51. Proton Radiotherapy for Pediatric Bladder/Prostate Rhabdomyosarcoma: Clinical Outcomes and Dosimetry Compared to Intensity-Modulated Radiation Therapy
- Author
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Alison M. Friedmann, Raphael V. Pieretti, Judith Adams, Shannon M. MacDonald, Torunn I. Yock, Nancy J. Tarbell, David A. Herrup, Shane E. Cotter, and Gregoire Robinson
- Subjects
Male ,Organs at Risk ,Cancer Research ,medicine.medical_treatment ,Urinary Bladder ,Prostate Rhabdomyosarcoma ,Prostate ,Rhabdomyosarcoma ,Testis ,Proton Therapy ,medicine ,Humans ,Dosimetry ,Radiology, Nuclear Medicine and imaging ,Growth Plate ,Pelvic Bones ,Proton therapy ,Retrospective Studies ,Chemotherapy ,Radiation ,business.industry ,Radiotherapy Planning, Computer-Assisted ,Infant ,Prostatic Neoplasms ,Femur Head ,Radiotherapy Dosage ,Retrospective cohort study ,medicine.disease ,Radiation therapy ,Treatment Outcome ,medicine.anatomical_structure ,Urinary Bladder Neoplasms ,Oncology ,Child, Preschool ,Radiotherapy, Intensity-Modulated ,Nuclear medicine ,business ,Follow-Up Studies - Abstract
Purpose In this study, we report the clinical outcomes of 7 children with bladder/prostate rhabdomyosarcoma (RMS) treated with proton radiation and compare proton treatment plans with matched intensity-modulated radiation therapy (IMRT) plans, with an emphasis on dose savings to reproductive and skeletal structures. Methods and Materials Follow-up consisted of scheduled clinic appointments at our institution or direct communication with the treating physicians for referred patients. Each proton radiotherapy plan used for treatment was directly compared to an IMRT plan generated for the study. Clinical target volumes and normal tissue volumes were held constant to facilitate dosimetric comparisons. Each plan was optimized for target coverage and normal tissue sparing. Results Seven male patients were treated with proton radiotherapy for bladder/prostate RMS at the Massachusetts General Hospital between 2002 and 2008. Median age at treatment was 30 months (11–70 months). Median follow-up was 27 months (10–90 months). Four patients underwent a gross total resection prior to radiation, and all patients received concurrent chemotherapy. Radiation doses ranged from 36 cobalt Gray equivalent (CGE) to 50.4 CGE. Five of 7 patients were without evidence of disease and with intact bladders at study completion. Target volume dosimetry was equivalent between the two modalities for all 7 patients. Proton radiotherapy led to a significant decrease in mean organ dose to the bladder (25.1 CGE vs. 33.2 Gy; p = 0.03), testes (0.0 CGE vs. 0.6 Gy; p = 0.016), femoral heads (1.6 CGE vs. 10.6 Gy; p = 0.016), growth plates (21.7 CGE vs. 32.4 Gy; p = 0.016), and pelvic bones (8.8 CGE vs. 13.5 Gy; p = 0.016) compared to IMRT. Conclusions This study provides evidence of significant dose savings to normal structures with proton radiotherapy compared to IMRT and is well tolerated in this patient population. The long-term impact of these reduced doses can be tested in future studies incorporating extended follow-up, objective outcome measures, and quality-of-life analyses.
- Published
- 2011
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