In children treated for abdominal neuroblastoma, the risk of developing clinically significant RT-related late toxicity of the kidney and liver is not appreciable, even when current DVH parameters for OARs are not achieved in planning. Toxicity outcomes did not necessarily correlate with present-day OAR dose constraints. Currently utilized DVH constraints are highly variable, and must be further studied and supported by toxicity outcomes to more accurately characterize risk of complications.
BACKGROUND:The use of radiation therapy (RT) ''cone-down'' boost to reduce high-dose treatment volumes according to tumor response to induction chemotherapy in patients with pediatric rhabdomyosarcoma (RMS) may reduce treatment morbidity, yet the impact on tumor control is unknown. METHODS: Fifty-five children, including 18 (33%) with parameningeal (PM) RMS and 37 (67%) with non-PM RMS, who received definitive treatment with chemotherapy and RT from April 2000 through January 2010 were retrospectively reviewed. RESULTS: In total, 28 patients (51%) received a cone-down boost. The high-dose boost volume was reduced by a median of 56% of the initial target volume (range, 5%-91%). The median time to initiating RT was 3 weeks for patients with PM RMS and 16 weeks for patients with non-PM RMS (P < .001). After a median follow-up of 41 months, local failure occurred in 5 patients (9%), including 2 patients who received a cone-down boost, and there were no marginal failures. Twelve patients (67%) with PM RMS had intracranial tumor extension. In this subgroup, 4 patients (30%) who received a cone-down boost and had 3 weeks between chemotherapy and RT initiation experienced leptomeningeal failure as their first site of disease progression, and a delayed time to RT initiation was associated with decreased survival (P ¼ .055) CONCLUSIONS: A cone-down boost allowed for significant reductions in high-dose RT treatment volume while maintaining excellent tumor control in most patients. However, in the subset of patients with PM RMS and intracranial tumor extension, early RT initiation and wider margin RT to cover adjacent areas at high risk for meningeal extension may be more important for adequate disease control. Cancer 2013;119:1578-85.
Objective The impact of radiation therapy (RT) timing and use of intensity-modulated radiation therapy (IMRT) in nonhead and neck pediatric rhabdomyosarcoma (RMS) is underreported. Methods Children with non-head and neck RMS treated definitively with chemotherapy and RT from December 2000 through May 2010 at our institution were identified for analysis. Kaplan-Meier estimates of time to local progression-free survival (PFS), disease-free survival, and overall survival were performed, and Cox proportional hazard model examined the relationship between local control and RT timing and the use of IMRT. Results Thirty seven children, including 25 patients with non-metastatic disease, 12 patients with metastatic disease, and a total of 44 tumors were identified. Three-year local PFS was 87 % (95 % CI: 0.79-0.93) for the non-metastatic group and 76 % (95 % CI: 0.63-0.88) for the metastatic group. Among the non-metastatic group, the median time from the start of chemotherapy to RT was 17 weeks (range 4-43) with only four patients treated within ≤12 weeks. Median RT timing for the metastatic group was 21 weeks (range 15-68). Among all patients, IMRT was used in 17 (39 %) cases. No significant association between local control and RT timing or use of IMRT was found. Conclusion Our data demonstrate good rates of local tumor control with delayed RT timing of greater than 12 weeks and the use of IMRT in a subset of pediatric patients with nonhead and neck RMS.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.