In an analysis from the Children’s Oncology Group (COG) ANBL0532 study reported in the Journal of Clinical Oncology, Liu et al found that a radiotherapy boost to the gross residual tumor in patients with high-risk neuroblastoma did not appear to improve outcomes compared with patients in another COG cohort in which no boost to residual tumor was administered.
“Boost radiotherapy to gross residual tumor present at the end of induction did not significantly improve 5-year cumulative incidence of local progression. These results highlight the need for new strategies to decrease the risk of locoregional failure.”— Liu et al
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Study Details
The phase III COG ANBL0532 study included evaluation of the effect of increasing the local dose of radiation to the residual primary tumor on cumulative incidence of local progression in newly diagnosed patients with high-risk neuroblastoma. Patients received single or tandem autologous stem cell transplantation after induction chemotherapy, with local treatment consisting of surgical resection during induction chemotherapy and radiotherapy after the last stem cell transplant.
For radiotherapy, a dose of 21.6 Gy was administered to the preoperative primary tumor volume. Patients with incomplete surgical resection received an additional boost of 14.4 Gy to the gross residual tumor.
In the current analysis, cumulative incidence of local progression, event-free survival, and overall survival were compared with outcomes in the COG A3973 high-risk neuroblastoma cohort, in which all patients received single stem cell transplant and radiotherapy at 21.6 Gy without a boost.
Key Findings
Among all 323 patients in the COG ANBL0532 study who received radiotherapy, 5-year cumulative incidence of local progression, event-free survival, and overall survival rates were 11.2%, 56.2%, and 68.4%, compared with 7.1% (P = .0590), 47.0% (P = .0090), and 57.4% (P = .0088) among all 328 patients in the COG A3973 high-risk neuroblastoma cohort who received radiotherapy.
Among 47 patients in cohort A3973 who had incomplete resection and received no radiotherapy boost, 5-year cumulative incidence of local progression, event-free survival, and overall survival rates were 10.6%, 48.9%, and 56.9%, compared with 16.3% (P = .4126), 50.9% (P = .5084), and 68.1% (P = .2835) among 74 patients in the ANBL0532 study who had residual disease and received a radiotherapy boost.
The investigators concluded, “Boost radiotherapy to gross residual tumor present at the end of induction did not significantly improve 5-year cumulative incidence of local progression. These results highlight the need for new strategies to decrease the risk of locoregional failure.”
Daphne A. Haas-Kogan, MD, of the Department of Radiation Oncology, Brigham and Women’s Hospital, Dana-Farber Cancer Institute, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by grants from the National Institutes of Health. For full disclosures of the study authors, visit ascopubs.org.
