[Show abstract][Hide abstract] ABSTRACT: PURPOSE: To compare volumetric modulated arc therapy (VMAT) with 3-dimensional conformal radiation therapy (3D-CRT) in the treatment of localized intracranial germinoma. We modeled the effect of the dosimetric differences on intelligence quotient (IQ). METHOD AND MATERIALS: Ten children with intracranial germinomas were used for planning. The prescription doses were 23.4 Gy to the ventricles followed by 21.6 Gy to the tumor located in the pineal region. For each child, a 3D-CRT and full arc VMAT was generated. Coverage of the target was assessed by computing a conformity index and heterogeneity index. We also generated VMAT plans with explicit temporal lobe sparing and with smaller ventricular margin expansions. Mean dose to the temporal lobe was used to estimate IQ 5 years after completion of radiation, using a patient age of 10 years. RESULTS: Compared with the 3D-CRT plan, VMAT improved conformality (conformity index 1.10 vs 1.85), with slightly higher heterogeneity (heterogeneity index 1.09 vs 1.06). The averaged mean doses for left and right temporal lobes were 31.3 and 31.7 Gy, respectively, for VMAT plans and 37.7 and 37.6 Gy for 3D-CRT plans. This difference in mean temporal lobe dose resulted in an estimated IQ difference of 3.1 points at 5 years after radiation therapy. When the temporal lobes were explicitly included in the VMAT optimization, the mean temporal lobe dose was reduced 5.6-5.7 Gy, resulting in an estimated IQ difference of an additional 3 points. Reducing the ventricular margin from 1.5 cm to 0.5 cm decreased mean temporal lobe dose 11.4-13.1 Gy, corresponding to an estimated increase in IQ of 7 points. CONCLUSION: For treatment of children with intracranial pure germinomas, VMAT compared with 3D-CRT provides increased conformality and reduces doses to normal tissue. This may result in improvements in IQ in these children.
No preview · Article · Apr 2012 · International journal of radiation oncology, biology, physics
[Show abstract][Hide abstract] ABSTRACT: Approximately 20% of children with Ewing sarcoma (EWS) and rhabdomyosarcoma (RMS) present with metastatic disease at initial diagnosis. Overall, the outcome is poor, with an event-free survival of < 20%. Local control at metastatic sites has not been previously reported. We reviewed control of metastatic sites in children with EWS and RMS that received curative intent radiation therapy to each metastatic site. In 13 children, at a median follow-up of 18 months, a single local failure was seen. Toxicity was minimal. Our data suggest that radiation therapy is effective and tolerable in children with metastatic EWS and RMS.
No preview · Article · Jul 2011 · Pediatric Blood & Cancer