ID #1021 Secondary analysis of outcome by treatment and age in ependymoma: A Report from the Children’s Oncology Group
Amy Smith, Shelly Lensing, Arzu Onar-Thomas, Holly Lindsay, Kelsey Bertrand, Thomas Merchant, Amar Gajjar, Sarah Leary, Maryam Fouladi, David Ellison, Nicholas ForemanAbstract
ACNS0831 Children’s Oncology Group study enrolled patients from 2010 to 2019 with the primary aim of determining whether post-irradiation chemotherapy offers a survival benefit to children with ependymoma. Of 449 eligible patients, 325 with GTR/NTR were randomized to RT alone or RT followed by chemotherapy. The primary aim did not show benefit for maintenance chemotherapy. Five-year EFS was 63.7% (95% CI 55.1-77.1%) for RT only (n = 161) versus 69.2% (60.8-76.3%) for RT-CHEMO (n = 164) (one-sided log-rank p = 0.299, HR = 0.866). Five-year OS was 86.9 (79.8-91.6%) for RT only versus 88.3 (81.8-92.6%) for RT-CHEMO (p = 0.172). Unplanned subset analyses were conducted to explore associations of age with EFS and OS in patients with initial GTR/NTR. Age was dichotomized using the median of 5 years. For patients < 5 years, there was no difference observed in outcome by randomized arm. For patients >5 years, there was a significantly better EFS and OS with chemotherapy. For patients >5 years old 5-year EFS was 77.0% (64.0-85.8%) and OS was 95.4% (86.4-98.5%) for the RT-CHEMO group compared to an EFS of 55.9% (42.4-67.4%) and OS of 78.1% (64.4-87.1%) for the RT only group (p = 0.010 and p = 0.0004, respectively). OS was significantly better with chemotherapy for children > 5 years with supratentorial (ST) ependymomas who had initial GTR/NTR, but not for PF tumors. The 5-year OS for those with PF tumors randomized to RT-CHEMO was 92.3% (78.0-97.5%) versus 75.7% (56.8-87.2%) for RT only (p = 0.058). For those with ST tumors (which were nearly all grade 3), in the RT-CHEMO group, the 5-year OS was 100% versus 81.7% (57.6-92.9%) for RT only (p = 0.020).
Conclusion
The association of outcome with age is intriguing and may warrant further investigation; however, it must be interpreted with caution given the unplanned sub-analysis and the clinical and molecular factors potentially confounded with age.
Acknowledgements
NCTN Operations Center Grant U10CA180866, NCTN Statistics & Data Center Grant U10CA180899, & St. Baldrick’s Foundation.