Delayed radiation therapy timing and use of intensity-modulated radiation therapy in non-head and neck pediatric rhabdomyosarcoma

Abstract

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.

Radiation therapy target volume reduction in pediatric rhabdomyosarcoma

“…Retrospective analyses of data from IRSG studies as well as multiple single‐institution series have assessed the impact of RT timing on local control (LC). Some studies suggest that early initiation of RT is important for LC in patients with meningeal impingement,3 whereas other investigations have demonstrated that delay of RT by 16 weeks or even longer may not compromise outcomes in patients with parameningeal (PM) RMS 4‐6…”

“…Some studies suggest that early initiation of RT is important for LC in patients with meningeal impingement, 3 whereas other investigations have demonstrated that delay of RT by 16 weeks or even longer may not compromise outcomes in patients with parameningeal (PM) RMS. [4][5][6] More recently, the development of advanced RT techniques, such as diagnostic image fusion for target delineation and intensity-modulated radiation therapy (IMRT) with daily image guidance, have enabled the confident delivery of more conformal treatments with the possibility of reduced margins for treatment uncertainties. Several institutions have now reported promising clinical experience with IMRT for pediatric RMS.…”

Rhabdomyosarcoma of the biliary tract: a case report

“…1,7 For EpSSG standard RT for RMS is delivered in once daily fractions to doses between 36 and 50.4Gy, varying according to the tumor histology, tumor response and IRS group. 7,8 Although the benefit of RT is widely accepted, no consensus guidelines exist regarding specific radiation therapy parameters such as the use of IMRT in non-head and neck RMS. In a recent but limited retrospective review analyzing, inter alia, the impact of the use of IMRT on local control in pediatric patients with non-head and neck RMS, authors found no negative effect of the use of IMRT on local control.…”

“…Yet, further analysis is required to evaluate the direct effects of this RT variable on treatment effectiveness as well as on treatment toxicity in non-head and neck RMS including biliary RMS. 8 Regarding medical treatment, all patients with biliary RMS receive chemotherapy based on the risk grouping. In the children's oncology group COG, the risk stratification system incorporates pretreatment staging, the extent of disease after surgical resection (clinical group).…”