or protons) vs 46 (66%) of those on EE2012, with 45 (33%) national data patients receiving PBT compared to 23 (33%) patients treated within EE2012. Treatment combinations are shown in Table 1.
Nationally, patients began chemotherapy a median of 13 (0-38) days after diagnosis; compared to a median of 15 (2-43) days in EE2012. Where surgery was the first local therapy, there was no difference in time from commencing chemotherapy to resection between national data patients and those on EE2012, with a median of 143 (132-205) days and 143 (127-328) respectively. Nationally there was a median of 146 (114-331) days between beginning chemotherapy and RT where RT was the first local therapy; this was 135 (113-259) in EE2012.
Comparison of local therapy revealed 9 (21%) of metastatic patients nationally had surgery vs 9 (45%) of those on EE2012. 38 (88%) of metastatic patients nationally had RT vs 13 (65%) of those on EE2012. Treatment combinations are shown in Table 2. Data on site of metastasis was available in EE2012; 7 (35%) of metastatic patients had extrapulmonary metastases.

Conclusion: This analysis confirmed sufficient data quality in national registry data to evaluate ES patient management in England. Over 50% of eligible children were recruited to the EE2012 trial. Patient characteristics were similar for those treated on and off-study, although a higher proportion off-study were metastatic. There was little difference in time before or between treatments for patients treated on- or off- study, though the median wait for RT was shorter on-trial. Differences in local control were observed, with more trial patients treated with surgery and fewer with RT. It is likely that the proportion of patients with extrapulmonary metastases differed, due to the initial exclusion of such patients from EE2012. This may explain the disparity in local therapy, as such patients less often undergo surgery.